Hello folks,

I'm posting this thread as an introduction, to catalogue my progress on working on my P38 and to ask questions so we can all can gather around my vehicle to ponder what's wrong with it ;)

Anyways, I became the proud owner of a 1999 diesel P38 with 295.000 kilometers on the clock about 10 months ago while I was studying in the Netherlands, drove it daily and never had a problem with the car aside from a knocking noise which was fixed by adding a bit of power steering fluid. All was well until I decided to take the car back home to Finland: near the end of the trip the car started shaking violently on the highway, with a grand amount of steam coming out of the exhaust. Seemed to me like a head gasket / cylinder head problem, and indeed, when I took the head off and had it pressure tested the cylinder head was found to be cracked. This explained why cylinders 5 and 6 were full of coolant when I started disassembly, the crack was located between the no. 6 cylinder intake and the coolant jacket. Turns out riding her in the summer heat for up to 8 hours at once was a bit much ;) For full disclosure, I received a transfer case overheat message a couple of times, which I responded to by letting the machine cool down. These messages and the catastrophic overheat may have something to do with each other.

Feeling less proud right about now, and strapped for cash, I decided to take the fate of the P38 into my own hands instead of employing a mechanic. I researched the car before buying it, thinking it might be fun to teach myself more about being a backyard grease monkey with this vehicle, and so I jumped and ended up taking myself straight to the deep end. But it's a challenge I'm motivated to face. I sourced another cylinder head from a disassembled BMW M51, put that in with fresh head and manifold gaskets and thermostat, and took out the sensors from the old head to be put in the replacement head. Took the time to ensure valves and camshaft were at TDC and had the timing locking pin in. Now the car starts up like a charm and idles and takes revs without any problematic noises, no leaks are to be seen after I did the final head bolt tightening cycle.

However, it's not all sunshine and rainbows. I'm stuck in what seems to be limp mode. My first bet after entering the limp mode lifestyle was to replace the auto transmission fluid and filter, thinking that the aforementioned overheat message + limp mode may have been caused due to low transmission fluid level and pressure, yet that did not resolve my limp problems. Furthermore, the old filter and fluid looked almost new, with no metal shavings or pieces to be found either in the pan or the filter, so old/burnt/low trans fluid wasn't the culprit.

Lacking a Nanocom diagnostic unit due to my post-studying financial situation/predicament/apocalypse, figuring out the problem is a bit of a guessing game. I need a car for my work and I planned the P38 to be my daily driver, and this is indeed a bit of a sticky situation (hilariously enough I also decided to become self-employed before my hillbilly wagon gave up on me). So getting the diagnostics on will have to wait for now. Anyways, the driving feeling is reminiscent of torque converter slipping, as I struggle to accelerate past 60 km/h downhill (don't ask me about the suffering I must endure uphill :rolleyes:), yet this lacking power symptom is also characteristic of limp mode. I do not feel any forward drive gear shifts (P-N-R-D shifts engage smoothly and without any rattle). The car puts out a lot of black exhaust when crawling uphill (most probably due to fuel-air mixture being throttled and wacky). Check engine light comes on not when I start the engine, but immediately when I move the transmission from park; the light stays on until after I reach a speed of about 30-40 km/h, after which it disappears for about 98% of the time, and then comes back full time at lower speeds.

I searched the forums and looked into the suggestions of fiddling around with MAP, EGR and inlet sensor connections, which did nothing in terms of limp mode. Too bad. However, I have a question about the no. 4 injector needle lift sensor. The sensor wiring was cut on the replacement cylinder head, so it lacked a connector, thus I wired the old connector to it. I have no idea if there's a difference between the negative and positive wires for the connection, so wiring it backwards may be the culprit for the limp mode. Does anyone know whether or not such a thing would be an issue? I'm also most probably going to check wiring for wear and clean the electrical connectors any day now.
 
Last edited:
Hello folks,

I'm posting this thread as an introduction, to catalogue my progress on working on my P38 and to ask questions so we can all can gather around my vehicle to ponder what's wrong with it ;)

Anyways, I became the proud owner of a 1999 diesel P38 with 295.000 kilometers on the clock about 10 months ago while I was studying in the Netherlands, drove it daily and never had a problem with the car aside from a knocking noise which was fixed by adding a bit of power steering fluid. All was well until I decided to take the car back home to Finland: near the end of the trip the car started shaking violently on the highway, with a grand amount of steam coming out of the exhaust. Seemed to me like a head gasket / cylinder head problem, and indeed, when I took the head off and had it pressure tested the cylinder head was found to be cracked. This explained why cylinders 5 and 6 were full of coolant when I started disassembly, the crack was located between the no. 6 cylinder intake and the coolant jacket. Turns out riding her in the summer heat for up to 8 hours at once was a bit much ;) For full disclosure, I received a transfer case overheat message a couple of times, which I responded to by letting the machine cool down. These messages and the catastrophic overheat may have something to do with each other.

