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I'll give that a try. Also, a couple other ideas:

1: This is my engine block ground from the coil. I get continuity to the hood mount ground, and the battery ground, so it's not NOT grounded. But I do get maybe resistance, 2Ω maybe... I'm wondering: does this ground from the coil contribute to spark strength? If so, perhaps a new ribbon all around, and clean shiny contacts would be smart.
View attachment 296160

2: I read a very interesting snippet in the engine section of the service manual. Trouble shooting EVERYthing, it ends up at the brake servo vacuum line as a check point as it can affect engine performance greatly. I havne't found exactly where it is, but it should be an easy check under the brake pedal and out the firewall. I would guess it's VERY old since I haven't replaced it. So, just another thought.

And, really, these things could possibly all add up.
If you look at a 95 EFI electrical manual you will see a condenser between coil +Ve and ground. None of this misfire happened until I put a new 4.0 V8 in. However all the ancillaries were off the old 3.9. The scope picture you show appears to show the coil -Ve signal and looks normal. My system was passing coil firing pulses back on to the +Ve 12 volt supply line. This line should be clean. Whether it is due to my Powersparks Viper dry coil I don’t know. The amplifier, as stated by the other poster, receives its input trigger from the pickup in the distributor. This triggers the amplifier to connect the coil primary to ground. The signal on your scope is that signal. Once the primary signal fires then the secondary part of the coil fires and produces the spark for the plugs. Of course as the coil pulse dies a back emf is generated and this is dissipated without issue. What I have and diminished is that secondary pulse is somehow getting onto the coil supply and causing miss fires. The condenser cured that. I have checked all earths/grounds wiring, shielding and connections and all are good. Grounds are less than 0.005 ohms. I think 2 ohms is too much but a better way would be to try and see what voltage is across the connection. I put a condenser on the alternator just to try it and for no other reason. At least you are on the right path so it’s a matter of eliminating each part.
I do know from long experience that the longer it takes to fix a problem such as this the simpler the cause in the end. Don’t waste your money throwing parts at it.
 

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Discussion Starter · #22 ·
Not sure what happened but my classic died on me in park and wouldn't start up. Oddly the battery was ok, but couldn't get the starter to turn until I put my Viking portable jumper on it. Happened down the street again, and had my Viking ready. Wouldn't start just turning the key even though the A/C was still blowing just fine. Put the jumper on and it started right up... Starter is totally fine, as is the battery. But, like I said, this truck has been running like crap for a couple of weeks. ABS threw a left front code, which I cleared... and it was fine. Came back later in the day.

I have to say that all of this really is feeling like an alternator, power, ground thing happening.

It's been talking to me for a while about this stuff, and I've been listening... just haven't been sure how to respond.

Bill, it takes me a few reads to absorb your detail, so give me a min to think on this stuff. I agree, I feel like it's something simple that I just can't see. I did pull Rovergauge data during that drive above, and there's no real data there, just that the engine speed dropped. That's it.
 

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It's always going to be good on these to verify and have installed good earthing given that the chassis and body are mounted via rubber bushes.

The earth line for running ignition is not that demanding and easily satisfied, but you'll usually see it more when cranking the starter motor if there's failure there. It's the highest load the earth strap has to be subjected to and will either stop working or get very hot if you crank it for any significant length of time.

If you input the jump pack earth straight to engine assembly (rather than battery terminal) it will effectively bypass the vehicle earth route and give you a start.

The earth strap on coil location of mine goes straight to engine block.

On competition cars I always use (in addition to vehicle earth route via chassis) an earth lead straight from battery earth terminal to motor block as assurance and reliability measure. A cheap and easy addition.
 

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Worth checking security of main power lead terminals on starter motor too.

If not familiar, drop the negative battery lead off first else the wrench used to tighten terminal will try and weld itself to any earthed point it touches as you work ! Also get red hot and burn your hand.
 

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Discussion Starter · #25 · (Edited)
@Bill B After some time off of this, and coming back to it, I'm starting to understand much more about it. Also THIS helped.

