73 replies to this topic

[Chris P Duck]

Well a sad update to this thread http://www.vx220.org...-problem/page-8 Took the car over to Joe's and with Vockys help they kindly swapped over the manifold, SC and endplate. Turned out the endplate was bent/warped and you could see that it had been leaking there so found the vacuum leak Did a big (3 hour) mapping session on the way back and all seemed fine. Also did a quick log and the TB is now sitting at 10% (as it should) when warm at idle rather than the 6% it was before. So I'm pretty certain there is no longer any vacuum leak However went to start it again this morning (first cold start since all the bits were swapped over) and it's no improvement. Honestly could have cried/sworn/taken a baseball bat to the bloody thing! Again needed 3 LONG cranks of between 5 and 10 seconds each before it finally spluttered into life. Once started all is fine, it's not rough, it doesn't stall, it's not down on power. It also starts fine when it's not stone cold, it's only after its sat overnight that I get the problem. Before this I'd already changed the injectors (as they were maxed out) Changed the fuel pump relay (as this cured Bargi's problem and he had the same sympotms) Out of ideas now so would be great fun if anyone had any suggestions?

[vocky]

could it be a duff / faulty fuel pump ?

 

might be worth sticking a fuel pressure gauge on 

[CHILL Gone DUTCH]

Has Tip got a similar issue

[siztenboots]

fuel filter service history?

[Chris P Duck]

Thanks guys, in my head a duff fuel pump would cause more problems under full load at 7'000rpm than it would trying to prime, but as you say worth sticking a gauge on. Though I think there's some debate over what's normal for the Walbro? Some say it drops the pressure the instant it stops priming and some say it holds it? Fuel filter was changed less than 2000 miles ago. It definately started when it was supercharged Things that changed that day: Air filter and pipework (Don't see how this could cause a problem) ECU repositioned, loom extended Manifold (Now changed over) Charger (Now changed over) End plate (Now changed over) Fuel tank (Don't see how this could cause a problem?) Fuel pump Rad (Don't see how this could cause a problem?) Injectors (Now changed over) CC system (Don't see how this could cause a problem?) Throttle body Tmap sensor OBD Tuner (on spare ECU) Have I missed anything? If not looking at the list I guess the logical order of likeliness/ease to test would be: Fuel pump > throttle body > Tmap sensor > ECU/ECU wiring?

[CHILL Gone DUTCH]

I Do wonder if there is some kind of cold start issue

[CHILL Gone DUTCH]

Can you post up your log Chris Will see if I can see some similarities between yours and tips ( who is having similar issues ) Which is different to others

Edited by CHILL Gone DUTCH, 22 February 2015 - 12:03 PM.

[Chris P Duck]

Will do, I'll try to do it before work tomorrow so I can log the start when it's a problem. I think it's unlikely there's an issue with OBD TBH how many of us are there running it now (including our Dutch friends). 2 with an issue seems to low to draw conclusions! And there were 3 of us with "OBD Cold start issues" at the start of the old thread. Then the other 2 were fixed by non OBD related faults...

[Bargi]

The relay problem I had was with the charge cooler. In the end Peter sent me 3 different maps with different advance settings and one of them endes up working really well. Still not as good as the CS map at starting but miles better than it was. Send him your current map and ask him to do his magic.

[Chris P Duck]

The relay problem I had was with the charge cooler. In the end Peter sent me 3 different maps with different advance settings and one of them endes up working really well. Still not as good as the CS map at starting but miles better than it was. Send him your current map and ask him to do his magic.

It was Pete-r I was a thinking of that had cold start problems that was cured with a fuel pump relay. Didn't realise yours was cured with a different map Bargi, were you having similar cold start problems?

[Bargi]

Yeah check out my post about the weird cranking error. Pretty sure you were the first one to post in it

[Bargi]

Though I think there's some debate over what's normal for the Walbro? Some say it drops the pressure the instant it stops priming and some say it holds it?

