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Registered
1970-1995 Range Rover Classic
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321 Posts
Discussion Starter #1
Hi All,

I'm looking for additional suggestions as I continue to troubleshoot

1999 RR 4.0L GEMs - Blew a head gasket on the passenger side (edge of block at cyl5). After completing the rebuild the engine struggles to start, has a rough idle, stalls if you give it gas and let off the throttle, and zero power under load. She's also super tough to restart if she stalls, or is warm.

From the rebuild: heads were machined, hot dipped, and valves re-done (grinding, and new guides). Everything else was cleaned but not replaced. The truck has brand new spark plugs, and has good spark on all 8.

The sounds/symptoms, point to an air-fuel issue. Initially, the symptoms pointed to a bad MAF - If any part of the intake was disconnected, the truck would stall. If I plugged part of the intake, the truck would run a bit better and, more importantly, wouldn't stall. I couldn't find a 20AM maf so I bought one from a BMW 328i as it has the same connector.

Before replacing the MAF, it threw a P1316 with nothing else. It cleared, came back one time, cleared again, and hasn't returned. Since switching the MAF, she idled, but still has no power under load. A new idle air bypass is arriving tomorrow and hopefully that helps as well.

I smoke tested the plenum and saw no leaks and there wasn't any change in RPM or strange smoke paths. The vacuum line from plenum to the fuel rail is attached. I don't see anything obviously disconnected

No Codes are being thrown at this time.

Thoughts or suggestions to get this truck back up and running would be greatly appreciated.
 

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Registered
1995-2002 Range Rover P38A
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771 Posts
Double/triple check you’ve got the leads on correctly, there numbered along the top edge of the coil mounting plate,, odds ( 1,3,5,7 ) lefthand side of car , evens on the right hand side, I’ve only ever had one run rough after a head job , was 3 & 5 on wrong
 

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1995-2002 Range Rover Classic
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1,413 Posts
your cam timing may be off by 180 degrees. this may have been an oversight during assembly, I made this mistake once and needles to say symptoms were nearly identical to your description.
 

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Premium Member
1970-1995 Range Rover Classic
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1,482 Posts
your cam timing may be off by 180 degrees. this may have been an oversight during assembly, I made this mistake once and needles to say symptoms were nearly identical to your description.
So he only has tear apart the front, as opposed to yanking the motor or tearing apart the top half...


Sent from my iPhone using Tapatalk
 

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1970-1995 Range Rover Classic
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321 Posts
Discussion Starter #6
bmw 328i maf installed
new idle air bypass installed

truck started, idled , but had no power through 2400RPM - foot on floor, 3000-3500rpm, could hit 40 mph but that was about it.

She wouldn't restart once it was parked in the driveway. It would crank, fire, but wouldn't stay running. Exhaust smelled of over-fueling.

Soo thinking I need to find a 20AM MAF for a P38 to test with a correct part
 

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Registered
1995-2002 Range Rover P38A
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5 Posts
http://www.rswsolutions.com/

Rangerover,

I have a1998 RR 4.6 HSE GEMS and have been using R. Storey Wilson’s (RSW Solutions)
“EAS UNLOCK V4” Tool (at above link) for years now. It has saved me $1,000.00 of dollars over thecost of repair bills!

He has OBDII SCANNERS for different models/years, sothey are not limited to just P38’s.

Do yourself a favor and buy this software/hardwaretool for your vehicle –you will NOT be disappointed.

Regards,
64Chris



 

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Premium Member
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1,309 Posts
Yes.. it will run in limp mode with the TPS disconnected. Any flashing CEL?
 

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Registered
1995-2002 Range Rover Classic
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1,413 Posts
So he only has tear apart the front, as opposed to yanking the motor or tearing apart the top half...


Sent from my iPhone using Tapatalk
he could do that but it is easier if the rockers are removed as well.
 

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2010-2012 Range Rover Sport
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7 Posts
ANY LUCK?
Have you tried compression testing? Valve seats could have been overcut preventing a good seal.
 

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Super Moderator
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2,199 Posts
Equally, if the heads have been skimmed and the valve seats recut, you may need to fit shims under the rocker pedestals to get the preload back in limits. With a combination of both jobs having been done, it may be that the valves are never fully closing, particularly when hot. See http://www.v8developments.co.uk/technical/valve_train/index.shtml
 

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1970-1995 Range Rover Classic
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321 Posts
Discussion Starter #13
I threw on 6 good ignition leads from my spare D2 parts and had a good run with the truck. So, between that and the p1316 code caught the other day I opted to purchase new p38-specific leads. I'm waiting on Kingsborne and UPS and will resume troubleshooting once those arrive and are installed.


Hopefully will pick this up on Friday... more likely Monday of next week :(
 

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1970-1995 Range Rover Classic
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321 Posts
Discussion Starter #15
So, after the new wires didn't resolve this, the signs/symptoms pointed to an issue with the CPS. Replaced that and it drove better, however, still not quite there. No additional codes

I noticed on torque pro that the TPS wasn't providing any feedback. So I unplugged it, and was finally able to drive the truck around the block.

Does anyone have a valid testing procedure for the TPS? I couldn't find expected voltage/resistance noted in the RAVE
 

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1995-2002 Range Rover Classic
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1,413 Posts
connect your obd 2 scanner go to components find graphing and see what each sensor is doing and perhaps how each cylinder is firing, you will need something higher end that your basic code reader. do a basic compression test or a cylinder leak down, check vacuum leaks, revisit your basic timing, check your injector connections one may not be fully plugged in.
99 was a model change over and mid year production thus you could have a gems or bosh engine, if you have the bosh engine, the iac plug is gray and it's connector interchanges with that of the left side coil. that of the coil is black, you may have cross connected those.
you are missing a signal somewhere either electrical or mechanical, start with electrical.
 

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1970-1995 Range Rover Classic
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321 Posts
Discussion Starter #18
I popped the top off the engine and discovered that there was a pool of gas (about 1 cup) in the intake (below the trumpet) for both cylinder 3 and 6. - The two injectors for those cylinders are off, but , based on the pool it looks like the valve might have clogged or something, instead of a blocked injector

Thoughts?
 

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1995-2002 Range Rover Classic
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1,413 Posts
bent push rods, not connected push rods, worn out cam lobes, broken rocker arms, would be the main reasons for valves not to open.
 
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