The back pulse is what I think is the key in understanding what the purpose of the supressor is. Again, there are folks that simply think the supressor is supposed to prevent your radio from buzzing. But it would seem rf interference is simply a symptom of a greater problem. EMF backpulse can cause "arcing at contacts, rf interference, and electronics damage" because there may be nearly 400V travelling back up the line. It's a thing, and it needs to be remedied. I dont fully understand why more folks don't have issues, but perhaps it's death by one-thousand cuts.

Understanding that the pickup coil / amplifier combo is generating the signal to the coil to fire is a key as well. I assumed it was always "on" but I can see that the magnetic field collapse is how the voltage is generated, so it's on/off/on/off nature is paramount to the system working. However, as I understand it, a magnetic field collapsing, or forming creates pulse... and the actual spark is is generated when it collapses. So, inbetween states you have this backpulse generated when the system BUILDS the magnetic field.

I've also been studying the circuit diagram in the workshop manual. It makes sense, though confusing because it's schematic is reverse of the real life layout. Hate that.

Maybe what I cant figure out is how you could measure the backpulse, as you did. Would you do that from ve+ to ground? I guess I thought that's what I was doing from ve+ to ve- but that only shows the amplifier pulse?

Also I measured my original bosch coil primary and secondary ohms. They look ok at 1Ω/7.8kΩ and that one doesn't arc, so I'm putting that one back in. I think those numbers are right on.

Lastly, I can't recall if mentioned this but I did put an autozone cap in there, but it's a like 20nF (if I recall) and I don't know the voltage rating. It might just be too small to do anything.
 

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@Bill B After some time off of this, and coming back to it, I'm starting to understand much more about it. Also THIS helped.

The back pulse is what I think is the key in understanding what the purpose of the supressor is. Again, there are folks that simply think the supressor is supposed to prevent your radio from buzzing. But it would seem rf interference is simply a symptom of a greater problem. EMF backpulse can cause "arcing at contacts, rf interference, and electronics damage" because there may be nearly 400V travelling back up the line. It's a thing, and it needs to be remedied. I dont fully understand why more folks don't have issues, but perhaps it's death by one-thousand cuts.

Understanding that the pickup coil / amplifier combo is generating the signal to the coil to fire is a key as well. I assumed it was always "on" but I can see that the magnetic field collapse is how the voltage is generated, so it's on/off/on/off nature is paramount to the system working. However, as I understand it, a magnetic field collapsing, or forming creates pulse... and the actual spark is is generated when it collapses. So, inbetween states you have this backpulse generated when the system BUILDS the magnetic field.

I've also been studying the circuit diagram in the workshop manual. It makes sense, though confusing because it's schematic is reverse of the real life layout. Hate that.

Maybe what I cant figure out is how you could measure the backpulse, as you did. Would you do that from ve+ to ground? I guess I thought that's what I was doing from ve+ to ve- but that only shows the amplifier pulse?

Also I measured my original bosch coil primary and secondary ohms. They look ok at 1Ω/7.8kΩ and that one doesn't arc, so I'm putting that one back in. I think those numbers are right on.

Lastly, I can't recall if mentioned this but I did put an autozone cap in there, but it's a like 20nF (if I recall) and I don't know the voltage rating. It might just be too small to do anything.
@Bill B After some time off of this, and coming back to it, I'm starting to understand much more about it. Also THIS helped.

The back pulse is what I think is the key in understanding what the purpose of the supressor is. Again, there are folks that simply think the supressor is supposed to prevent your radio from buzzing. But it would seem rf interference is simply a symptom of a greater problem. EMF backpulse can cause "arcing at contacts, rf interference, and electronics damage" because there may be nearly 400V travelling back up the line. It's a thing, and it needs to be remedied. I dont fully understand why more folks don't have issues, but perhaps it's death by one-thousand cuts.

