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Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
Total loss. Did a easy swap of a ported Intake manifold, new fuel injectors (still 19LB) and ported new runners. Ran perfect before swap.
Now the RPM race all over the place, and within 2 minutes the headers are red hot and coolant is bubbling in the overflow tank.
Took it apart twice and put it back together.
Timing is dead on. Even removed the timing cover. Tried different advance/retard no luck. Changed from aftermarket to stock chip no difference. Power to the ECU. no vacuum leaks. No codes.
1991 Z 305 TPI auto, original cam. Only mods besides this are headers/exhaust/TB...all done years prior to this swap.
Sounds like its super lean or a BIG vacuum leak. I've heard people say that have no leaks and turns out they did. I'd use a homemade smoke machine to test that. http://www.r3vlimited.com/board/showthread.php?t=274418
Check your fuel pressure and I wouldn't rule out the injectors being bad.
And as Big Hammer pointed out, if you took the manifold off the block you could've put the gaskets on wrong.
If you never unplugged that timing wire when you set your timing, it will be set quite retarded. This causes a pile of heat to enter your headers and coolant system.
Hi BigH...yes I unplugged that. Have set the timing to 6degrees before. And tried every setting on the timing after with cable and cable unplugged. Removed the timing cover and #1 sparkplug just to make sure it was deal on.
Just thinking out loud... If all the header pipes are glowing hot it sounds like retarded timing. If it's only a few you might have a couple plug wires messed up.
Good for thinking out loud! Cause I'm frustrated ha. Yes plug wiring is correct..even drew it out on a piece of paper from my manuals..then took a blank piece of paper and went to the garage and drew it out...just to make sure I was not having a brain cramp.
Advanced timing light also indicates dead on. I'm sure timing is not an issue. Have tried all different degrees on the tab and little to no effect on the main issues. They are Hooker ceramics 2055, and I know they run abit hotter, but are blood red in a minute, and coolant bubbling in the O/F.
Problem is ignition timing. Pure and simple. Don't protest; the problem is ignition timing. It's retarded. ALOT.
Put down the light, and just advance it about 30°.
See what happens. It works like this:
Adjust it.
Better/worse?
Better: adjust it some more the same way.
Worse: adjust it back to where it was, and a little bit more.
Better/worse?
Better: adjust it some more the same way.
Worse: adjust it back to where it was, and a little bit more.
Better/worse?
Better: adjust it some more the same way.
Worse: adjust it back to where it was, and a little bit more.
Better/worse?
Better: adjust it some more the same way.
Worse: adjust it back to where it was, and a little bit more.
Better/worse?
Better: adjust it some more the same way.
Worse: adjust it back to where it was, and a little bit more.
Better/worse?
Better: adjust it some more the same way.
Worse: adjust it back to where it was, and a little bit more.
Better/worse?
Better: adjust it some more the same way.
Worse: adjust it back to where it was, and a little bit more.
Better/worse?
Better: adjust it some more the same way.
Worse: adjust it back to where it was, and a little bit more.
Presently you will come to a place where no further adjustment makes it "better". In the case of ignition timing, "better" might be any combination of attributes that are affected by it, such as gas mileage, crisp throttle response, cool running temp, freedom from pinging under all but the most extreme conditions, cool exhaust temps, and so on. At that point, you have just made that one particular thing AS GOOD AS IT GETS; no further improvement is possible. And best of all, YOU get to pick the attributes of YOUR car's performance that are most important to YOU while YOU are using YOUR car the way YOU use it where YOU live with the fuel YOU put in it. YOU are in control, not "book" and "spec".
NOW, since after doing this your car will be running AS GOOD AS IT POSSIBLY CAN by making that particular adjustment, you may pick your "light" back up, and see WHERE IT IS; and next time somebody thinks THEY know better what YOUR ENGINE wants than YOUR ENGINE does, you will know right where to put it back to.
We call this process "tuning". Of course you can get much greater control over more things by "burning" "chip"; but as far as a mechanical setting, you just maxed it out.
If I may paraphrase one of The Great Ones in a COMPLETELY unrelated field, but whose wisdom (much like my signature) is so widely applicable as to be almost universal, ....
"If it RUNS good, it IS good".
NEVER forget that. It's so simple it hurts. It just WORKS. Don't outsmart yourself over something that blindingly obvious.
