Poor idle at startup

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Fourrunner

SILVER Star
Joined
Jul 30, 2003
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149
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1,780
Location
Syracuse, Utah
Well...tried just about everything. Recently replaced just about every common thing that might affect idle that I can think of and still seem to have rough idle at cold and hot startup. I have replaced the cap, rotor, wires, plugs, had the carb rebuilt by Jim and even through a vacuum gauge on it tonight. Last week i set the timing and checked valves to make sure everything was ok there. My timing was a little off, so I put it back into spec (7 deg. BTDC). I also found that the egr line that leads from the exhaust to the carb was completely clogged with carbon deposits so I cleaned that out. My vacuum comes in at about 17-18mm HG. When we say steady needle on the vacuum gauge, mine seems to flucuate about .5mm HG. Is that OK? What else could it be? It seems to run better, but not flawlessly at idle after driving around. Could this be the infamous cracked intake manifold issue? When the thing gets warm, the crack closes up, but not completly. Any thoughts would be appreciated.
 
Just for giggles ... run a secondary ground wire off of the fuel cut solenoid (FCS). Near the carb there's a connector for the FCS. Easy to patch a wire into the connector without cutting anything. Double check and be sure you have the negative ground wire and not the positive power.

If it works thank LowTide, he showed me this bypass. Somewhere there's a bad ground.

Cheers,
Cahil
 
No Problem....Only took me 1.5 years to figure it out (freakin a)
 
My land cruiser (fj62) has had a similiar problem. When it was cold or rainy and when i was in four wheel drive it had a hard time idleing. It took me awhile to figure it out I don't know if you have tried this but my air intake had a crack in it and it was letting unmetered air in, it also caused my engine to detonate under load.
 
Yes, but that does not always mean its good....Somtimes my FCS worked and somtimes it did not...Irratic ground...


Just run a wire to the ground off the neg. side......what could it hurt...its worth a try mandinga

I dint think it was my prob. either, til i tryed it and was mad I did not try it sooner...
 
In all my investigations, I noticed that a loud noise was coming from my smog pump when I disconnected the outlet hose from it. Would this affect the way the truck runs?
 
I don't think vacum is your problem, I have the same small "wiggle" in my vacum readings. I wonder if your EGR valve is sticking open?

Good times.
 
If you're pulling the egr there are three hoses on the that you should pull and plug. When my egr was sticking it ran like crap all the time.
 
Hey Hilander just noticed you where from Eagle River AK. That is where my brother lives..hehe. Anyway, will try that. I have a spare EGR valve so may try to replace it and see if that makes a difference.
 
Easy way to test EGR is to blow air into it while the truck is running. if it runs a lot better than the EGR was stuck. Usually a stuck EGR will cause the truck to almost not run at all with a horrible, lopeing idle. You can also use a vac sucker on the EGR and see if you can get it to move.

Hook the vac gauge up and adv the timing while watching it. Tke the timing af far advanced as you can. You will be at the limit of adv when the vac gauge rises then falls back a bit. Retard it a few degrees and see if it pings under load. If it pings retard a bit more.

Once the timing is advanced adj the idle mixture with the vac gauge. You should be able to get 20+ lbs of vac. This might very well fix your idle issues.
 

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