I've now invested almost as much into parts and tools that I have into the cost of buying this van!

I'm about to head back out front to play with this van again, but I'm seeing something which I'm not sure is good or not:

Base timing is 12 btdc (should be 10, according to the emissions tag), but running is sitting at around 24-26 btdc. I know the PCM can adjust it upwards of 10-12 degrees based on various inputs, but does this sound good or bad? When I adjust the timing downwards to 10, the engine starts to stutter a bit. Brought it to 8 the other day, and it actually sputtered and died.

Friend that works at a retail-chain muffler shop says that it's possible the timing chain has jumped? I know it's a lengthy procedure to get to the chain, and if I'm there, I might as well replace it if it doesn't look too good.

If anyone has any input, I'd really appreciate it. The van runs sluggishly, I give it gas and it doesn't respond very well, so I'm trying to get to the bottom of all of this. The computer isn't throwing any errors, either, at this point.

If it is like the old S-10s, you have to disconnect the tan wire to the ECM to get a correct base timing reading...

On this engine, there's a little wire (tan w/ black stripe) that you have to ground (located on the passenger-side column). Once this is done, base timing is in effect. I've done this and base timing is at 12 right now. When I unhook the jumper wire, I see 24-26 btdc for timing. This is where I'm concerned. :(

If it is like the old S-10s, you have to disconnect the tan wire to the ECM to get a correct base timing reading...

Well, even if the chain jumped, the relationship between base timing with wire shorted and not would still be the same number of degrees, I would think. It's been so long since I messed with one of those I can't remember if that spread sounds correct or not, but I think so.

How many miles do you have on it? Have you checked it with a vacuum gauge? If the chain jumped you'll have a very low idle vacuum reading, steady but low.

I'd like to think, as well, that base and running timing would be the same, but it seems that my PCM is adjusting the timing as far as it can adjust it, so there's an issue...

Well, even if the chain jumped, the relationship between base timing with wire shorted and not would still be the same number of degrees, I would think. It's been so long since I messed with one of those I can't remember if that spread sounds correct or not, but I think so.
Van has 102k miles on it, and I haven't done any vacumn testing on it as of yet. Not me personally, at any rate.
When the van runs, it sounds like there's a vacumn leak *somewhere*, though I haven't been able to pin-point it as of yet. Will look further into it, then. :)

How many miles do you have on it? Have you checked it with a vacuum gauge? If the chain jumped you'll have a very low idle vacuum reading, steady but low.

here is what i found on mitchell ondemand 5......


https://www.sharemation.com/tblake05/timing.bmp?uniq=rarw0k

appanently your not suposed to ground the wire, but simply disconnect it. Maybe that could be the issue. I did look up a 1994 lumina 1pv with the 3.1L V6, i hope that is correct.

appanently your not suposed to ground the wire, but simply disconnect it. Maybe that could be the issue. I did look up a 1994 lumina 1pv with the 3.1L V6, i hope that is correct.

Oh wow. I've never seen anywhere to plug it back into, no "other end" as it were. It's just dangling out there with nothing else connected into it. With it disconnected, the timing is scary, but with it connected it's 12 btdc. So now I'm at a total loss, besides vacumn somewhere, of where to go from here. Anything to my friend saying the timing chain may have jumped?

I'm installing my new torque strut right now, will take a look at this and try to find some good guage wire to wire into it and then report back how it goes! :)

I'm not sure if the automotive god(s) are smiling down on me, but found something interesting: A cracked vacuum hose boot at the rear of the throttle body (the second hose, facing the driver). Am going to see if I can find a replacement for that from AutoZone, or if I have to contact a higher authority.

Took off the air cleaner assembly to check for any loose/missing lines, and found one! Hopefully this'll help. I'll recheck timing after I get that put on, and I'll make sure to connect the EST wire back to ground again (can't find anything else it'd plug into...)

Thanks again for all the help, and I'll post again once I get everything put back together! :)

Replaced the vacuum boot, but nothing seems to have changed.
Found out a few nifty things, though:
- If you ground the EST wire, it'll go to a default value plus a little advance.
- The "other half" of the EST Bypass wire doesn't seem to exist; this is the other half of my original problem.
- With the wire disconnected (like it's been), it should be running at base timing. I'm finding it hard to believe that my base timing is 26 BTDC, which means that if I do find the other end of my EST Bypass wire, the entire timing curve is grossly off.

Another thought that occured to me: Could the previous owner have taken the distributor assembly out, and not put it back in properly, thereby killing the timing. I've tried to tweak the timing (with this dandy EST wire disconnected) and when I get close to about 20 degrees BTDC, the engine stalls and dies. Just a thought.

And if I'm missing anything blindingly obvious, please feel to point it out. I'm a newbie-type of home-mechanic, so I'm going through this half-blind, it seems.

did you find the correct marks on the balancer? Im not sure how yours is set up, but i worked on a car where the balancer was bolted to the crank with 4 bolts spaced evenly apart. there was a little alignment tab that got lost somewhere in the valve job, which made the balence bolt up in any direction. I didnt realize that untill i went to time the ignition, all the belts on and the car running very good. OOPS. So i ended up ripping the 2 V-belts off and the serpentine belt off and aligning the balancer correctly. I did realize (being a 4 cylinder and 4 different combinations the balancer could bolt up to the crank) that i could have just swapped through the plug wires with the timing light to find which one would work, but i decided to fix it right so the poor soul that has to work on it next time knows whats going on. 1992 mitsubishi eclipse gs 2.0L 4 cylinder. Apparently the timing belt was just changed, but they didnt inspect anything, cause the automatic tensioner went out, and the crank stripped the teeth off the timing belt and bent all 8 exhaust valves. fun job. But anywyas, just make sure you have it all put back together correctly, and know the timing marks on the balancer. It doesnt make sense though how mitchell ondemand say something different than what your doing. can i get a vin please, and i'll look up for sure exactly what it is? Not that i dont trust you, its just that a lot of times people buy cars and the seller says its a 1994 and it turns out to be a 93. just a thought. then i can get you the correct timing specs.

