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Starting Problem

cogs

By cogs,
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cogs Experienced

cogs

Posted
Posted

hey guys, I've just bought an R32 GTS-T and it's got a starting problem. The guy I bought it off told me that sometimes on cold mornings when you first start the car it sometimes takes a couple of tries to start it. He said it was because of the aftermarket cams not always being in the right position or something to kick over and it takes a couple of goes before they are in the right position? Now I dont think he's lying to me because I know him and he was honest with me about eveything else about the car, but it could be that he is wrong or mislead.

It started fine driving it home from his place after I bought it and has done so on a few other occasions but most of the time it wont start first try (and not just cold starts) and so now I just give it a bit of gas when I kick it over to "blip" the revs up and it will then hold idle and be fine.

What happens most of the time is you kick it over and the revs start to climb like it would normally but then the engine dies at around 200-300rpm.. but if you give it some throttle it is fine.

A mate of mine said it could be my starter motor?? I really have no idea, especially about the whole cams thing so I wanted to get some info from you guys.

The car has a bigger fuel pump (I dont try starting it till it finishes priming itself), an adjustable fuel pressure regulator and possibly bigger injectors (previous owner believed this and my mates say it would have to for the power its making).

Not sure what other info is relevant, could it be something to do with the battery, I'm not sure how hold it is and havent had it tested?

Any help would be greatly appreciated! I'm hoping it's not anything major!! :mad:

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blind_elk Grand Master

blind_elk

Posted
Posted

Well, someone has gotten hold of the prickly end of the pineapple. The cams don't have to get themselves "in the right position". The cams have a constant angular relationship to the crank, so they are either in the right position or they aren't.

Is this engine running aftermarket ECU? (if its making power, then it probably is).

What is the fuel pressure while cranking?

Does the water temp sensor for the ECU work?

Does the AAC valve work properly?

Does the Cold Start Air valve (under the inlet plenum) work properly?

BH_SLO32 Proficient

BH_SLO32

Posted
Posted

What fuel pump does it have? The bosch o44 pump in my previous 32 did not hold the pressure in the supply line once it was switched off. I could literally watch the fuel pressure drop when the engine was switched off. As a result the brief priming period offered by the ECU was not sufficient to build up system pressure resulting in multiple cranks to get the engine started. This is a good place to start looking.

Cheers

cogs Experienced

cogs

Posted
  • Author
Posted

blind_elk- Is this engine running aftermarket ECU? (if its making power, then it probably is).

No, still running factory ECU.

What is the fuel pressure while cranking?

Fuel pressure (according to gauge on regulator) while cranking is 60psi (which is what it is when its at idle). Pressure drops back to zero if engine doesnt kick over.

Does the water temp sensor for the ECU work?

Not sure how to check this?? I ran a check on the ECU and it came up with 55 (all clear).

Does the AAC valve work properly?

Not sure, will look into it.

Does the Cold Start Air valve (under the inlet plenum) work properly?

Will look into this also.

BH_SLO32- It's got a 550hp walbro fuel pump.

Thanks for the replies.

cogs Experienced

cogs

Posted
  • Author
Posted

I don't think so because it does it even when the car hasn't been left for very long.

For example, the day I bought the car it started fine driving it home then I stopped and got petrol and it took a few goes to start it again..

Most of the time I just "blip" the throttle as soon as I finish cranking the engine to make sure it starts fine.

If I dont give it any gas it will either

1) Revs climb to 200-300 then loses revs and engine stalls

2) Starts fine on its own

3) Car splutters at very low rpm (around 100rpm) trying to keep running but sounding like it will stall at any minute (I end up hitting the throttle to bump the revs up and then its fine and idles normally)

AzzurrA Grand Master

AzzurrA

Posted
Posted
3) Car splutters at very low rpm (around 100rpm) trying to keep running but sounding like it will stall at any minute (I end up hitting the throttle to bump the revs up and then its fine and idles normally)

you described what my car does in the mornings, right there.

has done for years

blind_elk Grand Master

blind_elk

Posted
Posted
Fuel pressure (according to gauge on regulator) while cranking is 60psi (which is what it is when its at idle).
WAY too much, particularly when combined with bigger injectors and a stock ECU. Spec is around 37.
cogs Experienced

cogs

Posted
  • Author
Posted
WAY too much, particularly when combined with bigger injectors and a stock ECU. Spec is around 37.

Yeh as I said not 100% sure if it has bigger injectors or not.

Car was apparently dyno tuned by previous owner about 2 weeks ago and fuel pressure regulator was adjusted to correct A/F mixture.

I can get a dyno sheet if that would help?

If 60psi is too much fuel pressure will it be running too rich all the time?

blind_elk Grand Master

blind_elk

Posted
Posted

Well, the pressure is almost double the standard pressure. So when the injector opens, nearly twice as much fuel is going to be injected. I'm surprised that running that rich it runs at all.

If they had to bump fuel pressure that much to correct the A/Fs, I'd be suspicious of the meter.

timheather Collaborator

timheather

Posted
Posted

Most 32s seem to act like this.... some of you may disagree, but after filling up from empty on boost98 (yeah I know heaps of you say it's bad, but I wanted to see for myself), mine seems to start heaps better now.... go figure??

  • 3 weeks later...
cogs Experienced

cogs

Posted
  • Author
Posted

anymore help people?

what should i check?

how do i check AAC, cold start valve etc. ??

"If they had to bump fuel pressure that much to correct the A/Fs, I'd be suspicious of the meter."

Car was tuned at 220rwkw @ 16psi when fuel pressure reg. was adjusted (to correct A/Fs). Would current fuel pressure be required for that boost/power level or do you still think A/F meter might be faulty? The guy I bought it off said the tuner cleaned the A/F meter.

I'm pretty sure fuel pressure was 60psi before, now at idle it shows 50psi.. and as someone else said, it drops pressure when car is off..

i.e. crank -> 50/60psi -> if engine doesnt start -> drops back to 0psi.

Car has 550hp walbro fuel pump.

I just need to know what I should be checking to try and fix this??

Thanks!

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