Well, today I got off work @ 0600 and started my car. I heard a knock,and then it ran like crap! sounded like the car was missing really bad! I drove home which is on the freeway for about 10 minutes. Got home and noticed that my header tube on No. 5 was glowing red. I have header wrap on my headers but I could still see the red on no. 5. After it cooled down, I pulled the plug wire and the boot was cracked from the heat. I replaced the wire, and thought that was the problem.....NOT my luck!!! I check timming and it's @ 8deg. advanced, where it's been for a long time.

So it's still missing. I"m thinking fuel, air spark. Thinking maybe one of my injectors are bad. So I tear it down, exchange injector no. 1 with injector no.5. I take it out, and no. 5 is still glowing!???

So I do a compression check, 175psi all banks! I"m thinking a burned valve, however, if memory serves me right, a burned valve will not hold pressure???right???

I changed my distributor cap, the plugs looked the same....IM stumped!!!

Can anyone help???????? P L E A S E

 

Only thing I can think of is the exhaust valve is sticking open. Apparently it closed for the compression test, but maybe it's sticking while running.
Might try removing the valve cover and watch it closely with eng idling. Take a good look at the valve spring also.

It's kind-of-a-long-shot, but it's all I can come up with at the moment.

 

Sounds like it could be faulty wiring to that one injector. Pick up a noid light set at autozone, and test the injector harness for pulse. Or use a testlight. Should have a hot on one wire with key on engine off, then a pulsing ground on the other wire while cranking (noid light is easier).

 

I don't have a noid light, but I do have a test light. I put it to both term's and both make the light come on as all of my injectors do.
???????????

 

Have you checked the valve train forbent pushrods, pulling rocker studs, bent/sticking valves, etc?

 

Vader,

I am currently checking my valve train by using a dial indicator. I"m going to compare the lift of no. 5 and another set of valves and see if there are any differences.

TY all for you help so far!

 

this seems so obvious that im assuming you just forgot to mention it but you did pull the spark plug and check it right? did you replace it?

 

yep

 

That's normal with key on and eng off (not cranking).
Power comes from the fuses to power one of the terminals.

Power is also going thru the other injs and back feeds the other injectors. This is why the other inj connector terminal has power.
If you disconnect all the injs, the second inj connector terminal will no longer have power.

When cranking (or running), the ECM provides a ground to the injs. Power will disappear from the second inj connector terminal for a few milliseconds and make the noid light flash.

 

Im going to guess its a bent or broken rocker stud. I know when I broke one the car was running horribly and the transmission didnt want to shift properly.

 

If you pull the valve cover and see that the valve train is operating normally (both valvesprings compress and depress normally, and you can see the valves are not sticking,) then I second that either there is a short to ground to that injector in the wiring, or the computer is starting to go bad. With the ignition on and engine off, do a resistance check from a known good ground, the the ground wire at the injector. If you have continuity, there's the problem. If you do find continuity, then unplug the computer, if there is still continuity, you know there is a short to ground in the wiring, if you get OL, then the computer is bad. Quick easy test.

 

Checked the valve springs/studs and injector. All check out fine! I have an extra ECM and swaped that out too with no results.

 

Do a standard compression test first. Eliminate the obvious.

Get a propane torch and shoot some propane into the inlet. If the motor or one cylinder has a fuel related problem ( lean) for what ever reason the extra fuel (propane) will smooth out the idle. And the pipe will stop glowing.
if this does not help its likely a over rich problem or a spark problem.

 

You could switch your injector wires from 5 to 7 and see if the problem moves or stays. It won't matter since it isn't sequencial injection and will isolate the problem from mechanical or electrical.
JM$.02,
Charlie

 

Did a compression check, 175 all banks! changed 5 and 7 injector wires, no change

 

I think you are on the wrong track.
Glowing Exhaust = hot exhaust = lean mixture
I would look for a intake leak, Inj o-ring Ect.
Think about it a torch gets hotter when you add oxygen
Not acetylene. Cause a miss and hot exhaust = to much air.

 

Checked that too! ran teh car and sqirted carb cleaner all over teh intake at all mating points. No change.

TY for your thoughs!

Keep m commin

 

Something really REALLY interesting! I opened up the valve cover on the passenger side. I thought, what the he11! Now I never suspected any problems from that side of the engine, but, the rocker arms broke on the inake and exhaust of valve no.6. I read a few post on the NLOC board adn this board about the screw in studs on AFR heads and how crappy they were! Well, I"m here to tell you it's TRUE! ONe of my rocker arm studs broke while backing off the nut. I'm going to replace all screw in studs. the pushrods are in the lifter valley I hope! Just hope no dammage has occured due to the push rods falling in the lifter valley?

Keep ya posted!

TY all again!

 

Well,

After I put new screw in studs, Two new push rods, flushed the engine with the gunk engine flush......changed oil, ran that for 1/2 hr (cheap oil). Then drained that out, and finally put in my AMSOIL and filter, she's purring like a kitten:hail: :lala:

Guess next time, I will inspect the entire valve train when I suspect a problem on only one side! The problem was two broken rocker arm studs whilch also resulted in a bent pushrod.

Thank you all for your help! :yourock:

 

I had a premonition - the power of the Dark Side...

