Slow to start when warm

[Jim Bowen 1]

Noticed this on my VR since getting it back.

 

Starts gets from cold, but when warm, say i've stopped and popped into a shop and then come back out.

 

Car can take more cranking to start and when it does it slowly splutters into life, giving it a quick tap of the throttle helps get it up to a proper idle.

 

Could this be fuel pump related? Its about the only thing left to change.

[Jim 1]

Would be interested to know this. Certainly not an uncommon VR6 quirk and have seen it myself on a few cars.

[g0ldf1ng3r 13]

Noticed this on my VR since getting it back.

 

Starts gets from cold, but when warm, say i've stopped and popped into a shop and then come back out.

 

Car can take more cranking to start and when it does it slowly splutters into life, giving it a quick tap of the throttle helps get it up to a proper idle.

 

Could this be fuel pump related? Its about the only thing left to change.

 

that used to happen on the gf's storm but has never happened on my VR

 

it still did it even after cam sensor, coil pack, magnecor leads, plugs etc

 

also, as per one of my earlier posts, the manual says never to give throttle when starting as can cause problems.....http://the-corrado.net/showthread.php?93383-Back-to-my-VR6-again-but&p=1096088#post1096088

[robrado974 1]

It maybe more return valve related . opologies if it was you who fitted a return on your pump Jim , I can't remember . However I don't think the fuel would leave the rail that quick (in and out of a shop) . Half an hour to an hour Maybe . If it was the pump or the valve I think you would have problems from cold too . I'm just trying to narrow it down , why would it start fine from cold and struggle from warm if both parts needed replacing ? . I think it would struggle all the time . This also would rule out the FPR, as you would have the same problem , hot or cold . Opologies again , but I'm sure that when I've followed your thread , I read that you had changed the senders ? .A sketchy sender to the ECU , will make problems when starting .

[g0ldf1ng3r 13]

that used to happen on the gf's storm but has never happened on my VR

 

it still did it even after cam sensor, coil pack, magnecor leads, plugs etc

 

also, as per one of my earlier posts, the manual says never to give throttle when starting as can cause problems.....http://the-corrado.net/showthread.php?93383-Back-to-my-VR6-again-but&p=1096088#post1096088

 

bearing in mind the above - the slightly longer turning over before firing up when warm didn't cause any running issues on the gf's storm once it was started. it simply took a few more cranks than my VR

[seanl82 23]

Mine is similar. Never fails to start, but cranks for 5-6 seconds when warm before firing as opposed to 1-2 when cold. Its fine for about 15 minutes the there is a sort of window between 15-45 minutes where its a bit more difficult. Where in the fuel system would the non return valve be fitted, directly in front of the pump on the feed line?

[Dox 22]

Poor hot starting is a typical Coolant Temp Sensor fault.

 

Is your aux coolant pump working?

[robrado974 1]

Mine is similar. Never fails to start, but cranks for 5-6 seconds when warm before firing as opposed to 1-2 when cold. Its fine for about 15 minutes the there is a sort of window between 15-45 minutes where its a bit more difficult. Where in the fuel system would the non return valve be fitted, directly in front of the pump on the feed line?

 

This was the problem I had Sean . FPR was changed and the sender to ECU .

[g0ldf1ng3r 13]

Mine is similar. Never fails to start, but cranks for 5-6 seconds when warm before firing as opposed to 1-2 when cold. Its fine for about 15 minutes the there is a sort of window between 15-45 minutes where its a bit more difficult. Where in the fuel system would the non return valve be fitted, directly in front of the pump on the feed line?

 

exactly what the gf's used to do

 

I will contact her & ask if it persisted after she had her aux water pump changed - but then I know the temp sensor was not changed at the same time

[seanl82 23]

Aux water pump was replaced for new with no change. I have a spare sensor so will try that first, as sods law would have it I sold a fuel rail with fpr from a low mileage vr Las week!

[robrado974 1]

From memory , I think the price was around £85.00 Sean .

