SketchyEngineering
New Member
- Posts
- 5
- Location
- Finland
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), 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.
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
), 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:
