I have a very different setup so if this is in the wrong section please move it to the appropriate area. Ok, I took an L98 out of an 85 Trans Am for my 55 Chevy. I used a painless wiring harness to set it up after attempting to make my own and frying the original computer. I got a replacement computer from an 85 Corvette with a Hypertech chip in it from Ebay. The person I got the Trans Am from had the engine replace and it was upgraded from a 305 to a 350. I thought that this engine and computer combo would be fine. It has a new cam and I have the cam card but don't know how to read it or what is relevent to this so just let me know what you need to know. I has Sanderson headers and a new O2 sensor. I used a piston stop and confirmed zero on my timing tab. I set the base timing at 6* and the start it up. The car runs and sounds fine but the headers start to glow within a couple of minutes at idle. I have an adjustable fuel pressure regulator and tried running the engine at 35, 45 and 55lb of fuel pressure. All three settings still made the headers glow but the richer it go the more my eyes burned in my garage, so I cant diagnose it as being a lean or rich problem. Please help!!

 

might be normal-my fiero's headers also glow,car runs
fine. could be late ignition timing too-did you set
timing with dizzy in bypass?

 

Yes, the timing was set with the distributor in bypass mode. I have been told that you run the potential of burning an exhaust valve if you are getting hot enough to glow your headers.

 

Could be an issue of your car running lean due to ECU problems. Our FSAE car has that problem when we run it lean, the headers turn orange fast. Check your ECU for error codes and try to post up a copy of the bin for others to look at.

 

Do all the header tubes glow, or only some? What do the plugs on those cylinders look like?

 

No, I've seen it from time to time, but I've had a few cars w/ headers and have never had that problem. I would pull the plugs and see what they look like? If they are white, then you are running lean. What temp is the motor running at??

 

Was the engine running like this when it was in the 85 Trans Am? Could the 305 injectors have been used for the 350? Im think the 19lb injectors will be okay but you have to increase the firing pulse inorder to compensate for the smaller injector. Also how old are the injectors and did you have them tested before install?

 

Advance the timing some and see what happenes

 

Ok, so far I have moved the timing up to 9* with the wire disconnected. Then I turned the fuel pressure back down to 45lbs. The car will idle without the headers glowing finally.

89RS, not sure what you mean by a bin. I'm kinda noob on TPI.

Air Adam, the #3 and 5 tubes glowed and later both collectors if I let it continue to run.

Air Adam, J91, the plugs looked kinda chalky white on the electrode strap but the porcelain was very black.

Wannab03SS, I don;t know how the motor ran. Car was assumed to have a dead fuel pump for 5 years so I replaced the fuse and fired it up. The valve covers leaked so bad that I didnt want to run it too much because of all the smoking. It was just a donor motor. I looked up the injectors in a book and they are from the 305 motor. They were not tested either. Also how would you adjust the pulse width?

 

Also I am getting a small amount of intermitent popping through the intake.

 

Plugs should be tan for proper mixture, I'd run the timing up to about 11-12* see how it runs? Clean the plugs and see what color you have. The timing was a good call NY87iroc. If the poping gets worse back it down, if not keep it there. Hard to know where it should be, your combo is wierd and not knowing cam specs, etc.
On the plugs white=lean, burning hot! Black too rich, too much fuel, you want tan on the electrode...Good luck, keep us posted..

 

I have the cam card. What info would you need to know?

 

It's lean. I'd increase the fuel pressure a bit. The headers were most likely glowing because the timing is retarded.

To increase the injector pulsewidth, you'll need to burn a custom computer chip. Many of us here can do it, check out the DIY PROM board for more info. If you're running a 305 tune on a 350, you will need to have to burn a new chip. You can probably get it to run OK, but you'll need to have the correct tune done for it to be perfect.

 

I replaced the ECU and prom with a corvette ECU (350 cu in) and a hypertech prom part# 11542 for corvette with 350. Should I understand that increasing the fuel pressure will force the smaller 305 injectors to spray more fuel at the given pulse width? If so how high should my fuel pressure be?

 

well right there is a HUGE problem. You're running a 350 chip with 305 injectors. The 350 program has the injector constant set for (edited)22lb injectors and you're only running 19lb injectors. You need to swap injectors to match the chip in the ECM, or you need to re-burn the chip with the injector constant to match your injectors.

