Vr6 slow starting / not starting first time

[pedrovr6 0]

Hi All,

Have read through similar topics but none seem to mention the exact problem that I have - recently bought a '94 Auto VR6, & am having issues with it starting slowly. It turns over for about 7/8 seconds, then I stop & turn over again & it starts pretty much straight away.

So I'm assuming it's a fuel related problem....people seem to mention fuel filters, fuel pumps, fuel pressure regulators, or fuel lift pump (assume VR6 has one of these?)....

Any advice/thoughts would be much appreciated!

Cheers!

[Pete 0]

I put a new pump in, and also had to change the filter and filter the fuel as the old pump was breaking up with some swarf in the tank.

 

Seems ok now, what happens if you go to ignition, and leave a few seconds before starting? fuel pump or valve will be orted then as its priming before you start it.

[pedrovr6 0]

Thanks for your reply....I've tried leaving ignition on for 10-15 seconds & then trying to start but doesn't seem to make much difference.

 

Although if the car has been running, I switch it off then then try to start again straight away it's fine, just if I leave it for 10/15 mins then try to start it won't start first time/starts very slowly....

[goozie 0]

I have been having the same problem as you pedro, and have done for a while, i did try putting another blue top temp sensor in which i got second hand and that did seem to cure it for a while, but the problem came back!! so this week i am going to purchase a brand new one and go from there, i will keep you posted with the out come.

[pedrovr6 0]

Ok thanks...yeah, be good to know if that solves the problem for you.

[dr_mat 0]

If you have access to a VAGCOM diags system, your first step would be to do a thorough check out using that. Look for solid faults (while the engine is running), check the measuring blocks outputs from the various temperature sensors, MAF and lambda to make sure they look sensible.

If you don't, pull a spark plug, check if it's sparking during that startup cycle, see if the car stinks excessively of fuel, check your MPG to see if it's burning masses or not. How does it run once it's going? Ultra-smooth but a bit down on power might imply it's over fuelling a lot.

You can also try an ECU reset, but that's will only help as a last resort if you *know* you had a faulty sensor that the ECU has adapted to. Otherwise it'll just make things worse for a while ...

[pedrovr6 0]

Thanks mate...don't have access to a VAGCOM but will try what you have suggested with spark plug. Once it's going it seems to run fine, smooth idling & pulls well. Doesn't seem to stink of fuel, and MPG is 20-22 round town, 32-35 on a run....not sure if that's good or not to be honest!

[dr_mat 0]

Those MPGs sound about normal tbh, nothing wrong with that.

[tony_ack 0]

Could be the crank sensor on its way out.

[dr_mat 0]

Crank sensor tends to go the opposite way - it'll die on you whilst driving and won't restart until things cool down. I don't think that's the problem here.

[floppyman 0]

Pedro are you from portugal?

[easypops 8]

Mine does exactly the same, been like that for a good while(years) and i just got used to it , so would like to see if you find out any answers :)

[pedrovr6 0]

Well I'm going to try a few of the cheaper/easier options first, so will let you know if I have any joy!

 

Floopyman, no I'm not from Portugal....my names Pete but I think PeteVR6 was already taken when I registered!!

[Kevin Bacon 5]

Sounds like either the pump not pressurising quickly enough, or the fuel pump relay not triggering whilst cranking.

 

If it starts straight away when hot, I'd lean more towards the pump as it means the fuel rail is filled and up to pressure. Clearly the pump is taking it's time to fill it up from cold, but it also has a non-return valve in it, so maybe that's just a bit sticky and allowing drain back?

 

Could also be a slight weep on the pressure supply hose (quite common) which is also reducing rail pressure over night.

[VR6Joni 0]

I've fixed this problem twice now, as Kev said above, its a leak on your injector rail. One of several things can cause it: fuel hose to rail connection, injector seals or the injectors them selves.

As mentioned many times before, when the car is stopped the fuel in the rail expands/boils with the engine latent heat, when it cools back down the fuel contracts again drawing in air, if you have a leak path its a matter of finding it. I suspect most problems are leaking injectors or you would see/smell signs of the leak when the engine is running, its probably also a reason fuel pumps only run continuously when the engine is running.

I'd go this order:

1)Reseat fuel hoses onto rail, cut a few mm off to be sure of good reseal.

2)Injector seal replacement (cheap o-rings), this is a ball ache by the way because if the injectors have not been removed before they will be stuck solid. Clean the rail injector seating very well!

3)Refurb (ultrasonic bath clean) / replace injectors.

[dr_mat 0]

Sounds like a good explanation to me! Check it out..

[pedrovr6 0]

Cheers for all the advice guys...should keep me occupied for a while! Will let you know if this sorts the problem...

[Pete 0]

Any update on this? I've had a new pump hich fixed things for a while but it's come back over the last couple of days.

[pedrovr6 0]

I haven't tried what Joni has suggested as yety, but have been putting injector cleaner in the fuel over the last week or so which seems to have helped a bit...doesn't start immediately, but certainly quicker than it did.

 

So may go down the injector cleaning route first....

[Pete 0]

Fuel pressure regulator also been suggested...