running problems

[jonnyshaw49]

hi i posted a thread on here a few weeks ago, i have been having problems with getting my gt turbo idling correctly, the engine has had a full rebuild, new oil cooler, alloy radiator and intercooler, new turbo, everything basicly. the car wouldnt idle untill warm, had to run the engine on choke at 2500-3000 revs untill fan kicks in half way temp. then the car would idle but lumpy and when you tapped the throttle would hesitate and cut out. i then rebuilt the carb all new gaskets, set acc pump arm to 5mm with drill bit, cleaned all jets, im running a 120 main jet i have t25 turbo and headwork, cam.the car wouldnt run at 1000 rpm unless the mixture screw was wound out 5 turns. since the carb rebuild i have set the mixture screw to 2 and half turns and it now idles but still slightly lumpy and doesnt hesitate when you press throttle. however it still doesnt idle untill fully warm and there is a strong smell of fuel seems to be coming from near the fuel pressure regulator,and its still slightly hunting. i hav checked for all leaks using carb cleaner and fairy liquid and no leaks, changed aei unit. anyone got any ideas as its doing my head in. went round to a lads house near me who has a gt turbo hadnt been run for a few weeks and his cracked up first time with no choke and ran perfectly.sorry for the big essay but its so anoying lol what can a faulty fuel regulator cause?

[michael tierney]

breather restrictor?

[jonnyshaw49]

I'm running breather cup mod and catch tank dun away with one way valve in manifold what do u mean by restrictor?

[Shane P]

I'm running breather cup mod and catch tank dun away with one way valve in manifold what do u mean by restrictor?

[James5]

I'm running breather cup mod and catch tank dun away with one way valve in manifold what do u mean by restrictor?

[jonnyshaw49]

yes that restrictor has been done away with as im running cup mod and catch tank. anyone any other ideas? could top dead centre sensor have anything to do with bad idle?? also can a faulty fuel pressure regulator cause lump idle??? thanks

[James5]

I reckon this is still carb related, have you got another known working carb that you could swap and try, or a spare cabr base that you could swap for your exisiting base.

[jonnyshaw49]

i tried it mate , but the other carbs arent in too good condition and this one has been fully rebuilt, i tried one carb and ran same but still have two others. i have tried swopping the jets from carb to carb but no difference, i get a strong smell of fuel near the fuel pressure regulator could this be the problem? I havnt got a spare to put on. i have tried spraying the carb base with carb cleaner running but no change in note so dont think any leaks. im thinking fuel pressure reg as its one of the only things havnt changed but dont want to be wasting cash. any way of checking fuel reg?

[TrixNFlix]

i tried it mate , but the other carbs arent in too good condition and this one has been fully rebuilt, i tried one carb and ran same but still have two others. i have tried swopping the jets from carb to carb but no difference, i get a strong smell of fuel near the fuel pressure regulator could this be the problem? I havnt got a spare to put on. i have tried spraying the carb base with carb cleaner running but no change in note so dont think any leaks. im thinking fuel pressure reg as its one of the only things havnt changed but dont want to be wasting cash. any way of checking fuel reg?

If you think its your fuel pressure reg, you can check its working by t ing into the fuel line before it goes ito the carb and fitting an old boost gauge. Tie this onto your window wiper as you dont want the fuel in the cockpit . At all times the gaue should read 4 psi above boost pressure. At idle it will be 4psi, i.e. 12psi boost= 16psi fuel pressure. If this is what you get there is no problem with your regulator. Make sure all fuel conections are tight if you try this.

[jonnyshaw49]

i will try this mate thanks alot, but can only try it on idle as car isnt mobile yet. so im looking for 4psi at idle.what if the psi is over or under is both ways faulty? try this tomorrow.

[TrixNFlix]

Yep faulty. You could put the front on axel stands, and change through a few gears if you have the balls to do it.

[jonnyshaw49]

the front is on bricks lol drivers shaft is out just passenger side in. should it be ok???

[TrixNFlix]

the front is on bricks lol drivers shaft is out just passenger side in. should it be ok???

Ive never tried it with one out, need the knowledge of one of the more experienced guys on here, But it might be a bit un balanced if nothing else

[michael tierney]

if u hav'nt got good vacuum at idle u should check your valve timing again!!

[jonnyshaw49]

what should the vaccuum at idle be mate thanks alot for ur help

[michael tierney]

should be about 15-20in/hg on ur vac/boost guage

[jonnyshaw49]

hi ive checked the fuel pressure regulator, at idle its reading just over 0.3 bar which is arounf 4.5 psi does this seem ok or should it be bang on 4 psi? going to check the vaccum now

[jonnyshaw49]

i have checked the vaccum at idle on 2 different boost guage and both are stayin at 0 on idle i have the guage plumbed into the driver side of carb onto the double t piece. what does 0 mean for vaccum at idle is it valve timing like micheal says. thanks

[Markey Mark (BD)]

You won't read vacum on the double T-piece as its before carb, you need to plumb the boost gauge into the AEI vacum line and measure it there.

[jonnyshaw49]

yeh just realised this mate, it needs to be into manifold so ill plu,b it into the aei line, which pipe is best for the boost guage to stay in permanently for most accurate reading?

[Markey Mark (BD)]

The AEI pipe