Tks Sofakingdom for the detail on that post and taking time to do it. Ill be doing everything here so far suggested and post results...so guys rock as usual
GM made different timing covers and balancers with the marks in different places. If you have a Mis matched set your timing could be way retarded but show that it's good.
Then with the timing wire hooked up, keep turning the distributor counter clockwise until the engine quits revving higher. Then back it off a touch. Let it idle and see if it still overheats.
Good point big hammer. Still original cause I am the original owner
If you are the original owner , then you should know if the Harmonic Dampener has ever been replaced . Has it ?
I ask this because it's a known failure that the rubber between the hub and the outside weight (where your timing mark is !) dries out and allows the outer ring to slip on the hub with the result of your timing marks being out of sync with what's actually going on , timing wise . I offer this up just as one possible scenario of why the factory timing marks could be tellin ya lies .
Bottom line = cherry red headers means fuel burning in the exhaust and like the guys have said , retarded (late) timing is the #1 culprit of this on an otherwise healthy* engine .....
* leaking or misadjusted (too tight so as to keep the valve from fully closing) exhaust valves can cause this also , did you alter any of the valve clearances during this manifold install , possibly getting them too tight ?
Orangebird, thanks! We did look at the Harmonic Dampener and it is original one, and is starting to show what u speak of, but not close to failure mode for a few years yet.
I did not do anything else, except straight replace of the bolt on parts. Was looking at the old intake and could have very easily blocked a cooling port. Pic there with a red pencil in the cooling port, and blank at other end. Quite easily could have the gasket blocking it as I never thought about that and was really focused on a nice clean work area on the engine for a good seal and looking at the intake ports only...the gaskets would fit perfectly blocking intake and exit of coolant.
Gonna do the 30 advance timing first and vacuum smoke job, and failing that, strip down to check that gasket.
Gotta funny feeling its the gasket blocking a cooling port.
you could pull your upper radiator hose of at the rad,...start it up, and see if water flows after the thermostat opens. that would tell ya if the intake gaskets are on backwards. i kinda think its your issue, but you never know.
Considering where the thermostat housing is on a TPI, you might be able to drain some coolant and remove the thermostat housing and look on there to see if the ports are blocked
"The simplest explanation that fits all the facts is usually the right one".
How does ANY proposed explanation that involves coolant passages, fit ALL THE FACTS? How does that account for red-hot headers?
Leave the coolant passages alone. Not saying they're "good"; not saying they're "not blocked"; not saying "you did the gasket right"; not saying "the gasket can't block the port". What I AM saying is, a farkled gasket DOES NOT fit ALL the facts, and therefore, should be ruled out as the cause of the cluster of symptoms you report.
NOTHING about the cooling system accounts for that, in fact. NOTHING. Again, I'm not telling you your cooling system is "perfect", there's "nothing wrong with your cooling system", or ANYTHING of the kind; only, THE COOLING SYSTEM CANNOT CAUSE WHAT'S HAPPENING. Leave it alone and devote your mental effort to things that CAN. Then once you have the immediate problem straightened out, if the cooling system still seems inadequate, THEN AND ONLY THEN, go back and dink with it. BUT NOT NOW.
Your problem is ignition timing. Quit posting on the Internet, quit accepting people who want to divert you down non-productive rabbit holes, quit thinking that just because "light" and "mark", the timing is right. IT'S NOT. Go crank it around A BUNCH; 30° is probably not enough to restore it to "right". But should be enough to tell you, whoaaaaaa, this was REALLY messed up, with a capital F.
Be logical. Go do it. Mark it first if you don't believe me so you can put it back. You won't want to do that though, you'll amaze yourself at how something so simple can have such far-reaching effects.
Orangebird, thanks! We did look at the Harmonic Dampener and it is original one, and is starting to show what u speak of, but not close to failure mode for a few years yet.
I did not do anything else, except straight replace of the bolt on parts. Was looking at the old intake and could have very easily blocked a cooling port. Pic there with a red pencil in the cooling port, and blank at other end. Quite easily could have the gasket blocking it as I never thought about that and was really focused on a nice clean work area on the engine for a good seal and looking at the intake ports only...the gaskets would fit perfectly blocking intake and exit of coolant.
Gonna do the 30 advance timing first and vacuum smoke job, and failing that, strip down to check that gasket.
