engine idling; timing prob.

[fxjnkmn]

Hello, I've been trying to fix my timing { 86 4.3 v6 carb type} for awhile someone told there is a timing thing hooked up to the distributer that maybe bad? I've ckd weights , vaccum, timimng chain, carb, it doesn't advance the way it should, and the idle is weird, I set it right ,but it runs on when shut off in park, or neutral.  

[roundedline]

I don't know what is causing the problem, but the thing connected to the distributor is the ESC if it is still there.  here  is a write-up on how to remove it.

www.73-87.com/7387garage/...screpl.htm

Chris Lucas
www.73-87chevytrucks.com
www.captkaoscustoms.com
Project Su
Jimmy 2WD Project

[Lt.Del]

As for your dieseling when turning the ignition off, it shouldn't keep trying to run on.

Here's what you can try...

Retard the timing a tad.  Throw a cooler spark plug in.  Ensure throttle plate closes all the way, leaving it open some after cut off lets too much fuel in the motor.  Decrease the idle rpms.

Try a few of these things and see what happens.


SgtDel

www.delbridge.net

[fxjnkmn]

Thanks, that's exactly what I was looking for. I've Played around with the timing, when I retard it just alittle the engine won't idle in drive, then I return the timing, and it won't shut off, knocking like it wants to jump out on the driveway, it runs above idle fine. I put a new timimng chain, carb, cap, wires, 3 different plug ranges. the dist cks out good. I've heard of doing this but only second hand, now I can fix my truck. I will post the results, again thank you, this has been driving me nuts for 2 years. Don

[Lt.Del]

You have mentioned you checked the vacuum.  You may want to recheck that.  If you turn your distributor so that it will idle, you say it diesels.  When you trun it back, it won't idle.  Not idling when the timing is right tell me

a.  Your idle screw is too low

b.  or, you have a vacuum problem, causing the engine not to idle correctly when timing is right.

For a vacuum diagnosis w/ out a vacuum guage, idle your engine. Take some starter fluid or WD40 and start spraying it around possible vacuum leaks.....intake gaskets, carb gasket, vacuum hose attachments, don't forget behind your carb--the vacuum connector into your intake that connect trans modulator (on auto trans).  That puppy should be screwed in tight.

When spraying, if the rpms go up, you found a vacuum leak.

You get the idea

SgtDel  

Edited by: SgtDel at: 12/24/05 12:50 pm

[fxjnkmn]

Well I got it done today, and everything is great, after disconnecting the timing control box, I reset the timing it, was about 4 degrees off . Now for the first time in 2 years, my truck shuts off in park, while the idle is nice in drive.  The drivablity is much better. futher tuning I was able to lower the idle mixture 3/4 of a turn.  So  thanks alot for the best help I've gotten oline so far.  Don

[Lt.Del]

Congratulations on finding/correcting the problem.  Luckily mine is a 79 and I don't have to worry about that.  It sounds like that timing box is a common malfunction on those year vehicles.  

--learn something new everyday.


SgtDel