Understanding that the pickup coil / amplifier combo is generating the signal to the coil to fire is a key as well. I assumed it was always "on" but I can see that the magnetic field collapse is how the voltage is generated, so it's on/off/on/off nature is paramount to the system working. However, as I understand it, a magnetic field collapsing, or forming creates pulse... and the actual spark is is generated when it collapses. So, inbetween states you have this backpulse generated when the system BUILDS the magnetic field.

I've also been studying the circuit diagram in the workshop manual. It makes sense, though confusing because it's schematic is reverse of the real life layout. Hate that.

Maybe what I cant figure out is how you could measure the backpulse, as you did. Would you do that from ve+ to ground? I guess I thought that's what I was doing from ve+ to ve- but that only shows the amplifier pulse?

Also I measured my original bosch coil primary and secondary ohms. They look ok at 1Ω/7.8kΩ and that one doesn't arc, so I'm putting that one back in. I think those numbers are right on.

Lastly, I can't recall if mentioned this but I did put an autozone cap in there, but it's a like 20nF (if I recall) and I don't know the voltage rating. It might just be too small to do anything.
I think you have the amplifier and coil relationship understood.
Put your scope between the +Ve terminal of the coil and chassis ground. Ideally this should show a straight line at 12v level with no noise or spikes. Mine had 40v spikes on it until I put a 2uF, microfarad,50v cap across those two points. The spikes then dropped to 2v or less and the engine ran like a sewing machine. I think 2nF, nano, is too small. On the electrical manual Z237 states it is for Ignition coil noise suppression which is supposedly for the described purpose. On mine it was not there. A lot of my issues started from upgrading the ignition system. Distributor, Amplifier, Plugs and Wires. I rebuilt the whole of the engine and wiring system. Remade all grounds, new connectors, rewrapped the loom. Distributor coil and amplifier were all Powersparks items. If I remove the capacitor all my problems come back.
Hope that helps
Bill
 

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Discussion Starter · #27 ·
Cool stuff. So, primary coil to ground looks like this:
Audio equipment Font Display device Rectangle Multimedia

ignition amplifier putting a 12v pulst to primary coil (ve-). Looks a little sloppy here and there. Spikes look around 30 to 40+ volts. Is that the EMF backpulse? The capacitor I have on the line is small, as you noted. But I don't know if it would have any effect on these spikes. I think these may be normal.

Next we have the condenser line (ve+) to ground:
Gadget Audio equipment Font Multimedia Display device

This one looks around 12V with some dips down to 10 here and there.

All in all, I'd say the coil and the distributor/amp are doing their job well, even with a small or removed capacitor. So maybe this was just an exersize in understanding this part of the system. From here, I've also made certaion all my HT wires are organized via the service manual to prevent cross talk.

At this point, I have to think, if my compression is good and my fuel pressure is good (both were checked by my LR mechanic), my fuel/air ratio is just messed up on account of a vacuum or air leak... I can't find any other issues with this pretty simple system.
 

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Cool stuff. So, primary coil to ground looks like this:
View attachment 296249
ignition amplifier putting a 12v pulst to primary coil (ve-). Looks a little sloppy here and there. Spikes look around 30 to 40+ volts. Is that the EMF backpulse? The capacitor I have on the line is small, as you noted. But I don't know if it would have any effect on these spikes. I think these may be normal.

Next we have the condenser line (ve+) to ground:
View attachment 296250
This one looks around 12V with some dips down to 10 here and there.

All in all, I'd say the coil and the distributor/amp are doing their job well, even with a small or removed capacitor. So maybe this was just an exersize in understanding this part of the system. From here, I've also made certaion all my HT wires are organized via the service manual to prevent cross talk.

