Sorry I haven't been back to respond guys, I've got a rotten cold and haven't worked on the car. I'm planning on upping the fuel pressure today and see what happens. I've got a feeling that's all it is. I WILL post results.

 

Okay, it is definitely too much fuel. I ran the fuel pressure up to 47 and the tubes were glowing at idle. Right now I have the pressure set at 37 and it is much better but still a slight glow. I'm going to try and advance the timing to see what that will do. Just to let everybody know, the cats are brand new high flow, the injectors are brand new pink tops from FiveO. The valves have been set twice and double checked both times. I did put 1.6 roller rockers on but I've never heard of anyone having issues like this with them. I'm hoping my hub is off some not allowing me to set timing correctly.
Keep the suggestions coming guys.

 

Here's what I believe is going on.

The combustion process is beginning too late. So the burning is continuing AFTER the exhaust valve has started to open and the burn is continuing in the header, making them glow from the very high heat.

This is usually caused by not enough ignition advance. Usually the cure is to advance the timing which begins the burn earlier so that it's completed by the time the exhaust valve begins to open.

The next possible cause is exhaust valves adjusted too tightly. This would cause them to not seat fully, allowing the burning mixture to sneak past into the header. Valves set too tightly usually show that by giving you a bad idle too.

The next, down the line, is a air/fuel mixture that is too LEAN, not too rich. A mixture that is too rich actually cools rather than heats. Lean mixtures burn a lot hotter than do rich mixtures. This is why additional power can often be found when the mixture is leaned out, but you'd have to be very careful in leaning the mixture. Go too far and engine parts damage will result. You'll torch the parts. I've seen quarter size holes burned in piston domes from running a too-lean mixture.

Of course there are also concerns that the fuel pressure is set too low and/or one or more injectors isn't contributing its fair share of fuel -as in the case of it being partially clogged.

A vacuum leak can cause extra air to enter the engine, thus leaning the mixture making the burn hotter. The 02 would detect this and the ECM will try to adjust for this, but the ECM only has a limited range of adjustablility, so it may not be able to compensate.

I've seen a crack in a header tube result in a Service Engine Soon light indicating a lean condition. Air gets sucked into the engine via the crack in the header, leaning the mixture that the 02 sees and reports.

A mis-firing plug or bad plug wire should do just the opposite. Each time the mis-fire occurs, that amount of a/f doesn't ignite, goes unburned and a rich indication results. Idle will suffer too.

Hope this helps; best I come up with.

Jake

 

Thanks JAKE, I will address your suggestions as they are in order:
Combustion SHOULD be good, I advanced the timing with the EST disconnected to 10 degrees. It's much better but I can still see color after the engine has been at about 1,500 rpm for about 30 seconds.
Valves are adjusted 1/2 turn after zero clearance. I double checked this.
Air/fuel,, the problem got worse as I raised the fuel pressure so it was definitely too rich at the start. With fp at 37 and timing at 10 adv. it is much better but I'm afraid to go further with either one.
No vacuum leaks or misfiring plugs, it idles smooth as silk, right at 850, what the chip was burned to.
Headers are brand new so no cracks.

 

Make sure your system is going closed loop too.

On my 86 I can jumper the ALDL with the engine idling and the blinking of the SES light tells me if the system is in Open or Closed loop.

One blink per second indicates Closed Loop and

Two and One-Half blinks per second indicates Open Loop.

Could it be 02 feedback to the ECM?

Jake

 

JAKE, at this point I have no idea what the hell it is but I do know I've about had it. I put a heated O2 sensor in when I installed the long tubes, I had to put it in the collector adapter, there was no bung in the headers. I will try what you said tomorrow and see if it's going closed loop. If it is then the next thing will be to take the 1.6 rockers off and go back to stock stamped 1.5's. I have checked the vacuum lines over and over, I don't think that's it. I have noticed that when I pull a line off at the back of the plenum that there's not much suction but those fittings are so small it's hard to tell. I had a vacuum gauge on it a while back and it held steady at around 14. This thing idles so smooth with no shake whatsoever I just can't believe I'm having all this trouble. Thanks for sticking with me.

 

These kinds of things can be elusive to track down, whenever I have a problem like this (luckily I haven't had any lately) I just check one thing at a time and, sooner or later, I find the cause.

As an example: Some years ago I had an bad idle condition. I could tell from my jumping vacuum gauge needle that it was due to a vacuum leak, but for the life of me, I couldn't find it.

I tried a several cans of spray carb cleaner, shooting at all the possible locations and still nothing. I finally was so frustrated that I broke out my garden hose and flooded the possible spots.

Low and behold it was an injector "O" ring, or to be more precise, two of them.

When I pulled the injectors, while doing some intake/runner mods,, I had failed to notice that one of the "O" rings didn't come off with one injector when I puled that injector out of the intake mainfold. So since I installed new "O" rings on all the injectors, one injector ended up having TWO "O" rings. That's where the vacuum leak was.

The water hose trick pin-pointed it. So I tore the intake back down, found the second "O" ring, removed it and when I re-installed everything I was good to go.

Just a story to illustrate how hard some of the problems can be to track down.

