Okay, so my silence doesn't mean that I fixed the problem, unfortunately... Here's what I've had a chance to try since the last posting.. Different ignition coil, different CMP sensor, different TPS, blocked off EGR, different injectors.. I tried to buy a PCM at the wreckers but they were all the wrong models. The fuel pressure is about 47 psi, but the crappy gauge I have could well be off by several psi. It doesn't fluctuate under load. I have also double checked for vacuum leaks and found nothing, even pulled off the evap purge line and plugged it.

When I changed the CMP sensor I did have another look at the distributor and rotor and I can't imagine what could be bad about them that wouldn't be visible? The rotor doesn't wobble and the distributor looks almost new.

Fuel consumption is up almost 50% - the other night I noted (via the scangauge) that it was at best 14 MPG, and more often like 12. Getting past 35mph is a chore and 50 is pretty much the absolute limit.

I have not yet had a chance to do a compression test, I was going to this evening but I couldn't find the right size plug socket.

 

Thank you keeping us updated. Did you by any chance take a look at the exhuast system, maybe it starting to plug up. That would cause lack of power.

 

Yeah that was actually my initial thought as well, and I tried running it with the exhaust disconnected at the manifold, no difference at all.

 

Okay, another update - the problem seems to have something to do with the distributor timing, which from what I can determine, has something to do with the fuel injection timing, since a timing light shows it doesn't have any bearing whatsoever on ignition timing.

Does anyone know how to properly set the timing on this item? My coworker did a pretty good job of it last night but it still had a little trouble at idle sometimes, it would stumble and die, and this morning another coworker said it sounded like there was some detonation. So I stupidly tried to adjust it further, and can't get it to run as good as last night, but better than it was before.

I should add that I tried various positions of the distributor and while some were better and some were worse, I couldn't find one that eliminated the stalling/popping. It ran best at or near maximum advance.

Ii should also mention something I've seen once or twice while driving recently, the tach will 'bounce' for lack of a better term, just suddenly jump from say 2k to 3.5k with no corresponding change in engine speed, typically happens when accelerating.. But I've only seen it a couple times maybe. Crankshaft sensor?

PS I do feel like an *** for double posting. Just FYI

 

DISTRIBUTOR - 3.0L
REMOVAL
Disconnect distributor connector from distributor Distributor Electrical Connector - 3.0L Engine
Loosen distributor cap retaining screws.
Lift cap of off distributor.
Rotate engine crankshaft until the distributor rotor points to the intake manifold plenum. Scribe a mark on the plenum in line with the rotor. The scribe line indicates where to position the rotor when reinstalling the distributor.
Remove distributor hold down nut Distributor Hold-Down
Carefully lift the distributor from the engine
INSTALLATION
Position distributor in engine. Make certain that the O-ring is properly seated on distributor. If O-ring is cracked or nicked replace with new one.
Carefully engage distributor drive with gear on camshaft. When the distributor is installed properly, the rotor will be in line with previously scribe line on air intake plenum. If engine was cranked while distributor was removed, it will be necessary to establish proper relationship between the distributor shaft and Number 1 piston position as follows:
Rotate the crankshaft until number one piston is at top of compression stroke.
Rotate rotor to number one rotor terminal Distributor Cap Terminal Routing, View from Top of Cap
Lower the distributor into the opening, engaging distributor drive with drive on camshaft. With distributor fully seated on engine, rotor should be under the number 1 terminal
Install the distributor cap. Ensure sure all high tension wires are firmly in the cap towers.
Install hold-down nut and tighten Distributor Hold-Down
Connect distributor electrical connector to distributor Distributor Electrical Connector - 3.0L Engine

 

Yeah, I've got the distributor gear set correctly (it actually won't run out of phase), but on mine the hold down bolt hole is slotted so the distributor will rotate like on a 'normal' engine. I have no idea how to correctly set this particular timing, and my Alldata doesn't show anything useful in that vein either. I've tried it on the "factory" setting (seen by where the washer obviously sat for many years) and that's no good, almost completely advanced seems to be the best but it's erratic at best. Maybe I should take a video today?

 

Well I know what is wrong with the van now - on the way home (maybe a block away) it made some heinous grunk-pop sounds and then *really* ran like poo. I let it cool down a bit and tested voltages on the CKP, had my leads hooked up and went to start it and it didn't sound right at all - like it was turning but had no compression. I thought maybe the starter maybe wasn't engaging fully or something and thought I'd check and see if the flex plate broke at the same time, so I pulled the starter.. Bottom line is the starter's fine, but the flex plate will turn all day while the other side of the motor just sits still.

It's sort of ironic that the flex plate turned out to be the problem, as I have read a thread about that and thought the guy was describing *exactly* my symptoms, except my van wasn't making any odd noises... until my drive home.

I'm planning on doing this on saturday, I will let you guys know if this is the problem for certain or not.

EDIT: Well the flex plate was totally broken, right around the crankshaft mating face. Presumably while it was cracked and rotating, part of the plate was rubbing on the oil seal housing, which caused a lip to form around the oil seal - I got it out okay but ruined an oil seal before I noticed the problem. I had to chip the major portion of the lip out with a screwdriver and then file it down to get the new seal in. We only got to the point where the transmission is back in and partially bolted on yesterday, so I haven't fired it up yet but we will finish it early today.