VP V6 slight trouble starting when warm

[vpshtb0x]

My VP V6 starts first kick when cold. When it is warm it will start first kick after leaving it for under 5 minutes.. any longer than that and it will turn over for about 20secs before starting and sometimes takes 2 attempts yet, if I roll start, it fires immediately. Any ideas on what this could be? Thanks.

[Colby844]

Hi ya does sound a tad very similar to a recent problem of mine (VP V6 also) i changed the fuel pressure regulator and solvered my starting issue instantly! its on the back of left hand side fuel injector rail as viewing from the front- it needs an allen key to remove so if ya can find a second hand one in a wrecking yard etc keep this in mind

[pjdm1980]

Maybe CAS, if it's happening when it's warm?

[Hangman]

As above, for my guess.

[vpshtb0x]

Fuel pressure regulator is a possibility. I currently have a V8 reg in it as the original had split. The V8 one runs the same pressure but, it had been previously used when I put it in. I doubt it would be the CAS as it's been happening for a while and, usually, they get worse over time and I've tried the trick of pouring cold water over it before to see if it helped and the same thing happened. I hope it's not the CAS because I reallllly don't want to change it. lol. I've put it into diagnostic mode and it has given the all clear there. I was thinking it may have been the IAC valve... I checked it and it seems to be working although, it doesn't move much and I am unsure as to how much it should move. Thanks for the input, guys. Any other ideas are also welcomed.

[Jxw]

Fuel pressure regulator is a possibility. I currently have a V8 reg in it as the original had split. The V8 one runs the same pressure but, it had been previously used when I put it in. I doubt it would be the CAS as it's been happening for a while and, usually, they get worse over time and I've tried the trick of pouring cold water over it before to see if it helped and the same thing happened. I hope it's not the CAS because I reallllly don't want to change it. lol. I've put it into diagnostic mode and it has given the all clear there. I was thinking it may have been the IAC valve... I checked it and it seems to be working although, it doesn't move much and I am unsure as to how much it should move. Thanks for the input, guys. Any other ideas are also welcomed.

you won't be able to move the iac in/out by hand, with the bonnet open and just switching to ign without going to start can you hear it making a quiet grinding/whirring noise? it won't do it for long just when it's initially switched to ignition for a few seconds, maybe get someone else to turn it to ign and you listen near the tb ...... if so means it's at least working and moving when the ecu tells it to, without removing it and plugging it into a stepper motor driver/ecu test bench there's not easy way to tell, or try it in another car if possible

a blast of wd40/crc/inox sprayed into the hole from the air cleaner side leading to it won't hurt if it's possibly sticking.

all plugs to the engine making good contact? earth points not loose? fuses in the engine bay all clean and no corrosion? as metal expands when hot maybe there's a bad contact that is ok when it's cold but not once warmed up and making a slightly bad connection causing issues when the starter is drawing current causing a voltage drop....

[strgas]

any signs of black smoke on hot start out the exhaust pipe ? sounds like the fuel pressure reg is leaking or injectors are dribbling when hot

[vpshtb0x]

That's how I tested the IAC.. it moved about 2mm. I've been over all the plugs, fuses, relays etc. I do occasionally get a little puff of smoke on start up. Think I'll change the fuel reg tomorrow and see what happens. I'll let you all know how I go. Thanks for the help!

[vpshtb0x]

Well, been a hell of a fortnight! Hit a roo on the morning I posted last so, I'd been concentrating on getting that fixed, then my computer decided it didn't want to start up, then I bought a VS wagon and have been toying around with that so, I haven't gotten around to my intermittent starting issue as yet. Hoping to get time to do it over the weekend but, currently, I'm more interested in getting the VS right so I can get it on the road and sell the VP.

[Vlad01]

Leaking injectors.

Mine does this after I got my injectors reco'd. I took them out and found 4 out of 6 leak where before I go them exchange reco'd they did not leak.

some reco huh. I complained and had my actual original 80,000km injectors reco'd for nothing and then they leaked after as well where before they didn't.

Don't know what this guy did to them but I just have to put up with it now.

It stopped doing this hard to start thing for 6 moths or so but when I had to take the tank out to fix the return line I found the 40,000km old pump's check valve failed, so I put in a new pump again and the hard to start thing came back straight away so it a definite injector leaking symptom for it to be hard to start after leaving it for a little while when its hot.