P38 2.5 low on power, can't reach max rpm

[Stavros1983]

Hi!

I´m a new owner of a P38 2.5 auto 1999.

I have read as many threads that I could find here before posting.
I bought it as a non runner and the previous owner had replaced the MAF sensor, in-tank pump, fuel and air filters, injector number 4 to a brand new one and lastly the temp sensor in the FIP.

New "new" in tank pump was dead and I replaced it. The car started immediately after that but was running rough and a lot of white smoke and terrible exhaust smell.
I blead hose to FIP and all injectors and adjusted the timing of the pump by reading modulation and advanced it a bit and ended up with about 55% on idle. I set the FIP mg/stroke to about 5.
The idle is a little high at about 830 rpm but I don't have Nanocom so can't adjust it electronically.
Needle lift sensor error was present intermittently before I timed it and adjusted mg/stroke.

The small outlet from the manifold to MAP-senors was broken so I removed the manifold and fixed that with a new metal fitting. I can blow thru the hose without problem. The MAF sensors gives a correct reading regarding EGR.
I cleaned the EGR and tested without vacuum attached to it.

The turbo boosts about 1 bar over atmospheric pressure - OBD data.

It won't rev in idle over 3800rpm and it's slow to drive - I can't feel the turbo boost like an ordinary diesel turbo. No smoke, neither white or black. Doesn't seem drink any coolant. I can hear the boost pressure release at throttle release to idle in neutral- pschhhhhh.

I also tested the new in tank fuel pump giving more than 180ml with relay bridged for 10sec. About 300ml.
Tested with MAF, MAP and injector 4 cable, egr vacuum disconnected - individual tests. No difference. My cps gives a consistent reading and modulation is stable at idle.

I’m starting to wonder if there is a blockage in the exhaust.

Would anyone be so kind and point me to the new viable thing to do.

Best wishes from Sweden

 

[Datatek]

Hi!

I´m a new owner of a P38 2.5 auto 1999.

I have read as many threads that I could find here before posting.
I bought it as a non runner and the previous owner had replaced the MAF sensor, in-tank pump, fuel and air filters, injector number 4 to a brand new one and lastly the temp sensor in the FIP.

New "new" in tank pump was dead and I replaced it. The car started immediately after that but was running rough and a lot of white smoke and terrible exhaust smell.
I blead hose to FIP and all injectors and adjusted the timing of the pump by reading modulation and advanced it a bit and ended up with about 55% on idle. I set the FIP mg/stroke to about 5.
The idle is a little high at about 830 rpm but I don't have Nanocom so can't adjust it electronically.
Needle lift sensor error was present intermittently before I timed it and adjusted mg/stroke.

The small outlet from the manifold to MAP-senors was broken so I removed the manifold and fixed that with a new metal fitting. I can blow thru the hose without problem. The MAF sensors gives a correct reading regarding EGR.
I cleaned the EGR and tested without vacuum attached to it.

The turbo boosts about 1 bar over atmospheric pressure - OBD data.

It won't rev in idle over 3800rpm and it's slow to drive - I can't feel the turbo boost like an ordinary diesel turbo. No smoke, neither white or black. Doesn't seem drink any coolant. I can hear the boost pressure release at throttle release to idle in neutral- pschhhhhh.

I also tested the new in tank fuel pump giving more than 180ml with relay bridged for 10sec. About 300ml.
Tested with MAF, MAP and injector 4 cable, egr vacuum disconnected - individual tests. No difference. My cps gives a consistent reading and modulation is stable at idle.

I’m starting to wonder if there is a blockage in the exhaust.

Would anyone be so kind and point me to the new viable thing to do.

Best wishes from Sweden

Check that the MAP sensor is working and try running with the MAF unplugged. There are a lot of "new" faulty MAF sensors about. 830rpm is OK. Also adjusting the FIP mg/stroke to about 5 may not be correct.

 

[Stavros1983]

Check that the MAP sensor is working and try running with the MAF unplugged. There are a lot of "new" faulty MAF sensors about. 830rpm is OK. Also adjusting the FIP mg/stroke to about 5 may not be correct.

Thanks. I have not noticed any improvements with MAF unplugged.
I just noticed that my Injector Actual is 0-0.75 on idle and Injector Set Point is 1.75. That offset seems to follow the revs...
Needle lift is within 40 to the RPM. It says timing mode 52% which i assume is the modulation.

 

[Salisbury Nick]

I had a loss of power when accelerating. The air intake pipe that connects the air filter to the intake manifold bridging the engine collapsed in itself when accelerating, then restored to normal shape when ticking over. New pipe transformed performance. Obviously you can’t see this happening when you are in the drivers seat so you need a mate to push the accelerator while you watch it. Also, similar result from a deformed and blocked air filter.

 

[Datatek]

Thanks. I have not noticed any improvements with MAF unplugged.
I just noticed that my Injector Actual is 0-0.75 on idle and Injector Set Point is 1.75. That offset seems to follow the revs...
Needle lift is within 40 to the RPM. It says timing mode 52% which i assume is the modulation.

On some cars, a faulty MAP sensor limits performance, try leaving the pipe to the manifold disconnected.

