Author Topic: More running issues  (Read 3213 times)

Offline z3i

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Re: More running issues
« Reply #15 on: March 26, 2013, 08:51:53 pm »
i did mone yesterday the piket way with  pressure guage and some hose through the window far from safe but it worked and ill remove it now all you need is a schreider valve fitting (excuse the spelling!) some r6 rubber hose from ebay at around £3 per meter and a guage that reads up to 100 psi you should have 40-45 psi at idle and plus whatever boost youre running at full boost.

Can i just attach my foot pump to it and put in the car? :P haha

Offline z3i

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Re: More running issues
« Reply #16 on: April 02, 2013, 08:44:12 pm »
bit of an update, been really busy as ive been breaking down lots due to dodgy wiring, relays and other reasons

put a full tank of v power in along with the new fuel filter and doesnt pink, so advanced the ignition to 5 deg before tdc and it pinks but know where near as bad, so bit of an improvement

adjusted the c02 pot today was reading 0 so adjusted it to 550 ohms bang on and the car will only hold an idle for around 5 seconds and then it cuts out, even on choke. starts fine though

so screwed it all the way in and it idles normally. what does this mean? is the lower the resistance the more fuel?

Offline z3i

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Re: More running issues
« Reply #17 on: April 08, 2013, 08:26:31 pm »
Checked my fuel pressure and it was 2.5bar at idle with the fuel regulator vacuum pipe plugged in and then rises to 3 bar with it unplugged
haynes states it should be 1.9 plugged in and 2.5 unplugged
also when i rev the car with the pipe plugged in the fuel pressure drops to under 2 bar of pressure. even under hard revving. surly the engine would need more fuel at higher rpm?
Then if i unplug the vacuum pipe and rev the engine, the gauge stays bang on 3 bar, whether its at idle or 6k rpm
is this normal?
could the regulator be at fault? is there much to go wrong with them?
im going to check my lift pump out and clean the gauze filter, and more than likely get a new inline pump as mines seen better days
any help would be much appreciated

Offline dub-disaster

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Re: More running issues
« Reply #18 on: April 08, 2013, 08:52:44 pm »
with the vacuum pipe plugged in you should definantly have more fuel pressure than that with positive pressure in the manifold.

remeber that the fuel regulator works on pressure and is not rpm related. The only thing that may have an effect on this is at idle rpm somtimes the alternator puts out a lower volatage untill you revv the engine and the voltage regulator cuts in to maintain a steady voltage.

yes its normal for the fuel pressure to stay at 3bar when the vacuum source is removed.



sounds like either the fuel pump is at fault or you havnt connected the correct pipework to the regulator. I think it may be the latter because i find it hard to belive that the fuel pump can deliver 3bar no problem but when you add a vacuum source it drops below two bar when infact it should rise not fall.

If i where you i would double check the vacuum plumbing, if you can t into the vacuum supply with a boost guage and prove youve got positive pressure there when the pump is dipping below 2bar then theres either something wrong with the pump or the regulator.

Where are you measuring fuel pressure from? Have you measured the pressure when the car is pinking ?
« Last Edit: April 08, 2013, 09:13:16 pm by dub-disaster »

Offline z3i

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Re: More running issues
« Reply #19 on: April 08, 2013, 09:23:21 pm »
No, i will do that next, i need to get a longer hose
All readings were at a standstill though there should still be a positive pressure?
theres a few vacuum tubs that im unsure where they go, one from the bottom of the throttle body is blanked off, and one on the main vacuum suply is blocked off
i haven't got a boost gauge, i took it out as it looked tacky, but i definitely need one so will plug it back in soon


Offline Andy

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Re: More running issues
« Reply #20 on: April 08, 2013, 09:47:09 pm »
Haynes specs are bollocks for the G40 in this instance.

The FPR will regulate to 3 bar relative to its reference of inlet manifold pressure. If you unplug the vacuum hose, then the reference pressure is atmospheric - so it stays at a fixed 3 bar.

If you're idling the engine (no load = no boost) the inlet manifold is in vacuum, so negative pressure - maybe around -0.5 bar. Therefore the gauge pressure you'll see is less than 3 bar. Your reading of 2.5 bar in this instance sounds about right (3 bar - 0.5 bar = 2.5). When you're revving the car in neutral you'll get more vacuum - hence the drop to 2 bar.

None of the fuel pressure tests you've done suggest any issues to me.

The way to check for sure is to load the car up with the pressure reg connected and see what the fuel pressure does. Running a bar of boost you should see a gauge fuel pressure of 4 bar (3 bar regulator + 1 bar manifold pressure).

Offline z3i

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Re: More running issues
« Reply #21 on: April 08, 2013, 10:00:54 pm »
Haynes specs are bollocks for the G40 in this instance.

The FPR will regulate to 3 bar relative to its reference of inlet manifold pressure. If you unplug the vacuum hose, then the reference pressure is atmospheric - so it stays at a fixed 3 bar.

If you're idling the engine (no load = no boost) the inlet manifold is in vacuum, so negative pressure - maybe around -0.5 bar. Therefore the gauge pressure you'll see is less than 3 bar. Your reading of 2.5 bar in this instance sounds about right (3 bar - 0.5 bar = 2.5). When you're revving the car in neutral you'll get more vacuum - hence the drop to 2 bar.

None of the fuel pressure tests you've done suggest any issues to me.

The way to check for sure is to load the car up with the pressure reg connected and see what the fuel pressure does. Running a bar of boost you should see a gauge fuel pressure of 4 bar (3 bar regulator + 1 bar manifold pressure).

ah thanks for that, makes sense now :) dont trust the haynes book of lies anymore
ok, will get some more hose and try again under boost (with a gauge) and driving

Offline Andy

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Re: More running issues
« Reply #22 on: April 11, 2013, 08:34:07 pm »
Replied to your last email mate - sounds like you've got a chip for G60 injectors in there, so I'd upgrade the standard injectors ASAP.

Offline z3i

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Re: More running issues
« Reply #23 on: April 11, 2013, 08:56:00 pm »
Replied to your last email mate - sounds like you've got a chip for G60 injectors in there, so I'd upgrade the standard injectors ASAP.

Your a legend mate! thanks for your help, i said to everyone i thought it was running lean as the spark plugs were white and people at work were just like "they look normal"!
i think some idiot has had a go with my car! when i got my injectors cleaned recently two of the pintle caps were missing which i thought was really strange :S

thanks again, congratulations on the baby :)
and july time would be good. i should have everything i need for it by then
Hopefully Tom still has his cleaned set of g60 injectors :D
Taylor