Chevy & GMC Vans

Finally got some things accomplished. Replaced the lower plenum gaskets, valve cover gaskets, upper gasket, cleaned all ports, egr, etc..., and started replacing vac lines. Started it today and it misses like mad and will only idle for a few seconds. Been reading a lot and I think I screwed up the timing when I replaced the distributor. I neglected to mark the rotor position. Doh!! #-o #-o

Not 100% sure if I need to pull the whole distributor again or just get a timing light and use the procedure in the manual (disconnect tan/blk wire, etc)?
Do I have to reposition the shaft before attempting to set the timing?
Do I have to find TDC?

I did figure out that if I disconnect the vacuum line on the passenger rear of the intake it will idle better, just not perfect. Does that mean anything?
If I turn the distributor CW it smooths out some too, but still misses?

Going to get a timing light tomorrow. Hopefully I didn't permanently screw something up.

Van is a 1995 LT AWD. Was running really rich prior to the above fixes. But it at least idled.

From what your describing,sure sounds like a bad vacuum leak over timing.

I found a line coming from the canister on the drivers side going back (not sure where it goes, guess through firewall) that is completely off. Will fix that and see what happens. Also going to get cylinder #1 to TDC and reinsert the distributor. Then set the timing. Ive never messed with timing before so we'll see how it goes.

One method for finding TDC before you pull the dizzy is pull number one plug,pull the valve cover for number one,watch the exhaust rocker go up and down,watch the intake rocker go up and down,insert a screw driver in number one spark plug hole,watch for the timing mark to get to -0-,look at the rotor to see if it is pointing at number one on the dizzy.If it is pointing on number one you don't need to pull the dizzy and if it isn't,you need to get a long screw driver for the oil pump drive slot and turn that with a flashlight shining down the hole so the slot is facing front to back straight.

the canister on the driver's side is the purge canister. the line routed to the back dives under the firewall and routes to the gas tank. If you are lucky (really lucky), resetting the timing will solve your problem. If I found myself in these circumstances, I'd surely try that first.
I'd say odds are your distributor shaft is off by a gear tooth or two. Frankly, having not marked the rotor position, I'm amazed it runs at all.

kings-x59 wrote: Frankly, having not marked the rotor position, I'm amazed it runs at all.

I agree. I'd start by re-timing the distributor. Or, since you're getting a timing light anyway, just check and see where the timing is at before you do anything else. If by some miracle you accidentally got it really close then it'll be an easy fix. If you've never used a timing light before it may be helpful to have someone with you that has. It's not rocket science, but having a guide always speeds up the learning curve.

WooHoo

Had a friend who is more knowledgeable than I stop by after work today to help out with the timing

Before he got there I swapped out my fuel pump since with the original one fuel pressure would drop 60 to 30 and then down from there within less than a min or two. Wasn't really too bad dropping the tank. Used my POS craftsman atv lift that now won't hold pressure. Anyway, got the pump in along with a new fuel filter. Pressure now holds just below 60 with engine off and running it is about 58 give or take.

Checked the timing first and it was showing about 40 deg advance. With trial and error we now believe it's right on. Seems like it was off a tooth or so. It is running much better. Idles fairly smooth and doesnt die and seems to have decent power. Friend said it pulls harder than his '88 s10.

Now to figure out the parasitic drain. The clock is always on. Should be an easy fix. Feels like it might need front rotors eventually too. It's also feels a little loose in the front, but I'm used to driving our jeeps that both have less than 20k on them so could just be normal for 200k.

For now I'm off to sit on the couch, have a beer, and watch Zombieland for the 3rd time this week. Gotta get up early to watch my nephew wrestle at states in Hershey in the AM. =D> =D>