Hello all....I REALLY NEED SOME HELP HERE...
I finished an LT1 conversion awhile back and have been hunting down the cause of a glowing exhaust manifold with no success.
When driving with RPMs above 2500, the passenger side exhaust manifold (seems to be mostly between cyl 4-6) glows RED HOT. I have no driveability problems, good power, all seems well. I believe im running VERY rich. Ive killed two 3 inch cats, and im getting about 10-11 MPG. This is a stock 5.7 LT1 from a 94 impala ss. The impala was rear ended and only had 65K on it.
Below are the things ive done to try to hunt this down.
-fuel pressure is 42 KOEO, 38 at idle
-swapped injectors side to side
-pressurized the rail with the injectors out of the intake
-no fuel in the regulator vac line
-vac is steady at 20
-vac at 2500 is steady at 23 for 1 minute straight
-resealed intake twice
-checked intake for cracks
-removed cat and muffler
-replaced exhaust manifold
-checked valve adjustment
-leak down test
-compression test
-measured cam lift with dial
-checked egr system
-checked AIR system
-replaced fuel filter
-no broken springs
-no bent push rods
-checked plug wire placement 5 times or better
-replaced plugs, wires, and installed MSD 6A
-The plugs on the driver bank are all normal...the #2 plug is normal, but 4,6,and8 are black..

I CANNOT FIGURE THIS ONE OUT!!!!
i find it almost impossible to be running lean...

I know perhaps i should have looked into this long ago, but when i did the conversion, i did not reinstall the knock sensors (the LT1 has a kn sensor on both the driver and pass side of the block). Neighter sensor is hooked up. The sensors are in the block, but their wiring was cut...
Can this situation put the engine into a "limp mode" and dump alot of fuel wile retarding the timing? If so, wouldnt i have a glow issue on both banks instead of just the pass?

One thing that is really driving me nuts here is i cannot pull my codes....the service light is on, but i cannot get it to flash....will codes flash if i were in a "limp mode" ?

Any help here will be very appreciated..
thanks
dave

P.S. Im running a consistant 150 def....i dont think i am ever getting it closed loop.... Can a "limp mode" dump so much fuel that the eng. will run this cool???

 

It's either too much fuel or too much timing. Pull a plug and read it, that will point you in the right direction. If it's sooty and fouled out then you're rich. Be careful running it that rich, it WILL wash the rings out. If they're burning ok, then time to look at timing. Valve and ignition. If the exhaust valve is opening too early then the charge is being pushed out the chambers before it's burned, and it's burning in the manifold.

I suspect something wrong in the particular cylinder, otherwise all 8 would glow.

Are you using the proper PCM?

Is it a new or used opti?

 

Keep in mind that running lean to the point of misfires will pretty much have the same symptoms of running too rich. I was just recently reminded of this fact.

I would adjust the CTS input (via tricker box) to get a quick handle on where it is fuel wise.
I'd also get rid of the CATs completely.

 

True, but glowing headers are usually because of fuel being burned in them instead of the chamber, not because of the egt's.

 

The engine is completely stock...other that MSD box(had this issue before box). I am using the stock manifolds. The opti was never removed from the engine...it is original vented.
The plugs on the drivers bank are normal as is plug #2. 4,6,and 8 are black fouled.

Does anyone have an input on the knock sensor situation?
Im really concerned that the lack of knock sensors is throwing the engine into a saftey mode and its dumping fuel and pulling timing....but why would only one side be glowing???
I know the the pcm only has one knock sensor wire and both run on that....

 

and yes the original PCM is being used as well.

Please keep in mind that this engine did not have these issues while it was in the impala...this engine was not beaten and only had 65K on it (parents car)....and ive had these issues since day one of the conversion...

 

is it possible there is some malfunction in
the air injection reactor system, and air is being pumped
into the smog tree when it shouldn't,
thus confusing the O2 sensor?

 

glowing pass. manifold is very common on LT1s, particularly B-body LT1s. Check to make sure you have no broken bolts or a cracked manifold. Any air leak before the O2 will blow fesh air past the O2 which makes the computer think it's ruunning lean so it dumps more gas in to richen to where it "thinks" it should be causing the manifold to glow I think thats how it works, i'll double check it later.