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**FIXED!!**DEFINITELY***Super HIGH idle after multiple parts replacement - TBI 1990 K1500 350engine

Just before winter I replaced the ICM and it seemed to fix the problem. I purchased a new distributor but did not find time to install it until last week along with a new intake manifold. I came across a good deal and couldn't pass it up (Edelbrock 3704 - basically and improved OEM intake). I put everything back together and started it up and timed it. With the timing advance connector (on the firewall) disconnected I started the engine and to my surprise it started right away. I set the timing to TDC with the advanced connector disabled. I reconnected the advanced connector in the engine seem to run/idle fine. The engine completely warmed up and ran for a long time without any surging or any issues. Just today I backed it out of the garage and drove it on the street around my neighborhood. The engine is extremely sluggish!! If I give it any gas it almost bogs down. I adjusted the TV cable but that did not seem to change anything. I pulled it into the garage to recheck the timing and my old friend, surging engine, came back. The engine would not stop surging. I checked the timing and it appeared to go from TDC to slightly retarded (the timing mark would move slightly to the right of TDC) as it surged. I loosened the distributor and as soon as I budged it the surging stopped. It totally stopped.

Distributor is brand new. It is a Billet distributor from summit. I don't think that's going to be the issue since the same issue existed before I put it in. Replacing the ICM last fall stop the problem but I did not take it out for a test drive back then.

When not surging, the engine idles at about 800 rpm. In order to drop it down to 700 or 750 I need to advance the timing considerably. Are there any other controls to adjust the idle besides adjusting the distributor or adjusting the throttle screw on the TBI?

Maybe partially spun Harmonic Balancer? Maybe time the engine to the proper idle and go from there?

I am completely out of ideas at this point. The Parts Canon is completely empty and I'm out of ammunition.


Oh yea...I open the throttle to read the engine once I had it set at TDC and the advanced connector disabled and the engine would jump from TDC to about 8 or 10° Advance even with the advanced disconnector disconnected. I thought the engine should stay at TDC no matter what if the advanced connector was disconnected?
 
You say the timing changes on it's own when it's hunting, did you check the timing chain for slack.
Sorry if I didn't read everything you already did.
 
Sometimes those cheap knockoff distributors are junk from the beginning. So be careful with a "summit" distributor. All that means is summit bought it from the lowest bidder and slapped their name on it.
 
ZombieK5 said:
It slightly retards.
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Understood, I'm leaning towards it's working, damn thing started right up and ran nice for a long time as I timed it.

Drove it and it was total shit. Take it out if idle it runs like a beater just found in a field
 
ZombieK5 said:
Oh yea...I open the throttle to read the engine once I had it set at TDC and the advanced connector disabled and the engine would jump from TDC to about 8 or 10° Advance even with the advanced disconnector disconnected. I thought the engine should stay at TDC no matter what if the advanced connector was disconnected?
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I don't know if that's true under all conditions. You're stopping the signal from reaching the ECM, but it may be commanding some advance or retard for another reason. It's also possible the pickup coil/module is wonky and you're firing on a rising edge sometimes and falling other times. I saw this once with my crank sensor when there was a little piece of iron stuck to it (it's external). The timing shifted a certain number of degrees.

It's not super rare for the timing marks to be off. The balancer ring can slip or someone may have swapped some parts, as there was more than one timing mark setup over the years. It wouldn't hurt to verify with straw in the plug hole or something.
 
Blue85 said:
I don't know if that's true under all conditions. You're stopping the signal from reaching the ECM, but it may be commanding some advance or retard for another reason. It's also possible the pickup coil/module is wonky and you're firing on a rising edge sometimes and falling other times. I saw this once with my crank sensor when there was a little piece of iron stuck to it (it's external). The timing shifted a certain number of degrees.

It's not super rare for the timing marks to be off. The balancer ring can slip or someone may have swapped some parts, as there was more than one timing mark setup over the years. It wouldn't hurt to verify with straw in the plug hole or something.
Click to expand...
Not familiar with the straw in the plug hole?

However, before starting, I rotated engine over to confirm TDC with piston on compression stroke. Of the Balancer mark is off, it isn't by much
 
236K on a SBC? Oh boy, yeah, I guarantee that timing chain has a mile of slop in it. Now it may not be the only problem, but, it’s another place to start.
 
For a 7" balancer, 1 degree is about 1/16" on the balancer.

