Perfect idle, power loss under acceleration, red hot exh.mani ...

[mihai clotan]

After a year's work and many problems along the way i got it running. At least idling. At idle she sound good, has that brap brap sound in the tail pipe, engine seems running round and good. All good until the test drive. Took off and it all seamed ok. Step on the gas, lightly and shifted second. Noticed smoke at the back. Normal. I have been flooding it wile try to get it running, plus with no tune yet, she runs rich. In second she immediately lost power. Like there is a cat. converter that i do not have . Engine did not die but was chocking under gas. Tried first gear. Same symptom. Pull in front of garage and looked at motor, exhaust mani was glowing. This whole thing lasted less then 5 min. I literally drove it 50 yards total.
One other thing i noticed. The turbo does not seem to pull good enough wile at idle rev it to 3500 . Blow off valve sounds like a waste-gate rather than BOV. Strange sound. Turbo does work, no question, but not sure how good. There is a manual boost control.
Any good suggestions would be taken in consideration and much appreciate it .

Thank you.

 

[Diamond Star Werks]

Check your timing. Sounds like your off. Could be the brap brap sound too. If the exhaust cam is off time it can do make it glowing hot. If you had power in first and not in second its probably how hot you got the turbo. Blowing such hot air in will cause the ecu to retard timing.

If timing is good on stock cams your idle should be nice and smooth not brap brap.

 

[mihai clotan]

Check your timing. Sounds like your off. Could be the brap brap sound too. If the exhaust cam is off time it can do make it glowing hot. If you had power in first and not in second its probably how hot you got the turbo. Blowing such hot air in will cause the ecu to retard timing.

If timing is good on stock cams your idle should be nice and smooth not brap brap.

Appreciate the input.
I did not list all mods, figure i have them listed in profile, whoever is interested in taking on this problem might glimpse at mods. But if you up for the challenge i don't mind list them again. It is a full build, cams are SII 274/274 11mm lift, cause of the brap. Built is done on a 1992 gsx motor, droped inside a 99. computer is a 96. You could be onto something with timing, thought of it, but it does not explain my sudden loss of power once engine heats up . At idle, engine ran for a longer time without getting mani. hot, turbo does sound a bit strange once it spools . Not a clean suction sound.

 

[Cdc1221]

I agree with mjcanada on this. Sounds like your exhaust cam is advanced too far, meaning your exhaust valves are opening well before BTDC. There are many people running 272s with a smooth idle, due to degreeing their cams in properly

 

[mihai clotan]

I agree with mjcanada on this. Sounds like your exhaust cam is advanced too far, meaning your exhaust valves are opening well before BTDC. There are many people running 272s with a smooth idle, due to degreeing their cams in properly

I run 274/274, not 272, in your opinion my loss of power ( almost a stole , same symptom as catalityc that went bad) once in gear is due to timing ? Ill open the.books again. If anybody has different ideas pls post it .

 

[Zack Huffman]

Grab your timing light, ground the timing terminal for the 96 ECU and adjust your 1G CAS until your base ignition timing is at 5* BTDC.

 

[WES_393]

I agree that you should check mechanical and ignition timing. Either one being off could allow fuel to burn in the exhaust manifold.

But other possibilities would be running lean or running rich. Both can create very high EGT's. Since you say you have smoke coming from the exhaust (which is not normal) I'm thinking your on the rich side. Very rich if the manifold is glowing after a 1-2 gear pull.

There are only two things I can think of that would cause you to run that rich under boost: A major boost leak or an issue with the fuel system. After a look at the timing, I would check for boost leaks using soapy water while pressurizing the intake pipes. If the problem persists, I would start checking the fuel system. Too much fuel pressure, injector stuck open, etc.

 

[mihai clotan]

Every thing you guys say makes logic sense. Will start with timing. You all talked about the red manifold , but nothing on the power loss. For some reason i feel the hot manifold is related to the loss of power , or vice versa . It is a total loss of power not just partial, as if there is no gas in the engine ...probably because it is burning in the manifold ....i might have more than one issue here..will do timing again and see where i get .I like the soapy water tip, thanks guys

 

[Diamond Star Werks]

Are you running cams and bigger injectors on a stock ecu?