 

[Stavros1983]

I had a loss of power when accelerating. The air intake pipe that connects the air filter to the intake manifold bridging the engine collapsed in itself when accelerating, then restored to normal shape when ticking over. New pipe transformed performance. Obviously you can’t see this happening when you are in the drivers seat so you need a mate to push the accelerator while you watch it. Also, similar result from a deformed and blocked air filter.

Hi. Thank you for your answer. I have checked all air pipes and hoses while a friend was revving the car. Looks to be in good order. I have also tried it without that big plastic pipe over the engine with the same result.

 

[Stavros1983]

On some cars, a faulty MAP sensor limits performance, try leaving the pipe to the manifold disconnected.

Thanks for the tip.I did disconnect the hose and tried but only in neutral. Did also try with the MAP plug disconnecte. No difference. I will try to run the car on the road tonight without the hose connected. My money is on the FIP but I´d love to be proven wrong on this instance..

 

[brianp38dse]

I have never heard a pssschhh on mine there is no dump valve to make that noise unless you have a split in the pipe work from turbo to inlet manifold you should not get a noise.

 

[Mark Piercy]

These fuel pumps can get jammed inside.. If you have a mooch on the tïtsnet, you'll find videos on this pump we're they have the center accelerator axle that jams up due to misalignment or debris in the pump... Mine will occasionally lose the pedal response after a while on cruise control. I just stamp the pedal and it'll come back without cutting the ignition.

 

[Stavros1983]

I have never heard a pssschhh on mine there is no dump valve to make that noise unless you have a split in the pipe work from turbo to inlet manifold you should not get a noise.

Im sorry, I made a bad description of the noise. If I disconnect the hose from the MAF and rev the car I can hear when the boost releases when I release the accelerator. It's not a dump valve sound. Sound like my other diesels I've had in the past. Maybe more like a foooooof sound. Just mentioned it to implicate that boost is building and releasing with the travel of the accelerator.Sorry for my bad English..

 

[brianp38dse]

Im sorry, I made a bad description of the noise. If I disconnect the hose from the MAF and rev the car I can hear when the boost releases when I release the accelerator. It's not a dump valve sound. Sound like my other diesels I've had in the past. Maybe more like a foooooof sound. Just mentioned it to implicate that boost is building and releasing with the travel of the accelerator.Sorry for my bad English..

Ah ok i was probably over reading it as well trying to think a bit out side the box.

 

[Stavros1983]

These fuel pumps can get jammed inside.. If you have a mooch on the tïtsnet, you'll find videos on this pump we're they have the center accelerator axle that jams up due to misalignment or debris in the pump... Mine will occasionally lose the pedal response after a while on cruise control. I just stamp the pedal and it'll come back without cutting the ignition.

I was curious and took of the top lid of the pump and looked at the potentiometer arm. It moves with spring tension but smooth thru out its travel. I was scratching my head a bit and wondering if the quantity adjustment inside would rectify my weird injector actual vs injector set point difference but this is my first time working on this type om engine and pump. I´m just an office guy thinking - how hard can it be.. So I´ll try to fiddle as little as possible with the inside of the pump at this moment.

 

[Stavros1983]

Ah ok i was probably over reading it as well trying to think a bit out side the box.

I appreciate all the help and outside of the box thinking! Is it fair to assume that since my obd reader shows boost pressure to increase with load to about 1 bar over atmospheric pressure, that the turbo and relevant hoses are working properly? Because the reading is from the MAP connected to the intake manifold?

 

[brianp38dse]

Sounds about right , what reader are you using as the doozel is not obd compliant very few will read a p38 doozel

 

[Stavros1983]

Sounds about right , what reader are you using as the doozel is not obd compliant very few will read a p38 doozel

Im using a Kingbolen Ediag. Bought it for my L320 TDV8 since it could do EAS calibration and some more. It has a separate profile just for P38 and Bosch EDC. Looks to be the same sub meny layout as the Nanocom Bosch EDC guide PDF ;Fueling, general and switching. Attached is a screenshot from one of two fueling menus.

Pretty good device. Can do a lot with a lot of different makes and models. Handy when friends call with errors on dash..

 

[brianp38dse]

Just look that one up very good price for what it does and more usefull than Nanocom if you have other motors

 

[Datatek]

Thanks for the tip.I did disconnect the hose and tried but only in neutral. Did also try with the MAP plug disconnecte. No difference. I will try to run the car on the road tonight without the hose connected. My money is on the FIP but I´d love to be proven wrong on this instance..

If unplugging the MAP sensor makes no difference, it sounds like the MAP sensor may be faulty,

 

[Datatek]

I was curious and took of the top lid of the pump and looked at the potentiometer arm. It moves with spring tension but smooth thru out its travel. I was scratching my head a bit and wondering if the quantity adjustment inside would rectify my weird injector actual vs injector set point difference but this is my first time working on this type om engine and pump. I´m just an office guy thinking - how hard can it be.. So I´ll try to fiddle as little as possible with the inside of the pump at this moment.

An injector actual vs injector set point difference seems to be normal from what I have seen.

 

[Stavros1983]

An injector actual vs injector set point difference seems to be normal from what I have seen.

Ok! Even showing 0 at idle for injector (timing) actual?

 

[Datatek]

Never seen zero.