At this point, I have to think, if my compression is good and my fuel pressure is good (both were checked by my LR mechanic), my fuel/air ratio is just messed up on account of a vacuum or air leak... I can't find any other issues with this pretty simple system.
The pictures pretty show what mine was like. That capacitor/condenser certainly reduces the ripple on the +Ve supply at the coil so it is doing its job. If you are still getting random misfires then it is now somewhere else. Smoke test the vacuum system. Timing check, mines about 8 degrees BTDC. Exhaust leak at manifold to Y pipe. Measure temperature across both catalytic converters. Mine was blocked and and a new Y pipe had 100 degrees F difference across to. How do your fuel trims look with and without the capacitor?
 

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I can't see that a capacitor on the ve+ line is fundamental to system function (as it is part of switching on mechanical ve- terminal) which doesn't mean it's doing nothing, just looks to me that it maybe part of a update strategy in response to amplifier lifing. The ve+ supply comes through on the same line piggyback from the amplifier and so may give a longevity advantage in cleaning that route of unwanted variance.

It may be desirable but doesn't look like it would prevent basic functioning if not present.

The first trace in two posts above, the 4th peak from left ? Looks like a positive spike on the ve- line in comparison to the others as I view it. Could that be one misfire recorded there ?
 

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There's some info from OP in previous posts that may be significant.

Note, I thought the boot maybe wasn't tight enough on the coil, so I adjusted it all the way down. Also, you can see the arc between the terminals in the 2nd pic, both sides. And yes I've tested 3 sets of wires, all seated correctly with a pop... then covering with the boot. This doesn't seem like a simple whoops.
The observation about #6 spark vs #1 along with above could be relevant in the whole system view.

IF (that's a big if) one or more of the plugs on even bank didn't make a spark then the coil remains charged fully as the rotor arm clears it's HT post in distributor cap and leaving no route to discharge. The next significant event in system is for the amp to close the earth switching transistor, and for a very short time this may coincide to allow the HT field to jump down to the ve- supplied coil post. This sequence giving a dead cylinder occasionally. There's not usually an earth there until amplifier makes this closure.

The test suggested to reduce plug gaps on even bank MAY find this as the voltage requirement to reach ionization (start of spark event in plug gap) is simply less demanding of coil and HT system. If it improves at all or changes it would give us a pointer as to what is happening in there.

If you try this and report we can discuss findings further.
 

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Discussion Starter · #31 ·
quick update to the above, I did regap the plugs at .035 (minimum end), on Champion RN11YCC's (from rovers north), and the original Magnecor 8.5mm HT wires that measure 1/2 the resistance of the replacements I ordered. I also cleaned the idle air control valve for good measure (it was pretty gunky). Still, it seems to be choking... and really it's kind of a rhythmic thing which leads me to a vacuum leak somewhere, though it's not obvious. When I roll along on a flat surface in drive it kind of lurches over and over... subtle, but it seems like an air pocket or choking of the system every cycle. I don't have a smoke machine but I can try and close off the system and pump. I've tried propane, but no results.

I also picked up some NGK's to give a try later if I run out of options. That's what was in there before.

It's p-o-s-s-i-b-l-e that when I put the ram housing and intake back on, that I didn't seal it perfectly. There's no gasket, so I used permatex, the red stuff. I may have botched it, but it's hard to tell with out smoke. And it wasn't doing this right after I installed it so... not sold on that theory yet.

I'm also going to do a compression test (again) today at temp.

The misfire theory @RRLondon and the spikes is really interesting. But I have tested the sparks and they're all sparking (with an in-line). I bought the other tester that lets me see the spark color, so I'll try that today too. I don't think the spark is missing actually, but I do think it's misfiring. I even wondered if the field crosstalk on the HT leads running by the injector harness was doing something weird. I seperated them. I also made sure my HT's were in the exact layout in the workshop man. Prevents possible crosstalk there too.
 

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I also picked up some NGK's to give a try later if I run out of options. That's what was in there before.
I'd definitely try those just to make sure something fundamental is not happening there.

I've a preference for NGK (not that I could say other brands are lacking) purely from being so used to the descriptors, heat range etc for both bikes and cars, also without any notable failures for many years.

Currently using NGK BPR6ES.
 

