i recently bought a 1994 Jimmy.
I followed the many different posts for trouble shooting, cranking no start.
Each time I replaced a part, it sounded closer to running, so I kept at it.
Started with "new" (rebuilt) Autoline spider as conditions led me to believe that was in part the issue. Didn't start/fire.
Cleaned out EGR. Did nothing.
Replaced fuel filter, tank and new pump. Tank is Dorman, pump is Delphi. Didn't start/fire. Fuel pressure koeo 62, holds over 55 for at least 10 minutes +.
Replaced cap and rotor, didn't start/fire.
Replaced spark plugs with ac delco, fired right up like it never had an issue. Ran for a few minutes then started surging. After about 5 minutes, shut right down, wouldn't start. Left it for several hours, tried again, hard start but did eventually start, after 5 minutes it again died.and wouldn't restart.
Tried this morning and after a difficult hard start, it ran again for about 5 minutes, with my foot on the pedal. If I let off, revs dropped and would stall.
This afternoon, it won't start at all, however, it sputters a little and tries to go, if I have my foot to the floor, but only fires for a moment then nothing.
I cleaned the IAC, did nothing to improve.
I'm stumped.....thinking I may have to replace the distributor and coil to eliminate them from the potential issues. I am on my own, so I can't spray starter fluid it while turning key on.
What's my next move? Remove plugs after cranking to see if they're wet? Remove plenum again to see if the "new" injectors are all up to par?
I just pulled the codes, 15-engine coolant sensor (low temp indicated), 22-throttle position sensor (signal low), 34-map sensor circuit error (signal low indicating high vacuum). Can I clean these sensors or have to replace?

 

Cleared the codes, tried starting again and got the occasional sputter, but not "catching" and running. But code 15 returned immediately.
Researched some more posts/forums/net and thought maybe it was an issue with the coolant temp sensor being that is code 15, which also is part of the Thermal Vacuum Switch which closes off vapours to the tank until engine is warmed up.
Have 5v to the plug so thought I'd check the sensor for operation. Put socket on it and it crumbled apart. So, off to the parts store and picked up a new one, checked it's operation with hot water and meter, it works so installed it. No change.
Last night, thinking why is this unit only firing after sitting for hours, perhaps weak spark so it only fires when fumes have evacuated. So, ordered a delphi coil last night on Amazon, arrived this afternoon. Gleefully thinking that has to be the problem, I installed it. Nothing happened with that addition either. At least I'm eliminating issues. Anyone have an idea? A friend said it was vacuum related, allowing unmeasured air in, I've changed the vacuum lines I can see and get to, that did nothing either.
Stumped....need help!

 

After replacing the coolant temp sensor, I now have code 14 and 15.
Both codes are opposite from each other regarding the sensor signal, how can that be?
This vehicle is clearly an engineering marvel, complements of GM.

 

So some info for readers. Code 14 and 15 will set automatically if you disconnect the pigtail from the coolant temp sensor (15) and if you jumper the pigtail (14).
I've had the engine stutter/spit/chug/surge and backfire, so I know its close.
Getting tons of fuel, you can smell it when cranking, so has to be something with spark.
Bought a set of spark plug leads yesterday, let it sit overnight and today if fired right up, without feathering the pedal. Ran kind of smooth for about a minute, then started surging again. In between the surge/shut down, you can hear the 6 cylinders (I hope its all six!) fire and surge, also comes with liberal amounts of flaming backfiring through the hole in the muffler, if you try to increase revs.
So at the least, if is firing up so that's encouraging.
But, there's no codes. Anyone have experience with a misfire/backfire/surge that isn't accompanied by codes???

 

When I first got the vehicle, I'd changed many things trying to get it going, including the oil and filter. Over the course of cranking trying to get it started, the unused gas had wound up in the crankcase. After changing both again, along with the new spark plug leads, the unit has come to life. No more backfiring, many hot/cold starts without issue.
It was a trying journey, as the codes thrown were inaccurate, although the spider and fuel pump did need replacing as both were faulty. So trying to troubleshoot something that had several issues to start with was difficult and frustrating.particularly when the initial codes did not return. I'd tested for spark and the spark plug leads, but they may have been in a weak condition although both appeared to be functional.

 

SPOKE TOO SOON!
This vehicle is really an engineering marvel as I posted before....
Took it for a drive to fuel up, about 15kms/10miles, each way. Ran great. That was two days ago.
Today, took it to town, about 20 kms/12/13 miles each way.
Ran great on the way there, on the way back slowing up to a stop light, I had to feather the pedal to keep from stalling.
For the rest of the trip home, it was running a little rough and trying to stall at intersections while turning, so had to keep one foot on the pedal, other on the brake.
Had to do some things around the yard, went to start about 3 hours later, fired right up, but running rough and after moving up the driveway about 50 feet, it stalled out and wouldn't start again.
Tried it a little later this evening, same thing, crank no start. Difference being this time (as opposed to when I was troubleshooting) I can't smell fuel.
Pulled code 32. I've done a little searching trying to find out as much as I can about 32. But, I can't see anywhere that the code would stop fuel flow.
Can anyone chime in with some assistance???

 

CONDENSED VERSION.
Bought the truck as a non-runner, but promised it was running before sitting. (likely several years)
Body/frame wise in pretty good condition for the rust belt here in Ontario.
Upon reading dozens of threads here and elsewhere, diagnosed issue after issue.

First was fuel pressure and related spider injector problems. Changed out fuel pump, which in turn lead to discovering rusted fuel tank, so replaced that, fuel pump and fuel filter.
That lead to the odd moment of temporarily firing.
Research suggested EGR plugged. It was a little congested, but cleaning it did not lead to a running condition.
Next up was the cap and rotor. That did nothing.
Pulled codes that indicated vacuum leak. Changes as many lines as i could get to. That also did nothing.
Those same codes did not return.
Replaced plugs and leads with Delco. Fired right up like nothing was ever wrong! But, shortly after (minutes) it began surging, sputtering and stalled. If left for a day it would do a rough start under similar condtions.

Note-When replacing a part, each time i attempted to start to see if that addressed the issue. Each time it seemed to either improve a little or it remained completely unreliable as to whether it would start, sputter, stall or simply crank no start. This vehicle had many issues being left dormant for a couple of years. :Likely false codes lead to replacing parts that may or may not have actually required replacement. But being that the vehicle is 27 years old I felt that replacement was best, at least to eliminate that particular issue.

Code 15 appears, addressed by replacing Thermal Vacuum Switch. Replaced switch, still had intermittent momentary rough start, stalling.
Crank no start condition continued. Difference being this time there was no fuel smell after cranking, which lead me to believe that the ECM wasn't allowing fuel to flow to injectors after initial key on (which is not controlled by ECM) Brought out two different spark testers, both indicated no spark. Just another of the intermittent issues that seems to plague this vehicle. However, with practically everything now new, there was really only the ECM or distributor left that could be the no spark issue.
Bought a new Spectra Premium distributor for $23 and installed it when it arrived 2 days later.
Turned key, and it fired up immediately. I've taken it out several times since, for about 200 miles total, countless cold and hot starts, no issues. Seems to run very well, with lots of power underfoot.

This was by far the most frustrating, longest troubleshooting period I've spent on a vehicle, literally 3 weeks of constant full day screwing around. So many things that could cause issues, were in fact, doing so. That being said, researching on this site at least opened my eyes to direction to follow, as symptoms that I had were mirrored by many other posters here.
However, this run range from 92 to 94/95 transition, are clearly saddled with a plethora more crank no start conditions then newer years.

 

Did you ever get it fixed? My 94w is doing similar things?