I'd suggest you check the resistance on all the injectors too. I'm wondering if one or more is reading low and could be at the heart of your problem. From what I've read, they should all read right at 16 ohms, since that's what the ECM drivers call for; high impedence injectors.

Keep us posted.

Jake

 

Went back to work on the Vette today. I have been all over the engine looking for vacuum leaks and have found none, when I pull one of the small lines at the rear of the plenum the idle changes so I think I can rule out vacuum leaks. I still had my old Hypertech chip so I put it back in and the results are the same, glowing tubes on both banks. I put the timing back to 6 degrees and put the fuel pressure back up to 47. I just can't believe it's the valve lash but after I post this I am going back out and take the 1.6 rockers off and put the stockers back on and set them again. I will check injector resistance first but they are all brand new and Bruce at FiveO assured me they were all good. I'm to the point of asking if there's anybody in Illinois who can scan this thing so I can just get it fixed. It's not costing me $$$ but it sure is costing me sleep.

 

I was packing my radiator in the dark once, holding revs up around 2k to get the coolant level to drop.

I was surprised that my tubes were glowing after 30 seconds or so. They were kind of dim, but it was clear they were starting to glow, both banks, all tubes. I don't think you can see them glow in the daytime, though.

I assume it is normal, but you just don't see it that often and its a suprise when they do glow.

 

tequilaboy, I have thought of that but I have built many an engine, one was an 800 horse 454 with Crower mechanical injection and none of them have ever done this. I'm just lost around elctronically controlled engines. You may be correct and I may be trying to fix something that I can't. However, read below what I found, I hope you don't have a problem you're not aware of.

JAKE, I tried pouring water on the intake today after all else failed and when I poured it on the driver's side the engine started to shake and I got white smoke out the exhaust. Now for the interesting part, I tore it all apart and I can't find a thing wrong! It looks as if the gasket did not seal well on the driver's side but there's no reason why. The heads are flat, they were just done by a machine shop. The intake is flat, I checked it tonight. The bolts go all the way in the holes so that's not it. I've found the problem but I haven't found a reason. I used 85 gaskets, IF there is a difference between 85 and 86 up. The heads are not new enough to be the different angled ones. I'll get new gaskets and bolt it all back together and see what happens then.

 

I am now having the same problem, mine were glowing this morning while I was holding the engine at 2000rpm to burp the cooling system. Everything is new and was set at 8* BTDC, except that I am using the original injectors. They werent glowing at all when I got back to Louisiana tonight, after a 700mi drive. Just another thing I have to fix

 

I have run across a couple of times that my exhaust was "hotter than normal", on my '91

1st time
I had a partially plugged injector #5, thus dumping fuel for this is on the same side as the o2 sensor. Two things I did, was isolate problem cylinder with a laser temp, then a screw driver to listen to all the injectors.

2nd
When I would sit too long at idle or above, a lean condition would develop, exhaust temp go up. I found out that the o2 wire was getting hot, thus resistence goes up, sending computer false signals.

3rd
Another area I had problems is partially shorting spark plug wires. Due to close proximity to the header tubes, burning through insulation.

Best to ya.....

 

You've found it! Definite sign of a vacuum leak.

Here's how I seal my intake.

First I clean both the manifold and the heads. I use a wire wheel in my drill to remove all the old gasket material that may be stuck. When attacking the heads, I cover the lifter valley with towels to prevent pieces of gasket material from falling into the oil pan; they'll block the oil pickup. I make sure I remove EVERY LITTLE PIECE of gasket material that falls on the towel.

I then use my Craftsman punch, part # 42885WF and dimple the underside of both ends of the intake at the front and rear (the China Wall areas).

I do the same thing to the block on what we refer to as the "China Walls".

I space the dimples about 1/16"-1/8" apart, so when I'm done each area will have lots of dimples - never counted them but around fifty at each area is ball park.

These dimples give the Sensor Safe silicone sealant (or Right Stuff if you prefer) something to "bite" into. They'll be no leaks if you dimple those areas. If you don't, over time, increasing crankcase pressure can end up pushing the silicone sealant out and an oil leak will develop.

I do a final wipe down - I use whatever I have handy that removes grease/oil, sometimes brake clearner, sometimes carb cleaner. Silicone sealant won't seal to an oily or greasy surface

With my fingers I apply a thin layer of silicone sealant on BOTH sides of the intake gaskets; yep, even those that have sealant around the intake ports. I also apply the same thin layer of sealant around ALL the water ports; BOTH sides.

I apply a 3/8"-7/16" (More than some mags use - I HATE LEAKS!!!) bead of sealant on both China Walls on the block and make sure I carry the sealant bead up onto the heads; right where the block meets the heads at the four corners.

I DO NOT allow the silicone to skin over - as some guys do. I've had the best success doing it WITHOUT letting is skin over and, by the way, my Corvette Shop Manual says to do it that way, too.

I set the intake manifold STRAIGHT DOWN; no fore or aft movement should occur. I look through the intake manifold bolt holes to keep the alignment as I set it down.

I use Anti-Seize on the intake manifold bolt threads.