So to have any degree of accuracy you need a piston stop through the plug hole. But I like to remove the rocker arms first to make sure the valve don't contact the piston stop. You stop it on both sides of TDC, then true TDC is exactly in the middle.

However, if that problem was the issue, you would think just moving the timing one way or another would fix it, and it shouldn't be intermittent. The ECU doesn't know if it's off, it just adjusts based on its parameters.

Something is causing intermittent issues, bad parts, bad connections, bad grounds, bad ECU, bad ignition module, bad distributor, etc.
 
folkenheath said:
For a 7" balancer, 1 degree is about 1/16" on the balancer.

So to have any degree of accuracy you need a piston stop through the plug hole. But I like to remove the rocker arms first to make sure the valve don't contact the piston stop. You stop it on both sides of TDC, then true TDC is exactly in the middle.

However, if that problem was the issue, you would think just moving the timing one way or another would fix it, and it shouldn't be intermittent. The ECU doesn't know if it's off, it just adjusts based on its parameters.

Something is causing intermittent issues, bad parts, bad connections, bad grounds, bad ECU, bad ignition module, bad distributor, etc.
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I let it sit for 30 min. Turned key and started right up but surged about 5 times the went away.

Idle settled at 740rpm, timing is about 8 degrees advanced and it's running great. But it bogged down again when I drove it.

WTF??


BTW, it bogs down in reverse so I don't think it's a Tranny issue.
 
folkenheath said:
For a 7" balancer, 1 degree is about 1/16" on the balancer.

So to have any degree of accuracy you need a piston stop through the plug hole. But I like to remove the rocker arms first to make sure the valve don't contact the piston stop. You stop it on both sides of TDC, then true TDC is exactly in the middle.

However, if that problem was the issue, you would think just moving the timing one way or another would fix it, and it shouldn't be intermittent. The ECU doesn't know if it's off, it just adjusts based on its parameters.

Something is causing intermittent issues, bad parts, bad connections, bad grounds, bad ECU, bad ignition module, bad distributor, etc.
Click to expand...
I'm already shopping long blocks. ATK on Summit has a long block for about $3500 +core.

Bare bones, 4 bolt mains and is priced right. Thoughts ?
 
Check the plug wire routing a couple more times.
 
BoondocK5 said:
236K on a SBC? Oh boy, yeah, I guarantee that timing chain has a mile of slop in it. Now it may not be the only problem, but, it’s another place to start.
Click to expand...
Timing chain is an interesting Theory. I disagree only because the surging went away as as soon as I budged the the distributor
 
ZombieK5 said:
I let it sit for 30 min. Turned key and started right up but surged about 5 times the went away.

Idle settled at 740rpm, timing is about 8 degrees advanced and it's running great. But it bogged down again when I drove it.

WTF??


BTW, it bogs down in reverse so I don't think it's a Tranny issue.
Click to expand...

Does your battery voltage fluctuate a lot when it surges?

Have you tried adding or subtracting 4 degrees at a time to see if it gets better or worse or stays the same?

ZombieK5 said:
I'm already shopping long blocks. ATK on Summit has a long block for about $3500 +core.

Bare bones, 4 bolt mains and is priced right. Thoughts ?
Click to expand...

I think I would do a compression and leak down before I bought a long block.
 
folkenheath said:
Does your battery voltage fluctuate a lot when it surges?

Have you tried adding or subtracting 4 degrees at a time to see if it gets better or worse or stays the same?



I think I would do a compression and leak down before I bought a long block.
Click to expand...
No battery fluctuations

Compression is bad on 4 cylinders.

Dry Test
1, 3 & 4 150psi
2 120psi
5, 6, 7 & 8 90 - 94psi

Wet Test
The 90psi cylinders went up to 120psi

However, THIS problem did not happen before I went crazy and replaced a ton of stuff. Went thru my list at the start of this thread. This included a new fuel tank including a new in tank Delphi fuel unit.
 
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ZombieK5 said:
Timing chain is an interesting Theory. I disagree only because the surging went away as as soon as I budged the the distributor
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Slop in the chain only makes a difference in certain conditions when it can go back and forth.
I had mine running pretty decent then the next day it would be erratic then back to smooth.
The chain made it consistent.
Just another thing to check
 
imiceman44 said:
Slop in the chain only makes a difference in certain conditions when it can go back and forth.
I had mine running pretty decent then the next day it would be erratic then back to smooth.
The chain made it consistent.
Just another thing to check
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Sucks because I really don't want to take the whole front of the engine apart again.
 
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