 

Ok thanks. I was thinking that I read that the 350 ran a 22lb injector as oposed to a 24, but like I have said, I'm noob. That in mind, my budget is running thin. Have any of you heard good or bad on the Summit brand injectors? Part# SUM-240024 vs the Venom VNM-HP-624-8 or Accel ACC-150824? I'm not trying to build a monster, just get good performance. Thanks for the help so far guys.

 

That was a typo, 350s had 22lb injectors. I apologize for the confusion.

I'm running Ford Motorsport injectors, but I'm not sure if they are still available. I've not heard good things about Accell injectors, Summit and Venom, I have no idea. Just look on e-bay or on here for some 350 injectors and have them cleaned...

 

What is int and ex lift and duration???? The other guys are right b'out 19lb injs, that is a problem...

 

int/exh duration = 211.8/220.9
lb lift = .289/.298

 

I'm trying to attach the cam card here. Not sure if I got it right though.

 

I'd set the fuel pressure to 50 PSI with the 19lb. injectors. TPI systems will do something called "Lean Pop", which is poping out the intake when you hit the throttle, which may be the other symptom you mentioned.

I'd bet that the Corvette PROM has too much timing for your engine.... A Corvette engine has Aluminum Heads and thus has more total timing advance, and 22lb. fuel injectors too..... Your Heads are Iron? I think I'd set the base timing to 2 deg. to help compensate.

 

I will try the 50lb fuel pressure. As I said before though when I have 6* of timing the headers glow. Since it stopped glowing at 9* wouldnt going even lower make this problem worse? I am also searching for the correct injectors and the heads are iron.

 

You, Sir, have just hit a home run. I should have thought of this and didnt. You are exactly right. I started with a corvette tune on my 383, and the stock corvette tunes have VERY aggressive timing curves, certainly not to be used with iron heads. This doesnt explain the glowing exhaust, but is a harbinger of things to come when you start driving the car, especially under a load. The engine will spark knock like crazy and you'll have to pull out all the timing you're putting in now to get it to idle correctly.

I strongly suggest you get the car professionally tuned if you want it to run properly. Where are you located?

 

I am in Olympia, WA. When you say tuned, do you mean having a custom prom chip burned?

 

Before you go jacking with your fuel pressure, check your Air/Fuel Ratio (AFR). If you are above stoich (14.7) at say 15 or higher, the engine is running lean. You need to check your ECU and make sure its telling the injectors to spray the proper amount of fuel. You can have your FP set at 50psi and the injectors firing hardly at all and that will cause the engine to run lean.

 

The 1985 Corvette 350 had CAST IRON heads. Aluminum heads did not appear until some time in the 1986 model year.

The 1985 model year f-body computer is a strange version in that it is only for the one year f-body TPI. You may need to spend some time looking in the DIY Prom board and the DFI and ECM board to find the differences.

The Corvette prom may also be different than f-body but I don't know.

If I recall, the 1985 Mass Air Flow Sensor was also a one year only item.

Your best bet may be to convert to 1986 or later wiring and computer to get much tuning ability (1989 prom is even better and works well with the 1986 up through 1989 stuff).

jms

 

How do I find the air/fuel ratio?

 

Yes, I mean having a custom tune burned. Ed Wright or PCMforless.com can get you close with a mail order tune, I had poor luck with pcmforless.com. If you want it tuned correctly, tuning in person is the best way. Your cam is far enough from stock that getting the car to idle properly, start when hot, not stall after revving, no idle surge, etc. will take some time to get right.

 

I was just about to type that, thank god I read your post!

 

hey guys you are all missing the boat here, the 85 corvette has 24lb injectors not 22 or 19. if you try to run either it will be lean. If you have 22's turning the pressure to 50 will help.

 

Is the tpi on the motor original to it? If the injectors are blue they are multecs(probally not since they came on 91-92) and multecs will shut down if the fuel pressure gets close to 50lbs. You can always send out for a chip($200 or less) that will get you closer to where you need to be and stop the timing curve problem.

 

The injectors are the stock 305 injectors from AC part# 5235047. They are black. Also I confirmed in the book "Chevy TPI Fuel Injection Swappers Guide", page 7, that the Corvette 350 aluminum heads didn't appear until mid 1986.

 

Timing should be 11-12* w/ the vlvlift and duration spec'd on that card. The injector issue needs to be fixed, IMO if that motor/pcm needs 24 lb injs, you should get them. I really don't know much about prom burning and exact parts needed for your combo. AFR is very important and should be correct to avoid damage to your motor...
These guys on here know alot more about EFI control than I do....