Feeling less proud right about now, and strapped for cash, I decided to take the fate of the P38 into my own hands instead of employing a mechanic. I researched the car before buying it, thinking it might be fun to teach myself more about being a backyard grease monkey with this vehicle, and so I jumped and ended up taking myself straight to the deep end. But it's a challenge I'm motivated to face. I sourced another cylinder head from a disassembled BMW M51, put that in with fresh head and manifold gaskets and thermostat, and took out the sensors from the old head to be put in the replacement head. Took the time to ensure valves and camshaft were at TDC and had the timing locking pin in. Now the car starts up like a charm and idles and takes revs without any problematic noises, no leaks are to be seen after I did the final head bolt tightening cycle.

However, it's not all sunshine and rainbows. I'm stuck in what seems to be limp mode. My first bet after entering the limp mode lifestyle was to replace the auto transmission fluid and filter, thinking that the aforementioned overheat message + limp mode may have been caused due to low transmission fluid level and pressure, yet that did not resolve my limp problems. Furthermore, the old filter and fluid looked almost new, with no metal shavings or pieces to be found either in the pan or the filter, so old/burnt/low trans fluid wasn't the culprit.

Lacking a Nanocom diagnostic unit due to my post-studying financial situation/predicament/apocalypse, figuring out the problem is a bit of a guessing game. I need a car for my work and I planned the P38 to be my daily driver, and this is indeed a bit of a sticky situation (hilariously enough I also decided to become self-employed before my hillbilly wagon gave up on me). So getting the diagnostics on will have to wait for now. Anyways, the driving feeling is reminiscent of torque converter slipping, as I struggle to accelerate past 60 km/h downhill (don't ask me about the suffering I must endure uphill :rolleyes:), yet this lacking power symptom is also characteristic of limp mode. I do not feel any forward drive gear shifts (P-N-R-D shifts engage smoothly and without any rattle). The car puts out a lot of black exhaust especially when crawling uphill (most probably due to fuel-air mixture being throttled and wacky). Check engine light comes on not when I start the engine, but immediately when I move the transmission from park; the light stays on until after I reach a speed of about 30-40 km/h, after which it disappears for about 98% of the time, and then comes back full time at lower speeds.

I searched the forums and looked into the suggestions of fiddling around with MAP, EGR and inlet sensor connections, which did nothing in terms of limp mode. Too bad. However, I have a question about the no. 4 injector needle lift sensor. The sensor wiring was cut on the replacement cylinder head, so it lacked a connector, thus I wired the old connector to it. I have no idea if there's a difference between the negative and positive wires for the connection, so wiring it backwards may be the culprit for the limp mode. Does anyone know whether or not such a thing would be an issue? I'm also most probably going to check wiring for wear and clean the electrical connectors any day now.
A duff injector 4 will certainly cause the MIL light. I'll check tomorrow if reverse polarity is likely to cause a problem. Another option is to try running with the MAF disconnected as that can cause problems. Have you checked the FIP timing? There should be no black smoke so it's over fuelling.
Leave the vacuum pipe off the EGR, plug the rubber pipe with an M5 screw.

Have you checked the viscous fan? Failure of the fan is a common cause of overheating and cracked heads.
 
A duff injector 4 will certainly cause the MIL light. I'll check tomorrow if reverse polarity is likely to cause a problem. Another option is to try running with the MAF disconnected as that can cause problems. Have you checked the FIP timing? There should be no black smoke so it's over fuelling.
Leave the vacuum pipe off the EGR, plug the rubber pipe with an M5 screw.

Have you checked the viscous fan? Failure of the fan is a common cause of overheating and cracked heads.

Hey, thanks for the reply. I did try running with the MAF disconnected (as far as I know it's the sensor in the housing next to the air filter), for about 500 meters. I'll take a drive tomorrow with the plug out to confirm and also see if the viscous fan is doing its thing. Thanks for the tip for blanking the EGR.

I haven't checked the FIP timing, which is something that's admittedly been on my mind. What tool(s) do you suggest?

edit. I also edited my post to reflect that the black smoke situation does not occur constantly, only when going up an inclination. It appears that maximum revs is around the 2000 - 2500 area, and the car does not do speeds beyond 30 km/h when going uphill.
 
Last edited:
Hey, thanks for the reply. I did try running with the MAF disconnected (as far as I know it's the sensor in the housing next to the air filter), for about 500 meters. I'll take a drive tomorrow with the plug out to confirm and also see if the viscous fan is doing its thing. Thanks for the tip for blanking the EGR.

I haven't checked the FIP timing, which is something that's admittedly been on my mind. What tool(s) do you suggest?
If you had diagnostics I could give you a simple way of doing the FIP timing. As you have no diagnostics you need to do the DTI method as described in RAVE the workshop manual.
 
If you had diagnostics I could give you a simple way of doing the FIP timing. As you have no diagnostics you need to do the DTI method as described in RAVE the workshop manual.