Gotta funny feeling its the gasket blocking a cooling port.
Originally Posted by sofakingdom
The ports probably aren't blocked.
But that aside:
Read my signature. Pay attention to EVERY WORD.
"The simplest explanation that fits all the facts is usually the right one".
How does ANY proposed explanation that involves coolant passages, fit ALL THE FACTS? How does that account for red-hot headers?
Leave the coolant passages alone. Not saying they're "good"; not saying they're "not blocked"; not saying "you did the gasket right"; not saying "the gasket can't block the port". What I AM saying is, a farkled gasket DOES NOT fit ALL the facts, and therefore, should be ruled out as the cause of the cluster of symptoms you report.
NOTHING about the cooling system accounts for that, in fact. NOTHING. Again, I'm not telling you your cooling system is "perfect", there's "nothing wrong with your cooling system", or ANYTHING of the kind; only, THE COOLING SYSTEM CANNOT CAUSE WHAT'S HAPPENING. Leave it alone and devote your mental effort to things that CAN. Then once you have the immediate problem straightened out, if the cooling system still seems inadequate, THEN AND ONLY THEN, go back and dink with it. BUT NOT NOW.
Your problem is ignition timing. Quit posting on the Internet, quit accepting people who want to divert you down non-productive rabbit holes, quit thinking that just because "light" and "mark", the timing is right. IT'S NOT. Go crank it around A BUNCH; 30° is probably not enough to restore it to "right". But should be enough to tell you, whoaaaaaa, this was REALLY messed up, with a capital F.
Be logical. Go do it. Mark it first if you don't believe me so you can put it back. You won't want to do that though, you'll amaze yourself at how something so simple can have such far-reaching effects.
You could have saved the panic attack if you just read a little better man
No panic attack; just some REALITY. Just trying to help keep you from wasting d00d's time on the cooling system. Specifically, because NOTHING about that accounts for ALL THE FACTS; in this case, red-hot headers.
In the meantime, he doesn't need to hear about gaskets. He needs help and encouragement to direct him TOWARD the problem, not AWAY FROM it.
Let's help him out: leave off talk about gaskets until he fixes the problem he ACTUALLY HAS. Then, maybe if there's still something wrong, we can revisit the other.
Patrick, let us know how it turns out when you advance the ignition timing. Pretty sure that's THE WHOLE problem, and you'll get it fixed without touching the cooling system.
OK folks, sorry for the late update! Never had much luck, so proceeded to haul it apart, and found the culprit.
You see in pic that the intake manifold gasket for the runner would look ok, as the Edelbrock only had the little hole and the gasket surrounded it. good to go with the Edelbrock runners! Well you can see the black marks from air being sucked in..not good to go after all.
I never tried the gasket against the runner, and you can see not a match at all in the other pic. 99.9% sure this is all my issues. In rebuilding phase now.
Be checking gaskets on both sides from now on!!
This would explain your high erratic idle, that's a pretty bad vacuum leak. But it wouldn't explain your red hot exhaust. It's been a while since I've had a TPI intake apart, but I think that small hole beside the runners is the EGR passage...
gasket perfect on the other side. Gaskets were perfect for stock runners, not so much the Edelbrock.
So I figure trying to do timing with this leak was impossible, so I just have it way off. I went from 30 degrees right to the other side of the spectrum, and I was either revving like crazy or stalling.
Rebuilding almost complete and will update all for the input!
Although the gaskets aren't correct, you're going to find that's still not the issue, even though when you put it back together you may correct the real problem which was timing. When you said that the idle went way up when you adjusted the timing, that would've corrected the glowing header issue. Good find with the gaskets though.
Yes they are Mr Gasket! So did a much more careful rebuild (cause I'm not a mechanic!!) and presto....everything dead on working perfect.
I really really really blamed the timing, even as the timing gun was dead on, and the idle was like anywhere from 3000 to stalling out on the retard, boiling antifreeze and red hot headers. Even to the point to taking off the timing cover, wondering if the balancer had slipped etc.
But at the end of the day, that open port to the EGR passage caused all of this.
Thanks all for the input and I have learned a lot from this...still not a mechanic but learning!
I thought that might be the source of the rpm's racing up. Vacuum leaks on a tpi manifold can be really hard to find even when they're that big of a leak. Glad you got it.
all for the input! 