 

Ok guys it is settled. I will definitely get the 24lb injectors asap. Thanks for the timing help too. I agree that more will probably be better since it glowed at 6* and not at 9*. I will bump it on up to the 11* - 12* range also. Thanks for all the help once again.

 

The tpi seems to love the base timing set pretty far advanced, my 87 305 likes 12*, if you get used injectors send them to a good shop like Cruzin Performance to make sure they are in good working order, Rich is the man and very helpful. Good luck

 

turn your fuel pressure up a little bit. your not getting enough fuel to put the fire out it is burning to long in the cilinder its not exploding it is burning and that is why your headers are glowing find out what fuel pressure should be on the injectors you have and start with that pressure.

 

This has more to do with cylinder head design than the fact that it is a TPI motor....

 

You clearly haven't read this thread, and dont know what is going on here. He does not have the correct fuel injectors to work with the computer chip he has. He is dealing with 19 lb injectors and his computer chip is burnt for 22lb injectors.

 

Are you sure about this???

Selfce, what year corvette is your hypertech chip for??

 

The ecm and hypertech prom are both for 85 corvette

 

I wonder if the Knock Detector is retarding the timing when you have the Base Timing set at 9+.....? (And that is why the Headers stop glowing)

 

I went into my old laptop that I used when I burned these chips. Here is the deal with the 85 weirdo vette. The injector is a 24lb Bosch rated at 3bar. But in 85 only, the stock fuel pressure was 36 not 43.5 like all the other years. I verified this with a 85 FSM. My computer records show the constant at 21.45 in the ecu. With the lower fuel pressure the 24 really is a 21.5, But, if you use a 85 ecu and use 43.5 psi rail pressure then a 22 is fine. So, I don't think thats his problem the more I think about it. He could have 19lb in there and if his fuel pressure is low it would also run lean. Maybe he can find a part number on his injectors and see. He could also have a clogged injector. TPI's run on 7 injectors with not to many problems except lean..

 

I've already said that the injectors are from a 305. They are AC part#5235047 which is a 19lb injector. I think this is the info you're looking for but if I'm mistaken, let me know.

 

Advance your timing more.

 

Been following this thread. If you need injectors we carry the bosch design lll's 19lb and 22lb, we also have 24lb ford motorsports. They all come with a 3 year warrantee and if you type in discount code: N665at checkout and you will receive a 10% discount on all of our products and services until March 15th. Hope this helps.

www.southbayfuelinjectors.com

 

make sure you are getting advance. most people thing WRONG on glowing headers...ill bet you the unburnt fuel is making them glow..you are RICH..AND more fuel is going to make the glowing headers WORSE. if your timing is retarded that will make EGTs climb too.

a knowitall stubborn old skool drag racer bud give me a VERY expensive quickfuel carb and RUINED a motor during breakin . when his headers started glowing from the excess fuel because of this.. (he had locked the timing at 15 degrees and jetted up the carb 10 sizes front and rear too large to be "safe") he kept putting bigger jets in. "its lean, its lean, this carb is junk" ..I told him he was wrong, it wouldnt idle and was belching black smoke.. I told him "it needs more timing and less jet."He wouldnt listen and got out the alcohol jets and washed the rings out. The motor never was right. HE cussed and cussed, and told me to take the JUNK carb.LOL I took the "bad" carb home, and put it on a ragged old cammed fuelie headed pickup (after returning it to very near the "as shipped" stock jetting) and did nothing but set the idle and mixture screws.

I dont know why you are rich, but i will bet dollars to donuts if you toss a wideband on it that it isnt a LEAN problem. Sounds like you were onto that when you saidat 45 and 55 psi it was burning your eyes more. Extremely lean at higher rpm can glow the exhaust, but too much fuel will do it everytime.With a wideband i have played at idle on several cars and never could get one lean enough to glow a header they ran rough and died first. I have seen an import car with an intermittant miss on one cylinder (bad plug wire)glow exhaust and get the cat so hot from unburnt exhaust that it set my neighbors yard on fire.. LOL

good luck and hope this helped.

 

i had the same problem. i set the timing at 12 degress btdc and the car ran fine. i just put another cam in and had to set the timing at 25 btdc. the last cam is pretty big though.