[jamin 0]

Aux water pump was replaced for new with no change. I have a spare sensor so will try that first, as sods law would have it I sold a fuel rail with fpr from a low mileage vr Las week!

 

Any update to this thread? I have exactly the same problem, starts 'on the button' when cold but once warm, takes a lot longer. I'm pretty sure I've also replaced my aux water pump, so hoping it's the sensor - where does this sensor live?

 

Would this show up as a fault on VAG-COM at all?

[robrado974 1]

From memory I can't remember which one it is , but your better off replacing all three in the block anyway . If you don't won't to replace them all , check out the cooling guide , this tells you everything you need to know . The vagcom will read these, mine was reading 76d all the time .

[jamin 0]

That cooling guide is most excellent, thanks for that. I ripped all three out last night, I've cleaned them up, but still going to replace them I think.

[fla 9]

I have the same issue although mine is now obd2. I assumed that it was something to do with the ecu immobiliser emulator I've installed? Perhaps not?

[Jim Bowen 1]

I've not really done much since posting the question, hardly using the car at the moment.

 

The only things that aren't new are:

-FPR

-Fuel pump

-ECU

-MAF

I'm actually struggling to think of anything else :lol:

 

I did fit the non-return valve into the fuel line (car already had one, but i made new fuel lines up so reused it)

[jamin 0]

Well, so far, so good. Replaced all three sensors tonight, cleaned up connectors etc. Ran the car for about 30 mins on idle, got the temps up to about 90 degrees, stopping and re-starting the car every 5 mins or so and it started just as it does from cold. It hasn't done that in a very long time.

 

I will repeat this at the weekend to be sure, but it looks like it might be fixed. Thanks again for the advice.

[robrado974 1]

Glad you got it sorted. One down , one to go . Any news Jim ?

[g0ldf1ng3r 13]

Well, so far, so good. Replaced all three sensors tonight, cleaned up connectors etc. Ran the car for about 30 mins on idle, got the temps up to about 90 degrees, stopping and re-starting the car every 5 mins or so and it started just as it does from cold. It hasn't done that in a very long time.

 

I will repeat this at the weekend to be sure, but it looks like it might be fixed. Thanks again for the advice.

 

cracking news - well done fella

 

fingers crossed Jim gets a similar result

[jamin 0]

cracking news - well done fella

 

fingers crossed Jim gets a similar result

 

Was an easy fix thanks to the advice on here!

 

yes, there is a good chance as its a common fault by all accounts.

[Jon_vr6 1]

So it is likely the blue one that was the cause

[jamin 0]

So it is likely the blue one that was the cause

 

Yes - that's the one apparently - I changed all 3 to be sure.

[jamin 0]

Well, so far, so good. Replaced all three sensors tonight, cleaned up connectors etc. Ran the car for about 30 mins on idle, got the temps up to about 90 degrees, stopping and re-starting the car every 5 mins or so and it started just as it does from cold. It hasn't done that in a very long time.

 

I will repeat this at the weekend to be sure, but it looks like it might be fixed. Thanks again for the advice.

 

Ok so its not completely fixed, grrrrr!!

 

I let the car warm up on idle on the driveway (its SORN right now) Sunday morning for about half an hour, fans came on, good I thought. I switched the engine off, waited a minute or so, restarted and its fine. Switched the engine off again and left it for around 15 minutes, tried to restart, engine was turning over fine, but no ignition for a fair few seconds, then suddenly is splutters into life.

 

So it starts from cold fine if left for days in between, but wont start fine if left for 15+ minutes once its up to temperature. Not sure what to try next TBH. Car is cranking fine so I am thinking its the ECU holding off the ignition - I might try pulling a spark plug out to check that during the restart - if that's fine then I guess its fuel related.

 

What is the FPR by the way? Fuel Pump Relay?

Edited January 25, 2016 by jamin

[fla 9]

fuel pressure regulator

[robrado974 1]

As Hasan said . This would be my next port of call .