1G Fuel Cut

[uglytalon92]

Hey I have a 92 Talon TSi awd. and its apparently was built, we just bought it, and when i take off its a nasty pull just nasty (fast) then at about 5k it hits a freaking wall almost like a rev limiter at 5k.

It was boosting at 23psi, so we turned it down to 18 and still does it. I'm gonna turn it down to 11.5 tonight and see what happens but I know it has a bad exhaust gasket where the downpipe connects to turbo and it might have a few small holes in ic pipe clamps.

So could I have fuel cut and boost leaks?

We replaced fuel pump fuel filter. Its got a Walbro 255 with 72# injectors and a 3in MAF. Stock TB. Built internals. Built head with 272 cams, and basicly everything else was neglected. (from the other guy we bought it from) We've got it to run but at 5k it just bucks hard and wont accelerate like a governer or rev limiter.

Any ideas? if you guys need more info to help me troubleshoot just ask.

 

[XiKeiyaZI]

Hey I have a 92 Talon TSi awd. and its apparently was built, we just bought it, and when i take off its a nasty pull just nasty (fast) then at about 5k it hits a freaking wall almost like a rev limiter at 5k.

It was boosting at 23psi, so we turned it down to 18 and still does it. I'm gonna turn it down to 11.5 tonight and see what happens but I know it has a bad exhaust gasket where the downpipe connects to turbo and it might have a few small holes in ic pipe clamps.

So could I have fuel cut and boost leaks?

We replaced fuel pump fuel filter. Its got a Walbro 255 with 72# injectors and a 3in MAF. Stock TB. Built internals. Built head with 272 cams, and basicly everything else was neglected. (from the other guy we bought it from) We've got it to run but at 5k it just bucks hard and wont accelerate like a governer or rev limiter.

Any ideas? if you guys need more info to help me troubleshoot just ask.

Now that's a prime example of fuel cut. Also I'm unaware as to what #72 injectors are?

 

[uglytalon92]

720cc. anyways... i fix an exhaust leak from the mani to the tuirbo and it stopped but at the same time i dropped the boost to 10psi instead of 11.5. now it doesnt cut but stutters at 4-5k rpm. why is it stuttering, and did it stop cutting bc of the leak or bc too much boost??? im not goping over stock range so why should it cut???

 

[XiKeiyaZI]

Again, boost leak. What you just fixed is a pre-turbo exhaust leak. This means that in order to generate that 11.5 PSI that you were seeing, your engine was dumping a TON of fuel to spool the turbo up to that. Also during the process, you were losing fuel that the 02 sensor could not read as it wasn't reaching it, thus it was telling the ECU that you were running a tad too lean and so you were running slightly more fuel. I had this issue on my GST for a while. After I resolved this my mileage raised, spool time raised, and power overall raised.

You've fixed one issue, do the rest. Make a tester and test your entire charge system in sections.

 

[uglytalon92]

ok. the makeshift gasket hasnt completley fixed the leak. the oem replacing is coming in tomorow. do you think the stutter will go away after that??? could it be a mix of both exhaust leak and a boost leak elswhere??? i tried turning my boost controler off to see when it would cut out or what reaction i will get. and it didnt cut out during 1st gear but i only spooled like 8psi in first close to redline.... is that stock for 1st gear??? or is that bc of the boost leaks that i didnt spool the full stock boost with the controler off.

 

[uglytalon92]

If we turn the boost down to 10-12 psi it wont cut but if it goes to about 14 or higher it will. Could the electronic boost controller cause the car to cut or the 3in MAF or MAFT?

The MAFT is all zeroed however I did richen the mid and wot knobs 1 click and I didn't fuel cut at 12psi anymore that's how we are running that boost now for. Before I messed with the MAFT we couldn't even see 10psi... any ideas??

 

[XiKeiyaZI]

Try rewiring your fuel pump, just for the security of mind.

 

[uglytalon92]

its all ready rewired. with a 255 pump. could it be the stock fpr??

 

[XiKeiyaZI]

Uhm. Absolutely. The Stock FPR cannot handle the flowing ability of a 255, especially with the added flow of it being rewired. You need to chuck that likely already blown FPR and grab an AFPR.

