White VR-4 difficult to warm start

[bradc]

I noticed this when I first got the car, I thought it could be a weak battery at first, or possibly fuel (when it was delivered it was bone dry and I threw in 10 litres of 91 to get me down the road), but I've reset the ecu and tried both BP's 98 and Gull's 95 without any difference.

Basically when the car is cold in the mornings (ambient around 10-15C) it starts fine and springs into life like any other VR-4, and the tappets are going like mad :)

When I have been driving the car, turn it off and turn it back on in the next half hour or so it starts fine as well, just as usual.

The time it has problems is when the car hasn't been running for hours, and when the ambient is 20C up to 25C (thats the highest the NZ weather has given me to try with so far).

It turns over ok, sort of starts then splutters a bit for about 2-3 seconds, then starts up. Any idea's?

The cambelt was done at 91km and it is at 119km now. It has been filled with 15w40 oil at 115km, the air cleaner is free and the car performs perfectly well without any problems at all once it is running.

Thanks in Advance

[StunEm]

It turns over ok, sort of starts then splutters a bit for about 2-3 seconds, then starts up.


It sounds like a hot soak sort of issue, the main problems it may be is a
-faulty fuel pressure regulator
-faulty fuel pump
-leaking injectors

Check the vacuum line onto the fuel pressure regulator as it may slowly leak fuel back to the fuel tank.
The fuel pump can be checked with fuel pressure and fuel flow tester.

hopefully others here may have had similar issues and they may be able to suggest possible problems.
Just wanted to add my two cents worth.:idea2:
Good Luck.

[bradc]

It does run fine under full throttle though. The idea of fuel pressure regulator letting fuel go back into the fuel tank does make sense though.

I've got a spare stock fuel pump and fuel regulator out of my purple facelift, so I will swap those across and see what happens :) Thanks for the idea's

[Kieran]

I've known a few pre-facelifts do this, but it's usually when they've been run for a bit, shut off and then re-started. THe symptoms are like 'heat evaporation' that you used to get on Carbed cars (R5 GT Turbo anyone?!).... Cleaning the idle stepper motor on mine seemed to solve that one.

[bradc]

I'm going to swap my facelift ecu in too, but I can't imagine that would fix it. I had idle stepper motor problems on my purple one, it would idle all over the place and sometimes stall. This car never does that, also if I step on the throttle it still takes a bit of time to start, so surely that would mean the idle stepper motor isn't the problem.

[KHK]

brad, what's the final finding?

[bradc]

haven't bothered to try and fix it!

[KHK]

haha, should not be your style

[Gowf]

I have had the same issue. After a drive, start it up and it idles really low, and sounds like its off a cylinder, but as soon as you rev it its fine.

I worried about it, and then forgot about it. Thankfully its not occured that often so im continuing to not worry about it until it gets worse. Would be interesting to know what it is though

[KHK]

i seem to have similar experience for several times, long time ago
but disappear without any reason

[bradc]

Mine doesn't do that, once it starts it is perfectly fine and runs at normal rpm, it is getting it started that is sometimes the difficult part.

My first attempt to fix it will be changing the plugs and then see what happens.

[ANTHONY]

I have had the same issue. After a drive, start it up and it idles really low, and sounds like its off a cylinder, but as soon as you rev it its fine.

I worried about it, and then forgot about it. Thankfully its not occured that often so im continuing to not worry about it until it gets worse. Would be interesting to know what it is thoughthats what i'm getting..

[d i c k i e s]

whoa? 5 months ago.

[orionn2o]

I get it too... but only on hot days.

And we aint had many this year!

[Turbo_Steve]

Those of you with a 'slight misfire on restart sometimes' sounds like an HT problem, either a faulty coilpack or (more likely) some moisture getting in next to the plug. It rattles around the bottom of the plug bore harmlessly until it gets warm, starts to vapourise, can't get out, and condenses on the el-ectrics as things start to cool. Then you get earthing where you shouldn't and
-misfire!-. Just a thought.


Brad, it's almost definitely a problem with the fuel reg/pump. My old would do it, quite often, and it was a teeny vacuum leak to one of the regs preventing it building up pressure straight away. It would go away on cold mornings, because the metal would contract where the split was, and the gap would close!