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1995-2002 Range Rover P38A
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Discussion Starter #1
Engine runs smooth at startup but after it gets to operating temp and goes into closed loop,
starts missing and running rough, with "Slow max 35mph" warning displayed.
Has p1777 gearbox fault cleared and not recurrent.
Has p1316 misfire. Pumped smoke to find vacuum leaks, none present. Cleared, returns after reaching closed loop on startup.
After engine is hot there is a single valve/lifter noise on right bank cyl 4 or 6?
Oil is not foamy nor is there any evidence of coolant leakage under oil filler cap, blackish brown and little sludge present.
Observing live data on obd2 port all the o2 sensors seem to be fine except the bank 2 after cat which is a little slow switching but
I don't think enough to cause the issue
I just took on this truck and I am unfamiliar with it. Here are my questions, unknown conditions.
1. Does the "EAS slow max 35 mph" warning put engine controls into limp in or similar fuel mapping?
2. The EAS was disabled and coils were installed without any kind of module to override becm presets.
I have found splices on the brown power wire under the relay panel as well as the black ground under same panel, but
if there was a loop around installed it is not there now. There is also a splice onto lime/white wire (fan?) under the relay panel also. Also found a
non original black wire running from relay panel area to the becm but is not connected anywhere. Dash display showing "eas fault" after startup.
after looking at Arnott instructions to override becm fault condition for eas, it appears this was either attempted or executed and subsequently reversed.
Question. As I have no idea who did this work, is this an older method of performing the needed alterations for manual override of EAS?
Question. Does the EAS being connected to throttle body vacuum port matter?
Question. Compressor plug is still connected inside EAS box, to eliminate EAS isn't it supposed to be unplugged?
Sorry for the mini novel, just trying to get this thing running properly.
Thanks in advance for any assistance.
 

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1: EAS has nothing to do with nor impact on the engine ECU.

2: EAS has no impact on BeCM either save for message delivery to the message centre. No idea what splice you are talking about. There is no splicing necessary when castrating and certainly nothing to do with the BeCM.

Next: As you have no EAS there is no reason to address manual override.

Next: The EAS has no connection to the throttle body in any way. EAS is a stand alone system.

Next: As the compressor is not doing anything there is no reason for it to be disconnected.


As mentioned above the EAS is a stand alone system with no real interface with other systems save for message deliver and a few sensors. It has no impact on engine operation. FOr this topic you can ignore the EAS system completely.

As far as how your rig was castrated it can be addressed at another time. It is safe to say that whomever did it had no clue what they were doing. Message removal instructions are available in existing threads.
 

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1995-2002 Range Rover P38A
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Discussion Starter #3
After digging into this engine problem, plugged gauge on fuel rail and key on 36psi stable dropped to 30 running.
coils, wires and plugs all working well. I located major vacuum leak at the upper intake to plenum mating area on pass side.
Q. I cannot find a gasket for the GEMS type plenum? This had been slathered with silicone RTV between the two parts. Is this correct?
 

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Q. I cannot find a gasket for the GEMS type plenum? This had been slathered with silicone RTV between the two parts. Is this correct?
No gasket on plenum to ram housing. RAVE states Loctite 577. I use a thin smear of Blue Hylomar on most joints of this type after lapping in for flatness. Whatever floats your boat I guess but slathering anything means that it gets into places you really dont want it!
 

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Discussion Starter #5
Disappointing, I really was hoping I was just using incorrect terminology in my search for a gasket/seal. This had the brown loctite around and under the blue RTV. It leaks mightily now and Loctite leads me to apprehension of inevitable leakage. Is there a phobia for fear of inlet air leaks?
 

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1995-2002 Range Rover P38A
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After digging into this engine problem, plugged gauge on fuel rail and key on 36psi stable dropped to 30 running.
Fuel pump is on it's way out, it should be around 35-36 psi all the time. That's probably the main cause of the rough running.
 

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You could try Anemophobia if you like :)
In the case of your plenum you might like to try this (I've never done it specifically on a GEMS plenum, but generically):
Remove any dowels etc from the surface to be flattened. Use Loctite 7200 to remove all traces of old gasket goo. Get hold of a suitably sized piece of plate glass. Put a smear of fine valve grinding paste around joint surface to be lapped. Place it joint surface down on the glass and, keeping it perfectly flat, move it around in a circular polishing motion. Replenish paste as required. When you have a matt grey joint surface all over, you're good to go AFTER cleaning thoroughly to remove every last molecule of grinding paste.
If you can't get a uniform joint surface, it's knackered so slather with RTV :)
 

