I have a 91 z28 with a new 383 stroker in it tested on the dyno no street use yet. so i thought that i finally had every thing back toghter and hooked up right but i was wrong. the car starts fine but after 2-3 minutes at idle the headers are glowing cherry red. i browsed the boards and sought the knowledge of some other people before posting. still i'm at a loss. i'm almost positive that i have the timing down but i'm still popping a 42 code. so thats still a potential problem. but the majority of people that i talk to say that i'm running lean. i called the tpis tech rep and asked what the deal is. he said it's normal to have the headers glow on a new engine, i don't think so. if i left the car run like that it's gonna melt everything near it. i also asked about an aftermarket fuel pump and injectors. tpis says 22lb injectors will feed a 450 hp motor and i'm at 400 give or take a few. so do i need bigger injectors or a more powerful fuel pump, or does anyone have any advice on the timing aspect. also is there a way to read out your injector harness to see excatually which clip goes to which injector, if i had these mixed up and they weren't firing at the right time in the right cylinder could this cause my problem. would the engine even start if the injectors were crossed? any advice at all would be greately appreciated. o yeah i forgot i'm almost positive that my egr routing on everything is correct alouth i don't have any pics to go off of, but everything seems to fall into place would i be popping a code if i had the air switching valve on backwards, and woulg the egr system have anything do do with my glowing headers problem thanks in advance dan

 

normal for who to have headers glow on a new engine? not me or any i ever did. either you're lean or the timings off.

 

The injector timing is a possability.
To test for a lean condition causeing the headers to glow
simply start the motor up and spray some propane (like from a propane torch) down the air inlet. If the glowing goes away it's was lean. If it makes no difference its probabily the timing.

Glowing headers at idle is not normal, EVER. Something is wrong. The TPIS tech twit guy probabily has less knowedge of motors than you do. Or was smoking something good.
At any rate do not operate the motor in that state for long or damage will result.

 

i still need to test the feul psi at WOT. if i get my48- 50 psi i'm gonna hold off on the injectors and feul pump. i did some shopping around and that stuff gets kinda pricey. Does shooting propane into the air inlet give the engine more octane? if i do this how long should i do it for, till the propane tank runns out? I'm still ondering if egr routing and operation would have anything to do with it? i messed around with the timing and i thought that the headers looked a little better but that might have been my imagiation.

 

Dan,

Once a code 42 is set the engine will run at base timing. IE: whatever the distributor is set to. The ECM stops all of it's timing adjustments. So basically the engine is running on a lot less timing then it should be. Glowing red headers will result.

RBob.

 

so if i reset the computer and the 42 code still remains what does that mean? something has to be going on there

 

Propane is a high octane fuel but will not raise the octane of the gasoline. Octane is not your problem. You're just using the propane to enrichen the mixture temperarily to test for a lean condition. If this is the problem you'll see the glow go away in a few (30) seconds. Don't run the motor like that for long.
If your egr is all messed up and is sucking air at idle that will cause a lean condition. Retarded ignition timing is probabily the cause.

 

bump your fuel psi up 5psi. I had the same problem with my vett, bumped the psi from 43.5 to 50...problem solved.

 

i have 52psi of fuel at idle goes to 45-46psi at wot. tried shooting propane into the throtale body , and it didn't help any. so it's my timing. i cleared the computer and the 42 code is gone now i have no check engine light. so this is what i'm left with if anyone has anything to add to my list please do so.

1. what i thought was TDC really wasn't and that's causing my timing to be grossley misadjusted.
2. is it possible to install the harmonic balaner wrong?
3. the o2 sensor is bad telling the computer to run lean. altough i don't have a o2 code.
4. erg routing is messing stuff up. still no code

if anyone knows or has pics of the egr stuff tell me if this is right.

i have the tube coming from the drivers header going into a t-fitting with the passenger header then into the inboard side of the air switching valve then the outboard side of the asv going into the tube that runs to the cat conv. gonna put in some pics that aren't the greatest. says my file is to big so no pics just wanna know which side of the switching valve goes where

 

this is a pic of the asv routing

 

I guess I'm old school, but I've always found glowing exhaust to be caused by too much unspent fuel reigniting in the primaries...either by a rich condition, or by late ignition timing.

Pull the plugs and see what they look like.

 

the plugs were totaly black but not oil.

 

Too uch fuel...either by retarded timing running rich.

Since you're a '91, you're Speed Density, could be because the PROM needs to be tweaked via MAP readings..assuming the 383 has more cam (lower vacuum readings at idle) than the stock calibration can correct for.

Or, timing is just too late.

Get the HB issues straightened out, check with the cam manufacturer for basetiming suggestion before going into the fuel system.

Code 42? Isn't that the code that's set once the EST bypass is disconnected? If so, probably nothing to worry about....Hmmn, you are disconnecting the EST bypass when setting basetiming?

 

The code 42 willnot go away unless you clear the codes by disconnecting the battery for 30sec. Once you disconnect the est wire, you will have a code 42 so try clearing the codes.

 

i cleared the codes already. i have no codes, right now. yeas i am disconnecting the ecm wire and hooking it back up when i am done