Complete power loss - then clears

[PROVR6 0]

Ive got an annoying problem that is bugging me. When I start the car from cold and set off the car is fine for about 5 mins then it just loses power and grinds to a halt (the symptoms are a bit like when you run out of petrol). When it starts to happen you can change down a gear and floor it and sometimes it clears it but usually comes back.

 

It happened today and I pulled over, it dosen't stall the engine although it tries too but the revs shoot up as its about to stall. If I give it some gas the rev counter goes up but the engine note dosen't correpsond like its being held back.

 

I turned the ignition off and started it again but it did the same thing. Left it a couple of mins, started and it was completely fine. It dosen;t do it at all once the engine is hot. It now seems to do this everytime I take it for a drive from cold (Usually left standing for a week between drives).

 

I think it first started after I changed my engine cover plastics. I disconnected the leads at the coil pack end and when I replaced them I noticed the white plastic bit inside one of them was very loose and had to be quite precise about lining it up when reconecting. Do you think it could be lead related? Ive had a new fuel filter in the last year.

 

Is this something that could be diagnosed by plugging into Vagcom? All help appreciated guys&girls.

[boost monkey 0]

possible electrical or sensor fault?

[dukest 0]

mine does this if you try to accelerate too hard in the first couple of minutes when cold, its almost like it shuts down for safety. doesnt always stall and normally recovers quickly but had to wait with the engine off for a good 30 seconds the last time.

 

i guess its kind of flooding to an extent while on the cold map? actually, i'll let other people do the speculating as i'm really not knowledgeable enough! :)

[PROVR6 0]

Thats a very good description Dukest of my symptoms. My car did it when I first got it but it hadn't been driven in 4 months and figured it was that. It was fine all summer but seems to have returned.

 

Its a bit disconcerting when the power goes and cars line up behind you while you look for a safe place to pull over. Turn it off leave about 30secs and its fine and won't do it again all day. Its like a misfire but prolonged. It also feels like lack of fuel. Could it be fuel pump or would that cause problems all the time? Would Vagcom diagnose the problem?

[Valerian 0]

Which engine are we talking about here?

[PROVR6 0]

Sorry should have said VR6.

[fla 9]

is it just when the car is cold? What about once its warmed up? My thoughts are a faulty ecu relay. What else happens, do the dash lights all come on? Can you replicate this with the throttle cable when the car is at standstill?

[PROVR6 0]

I have replaced the fuel pump relay in the last month. It only does it when its first started from cold but not until about 2 mins worth of driving. No lights come on the dash until you pull over when the battery light starts to flicker when the engine tries to stall. If i wait about 30secs & start it again its usually fine, but I had to start it twice today to clear the problem. It starts up very easily.

 

The problem dosen't occur when idling and engine revs cleanly when you pull the throttle form within the bay.

 

When it starts to happen you can't acclerate properly and can't get over about 50mph. If you drop a gear & floor it in anger it does accelerate after an initial hesitancy (like turbo lag) but once you change up you can't accelerate and have to pull over and stop.

 

Im thinking it could be either ignition leads, coilpack or fuel pump but its weird that it drives without fault after the initial problem.

[Paulhan 0]

Have you thought it might be the catalytic converter. A bit of mine broke off and would partially block the exhaust. A piece of converter the size of a plum dropped out of the exhaust and everything worked again.

[G60SC_Stoney 0]

my VR6 also does this when cold, sualy on the way to work in the mornings when the negines been on for about 30 seconds, does feel like a fuelling problem, going to give her a good service in the next few weeksand replace a load of parts so we will see what happens after that!

[PROVR6 0]

Finally got round to cleaning my MAF and ISV. Took the car for a run and all was fine. That dosen't mean to say its cured the problem as some days it dosen't do it.

 

Paulhan: The Cat is a posibility and I do have a spare which I thought I was going to need to pass emissions on the MOT but didn't need it. I might give that a try. I have driven other cars where the CAT has failed and they were down on power but would still accelerate. If it was the CAT would it not do it all the time?

 

Stoney: Glad Im not the only one, but sorry yours does it too.

[samthegram 10]

Funny, mine does the exact same thing but is a 2ltr 16v. I have replaced rotor arm, dizzy cap, o.e leads, plugs ,coil pack and battery! The only ignition part i havn't changed is the ignition amplifier which is on its way and hopefully will cure it. I sympathise with you 'cos it is well annoying :mad2:

[PROVR6 0]

Had to use the Car for work all this week as my missus car failed its MOT. First day it had the hold back but Ive worked out I don't have to stop the car, If I just floor it when it starts to happen it clears after about 3 goes.

 

The rest of the week it did not do it once, so it could be related to the fact that the car stands for a week between drives???

[markrtw 0]

Blockage in the fuel filter?

[PROVR6 0]

It Had a new fuel filter about 6 months ago. When the garage changed it they said there was a hell of a lot of shit in there and the fuel lines. They ran quite a bit of fuel cleaner through the system and Ive also used a lot of redex which I would have thought would have cleared any blockages.

[dr_mat 0]

If you get VAGCOM on it you'll see if there's any faulty sensors. Most likely is a temp sensor so the engine is running on in cold-start mode beyond when it needs to. You can read off the values live so it should be pretty obvious.

So the other related symptoms would be overfuelling and bad economy.

[markrtw 0]

Possible that if there was a load of crap in the bottom of the tank, that more has washed down into the system? It's a cheap/easy enough thing to replace. Redex will disolve deposits that clog up injectors, but it will not get rid foreign bodies in the fuel.

[markrtw 0]

From another thread...

" A VR6 will only stop if it receives no signal from the crank sensor or no fuel from the pump. Starting there is always a good start and then move onto the the associated items. Relays and the like. ""

[dr_mat 0]

The only sensible way to test the crank sensor is with an oscilloscope. You might be aswell to pick one up cheap on ebay and just swap it for fun. They're expensive new though..

[samthegram 10]

changed my crank sensor + complete dizzy and now it runs perfect, yipeeee :clap:

[ZippyVR6 0]

What did you use to clean the MAF please?

[boost monkey 0]

I think carb cleaner works pretty good.