The engine is a 406, Stealth Ram, with Pro Topline 200cc heads, running a modified speed density EEPROM. What would cause my headers to glow while running rich? I thought that was a condition only seen when extemely lean. At idle, my BLM's stay at 108, and the Heated O2 reading is about .900 mV. The base timing is set at 7.5 deg. I'll have more info when I can get my hands on the DataMaster log (dont have it on me right now). This "testing run" was performed using NGK FR5's, which are hotter than the NGK equiv. of Champion C59C that I was running before. Any suggestions?

 

Yep, unburnt fuel is reigniting in the primaries.

If mechanically everything is good (no open injectors, fuel in the regulator, etc.) then you probably need to do some PROM work... one thought though, you may benefit from increasing/advancing the basetiming.

 

Thanks for the suggestion. Anyone else what to chime in?

 

Overly rich or retarded timing will cause this. Both together = roasted plug wires, ask me how I know

 

Well, I've actually ran SO rich that gas was dripping out of my headers (2 injectors were stuck open) and my headers did not glow.

I've only seen my headers glow when a lean condition occured.



Scott's header glow came from switching from cold #9 NGK non-resistor racing plugs to alot hotter #5 NGK resistor style plugs. (That was the only change). It was running alot richer when we had the colder plugs in it and headers did not glow.

That's why I'm unsure on the "After-burn" running to rich theory causing headers to glow.

 

A lean condition can cause this at cruise, but not at idle. My money is on the timing.

 

Ok, then why wouldnt the headers glow when that motor had colder plugs in it?

 

timing and to lean woul dbe the 1st things Id check

 

I think it's too lean myself, but why is the o2 volts at .900 + (which is rich) and the block learns show 108 (maxed out rich) in the ECM?

If the motor was lean, then the Block Learns would be closer to 160 (which is lean).

Any thoughts?

By the way, I set his base timing to 7.5 degrees base (to get the motor to idle).

I also set his injector constant to 30 (he has 30 lb. SVO injectors).

 

May want to set the inj constant at a larger number. IIRC, SVO's are rated with a lower pressure...so if you're running "GM" pressure, you'll actaully have more fuel than needed.

What's the injector PW at idle? Are you at a point where it won't go any smaller?

 

Yea, I know about the SVO's. They are rated at flow pounds @ 39.5 PSI compared to GM's 42 PSI.

Fuel pressure was set to 39.5 - 40 PSI with vaccum line off at idle. Raising the fuel pressure to 42 PSI actually took longer to glow headers than 40 PSI, by a 10 - 15 second window or so.

 

Got the valves set properly? Did you degree the cam?
Bad O2 sensor?
What kind of voltage is the ECM reporting?


I run my SVO 24#s at 56psi with .bin constant of 24, BLMs are damn close to 128 at cruise for me. My idle BLMs however are in the 140s do to the big cam and 700rpm idle

 

The valves have been dry-set, but the final lash setting has not been made with the motor running. The O2 sensor is a brand new Bosh Heated unit, and the heater circuit is wired up correctly and is working. The ECM is reporing ~.900mV from the O2 sensor when in open loop, but when closed loop is reached the O2 voltage jumps around a lot, but stays around .900mV most of the time. Mike (1bad91z) has the Datamaster log on his laptop, hopefully after lookin at that we can get a few more clues.

 

Meaning from the alternator.

 

If you time the engine such that you 'accidentally' set it to 10d retarded instead of 10d advanced (many people have done this - especially when installing a different harmonic balancer) then the spark will be firing too late in the cycle allowing the fuel mixture to continue combustion into the headers. This causes the headers to glow nice and bright ... and will also give you rich O2 readings and high BLMs. I've seen this several times. The only way to be absolutely sure is to put a degree wheel on the front of the engine and locate TDC using the degree wheel and a tdc piston stop. Rotate to the left until it hits. Mark that spot. Rotate to the right until it hits. Mark that spot. The difference between the two spots is true TDC.

Tim

 

I'm not sure what voltage the ECM is seeing, I'll look in the log when I get it, if its there.

TRAXION - The balancer (Fluidamper) was installed by the builder, the same one who degreed the cam. I'll try upping the timing a little, and if that seems to have no effect, I'll see what I can do about finding a degree wheel.

 

Did you disconnect the spark advance wire on the engine harness when setting base timing? This is sometimes forgotten when setting timing. I just recently did this myself.

Good luck!

 

Yes, the ESC wire was disconnected when setting the base timing.

 

TRAXION -

I tried the other side of 10 on Scott's dampener and closer I got to it that way, the motor didnt want to run. But, I will play with the timing some more and see if it stops glowing headers. It's weird, cause the only thing I changed on his motor was switching to a warmer plug!

Oh well, I guess we'll see this weekend.

 

My headers were glowing red until I adjusted th e vlalves. They were too tight causeing fuel to dump into the headers.