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Discussion Starter · #33 ·
UPDATE: Had a thought that maybe the exhaust or cat was blocked... pulled the O2 and ran it for a minute. Same sad jerkiness. So, crossed that off the list.

I did my compression test this afternoon. The crank compression shows all around 150-155 psi. Like, that's amazing because my LR Tech had told me they were 110 PSI. I guess he did them cold? Anyway, I did them hot and came back with this great news. I did a dynamic crank while on a couple of them, that came back at 90 PSI, which seems pretty good.

While doing the compression tests, I pulled out plug #4 and upon inspection, little f*cker had cracked the tiny ceramic inside covering the electrode so it was sliding up and down the electrode. !!!

I had these out before and didn't notice a thing, but THIS could have been a problem.

I installed a new NGK BPR6ES (good thing that's what I got!), and the thing made a TOTALLY different sound. It was almost crack-popping for a while... then warmed up and was better.

So I'm going to put all of them in tomorrow. I'm going with the .03 gap they came with, unless .035 seems better.
 

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Discussion Starter · #34 ·
Ok, so I replaced all champion 12YCC's with NGK's gapped around .033+. It def started up solid, and kept a nice hard idle going. Something I've noticed, and maybe this is the next tell:

It's running "ok" ... yet feels like it's hesitating or micro-stalling in idle... kind of just a vibration that's off. I notice it gets worse if I hit the throttle, and then bring it back down to idle. It feels like it struggles more after a snap like that.

I can't find a vacuum leak testing with propane, but I feel like this could be a leak somewhere in the vacuum or.... maybe exhaust, even though I have had both exhaust manifold gaskets replaced and they don't have any visible cracks. I did pull an O2 out as noted, to see if there was blockage. Seemed the same.

My vacuum hose for the ac/heat (to the vacuum ball) at the intake is 15 inches. Does that seem about right? It's solid, and if I hit the throttle, it dips down for a hot second, and right back to 15. I do see the vacuum dance -1 or -2 inches when I feel that hesitation, but it's no more than a little... and could be chicken/egg.

Taking to my LR tech for a full smoke, vacuum/evap/exhaust check tomorrow. VERY interested to see because I think I've covered everything I can without some heavy lifting.
 

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Hopefully with the broken plug detected that's a piece that will bring it closer to solving the problem you have.

Admittedly I've not had cause to exhamine absolute vacuum numbers on them , and so not much to contribute there.

You were mulling over the coil resistance earlier, did you come to a conclusion there?
The impact the primary resistance has on system performance is related to switching time to "fill" the coil while earthed.
Points systems had more resistance on primary mainly because "dwell" characteristics although geometrically consistent with mechanical switching, change in time as rpm of motor shifts. The coil just sees time and will use an aggregated primary resistance to cover this while not filling too quickly and causing excess heat in coil from saturation.
Electronic systems hold notional dwell as time base only throughout motor rpm range as they are not confined to fixed mechanical setup design.
What this means to us on here is that the fill time (the period the amplifier has the earth circuit connected) is a constant throughout the whole engine rpm range, but has to be matched concisely with a coil of correct primary resistance.

If you raise the primary resistance, then the coil will need longer to aquire full discharge voltage. Ergo higher figure here will give incomplete capacity to spark output.

Your old coil seems to be in range 0.7 ? but can't find what you measured the new one at.
 

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Ok, so I replaced all champion 12YCC's with NGK's gapped around .033+. It def started up solid, and kept a nice hard idle going. Something I've noticed, and maybe this is the next tell:

It's running "ok" ... yet feels like it's hesitating or micro-stalling in idle... kind of just a vibration that's off. I notice it gets worse if I hit the throttle, and then bring it back down to idle. It feels like it struggles more after a snap like that.

I can't find a vacuum leak testing with propane, but I feel like this could be a leak somewhere in the vacuum or.... maybe exhaust, even though I have had both exhaust manifold gaskets replaced and they don't have any visible cracks. I did pull an O2 out as noted, to see if there was blockage. Seemed the same.