 

vader,

I got a little tunnel vission and since the symptoms were only on the drivers side header, i only looked at the drivers side valves. Guess I would have saved a lot of guess work by taking the passengers side valve covers off! :nono:

live an learn the hard way

 

OK, NOW i'm ready to take this ****ing car to the junk yard! It seems to run fine, Idle's perfect, BUT BUT>>>>>>>>>>>>> took it out for a run, come home and the no.5 header tube is red! I'm so pissed that I think I should crap on the hood and write for sale on the windshield!!!!,

ONce again,

Checked fuel pressure 48psi
Changed injectors
compression check 175 around on all 8 cylinders
lashed valves, changed broken rocker arm studs on OPPOSITE SIDE

I am going on vacation tomorrow and will not be back for 10 days, IF YOU HAVE ANY THOUGHS OR COMMENTS that may help me find out what's up, PLEASE DO!!!!

As for now, I"m gonna wait for it to cool down, take it for a spin with out the no.5 spark plug wire on and then look at the header tube! I hate this car!

 

OK, I unpluged the no.5 spark plug wire and ran it on the freeway, got on it a bit on the way home to put a load on the engine. With the plug wire no.5 unpluged.....the no.5 header tube did not glow??? Did a compression check and all cylinders are 175psi. So a burned valve is not so possible. changed the fuel injectors, so that aint the probleml Lashed the valves while cold and put them 1/2 turn past zero lash. then I warmed the engine up, then hot lashed them. the cold lash was almost perfect becasue after 1/2 turn, they started clacking while the engine was running and warm. Then, I went to zero lash and did the same.

I have no idea????

PLEASE HELP:hail: I'm going nuts and my wife is gettin pissed:lala:

 

You have a vacuum leak on that one cylinder.

 

Don't think so. Vacume is a steady 17inches. idles perfect, did the carb cleaner test on every area with no change in idle..

 

If it was a vacume leak between the no.5 cylinder and either 3 or 7, the compression test should have displayed some differences. BUt I got a pressure of 175 in all cylinders? Unless there is some other way to check for a leak between the cylinders? Anyother thoughts? Keep M comming please

 

Out of curiosity, did you ever run the test that I stated above to verify that there is not a problem in the wiring of that injector... because there could be a short in the wiring from the computer, which would still cause this to all be happening even after you changed the ECM. Just wondering if you did or not..?

 

There is a possibility of a vacuum leak between the intake base and the head on the bottom, sucking from the crankcase. You could see if you have crankcase vacuum with the pcv unhooked. I don't think you would be but, I also would double check the plug wires to make sure you aren't running with 5 and 7 switched. Just a couple thoughts I had, hope one works for you,
Charlie

 

Well,
back from the vacation from hell! Got to thinking, I really think it has something to do with teh valves, one burned or somethein like that! figure I have a vacume leak and should have done a leak down test which would show a small leak, which I'm guessing I have! I'm going to tear it down.........again, get teh head tested. That's all it could be! Yes, I did changed injector connctions and no change. Nor did the swap of the two ecm's make any difference. I do not have a leak down tester, however, I think that is my only logical conclusion....vacume leak in the head some where? Keep ya updated!

 

It cant be a wiring or cpu problem because the car is batch fire. Half of the cylinders would have the same problem. You might want to check and make sure your plug wires arent crossed. You could have a crossfire from another cylineder.

 

I think the vacation did me good! Got to thinking and one thing I have not tried was a leak down test. I have no access to a leak down tester, but, I bet I have a vacume leak from one of my valves on cylinder no.5. the compressin test showed fine, but if I had a tiny leak due to a burned valve, that would still hold compression, yet cause me to run lean. I bet that is the problem. I'm going to start tearing down the engine and pull that head. first,I'm gonna check the header tube when I pull it, but I bet it is the no.5 valves casuing teh problem.......We will see!

 

A vacuum leak has nothing to do with the valves.
A compression test or a leakdown test will not detect a vacuum leak.
Its between the head and intake manifold on one cylinder. Coulld be on the lowerpart of the port leaking into the lifter valley.

Shoot some propane gas in to the motor's air inlet to see if it smooths out or speeds up.
The propane will enrichen the lean cylinder correcting the mixture. The extra propane won't hurt the motor.

Re-inspect the valves ( broken exhaust rocker again) interference.

 

Could be a real weak or broken valve spring. That would explain normal compression while cranking but a miss while running, power loss, backfire, glowing headers, etc.

 

NOPE! Took my head to the machine shop, springs are good. They did a leak down test and it showed the no.7 exhaust a bit weak, so they fixed that. But the machine shop said that the head should not be casuing teh problem i'm havnig. One thing I did find was that the exhaust dough nut gasket where the header mates was a bit frail. Wondering if that may have been the problem? doubt it, if i had an exhaust leak, one would think that all header tubes would glow? Hoping ti will be back together Firday...work tomorrow Kind of glad to be working on my car right now.....Our beloved German Shepard passed away this week and it's been difficult

 

clogged injector

 

NOPE! I changed injectors, acutally switched no.1 with no.5. AFter taking the head off and having a leak down test preformed which showed the heads are in perfect working order. The header tube still Glows red! WTF???????????

 

I thought you said you switched injector PLUGS not injectors; try switching the plugs on the top with the one right next to it.

 

Did that too! Goes intothe shop on Tuesday! I've doen everythign a GM shop would do already so it's going to a tpi specaility place in Auburn. Will keep you all posted!