1G running hell rough over 5psi

[RAd28]

hey guys, had to replace the turbos on my 1G yesterday, now she runs really rough when you approach 5psi, and really bad just over it, but it won't make more then about 6-7psi total... i'm THINKING, that the problem mihgt be the rear wastegate. when we installed it, we didn't have proper vacuum hose for the acctuator line, so we used something much smaller, i THINK this is causing the wastegate to open sooner, and so kills performance, this would also give the terrible sound it makes... am i right? or am i barking up the wrong tree??

[willwal98]

i'd be guessing air leaks.I don't think the thinner line would cause it to hold less boost because it's still the same pressue, if anything it would delay it becuase the smaller tube would restrict the flow. A small air leak would be hard to notice off boost but on boost it will become much worse (more air being lost, leak increasing in size). I'd check all the host joins, if you have the stock rubber ones they may have cracks in them, make sure the bolts for your air piping are sealing properly, those rear ones are hard to get to in an RA2#.

[CrUZida]

What are the plugs gapped to?
Is the fuel pump good?
Is the fuel filter newish?

[Hydra]

It sounds like a leak on the exhaust side just before the turbo's. I had a similar problem. Just make sure the bolts/nuts are tight and make sure the gaskets are sealing nicely.

[IN 05 NT]

maybe the vac liner is closing on itself under vac???

[mic*]

Id be looking for inlet leaks, then exhaust leaks. Leaking metered air will bugger up mixtures... But look for leaks in general.

Sorry to hijack the thread, but can anyone tell me what sort of flow the AFM in a gen3 1G-GZE will swallow before it maxes out? Is there a fuel cut on the factory management? If so at what point? Thanx

[willwal98]

no fuel cut that I am aware of and i'm pretty sure it will be 15PSI limit. The actual flow that results in I just don't know. I'm sure there are plenty of people on Toymods that will know.

[mic*]

I've heard of people playing with the spring in an AFM...

Isnt that just stretching the same sensor signal range out over a greater flow range...? In other words - inaccurate???

[willwal98]

true, would not recommend it. Basically once you have played with the spring it won't max out as soon, say 20psi but will only put in the same amount of fuel as at 15psi. You would need to adjust your fuel pressure or injectors or both to get the same amount of fuel in. Not worth the hassle IMO. If you have decent turbos, get an aftermarket ECU and run 25PSI

[mic*]

I have standard 1g-gZe. Supercharger has just been girfted with a new boss today to mount the classic falcon A/C pulley... However, most of the testimonys to this mod i hear are on 4A's - ie an SC12 charger. After sourcing the falcon A/C im thinkin this thing is tiny... Hoping the boost is not gonna be too high for AFM & ECU, and whether the efficiency (or lack thereof) is bearable...

[RAd28]

well i tried with a larger hose for the wastegate, did bugger all... i couldn't understand why it would cause the wastegate to open earlier, but i could see that if it WAS opening then it'd kill performance...

CrUZida - haven't touched anything there.. was running fine before the weekend (apart from a screwed turbo)

Hyrda - i'm inclined to agree with this one... i just don't want it to be... 'cause getting the turbos off in the first place was a **** of a job... hoping to find the solution elsewhere first...

IN 05 NT - doubt it... did the same thing with bigger hose...

Mic* - would a boost leak cause it to sound like a dog? the (horrible barfy) noise is coming from the rear of the exhaust... so on that point i tend to think it might NOT be a manifold leak.. 'cause i'm sure i would notice a manifold leak moreso coming from the engine bay...
hi-jacking bastard

[mic*]

Peoples' description of sound is the reason god gave us ears of our own each....

Hard to say mate but if the mixture is hella rich it "could" sound "barfy like a dog"... ?

Its difficult to find high psi leaks sometimes, coz you wont make much boost with the engine free-spinning - in other words, head under bonnet pulling throttle cable, and listening for leaks doesnt always yeild results...

[RAd28]

Peoples' description of sound is the reason god gave us ears....

No no... i'm pretty sure god gave us ears just to hold our sunnies up...

[Hydra]

Drive next to a brick wall with the window down Thats what clued me in on exhaust leaks before the turbo...

[willwal98]

just to confirm, are you sure the turbos you put on are good? If one is siezed or has a LOT of play it would cause spooling issues. I'd still be saying there is some air being metered that insn't making it to the engine. Exhaust leak is a decent explaination aswell.