Apexi safc

 

[mihai clotan]

Apexi safc

Yes GSC SII 274/274 and 780 injectors , i do have an apexi base setings, stock ecu

Timming checked, is good, turbo checked, air leek checked....cant find the tumor in this thing

According to serial number on the ecu, it is out of 96 gsx non eprom .

 

[Diamond Star Werks]

Sounds like your running too lean. You need a better tuner than safc. Your past its helpful capabilities.

 

[mihai clotan]

I left the stock ecu and safco in the idea that i was breaking the engine in, then make some upgrades and tune it. Car has 0 miles . I build it from ground up .
I am running rich, at idle she runs 12.7 aem air/ fuel gauge , when i give it gas mixture slightly drops to 12.2 , but when i release the throtle it jumps to 15_16 and stoles. Also if i apply.hard throttle from idle, it will studer and stole. I have to gradually apply throttle in order to keep it running. I suspect air and gas problem, just dont know were to look for it anymore.

 

[Diamond Star Werks]

Its always going to go lean when you let off the gas because of fuel cut. You should be 14.7 at idle not 12.7. If thats the then your running pig rich not lean. You need to lean that out. If your breaking in you need as little idle time as possible. Is your bov recirculated?

 

[93xsg]

running rich or lean can cause overheating and loss of power.

I have a SAFC in my car and had 650cc injectors. AFter I rebuilt the engine I put stock injectors in to necessitate the need for as much tuning.

Fixed most of my problem but i still had to do a tiny but of tuning due to upgraded intake and turbo.



Just an idea if your timing checks out and you have your stock injectors around still

 

[mihai clotan]

Its always going to go lean when you let off the gas because of fuel cut. You should be 14.7 at idle not 12.7. If thats the then your running pig rich not lean. You need to lean that out. If your breaking in you need as little idle time as possible. Is your bov recirculated?

It did idle around 14, i mess around with throttle body screw and made it richer ( 12.7 ) at idle, will put that back to 14 ....under throttle will go down in the 12_13 .....when i let of goes 16_17 eventualy dies ...bov not recirculated

running rich or lean can cause overheating and loss of power.

I have a SAFC in my car and had 650cc injectors. AFter I rebuilt the engine I put stock injectors in to necessitate the need for as much tuning.

Fixed most of my problem but i still had to do a tiny but of tuning due to upgraded intake and turbo.



Just an idea if your timing checks out and you have your stock injectors around still

Thinking to get stock fuel pump and injectros, at least ill eliminate another possibility.

 

[WES_393]

Sounds like your running too lean. You need a better tuner than safc. Your past its helpful capabilities.

Yes, 780cc is too big for an SAFC. It can't compensate anymore just by messing with the MAF signal. But that won't make the car run lean, it will make it run rich.

So OP, I would swap in some stock injectors and zero out the SAFC corrections if any have been made. That should tell you whether it's a problem with too large of injectors (which I'd put money on) or if something else is causing the rich condition. I wouldn't swap in a stock fuel pump just yet, we want to isolate the problem by swapping parts one at a time.

 

[mihai clotan]

Yes, 780cc is too big for an SAFC. It can't compensate anymore just by messing with the MAF signal. But that won't make the car run lean, it will make it run rich.

So OP, I would swap in some stock injectors and zero out the SAFC corrections if any have been made. That should tell you whether it's a problem with too large of injectors (which I'd put money on) or if something else is causing the rich condition. I wouldn't swap in a stock fuel pump just yet, we want to isolate the problem by swapping parts one at a time.

Agree 100%, and it is exactly what i am doing , will post rezults later

New Info.

I just heard fuel pump running non stop with engine off, ignition to on position. I paid attention to the fuel pressure regulator, and i can her gas rushing pass it into the return line. It seems its a non stop recirculation of gas. I bought the car with a Walbro 255 installed in it. I presume pump is wired direct. Could this influence the rich mixture and most my problem???

