pd 150 intermittent trouble starting

**rs250gpracer** · 01-05-2010,06:10 PM

MY car sometimes starts instantlly no matter if warm or cold, other times car has trouble starting, at first i thought it was only from cold start but yesterday i did a 30 mile drive then stopped at the chippy for food on the way home, the car was obviouslly hot when i stopped at the shop. 5 min in the chippy and it took 4 attempts to start ..... it throws smoke out of the back each time it has this trouble starting. its like it 'half starts' and fails to kick in proper. when its starting in this state the revs seem to have no effect at all. then after a few seconds its like something becomes unstuck and the engine changes note to normal and my accelerator works and the car is running as normal again.

any ides?

a fault was found but im not sure if this was from my boost pipes that ive just fixed ( i am definatelly NOT leaking boost now) .......

1 fault found
4 - air flow flap positioning motor (v71)

37-00 faulty
37-00 faulty

**rs250gpracer** · 01-05-2010,06:34 PM

Originally Posted by rs250gpracer

MY car sometimes starts instantlly no matter if warm or cold, other times car has trouble starting, at first i thought it was only from cold start but yesterday i did a 30 mile drive then stopped at the chippy for food on the way home, the car was obviouslly hot when i stopped at the shop. 5 min in the chippy and it took 4 attempts to start ..... it throws smoke out of the back each time it has this trouble starting. its like it 'half starts' and fails to kick in proper. when its starting in this state the revs seem to have no effect at all. then after a few seconds its like something becomes unstuck and the engine changes note to normal and my accelerator works and the car is running as normal again.

any ides?

a fault was found but im not sure if this was from my boost pipes that ive just fixed ( i am definatelly NOT leaking boost now) .......

1 fault found
4 - air flow flap positioning motor (v71)

37-00 faulty
37-00 faulty

ok i think the fault code is part of my climatronic system which seems to be working fine, once it did stick on hot for a day then seemed to fix itself, either way i dont think it has anything to do with my poor starting problem that is getting worse.

i dont know much about the EGR but can this stick when switching off the car and therfor cause trouble on next start, regardless if the car is hot or cold?

helppppp meeeeee im going mad!!!!!!!!!

**Crasher** · 01-05-2010,07:22 PM

I think you may have a clogged up EGR valve but it will not be the EGR itself that is causing the problem. There is a flap in the EGR valve body that shuts down the engine faster and if the EGR valve gets very clogged up these can stick shut. Start and stop the engine and you will se how it flips closed on shut down and then drops back again a second of two later, or at least it is supposed to drop back.

**rs250gpracer** · 02-05-2010,06:22 PM

Originally Posted by Crasher

I think you may have a clogged up EGR valve but it will not be the EGR itself that is causing the problem. There is a flap in the EGR valve body that shuts down the engine faster and if the EGR valve gets very clogged up these can stick shut. Start and stop the engine and you will se how it flips closed on shut down and then drops back again a second of two later, or at least it is supposed to drop back.

Thanks crasher, i will try and find the EGR flap then get someone to start and stop the car so i can see how it works. If i can find this stick shut just once then i will know its the problem.
Im thinking excessive carbon buildup could be from my car running too much fuel and not enough air for quite a while (boost leaks ... now fixed). It used to smoke a LOT of black smoke, now the boost leaks are fixed the smoke has cleared a lot, however i still have more dark smoke than i should have.

**Crasher** · 03-05-2010,01:27 PM

They clog up anyway, you can see the valve and operate the key yourself by reaching through the open door and sticking your head around the bonnet. I don’t have a pic at home.

**rs250gpracer** · 03-05-2010,08:37 PM

Originally Posted by Crasher

They clog up anyway, you can see the valve and operate the key yourself by reaching through the open door and sticking your head around the bonnet. I don’t have a pic at home.

Thank you very much crasher your advise is appreciated very much!!!!!!

I had a look, found the valve no problem, i pressed it shut by hand just to see if it stuck or felt rough and sticky ..... it stuck in on the 2nd press and i can feel a lot of crap that must be inside it. My start problem was as you said, when the valve sticks my car does not want to restart. at least now before i start my car i just pop the bonnet and have a quick look to see if its still stuck from the last shut down. If it is then i just unstick it and my car will start no problem.

So now i know for sure the EGR valve is blocked should i replace it with new or will it be just as good if i take it off and clean it, if it can be cleaned back to as new performance what kind of solvent do you use?

Thank you for all your help so far crasher

**Crasher** · 03-05-2010,11:22 PM

It depends on how you value your time against money or maybe your skin over money. Replacing the EGR valve costs about £160 genuine (from memory, less from places like GSF) for part number 038 131 501 AT but cleaning them is a sod of a job. I use paint stripper (after carefully unclipping the plastic valve) and then Traffic Film Remover but it takes a good couple of hours work and if I have to balance that against the cost of a new valve, the new valve makes more sense for the customer. Remember that paint stripper burns like hell if you get it on your skin. I used it last week to clean a 1.8T sump and even with three pairs of nitrile gloves it was burning my hands really badly.

**MagicMat** · 07-05-2010,11:58 AM

You manage to fix this fella?

I have a similar problem on my 115 TDI,

Sometimes from cold it just doesnt like to start, Its usually needs some gas while turning the key and that does the trick.

Things i've done:
- changed crank sensor
- New VW MAF
- New Starter Motor
- New Proper glow plugs
- Had the inlet manifold put in an ultrasonic bath to clean it.
- Cleaned EGR with a toothbrush and oil degreaser.
- For another fault i changed the injectors and seals

- Starting to think that i should check the shut down flap and maybe also have the EGR put the ultrasonic bath to make sure its properly clean.

Is there any thing else i could try crasher?

**rs250gpracer** · 07-05-2010,10:44 PM

Originally Posted by MagicMat

You manage to fix this fella?

I have a similar problem on my 115 TDI,

Sometimes from cold it just doesnt like to start, Its usually needs some gas while turning the key and that does the trick.

Things i've done:
- changed crank sensor
- New VW MAF
- New Starter Motor
- New Proper glow plugs
- Had the inlet manifold put in an ultrasonic bath to clean it.
- Cleaned EGR with a toothbrush and oil degreaser.

- Starting to think that i should check the shut down flap and maybe also have the EGR put the ultrasonic bath to make sure its properly clean.

Is there any thing else i could try crasher?

not fixed no but its been correctlly diagnosed, my egr valve is sticking in the closed position when i shut my car down, if its still stuck down when i try to start the car i will have big trouble starting it. as long as i check to make sure the valve is open before i start it and if it isnt then i just unstick it in 1 second with my hand .... car starts instant.

its just tempory untill i have a new egr valve fitted, im not cleaning it im going to replace it.

I very much doubt your trouble is the EGR, i dont see how yours can be sticking if you have took it off and cleaned it. mine will be far worse than yours ever was i think (its got so clogged up its visiblly sticking shut).

good luck with yours, maybe it could be a sensor somewhere or i have heard the trouble starting problem liek yours from injector seals.

warning i only know what i have learned on this site so dont run out getting new seals, i would continue to research if i was you.