Def drops instantly with Walbro on mine. By again no probs when on CS map.

It definately started when it was supercharged

So when you went to Dutch ECU? As I mentioned ping Peter. The only other thing I needed to do after I swapped was drop the plug gap to .75mm to solve stuttering under load. It shouldn't affect starting but hey its £6 from Halfords for the tool and who knows.

[CHILL Gone DUTCH]

Is this a issue with aftermarket cams ?

[Nev]

Are you sure your injectors are actually atomising the fuel, rather than letting it drip out? If you are having continuous cold start issues, be wary of allowing liquid fuel fall into the cylinders, in time it may thin the oil and cause bore wash. Just sniff the oil and change it regularly until you manage to fix the starting issue. Good luck.

Edited by Nev, 22 February 2015 - 06:21 PM.

[Chris P Duck]

yeah check out my post about the weird cranking error. Pretty sure you were the first one to post in it

I thought I'd looked there, last one I found from you was about using a different throttle body and checking the fuel pressure? Unless I missed one?

Def drops instantly with Walbro on mine. By again no probs when on CS map.

Ok, so when I test as long as it hits 3.8psi while priming, cranking and running then all is ok there? Even if it drops back to nothing instantly.

So when you went to Dutch ECU? As I mentioned ping Peter. The only other thing I needed to do after I swapped was drop the plug gap to .75mm to solve stuttering under load. It shouldn't affect starting but hey its £6 from Halfords for the tool and who knows.

I've already spoken to Peter and he sent me 3 adjusted maps, didn't seem to make a difference but I didn't test thoroughly as by this point I'd found the vacuum leak and (stupidly) thought all faults were caused by the same problem. Will ping him again as I'll need him to adjust my current map (which is set up for no vacuum leak )

Is this a issue with aftermarket cams ?

Another possibility I guess. I have aftermarket a cams yes.

Are you sure your injectors are actually atomising the fuel, rather than letting it drip out?

I've changed the injectors for a different type (and adjusted map to suit) the old type have been used by many as have the type I changed to, which were brand new. So although I don't know they're atomising, assuming they are being supplied with the correct fuel pressure I would assume all is fine there.

[Chris P Duck]

If you are having continuous cold start issues, be wary of allowing liquid fuel fall into the cylinders, in time it may thin the oil and cause bore wash. Just sniff the oil and change it regularly until you manage to fix the starting issue. Good luck.

Cheers for the tip!

[Bargi]

Is this a issue with aftermarket cams ?

Possibly. In my case it was no difference with std head and cams or Saab head and cams. There was an update Peter did for the high lift cams that made drivabilty a low speed much better, no difference in cold start though

[Bargi]

yeah check out my post about the weird cranking error. Pretty sure you were the first one to post in it

I thought I'd looked there, last one I found from you was about using a different throttle body and checking the fuel pressure? Unless I missed one?

Yeah, different TB made no difference.

Def drops instantly with Walbro on mine. By again no probs when on CS map.

Ok, so when I test as long as it hits 3.8psi while priming, cranking and running then all is ok there? Even if it drops back to nothing instantly.

Yep, Vocky also confirmed this as well Its right bloody annoying Mine wasnt as bad as yours though, was always first try but 3-5 seconds of cranking

[TheRealVXed]

When the car has been sat for a while (i.e. when it's stone cold...) perhaps all the fuel is returning to the tank.  Ergo when you go to start it, the pump has to pump the fuel all the way through the empty lines.  This could be something causing your issue.  After it's been sat and fully cooled if you undo the fuel pressure release valve do you get any fuel coming out?

[Chris P Duck]

Well that was unsuccessful! Borrowed a fuel pressure gauge but none of the adapters fitted. Thought I'd log the cold start and it started fine (literally 1.5s of cranking off the log) Not unusual for it to start ok, just a pain when I want to log it not starting!