 

Well, we changed the plugs back to the C59C's (cooold plugs, thats what Pro Topline reccomends), and checked and re-set the timing to what its supposed to be (at least, a LOT closer to what its supposed to be) 7.5 DEG ADVANCED, lol. It was in fact at 7.5 deg retarded. Now I have MUCH better throttle response, but the headers are glowing like mad, yet I'm still pig rich. When we first started the car, cold, in open loop, I was getting O2 readings of ~500mV. As soon as the car went to closed loop, readings went to ~900mV. I'm not sure exactly when the headers started glowing (and my coolant temp started to SKYROCKET), but I am pretty sure it began after entering closed loop. Our next step is to try to adjust the valves (as mentioned above), but we cant do it with the headers glowing. Hopefully, if I unplug the O2 sensor and force open loop, the headers will stay normal. Any other suggestions guys, other than driving (well, pushing), the car into a lake?

 

You dont have to run the motor to set the valves properly. It is something that is nice to do once everything else is in check: proper timing, stable idle, cooling stability, etc...

Follow this tech article and everything should be good to go with the valves. However only go 1/2 turn past zero lash not 1 turn as advised in the article, this should get you damn close to **** on, and then go back to set the valves dyanmically once everything is up and running properly.

http://64.90.9.168/cranecams/pdf/346e.pdf

 

Thats how we set the valves initially, with only 1/2 turn as you suggested. I guess now that they are all pumped up, the setting would be different now, meaning that they are all tighter than originally set. Thanks for the tip!

 

I have never had a problem initially setting valves dry, however results may differ from person to person.

Letting them pump up and then setting them may help out a bunch for your case.

1. Start the motor, let it run a couple minutes, with or without valve covers, there is not alot of splash on roller rockers at idle.

2. Shut it down and then loosen all the adjusting nuts, valves should be pumped up and ready to be set.

3. Set valves according to spec, pull the pluga as its gonna be a beotch to turn that motor.

 

Lean idle doesn't cause fuel to burn up in the exhuast & make it glow. Retarded timing, over-rich, misadjusted valves, or cam timing off is the only things that will do that.
Note: Too rich idle will usually not even cause the exhaust to glow unless something else is also wrong, namely the timing.

 

I went through this not too long ago, tried all of the basics... narrowed it down to a vaccum leak. My injectors weren't sealing to the Mini Ram, they were Accels. I tried 3 new sets of injector o-rings to no avail. Finally I broke down & bought a set of tried and true SVO 30's, problem was solved instantly. This may or may not be your problem... just sharing my personal experience. HTH

 

Are you sure the ECM is OK? I recently worked on two 3800 cars that as soon as it went into closed loop, the O2 sensor pegged at 1092mV, which fooled the ECM into thinking it was rich, which took fuel away making the engine actually run lean.

When the O2 sensor goes up to 900mV, unplug the O2 sensor, Datamaster should show a reading of 450mV (+/- 20mV) w/ the sensor unplugged. If not, then you probably have a bad ECM.

 

And for the record, YES, lean exhaust CAN cause headers to glow red.

 

Your intake manifold may not be sealed properly. My uncle has a lot of experience with SBCs, and when I got headers glowing, he told me to check around the intake base for leaks, like spray WD40 along the gasket and see if the engine note changes. Obviously, if ALL of your primaries are glowing, the chances are slim of this type of leak occuring. Still, check for any type of air leak into the engine.

 

All of the primaries are glowing, so I dont think its an intake gasket leak. If it comes down to it not being anything else, I'll check it out.

GMTech: The O2 sensor never "pegs", it still fluctuates, but stays on the rich side of things. I really dont think there is anything wrong with the ECM, but I have access to 2 that I can test with, 1 I KNOW is good (currently running my sisters car), the other I'm not sure about.

 

Actually Scott, when I dry-set your valves, I took it to zero lash and then went 1/4 turn. I think your pushrods are too long. The timing is dead-on and you are running rich as hell. The o2 sensor is working because it Oscillates (voltage fluxuating in it's cycle).

Just take both valve covers off, un-plug o2 sensor, and loosen every rocker 1/4 of a turn. Then crank the motor and let it run. Quiet any rockers that are tapping. Then do one at a time (loosening the rocker till it taps, then tighten just enough till it's quiet, then tighten 1/4 turn and lock jam-nut). Now, your valves will be set perfectly. If the headers are still glowing after that, then you need to invest in a pushrod length checker (the adjustable rod style).

 

OK, the valves are now set properly, and the glowing @ idle has gone away, as well as the overheating problem. We let it go into closed loop yesterday, and the headers were fine, for about 2 or 3 minutes. As soon as I brought it up to 1500 RPM and held it for a few seconds, the BLM's went from 108 to 128, then back down to 108 after a few seconds, then the headers started glowing. I was at about 33* spark advance, with a MAP of ~48 to 49 Kpa. Any ideas?