headers glowing at idle

[KevinB]

Ok....I'm back with another problem from the car from hell lol. Same car that was in another thread I started about a possible stuck injector. For those that didn't see that one....I'm working on a car that has sat for a long time. Many have worked on it but it has never ran. I got it running pretty good now but another issue has popped up. Car is a 85 with a 4.1 and a 87 conversion with a new caspers harness.

Car idles great, runs wot at 20 psi pretty strong. But the damn headers glow on the drivers side when idling. Fuel pressure is correct, stock 02 numbers look good, idles and starts great. Drives great too. Plugs look clean. I'm thinking its a timing issue. I replaced the esc and no change. In fact, the idle rpm doesn't change when the esc is unplugged...not sure if its suppose to though. I need to put a timing light on it to see if the timing is moving like it should when running. Anyone else ever had this?

 

[HighPSI]

Sounds like it's running at base timing without any EST signal from the ECM.

Hurry up and finish that project. You've got things to do this weekend :biggrin:

 

[KevinB]

Sounds like it's running at base timing without any EST signal from the ECM

That's what I'm thinking too. Had this happen on my old car after I rewired it. I left out the bypass wire from the esc to the ecm. I'm hoping that's it. Have a big project on another car starting Friday. This car is killing me lol.

 

[SCOOBY DOO]

Almost sounds like the timing's retarded on it.

 

[bison]

Ok....I'm back with another problem from the car from hell lol. Same car that was in another thread I started about a possible stuck injector. For those that didn't see that one....I'm working on a car that has sat for a long time. Many have worked on it but it has never ran. I got it running pretty good now but another issue has popped up. Car is a 85 with a 4.1 and a 87 conversion with a new caspers harness.

Car idles great, runs wot at 20 psi pretty strong. But the damn headers glow on the drivers side when idling. Fuel pressure is correct, stock 02 numbers look good, idles and starts great. Drives great too. Plugs look clean. I'm thinking its a timing issue. I replaced the esc and no change. In fact, the idle rpm doesn't change when the esc is unplugged...not sure if its suppose to though. I need to put a timing light on it to see if the timing is moving like it should when running. Anyone else ever had this?

Ive had it. Not with a stock ecm though. check the timing

 

[KevinB]

Ive had it. Not with a stock ecm though. check the timing

Yeah, this is a stock ecm car. Guess I will verify wiring and timing tomorrow. I already found one small issue with the 5 volt reference wiring in this harness, so anything is possible.

 

[I8AV8]

Timing

My car had the same problem years ago. It seems that when they rebuilt my engine, they did not torque the harmonic balancer to the required 200lbs. Check your timing and then the balancer. Sounds like it slipped.

 

[Slow91z]

My car had the same problem years ago. It seems that when they rebuilt my engine, they did not torque the harmonic balancer to the required 200lbs. Check your timing and then the balancer. Sounds like it slipped.

Not sure how that's possible since there is a keyway for the balancer...It could come loose, but until it actually started coming off I can't see how it would be affected...Now I guess the crank sensor ring could be on wrong.

Interesting problem Kev.

 

[KevinB]

Not sure how that's possible since there is a keyway for the balancer...It could come loose, but until it actually started coming off I can't see how it would be affected...Now I guess the crank sensor ring could be on wrong.

Interesting problem Kev.

This car is full of interesting problems. Hopefully I can get them all figured out because he's already got a room at bg. Says he's coming after you in ths

 

[Slow91z]

This car is full of interesting problems. Hopefully I can get them all figured out because he's already got a room at bg. Says he's coming after you in ths

He has much bigger problems then me if he's running THS.

 

[UncleDave]

That's what I'm thinking too. Had this happen on my old car after I rewired it. I left out the bypass wire from the esc to the ecm. I'm hoping that's it. Have a big project on another car starting Friday. This car is killing me lol.

Wouldn't a break in the bypass circuit throw a Code 42? Or is that only between the ECM and module?

 

[KevinB]

OK...timing is roughly 35 degrees at idle. Took balancer off. Relucter ring looks the same as a known good one. Timing moves when throttle is applied. So, timing from the ecm is working.

 

[NM Tom]

Could be a crack or leak in the header pulling in air and then burning it in the header with unburnt gas causing the temps to ramp up. What are the idle BLM's?

 

[KevinB]

Could be a crack or leak in the header pulling in air and then burning it in the header with unburnt gas causing the temps to ramp up. What are the idle BLM's?

Haven't checked That but will put that on the list to check out. Car does not have a exhaust leak that can be heard though. Idle blms are a little on the high side but not way out of range. Also going to run through the lash tomorrow. Its got roller rockers. Haven't checked those out yet.

 

[John Wilde]

Have you verified the cam is lined up correctly?

 

[NM Tom]

Haven't checked That but will put that on the list to check out. Car does not have a exhaust leak that can be heard though. Idle blms are a little on the high side but not way out of range. Also going to run through the lash tomorrow. Its got roller rockers. Haven't checked those out yet.

If the raised BLM's are caused by a exhaust leak then the ECM will be adding fuel making it richer and thus giving it the raw unburnt fuel needed to burn the extra O2 being drawn into the header...causing a vicious cycle of higher exhaust temps. Sometimes the header cracks will not be heard, at least mine never were!

 

[Woody]

Sounds like a vacum leak........I had the same thing happen when I installed an intake on a 400 ci small block chevy......anyway, we had a leak on the passenger side of the intake, and it caused the headers to get cherry red..........The engine ran fine, idel was good, etc...........then we found the leak...Good Luck

 

[Chuck Leeper]

Any significant diff in temp readings w/ an IR gun?

 

[KevinB]

Have you verified the cam is lined up correctly?

Not yet.

Any significant diff in temp readings w/ an IR gun?

About 850 degrees right off the port. Not hot enough to make it glow. I'm really thinking the header crack theory at the moment. Headers are not leaking at the port, but rather down by the area on the drivers side where they like to crack.

I guess I will check for header leaks and intake leaks next. If it is an intake leak, its not on the top side. I drenched the whole intake pretty much with starting fluid. No change in idle at all.

 

[KevinB]

Still can't figure this b!tch out

It's not:

headers: replaced with known good.
cam sensor: reset
chip and injectors: replaced 3 times
ecm: replaced
o2's about right for idle...int bounces between 126 and 136
valve lash: backed roller rockers out so much they were ticking and still did it.
no vac leaks on the top end. may remove intake and check for under intake leaks...but it's pulling good vac
timing is correct. switched balancers even with the one off my car. timing was also checked with light.

MAF has a trans+. Set all 3 settings (10% rich and lean).

I guess next few steps are: verify cam timing. pull intake. Maybe take rjc plate off.

Car idles are runs great.....I don't freaking get it!!!!!!!!1

Didn't replace coil pack and module yet...can't see that being an issue though.