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Discussion Starter #8
Made a gasket out of paper gasket material. No leaks at this spot any longer.
Ok, correct me if I am wrong here but. Here is my live data from Innova 3160 scantool,
Fuel sys --- CL
IAT ------ 110
SPARK ADV - 31
MAF ----- 0.015
TPS ----- 10.1 NOTICE THIS IS AT IDLE
STFT B1 - -25.0
LTFT B1 - -2.3
STFT B2 - -25.0
LTFT B2 - -2.3
While this ran up to temp again it ran beautifully open loop until the 02 sensors told the ecm to adjust fuel trims.
So when I noticed the TPS wont go to .6 - .75 or nearby I realize why it is out of tune. Now how to get the TPS value back to the what it should say not 10.1.
Read older posts on similar issue and see the stop on the throttle plate shaft mod, however this is just wrong that the new sensor is that far off of the stored value.
 

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Discussion Starter #9
Question, I do not know where the TPS was swapped (this one is not new), but perhaps the ECM was replaced, whatever
the TPS is reading 10.1 at rest. I have read older posts describing bending the tab on the linkage to get to the correct value
but I can see the small nub under the tab that allows for this to be set.
Q?
1.Can this set screw be accessed from underneath? (looked with my dentist mirror but very tight)
2.The correct value is .6 to .75 correct?
3. Will this "learn" by driving truck or will it only be corrected by physical adjustment or logical interface.
 

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1995-2002 Range Rover P38A
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It should learn but in my experience it takes a while for it to change. Mine used to show 8% and has, over a few thousand miles, dropped to 4%. If you have the correct diagnostics, you can do an adaptive reset to force it to change. However, I'd look at your MAF too, the reading from that seems awfully low although you don't say what units the reading is in.
 

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TPS reading is not as far off as you may think. Max voltage is 5V. Correct is 0.6V. This equates to an INNOVA reading of 12.0. So 10.0 is actually 0.5V. I have the same scanner, and that is how it works. So, it looks like the TPS is correctly set.
So 0.0V = 0 5.0V = 100 and it is a linear scale.
 

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1995-2002 Range Rover P38A
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I think the my 01 has the TPS reading at about 10% when it is fully closed too. It is also one of the values that the ECU can 'adapt' so if the sensor reads slightly high/low at idle it will learn this and take that as it's new closed point.

I also wouldn't think that it would cause rough running as it is one of the sensors (if memory serves) that the ecu uses for open loop fuelling. I think it compares the TPS value to its fuel map and uses that and the MAF in open loop running.

I would also be leaning towards the MAF being dirty, as I've had the issue on mine where it ran badly in closed loop and a new genuine Bosch MAF sorted it out.

I have a 2001 though and they are known for the MAF going faulty, whereas earlier GEMS ones seem to respond well to being cleaned.
 

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Discussion Starter #13
The maf value is in lb/min. What are normal maf numbers in the gems system.
Well, I massaged the wee little stump and got the tps to read just at 1.0 and bam!
fuel trims stopped going total negative and the rough idle smoothed out.
Drove around the block and the blasted trans started to fail. Pulled off and checked the
fluid level and there was no fluid on the dipstick. I had just changed oil and filter as the tappet
noise is like fingernails on a chalkboard. Put atf in her, I got about a pint into the dipstick
tube and it was full. I knew that was not possible so I went below decks to see if something was pinched or
plugged etc. So I see these air lines from the gearbox and the dif housing and they are all wound up and zip
tied like the air tubes for the suspension that was converted. On the end of the hose for the gearbox is a plug...
Popped it off and glug glug, down the hatch, added about three pints in total and ran it through the gears while running
and added a bit more. So while I am under there I see no inspection cover at front of bell housing, look up at the
flexplate and by glory there is a bent screw protruding to the inboard side of the teeth at about a 45deg angle along with
the other bits from the sensor screwed to the block.
So now the TPS mischeiviously repopulated the numbers with a at idle number of 4.7
and my fuel trims are going negative again. Now this time they do it gradually. starts out at 00 and slowly bumps a few points at a time moves back to stft -25.0 and ltft -2.3 rough idle in tow. A bit less though I must acknowledge.
I have a very strong magnifier that was poached from an old dental xray tooth zapper, (dont ask about the radiation levels)
and whilst I sprayed the maf with crc t-body cleaner I am visually confirming it is free of visual contaminants.
I swapped it with another maf I inherited from the chap that unloaded this prize on me, and the readings are exactly the same (not saying they both are not bad), but I am more concerned with the crank sensor at this point.
Q.
Has anyone seen this happen to a crank sensor? I can see teeth in the inboard row that took it on the chin. Please don't
tell me this needs a sensor and flexplate.

going through the fuse panel (brilliantly placed) between the battery and the coolant tank. Already I can see rl 12 area under the box has white crud all about that corner.
Many thanks to all for your knowledge.
 