I follow GM's recommended torque sequence, which, for my 86, is different from the usual method of starting at the center bolts and working toward the end bolts. Must be a good reason for GM recommending it, so I figure no need to re-invent the wheel.

I torque the bolts to 35 FT./LBS, then go inside the hose for a couple of hours. When I return to the garage I check the torque. I usually find the torque has lessened, so I pull the bolts back to 35#.

More waiting and re-checking. A third torque is usually needed, but the third time around not all the bolts will need to be pulled back to 35#.

I continue to do this until all the bolts hold the torque setting.

Explanation: As the manifold gasket is torqued, it compresses a little which results in lower torque. Some gaskets compress more than others: I use Mr. Gasket Ultra Seals, about $10 at my local auto parts store, like O'Reilly's.

If you do it this way, you won't have a vacuum leak and no oil leak will pop up a few thousand miles down the road.

After the rest is reassembled, I take the engine through several heating and cooling cycles, then re-check the intake manifold bolts. Since I can no longer get my torque wrench on many of them, I just check that none is noticably looser than any of the others. When you screw on these suckas long enough you develop a "feel" of when a bolt is tightened enough and when it's not.

Hope this helps.

Jake

 

If you just re-built the engine and had the cylinders bored oversize and have new pistons, then you're not going to want to hear this, but another possibility is that your engine is burning oil in the headers.

Is your oil getting dark and dirty fairly quickly?
Are your plugs oily?
Any visible exhaust emmissions at startup or idle?

If you don't have a good ring seal, then you'll have some blow by, which will result in excess crankcase pressure (even with a PCV system). That excess crankcase pressure will force oil down the valve guides (even new guides w/new valves), and that oil winds up in the intake manifold and in the cylinder (from the intake valve) and in the exhaust (from the exhaust valve guide). You may have oil burning slowly in the header primaries causing them to get hot and glow.

I speak from experience. I was having the same problem (glowing headers at a fast idle), and my engine used oil. Buy it also made very good power - 330 rwhp and ran 114mph in the qtr from a .060" over 350.

I chased all the same things you and everyone else in this thread has suggested. Finally, I pulled the engine, re-honed the cylinders with a torque plate (which was not used the first time), replaced the Keith Black pistons (not saying anything was wrong with them), with Mahle pistons and rings. And now I've got the best ring seal of any engine I've ever built. My oil stays clean, the plugs are dry and with a nearly white colored porcelain (sp?), it uses very little, if any, oil, and I picked up 18rwhp in the process. And the headers don't glow when I hold a fast idle.

For what that's worth...

Dan

 

JAKE, the only difference in your method and mine is that I have never used sealant on the gaskets themselves but I'm going to this time. I also like the idea of re-torquing like you do, something I've never done with an intake but it makes a lot of sense. Can't get gaskets now until Monday so I'll post again when it's all back together. I really appreciate your time and suggestions. One more thing, I have an 85 shop manual so it won't show the intake tightening sequence on aluminum heads, could you let me know what that sequence is?

danno85, thanks for your suggestion but the short block was not touched this time but it only has about 10,000 miles on it with no oil consumption to speak of. Plugs are always clean.

 

Hang on, let me look it up.

What about AutoZone for the gaskets? They're open Sunday.

Jake

 

Already checked Auto Zone, they have them for 85 w/ iron heads but not 86 up w/ aluminum heads. I'm going to get the aluminum head gaskets even though the only difference is probably the heat crossover.

 

Here's a quote on the sealant: "At time of installation surface area must be free of oil and (the) sealing compound must be wet to touch when bolts/screws are torqued".

The Shop Manual shows a two step process; First a SNUG TIGHTENING SEQUENCE then, second, a TIGHTENING SEQUENCE.

The SNUG SEQUENCE begins at the center, BUT instead of going from side to side, you first SNUG the two center bolts on the DRIVER'S SIDE (the rear one first then the front one), then the two center bolts on the passenger side ( the front one first then the rear one).

Next you SNUG the two rear-most bolts on the passenger side, the front one first then the rear one.

That's it for snugging.

Now we move to torquing:

Torque the two front bolts on the driver's side, the rear one then the front one

Torque the two center bolts on the driver's side, the front one then the rear one

Torque the two rear most bolts on the driver's side, the front one then the rear one, then

Torque the two front bolts on the passenger side, the rear one then the front one, then

Torque the two center bolts on the passenger side, the front one then the rear one, then

Torque the two rear most bolts on the passenger side, the front one then the rear one.

So, as you see, you torque down one side (the driver's) before torquing down the passenger side.

I always use four steps in torquing down the intake just to make sure it pulls down evenly.

I SNUG, them - using the above sequence - then torque them to 10ft/lbs, then 20, then 30 and finally 35 fl/lbs

The shop manual shows 25-45 ft./lbs for the torque spec. I opt for 35 which is right in the middle.

If you get gaskets with blocked openings in them, the block openings in gaskets to be positioned at rear of engine.

Hope you can understand the sequence above. If not let me know.

Jake

 

Okay, I understand.

Jake

 

Thanks for the sequence JAKE, I understand and will do it that way. Wish you were closer, I'd buy you supper.