 

[laserspeeddemon]

I agree that you should check mechanical and ignition timing. Either one being off could allow fuel to burn in the exhaust manifold.

But other possibilities would be running lean or running rich. Both can create very high EGT's. Since you say you have smoke coming from the exhaust (which is not normal) I'm thinking your on the rich side. Very rich if the manifold is glowing after a 1-2 gear pull.

There are only two things I can think of that would cause you to run that rich under boost: A major boost leak or an issue with the fuel system. After a look at the timing, I would check for boost leaks using soapy water while pressurizing the intake pipes. If the problem persists, I would start checking the fuel system. Too much fuel pressure, injector stuck open, etc.

This is pretty spot on. But because I also would suggest looking at the timing on the exhaust cam; it could be advanced a bit. This would cause the exhaust valves to close too late allowing some unburnt air/fuel mixture into the exhaust manifold. At the temperatures that the exhaust manifold gets it can cause the unburnt mixture to detonate. This creates and incredible reduction in spool....very bad for turbos though.

 

[Cdc1221]

This is pretty spot on. But because I also would suggest looking at the timing on the exhaust cam; it could be retarded a bit. This would cause the exhaust valves to close too late allowing some unburnt air/fuel mixture into the exhaust manifold. At the temperatures that the exhaust manifold gets it can cause the unburnt mixture to detonate. This creates and incredible reduction in spool....very bad for turbos though.

You mean advanced and opening too early? Because retarded and opening too late causes nasty little things like pistons hitting valves .

 

[laserspeeddemon]

Sorry, I was looking at it upside down.

 

[Cdc1221]

Agree 100%, and it is exactly what i am doing , will post rezults later

New Info.

I just heard fuel pump running non stop with engine off, ignition to on position. I paid attention to the fuel pressure regulator, and i can her gas rushing pass it into the return line. It seems its a non stop recirculation of gas. I bought the car with a Walbro 255 installed in it. I presume pump is wired direct. Could this influence the rich mixture and most my problem???

Possibly, or youve overrun the stock fpr, losing fuel pressure, and are leaning out too bad

 

[laserspeeddemon]

Pump should be ran on a relay. Not direct. If you're running a 255 rewired, it will definitely alter your fuel control. This cause a richer idle and if you try to adjust it in your software you could end up leaning out at WOT.

 

[mihai clotan]

Pump should be ran on a relay. Not direct. If you're running a 255 rewired, it will definitely alter your fuel control. This cause a richer idle and if you try to adjust it in your software you could end up leaning out at WOT.[/QUOTE

I THINK THE DIAGNOSES IS BAD FPR .( at least on the running to rich/lean loss of power issue, will deal with red hot manifold asap )

REASON : THE GAS PUMP NEVER STOPS WILST EGNITION TO ON, WHICH MEANS PRESURE IS NOT BUILDING IN THE LINE, ALSO I CAN HEAR GAS RECIRCULATING BACK INTO RETURN LINE.

i see the relay, chasing the wire, so relay is there, i think as someone mentioned above, the fpr gets overpassed, maybe because walbro 255 creates a bit to much pressure for stock fpr!!!!( heard from couple of guys they run that pump on stock fpr but who knows, my gsx is that bi*** that wants steak not chicken ), i have couple spare fpr's that i tried on, no difference, unless they are all busted. Anyhow, since i replace injectors and got no result, i am ordering right now an fpr....any suggestions on what the brand?

by the way~ thanks to everyone who took some time to throw me couple ideas in a time i lost some confidence
will post asap to confirm fix ( hope to god for that engine's sake )

 

[laserspeeddemon]

That's actually opposite. The FPR can not evacuate as much fuel pressure as the 255 can push out into the fuel rail because of the small bore of the outlet on the FPR. If you have a rewired 255, then you NEED a APFR anyway, so go ahead and replace it. If it's stuck open that could cause other problems, so replacing it should also alleviate this problem.

 

[mihai clotan]

problem solved ..it was a shorted knock sensor wire ...