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Sounds like you need to download RAVE as all the data you need is in there!

Air mass flow at sea level - Engine fully warm, in neutral gear, with all loads off
At Idle ............................................................................... 20 kg/hr ± 3 kg\hr
At 2500 rev/min ................................................................ 61 kg\hr ± 3 kg\hr

Wound up and zip tied pipes are likely to be breather tubes. Correct routings are in RAVE but for starters they should be able to breathe (doh!) and the open end should be somewhere up above where water could get when wading. Blocked off breathers will lead to leaks as well as making it slow to fill gearbox via dipstick tube.

Tappets don't screech like nails on a blackboard. They just tap. If you have a screech it's not likely to be tappets.

ATF should be checked (as per RAVE or your owners manual- OK, thats the last time I'll mention it!) level ground, engine cold and running, brakes on, cycle through gears to 1st and back, into Park. Dip and add fluid via dipstick tube as required.

Trans fail may just be battery. Charge it!

Land Rover didn't use bent screws to install CPS or have broken/ missing teeth. Take picture and post if you can. You said don't tell you the flex plate/ CPS is damaged, so I won't, but...
 

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The GEMS ones were known at one point for the tip of the crank sensor to hit the reluctor teeth on the flywheel and either damage the teeth or bend the tip of the crank sensor. Which is what it sounds like you might have.

Apparantly the teeth can be welded back on, or replacements made/welded on. I don't know what causes it to happen, but I suspect it has something to do with a flex plate failure or something like that.
 

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Discussion Starter #16
Ok I will put a pic of cps sensor up before I pull it out.
I have the rave on my desktop, it just takes a bit of time to learn to navigate thru it.
Agreed, flow data way off on the MAF as .014 lb/min is about .5 kg/hr which means essentially zero airflow measured.
Should have been more clear, tappet noise (tapping) is a similar effect on my nervous system as nails on a chalkboard. drives me Batty!
Been charging battery each nite on the multi-stage voltage minder, and seems to be helping as I am getting fewer bings and bongs and lights and other pinball wizard action when I put the ball in play (Key On).
If the crank sensor is jacked, will it not affect the system in open loop as well as CL?
As Robby Robot would say "does not compute", when the tps briefly was telling the ecm it was at zero, the engine ran good for 10 minutes and I drove it.
 

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Discussion Starter #17
More fun this week, I eased the bent screw out of the CPS hold down piece. The crank position sensor is putting out voltage on the bench and has continuity on the ground (earth) circuit. So that is not the problem. I ran a pressurized injector service on the fuel rail and injectors and that smoothed things out nicely. Looks like I will need to remove the ram housing and look at the injectors and test them for spray pattern and output etc. Correct me if I am wrong but if one or more are clogged then the ecm is going to shut down the air and trim out the fuel to deal with the lean condition.
Rave shows in detail how the driveplate works on the later model but not the Sagem, will the absence of on inboard tooth cause a significant issue? All the remaining teeth are there although some needed a bit of (careful) straightening.
 

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Discussion Starter #18
Forgot to add, I still have the original issue of this thread, random misfire that develops at closed loop condition. It is making me nuts.
Additionally, I did test fuel pressure again, and under load, the results are 35 at start and 36 to 39/40 psi throttle up. Started to get a neat light show with all my lights and illuminations surging wildly. Tested alternator which must be expiring. It zooms back and forth from 15.6 to 14.5v when testing main supply wire grounding to neg batt term.
Gotta get her smogged, this is making my noggin hurt.
 

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Discussion Starter #19
FYI, the cause for the discrepancy in the fuel pressure tests was, the first test was performed with my Fuel injection cleaning system as the gauge, which is fine except that the clarity is horrible on the acrylic lens due to years of exposure to chems. Latest test was a regular straight hose from rail to fuel pressure gauge.
Secondly regarding my question about the reluctor teeth (term encountered here) I meant to ask
"will the absence of ONE inboard tooth cause a significant issue?"
Also is there more to the surging power than just the alternator going wonky? I assume this could cause
much of the chaos with this rig. Based upon all I have come to learn about this model's need for sound electrical systems integrity.
 

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Discussion Starter #20
As not to seem ignorant to all of your great help, I swapped the MAF with a Lucas made spare that I cleaned with T-body cleaner and a super fine poly brush and it is responding to increased RPMs. The scantool reads the same base reading at idle (800rpm) of .018 lb/min and climbs to .038 even .040 at around 3000 rpm. Also backprobed the signal wire .18v base and .40v @ 3000rpm. This appears to work out to 5 kg/hr and climbing to 10 kg/hr at 3000rpm. I know this is way low but...
Q? Is it working or is something else acting on it?
Replacing alternator before I go further.
Thanks to all helping. Truly appreciated.
 
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