diesel, poor acceleration, worse than expected!!

Does it need resetting that often then, what a con

Nanocom is a dedicated diagnostic unit that will read all the systems on a p38 especially the diesel ecu.

Have you by any chance done or had the pump top seals replaced? Sounds like the pump top could be out of place? I had to do mine. Unfortunately without the nanocom to help. I had no real acceleration after replacing the seals at first and had to readjust it again. Not to advise doing it without the diagnostic!

keithcanfixit said:

Does it need resetting that often then, what a con

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The revs at idle to 750 rpm? No, never. If you're having to do that you're masking a problem in my opinion. Unless someone has stuffed it playing with the ECU. However, working out what that underlying problem is very difficult without diagnostics and due to the age of the car it needs special stuff as ODB just won't communicate. The Nanocom is the best bang for your buck although Hawkeye and Lynx are cheaper and can do most things. Most people who buy Hawkeye end up getting a Nanocom later from what I've seen. Most people that buy Lynx just run themselves over.

Grrrrrr said:

The revs at idle to 750 rpm? No, never. If you're having to do that you're masking a problem in my opinion. Unless someone has stuffed it playing with the ECU. However, working out what that underlying problem is very difficult without diagnostics and due to the age of the car it needs special stuff as ODB just won't communicate. The Nanocom is the best bang for your buck although Hawkeye and Lynx are cheaper and can do most things. Most people who buy Hawkeye end up getting a Nanocom later from what I've seen. Most people that buy Lynx just run themselves over.

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First job he needs to find out why idle is so slow. A Nanocom will help him with that. If the idle value is set at 128 then it is highly likely the pump centre section has been removed and not fitted correctly. Unless the tacho is being misread, the engine should never run below 500 RPM it should stop. It is important to establish what the ECU idle value is set at and what fault codes may exist. That is the first job, speculative comments only confuse the issue. He needs to know the actuals not the maybes.

Thanks for your replies Guys, no nothing known regards pump as only bought car last week,quite a comprehensive service history with no mention of any work on pump, I presume you are referring to the fuel pump and not the air suspension one. Will my OBD 2 not give me any clues then, why would someone fiddle with fuel pump, are they prone to be problematical ?

A generic obd 2 will not ready anything on a diesel it needs very specific readers for that as said nanocom is the kiddy
If the top part of the fuel pump was leaking it may well have had a gasket kit and if its not done very carefully to get all the parts right in side ( there is a collar and pin set up that has to be spot on) and the pump top in the correct place we are talking fractions of mm here then the pump does silly things.

Thanks for tips, will start wading through list though it has been behaving itself for the last 2 days, maybe calm before the storm, who knows......

keithcanfixit said:

Thanks for tips, will start wading through list though it has been behaving itself for the last 2 days, maybe calm before the storm, who knows......

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See post #45 and take note or you will be going around in circles for ever. Good luck.

I had exactly this problem on a P38 I bought. After much checking of all the usual stuff on the engine I discovered the problem was low oil level in gearbox.

RC51Rider said:

I had exactly this problem on a P38 I bought. After much checking of all the usual stuff on the engine I discovered the problem was low oil level in gearbox.

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There are a few things low gearbox oil level can cause, but low idle speed is not one of them.

Agreed - I missed the low idle issue, I was referring to the apparent inability to pull away as described in the original post.

Thanks, was going to check all fluid levels as a matter of routine anyway and did wonder whether low oil in box would cause sluggish problem but the low tickover is strange especially as she ticks over smoothly,no labouring or stalling almost as if tacho is misreading output, is output to tacho a hall effect transistor sytem ?

keithcanfixit said:

Thanks, was going to check all fluid levels as a matter of routine anyway and did wonder whether low oil in box would cause sluggish problem but the low tickover is strange especially as she ticks over smoothly,no labouring or stalling almost as if tacho is misreading output, is output to tacho a hall effect transistor sytem ?

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Tacho is driven from Engine ECU at three beats per revolution.

Thanks Wammers

OH B>>>OCKS, battery has decided to give up the ghost tonight so now £115 lighter than I was when I walked through the door, just for future reference if anyone is selling a good working complete Nanocom suitable for my 2000 plate P38 2.5lt diesel in the future at a reasonable price please give me first refusal, many thanks

Good Evening Chaps, well having replaced battery and then alternator as it was shot have now turned to looking at and sorting out various oil leaks and stripped bolt thread on egr valve (helicoil kit is in the garage somewhere I know) but while doing this have noticed leakoff pipes on injectors are completely shot, have ordered knew braided pipe and new pipe to turbo while I am at it but what I would like to know is despite looking through RAVE are the leak off pipes just a push fit or do they have a clip system like previous diesels I have dealt with, cannot see clearly without actually cutting pipes off as braiding has unfurled masking ends, all help appreciated, many thanks

Just push fit, but put some heat shrink on the ends to stop them splitting and holds them on better, they are notorious for leaking even if new.

Don't get the cheap leak-off pipe as it will only last a year or so. You need the proper Bosch stuff. Even better if you can source the quality stuff from Germany.

The diesels are slow but yours sounds painful.

It's also ringing fuel starvation alarm bells. Broken down pipes, weak pump or just a dodgy fuel filter. Blocked air would also be showing same symptoms.

Just my thoughts..