I see. I do feel more confident about getting the timing right with a diagnostic tool rather than a timing gauge, and Nanocom is on my shopping list anyways. I was under the impression that timing needs to be adjusted mechanically, but I'm happy to be proven wrong.
 
Black smoke and no power sounds like the turbo pipe has popped off the intercooler or delaminated inside blocking the flow.
 
Is it struggling for fuel, blocked air filter or fuel filter or bad in tank pump as well as all above ... :eek:..
 
I see. I do feel more confident about getting the timing right with a diagnostic tool rather than a timing gauge, and Nanocom is on my shopping list anyways. I was under the impression that timing needs to be adjusted mechanically, but I'm happy to be proven wrong.
The FIP is adjusted mechanically but I have an easy way of doing itaccurately using the readings from nanocom rather than using the DTI which is hard to get accurate.
 
Alrighty then, took a look in the engine bay and found a winner amongst these tips.

Black smoke and no power sounds like the turbo pipe has popped off the intercooler or delaminated inside blocking the flow.

The turbo intake/intercooler hoses have been replaced with blue silicone ones, and they're all fresh and clean, so they're good to go. However, I ran into a very embarrassing mistake - I didn't tighten the clip well enough on the hose attached between the intercooler and the turbo itself, and the intercooler hose had slipped off. Oops. So all that air pressure was pushed into the engine bay instead of the engine. I fixed that right up and the car rides much better, I can actually accelerate uphill now. Also the black smoke issue is now a thing of the past.

Nevertheless, car's still a bit gutless, especially accelerating from standstill, noticeably but not much worse than before the cylinder head failure. Furthermore, I still got the check engine light, although now only during standstill/idling. I'm willing to bet that this is a timing or compression issue; the replacement head may not have been entirely flat, or there's an issue with the quality of my work. In any case, the car drives satisfactorily, but not entirely like it used to.

Or the map sensor 3mm pipe has come off

Checked the MAP pipe about a week ago + cleaned it with carb cleaner, MAP sensor works fortunately.

Is it struggling for fuel, blocked air filter or fuel filter or bad in tank pump as well as all above ... :eek:..

Air filter looks fine, fuel filter was replaced in April, hope the in tank pump is still good for a few miles. Kinda worried about the in tank pump though, seems like a time bomb just waiting to leave the car stranded in the middle of nowhere.

The FIP is adjusted mechanically but I have an easy way of doing itaccurately using the readings from nanocom rather than using the DTI which is hard to get accurate.

Alright, sounds like adjusting timing isn't an insurmountable task with the diagnostics. I'll get back to you about this when I get my hands on a Nanocom, I'm most probably doing an EAS valve block refurbish to make EAS survive the upcoming winter and I need Nanocom for that. Heard that the valve block o-rings shrink when it gets cold, causing air pressure to be quickly lost, and this is a problem for me.

edit. oh yeah, also checked the viscous coupling fan. Working as intended
 
Last edited:
Alrighty then, took a look in the engine bay and found a winner amongst these tips.



The turbo intake/intercooler hoses have been replaced with blue silicone ones, and they're all fresh and clean, so they're good to go. However, I ran into a very embarrassing mistake - I didn't tighten the clip well enough on the hose attached between the intercooler and the turbo itself, and the intercooler hose had slipped off. Oops. So all that air pressure was pushed into the engine bay instead of the engine. I fixed that right up and the car rides much better, I can actually accelerate uphill now. Also the black smoke issue is now a thing of the past.

Nevertheless, car's still a bit gutless, especially accelerating from standstill, noticeably but not much worse than before the cylinder head failure. Furthermore, I still got the check engine light, although now only during standstill/idling. I'm willing to bet that this is a timing or compression issue; the replacement head may not have been entirely flat, or there's an issue with the quality of my work. In any case, the car drives satisfactorily, but not entirely like it used to.



Checked the MAP pipe about a week ago + cleaned it with carb cleaner, MAP sensor works fortunately.



Air filter looks fine, fuel filter was replaced in April, hope the in tank pump is still good for a few miles. Kinda worried about the in tank pump though, seems like a time bomb just waiting to leave the car stranded in the middle of nowhere.



Alright, sounds like adjusting timing isn't an insurmountable task with the diagnostics. I'll get back to you about this when I get my hands on a Nanocom, I'm most probably doing an EAS valve block refurbish to make EAS survive the upcoming winter and I need Nanocom for that. Heard that the valve block o-rings shrink when it gets cold, causing air pressure to be quickly lost, and this is a problem for me.
@Jersey38 has a Nanocom for sale and he is in the UK at the moment.
 
Last edited:
seems like a time bomb just waiting to leave the car stranded in the middle of nowhere.
If the pump fails it just makes the car a bit sluggish especially going up hills ,,and poor starting when the tank is near empty,,its not one that fails leaving you stranded ,the beast should still run and get you home...;)..
 

Similar threads