My vacuum hose for the ac/heat (to the vacuum ball) at the intake is 15 inches. Does that seem about right? It's solid, and if I hit the throttle, it dips down for a hot second, and right back to 15. I do see the vacuum dance -1 or -2 inches when I feel that hesitation, but it's no more than a little... and could be chicken/egg.

Taking to my LR tech for a full smoke, vacuum/evap/exhaust check tomorrow. VERY interested to see because I think I've covered everything I can without some heavy lifting.
15 inches is a pretty good for vacuum. Even though I have a cheap smoke machine the best method I have used is a bottle of sea foam. I made up a rubber hose that would fit the PCV inlet manifold nipple, it’s the one on the inlet manifold throttle side at the front. When you take off the PCV hose plug the open end of the hose. Then I put a smaller diameter rubber hose inside the rubber nipple adapter hose and on punching a hole through the cap of the sea foam container put the thinner hose into the bottle. Run the car until half the Seafoam has gone then switch off the engine. Wait 5 minutes and then run the engine. Within a minute you will see every leak in the inlet and exhaust system, fill your garage with white smoke and fumigate the yard. It’s is a pretty impressive smoke screen. It will all burn off in minutes. The neighbours might be surprised but no worries. The snap throttle tests should not give any hesitation. The idle should be smooth and not vary. Once you do the leak tests and any repairs look at your fuel trim on Roverguage. As far as the blocked cats go the only way to tell is temperature difference across them. Mine are about 370F inlet side and 460F outlet side.
 

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Discussion Starter · #37 ·
@Bill B Did you use the Top Engine Seafoam for this? I just did the intake, with the attachment that goes into the throttle. I didn't get any major white smoke at all. I did the "hot soak" and everything.

If it's the other bottle, I have one! So you're sucking the liquid into the intake at the PCV: NOT on the valve cover, as that's not suction... but at right by the TPS (just before the throttle)? Or the other attach down by the injectors?

This was where the TOP ENGINE aerosol stuff went in too, but they have you take off the intake hose just before the throttle. It's a bish to do it, but I did...

So does your. method drip down into the engine oil somehow? I guess I don't follow this clean, but I like the idea of it.
 

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@Bill B Did you use the Top Engine Seafoam for this? I just did the intake, with the attachment that goes into the throttle. I didn't get any major white smoke at all. I did the "hot soak" and everything.

If it's the other bottle, I have one! So you're sucking the liquid into the intake at the PCV: NOT on the valve cover, as that's not suction... but at right by the TPS (just before the throttle)? Or the other attach down by the injectors?

This was where the TOP ENGINE aerosol stuff went in too, but they have you take off the intake hose just before the throttle. It's a bish to do it, but I did...

So does your. method drip down into the engine oil somehow? I guess I don't follow this clean, but I like the idea of it.
[/

I use the front nipple on the intake manifold which has full vacuum. It’s not really near the TPS but that fat pipe next to the TPS has the same vacuum. It is part of the T Piece. One hose goes to right rocker cover, one hose goes next to the TPS and one hose, connected to the middle of the T, which is a restricted pipe, goes to where I connect in. It used to be just Seafoam but now they have come up with other kinds so I guess the TOP Engine stuff is what we used to use. Once the engine runs the vacuum will suck that stuff out of the tin really quick so you will have to guess when half is gone, get someone to switch off the engine for you. It will start smoking out of the exhaust with white clouds of smoke. Keep the engine off for 3-4 minutes then start it up and there will be white smoke pouring out of the exhaust and anywhere else there is a leak. Vacuum leaks are best investigated with a smoke machine as you need the engine off and positive pressure in the inlet manifold.
There shouldn’t be any way that the Seafoam gets in the oil unless your rings are bad and your compression is about the same a as mine. It goes into the inlet manifold then into the cylinder out with the exhaust stroke and into the exhaust manifold and through the exhaust system and o.it the pipe. It’s not rocket science.
If you are researching Rover V8 there are lots of other forums I.e Triumph, MG, Morgan TVR they all have versions of the V8 and 14CUX control system. Richard Turner once said to me that the Rover V8 is a pretty crude engine and not to over think it. Pushrods can be different lengths, laying a flat bar across the spring caps doesn’t necessarily have to show all the caps are level. There is plenty of slack in the valve train and the engine will run happily in spite of it. He was right.
You are getting there.
1. Fuel supply and pressure
2. Good spark and timing
3. No vacuum leaks or exhaust leaks
4. Good sensors IAC Fuel temp, Water temp, Speed transducer on transfer case, timing signal
from coil to ECU.
5. Good injectors
They are all checkable. Its just like an orchestra , sometimes someone decides to play something else and the result is irritating. Once they are all on the same page it’s music to the ear.
Don’t give up as when you eventually find it you will be mad it took so long and was so obvious. However you will now know your EFI and engine system really well.
Good luck
 

