The 2.8l in my s10 below 2000 rpms has a funny idle, or pulls back on timing. I have checked cylinder compression, all are fairly close. This is a TBI motor, and I know its not in a 3rd gen, but people on here are WAY more knowlegable then on my s10 site. It ran fine before I pulled my intake off to fix a coolent leak. After I assembled it, it has this funny idle. Please throw some ideas at me to check or get my thoughts spinning. Thanks

 

vacuum/intake gasket leak. take back apart and use better silicone

 

No silcone to use, it was all hard "metal" gaskets. Could it be timing or anything of that nature? If I have to take it back apart, I am putting a mpfi top on the damn thing, and hope that gives me more power.

 

I tickered with it last night, found my 4 dist wires clamped underneath the dist hold down bolt, undid it, fixed the wires. It does it worse now. I very possibly moved the dist while doing this. Does this sound like a timing symptom?? Also, the prev owner possibly installed a very large cam in it, and maybe the 3.4l stroker kit, this thing has WAY more pull then any 2.8l I have seen. If it has a very large cam, does the timing need to me adjusted accordingly??

 

If the guy put a cam in, and messed with the valve timing (alignment of cam gear to crank gear), it could definately cause problems. Most cams now are ground to be installed "straight up", with 0 degrees advance/retard of CAM timing... whereas, years ago, you might get extra power by playing with the valve timing.

As far as IGNITION timing, if the cam is meant for the engine, you should be fine running at the stock spec. If the guy installed a narrow centerline'd low vacuum cam with huge lobes, it's a racing only/off road cam, and you'll never get good streetability (or pass emissions) with it.

Following chc's idea, try putting a vacuum gauge on it and see what you get. How did you drop the distributor back in after fixing the coolant leak? You might want to start from "nothing", remove the distributor, bring the #1 cyl up to TDC, and drop the distributor back in.

 

I did that with the cylinder 1tdc, infact, thats where it was when i parked it, and I didn't rotate the engine w/o the dist in it. It ran fine before I pulled it, and I have timing (I think) at 0 or 1deg. Unless I bumped it last night. I know the guy before me made the truck for racing, so I wouldn't put it past him for a huge cam. It just bothers me I didn't know, or check timing before I pulled it apart so I have no clue as to where it was before.