 

[uglytalon92]

btw ty for actually helping me out. noones really been able to help me so far.. anywho what can happen if it doesnt get replaced soon??? and my maft seems to affect the cut alot. i havent gotten the idle set right just yet but with the wot set 1 or 2 clicks lean it wont fuel cut and pulls strong above 4krpm. but its like bogging from 1to 3krpm. should i go richer or leaner...?? i have no tunner or wideband. i just need a advice untill then bc its running like shit. i will buy the afpr. but does the 1g in mid need to be richened or leaned (normaly) so that it doesnt bog..

 

[XiKeiyaZI]

btw ty for actually helping me out. noones really been able to help me so far.. anywho what can happen if it doesnt get replaced soon??? and my maft seems to affect the cut alot. i havent gotten the idle set right just yet but with the wot set 1 or 2 clicks lean it wont fuel cut and pulls strong above 4krpm. but its like bogging from 1to 3krpm. should i go richer or leaner...?? i have no tunner or wideband. i just need a advice untill then bc its running like shit. i will buy the afpr. but does the 1g in mid need to be richened or leaned (normaly) so that it doesnt bog..

Well, I don't want to sound preachy here at all... but here is the cold, hard truth. You should not be making any tuning adjustments on that vehicle until you at least acquire a Wideband. You need to be able to monitor what your AFR's are so that you don't near the threshold of melting things and destroying that engine. You should set the MAFT to what you are running and leave it be. I haven't looked at your profile, but if you are running stock injectors then zero it all out and leave the settings as stock.

The thing about running a Wally 255 on a stock FPR is that the FPR cannot tolerate the amount of flow that a 255 induces. This will over-run the FPR and you will run retarded rich. The worst that will happen is you will foul plugs, destroy your 02 sensor, and soak your cylinders with fuel. It's not a pretty thing to do. So go ahead and order an AFPR and save your engine. Once you get it in, adjust it for the proper flow and then look into getting a wideband. Once that's handled, then you can begin basic tuning. I wouldn't recommend anything crazy, though, until you can log Knock so as you don't blow your engine sky-high.

By the way, the help is what should be expected. If you're truly interested in learning how to maintain your vehicle and seek out the best for it, then that's great.

 

[uglytalon92]

ok, thank you. got it. i only messed with it bc zeroed out it ran worse... is it ok to keep it zeroed if it barely wants top run?? i mean i totaly understand not tunning without knowing whats going on in the engine... but if 1 click makes the car drivable would that be ok?? if not thats fine il zero them out again.

 

[XiKeiyaZI]

Which direction are you going when you adjust it?

 

[uglytalon92]

well to the right ( rich) makes it run like donkey poop... but left lean lessens the cut and makes the ride alot smoother and not as shuddery. but like i said we only go 1 click or so. now my theory is that the pressure regulater is shot and as we drive it builds too much pressure thats why it runs great then about an hr or so in and it starts cutting and i have to lean her out one more for it to stop. we bought an afpr however the adapter they gave us does not work with stock rail how did you guys hook yours up???

 

[uglytalon92]

btw i installed an afpr and set the fp at 42 with vacuum off. onj its at about 36.. is this right?? and im still fuel cutting around 5500rpm in between 11 and 13psi. i dont know if this matters but the ecu that came in the car says auto on it in sharpie like he picked it up from a junkyard... we own a 5spd... could this cause issues.. we have no safc or wideband.. only the translater to tune with..

 

[XiKeiyaZI]

btw i installed an afpr and set the fp at 42 with vacuum off. onj its at about 36.. is this right?? and im still fuel cutting around 5500rpm in between 11 and 13psi. i dont know if this matters but the ecu that came in the car says auto on it in sharpie like he picked it up from a junkyard... we own a 5spd... could this cause issues.. we have no safc or wideband.. only the translater to tune with..

If I recall correctly, the Autos came with smaller injectors. Someone can chime in on this and either correct me or ensure this. You should look into a 5Spd ECU. In fact, I may have one laying around somewhere.

The way you adjusted the AFPR was perfect, by the way. It will drop a bit once you put the vacuum line back on.

 

[uglytalon92]

I know about it dropping after vacuum line connect but the autos also came with different cams? Could this cause a misfire in the top end?

It sounds like a subaru or machine gun soon as I enter boost. We are very concerened for the life of this car. We're trying to fix stuff ASAP. Could the auto ECU also contribute to not being able to boost over like 12 or 13psi?

 

[iminadaze]

You are going to have to flash the stock ecu and tune for those 720 injectors, DSMlink can disable the fuel cut.

 

[uglytalon92]

Oh sry I havnt changed my profle but aparently there stock... they look just like stock 450's. Do I want to disable it isn't that dangerous?