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Discussion Starter · #39 ·
Awesome @Bill B. I did the TOP engine but as the directions indicate, pulling the pipe at the intake before the throttle, and the whole can went in. It's been running pretty well, though oddly as I might have said above, no huge plumes of white smoke. ?? Just a little for a few minutes. Surprised me.

Now, this afternoon I dropped it off for a leak test with my LR Master Tech, and we went over all the stuff I've done. I'd forgotten to mention one thing about all the work I've put in: the fuel pressure was ok at the rail, but I had noted earlier that the vacuum line out of the fuel pressure regulator didn't hold vacuum at the diaphragm. So, that said, here's the theory:

It is POSSIBLE that if the internals of the vacuum are rotted out so as the diaphragm won't hold from vacuum, it's likely the pressure his building in the fuel rail, and... where would the pressure build? In the short side, by the regulator... on the right.

That would be in line with the O2 picking up rich running on that side, and the overfueling/misfire. SO, I should have details on that tomorrow. But, most likely, it's a very good thing to replace.

Also, the car was running pretty dang good today. Those NGK's made a world of difference. The clean IACV may be settling in too. Feeling closer to what I want. But, that fuel regulator is next... and may be the culprit. Standby!
 

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Awesome @Bill B. I did the TOP engine but as the directions indicate, pulling the pipe at the intake before the throttle, and the whole can went in. It's been running pretty well, though oddly as I might have said above, no huge plumes of white smoke. ?? Just a little for a few minutes. Surprised me.

Now, this afternoon I dropped it off for a leak test with my LR Master Tech, and we went over all the stuff I've done. I'd forgotten to mention one thing about all the work I've put in: the fuel pressure was ok at the rail, but I had noted earlier that the vacuum line out of the fuel pressure regulator didn't hold vacuum at the diaphragm. So, that said, here's the theory:

It is POSSIBLE that if the internals of the vacuum are rotted out so as the diaphragm won't hold from vacuum, it's likely the pressure his building in the fuel rail, and... where would the pressure build? In the short side, by the regulator... on the right.

That would be in line with the O2 picking up rich running on that side, and the overfueling/misfire. SO, I should have details on that tomorrow. But, most likely, it's a very good thing to replace.

Also, the car was running pretty dang good today. Those NGK's made a world of difference. The clean IACV may be settling in too. Feeling closer to what I want. But, that fuel regulator is next... and may be the culprit. Standby!
The fuel regulator sets the pressure for the whole rail as it is one loop. If you ha ent already done it change out all the vacuum hoses. They go hard and either split of make a sloppy fit to the pipe nipples. I take it the fuel regulator vacuum hose does go to the IAC flange at the back of the inlet manifold.
It’s a real mystery where your Seafoam went as once it gets into the combustion chamber it vaporizes. If you put it in prior to the throttle plate then it either goes round the plate into the intake manifold and gets sucked into the pistons or drips out onto the top of the left rocker cover and you would surely notice it, or possibly runs down into your air filter box via the hose and MAF. To many other routes for it to go.
 
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