No worries!

VIN: 1GNDU06DXRT155061

Am going out right now to play with it some more and see where it stands. I can't find my vacuum guage to plug into cylinder 1 to make sure that TDC and the distributor match...

Cranked the engine to TDC (per manual, it says line up the timing line on the crank to the "0" mark on the timing plate) and the rotor seems to be sitting at 1, so I think it's okay on that mark.

Took another good look at the emissions label, and it says to set base timing, the ESC wire must be grounded and timing (per this label) is 10 BTDC. So I ground the wire, and eventually get it set to 10 BTDC and it runs rough as hell. Almost sounds like a diesel engine. Unground the ESC wire, and the timing shifts to about 22-24 degrees now.

I'm assuming that the emissions label is going to be the most accurate source of these points, versus the Haynes manual, so I'm following the label. I've tried to find any other possible point where the ESC bypass wire could plug into (including seeing if a wire got ripped out of the connecting harness downstream) but I can't find a single thing. So I'm running the engine without the ESC wire plugged into anything.

I have a 95, 3.1, apv and recently went through this. I first had to cut and install my own spade connectors as the EST wire had none. Once I had connectors applied I disconnect the connectors, letting them dangle and not touching anything. That allowed me to get to base timing. The timing advance IS much greater than the base timing. I also had the vacuum issue at the T-body. Had to get creative to replace that connection.

I have a 95, 3.1, apv and recently went through this. I first had to cut and install my own spade connectors as the EST wire had none. Once I had connectors applied I disconnect the connectors, letting them dangle and not touching anything. That allowed me to get to base timing. The timing advance IS much greater than the base timing. I also had the vacuum issue at the T-body. Had to get creative to replace that connection.

Replacing the broken connection the throttle body was fun. Borrowed another connection from another area of the engine and put an AutoZone packaged replacement on the spot where I borrowed. But it worked fine :)

What gets me about this ESC wire is that there's no evidence of there ever having been "the other end" of it down stream, just the wire sticking out of the bundle up at the very top of the right/passenger shock tower, so I'm at a loss. And the VEHI label says nothing about connecting or disconnecting a wire, just says to ground the wire to get base timing (I can snap a pic of these items, if anyone wants to see 'em).

ok, lets see, if you dont mind snapping a photo.

Then it is possible you also do not have a connector to disconnect...
I choose an easy access point on the EST wire and cut the wire, stripped both sides of the cut and installed a male and female spade type connectors with a crimp tool. Reconnect them and once the engine is at normal operating temp. disconnect the wire and set your base timing. There is an earlier post where I too linked a photo. Not sure how to get back to it. But it shows the lack of connectors.

Okay, my appologies for my long absense while you guys are trying to help me. Dealing with family and law-related stuff isn't as fun as one may think.

Posting a few pics to hopefully give the group more information:

http://www.tluw.net/images/94LuminaAPV/94LuminaAPV-ESCWire.jpg
(38.9KB - ESC wire where it comes out of the bundle, passenger shock tower)

http://www.tluw.net/images/94LuminaAPV/94LuminaAPV-VEHL.jpg
(70.8KB - The Emissions label for this vehicle, the timing didn't get included, but the label says 10 BTDC, iirc)

http://www.tluw.net/images/94LuminaAPV/94LuminaAPV-WiringHarness.jpg
(34.2KB - The wiring harness at the end of the wire bundle that the ESC wire should be in)

If I need to go through and make a connector for the other side of this wire, I have found where the "tan with black stripe" wire goes into the downstream wiring harness, but I'm not able to trace it back up to where it should terminate into a connector.

Thanks again guys for all your help!

im stumped, did you grab a compression or vacuum tester to verify cam timing hasn't jumped?

im stumped, did you grab a compression or vacuum tester to verify cam timing hasn't jumped?

I used to have a tester, but it's since gone south (no, really, I think it sprouted wings and flew south...) so I'm gunna' go get some from AutoZone if they rent them out.

The only other thing I was thinking was that the distributor was taken out and not put back in at Cyl 1 TDC.

I'll go through the compression and see what I can find!

but if the distritor was put in incorrectly, if you get the timing at 10 degrees btdt, reguardless if its off a tooth on the crank, it shouldnt matter, it only has to spin.

Okay, wow. It's been a while since I last typed in this post.

What's happened since:
* Found that the air-cleaner-to-throttle-body-mating-surface doesn't have a gasket, or rather, it looks like it's just disintegrated to death.
* The firewall-side valve cover: (the hole that the hose goes into that goes into the aircleaner) The hose fit into this very loose, which may account for the rough idle, perhaps?
* Still no "other side" of the ESC wire, but I've been able to (after fixing the two above issues) finally get base timing set to 10 degrees (yay!).

Took it in for california smog today, and it finally passed with flying colours. Everything was at or under AVG (with the exception of NO [15 MPH measured at 153, 25 MPH measured at 31...]).

Thanks again to everyone for allll of their help! Now I get to change the outter tie-rod ends... Stearing is sloppy, and the rubber piece on the joint is virtually falling off.

Gotta' love used cars! ;)