'95 Chevy S10 not starting

[kl3vr]

Hello!

A few minutes into a summer's evening drive, the engine shuts off and will not start.

We've determined that there is fuel to the fuel injectors and they are clicking. There is a strong spark coming from the distributor. When there is fire, from cranking the motor, it results in a backfire in the intake manifold. As for the OBD, it's a 16 pin connector that when I shorted pins 5 and 6 (top-right pins) with a paper clip, gave all code 12s (not sure if it's OBDI or II)


Any ideas?

[vgames33]

I'm guessing its a 4.3 since you mention a distributor.

How did you check the injectors? I thought the 4.3 Vortec engine ran that spider assembly inside the manifold?

All I can suggest is to check fuel pressure (with an actual gauge, not your ear), ignition timing, and compression.

[kl3vr]

Sorry, its the 4 cyl., distributor may have been the wrong word. A mobile mechanic came by and said he could hear the fuel injectors clicking and could smell fuel, but no actual tests were done.

I'm afraid all those tests are above my ability, as i have no gauges or timing testers.

[vgames33]

2.2 has a coil pack with no distributor. It should have external fuel injectors as well, but I'm not 100% as to whether or not it has a test port.

You can try a little starting fluid into the intake. If it fires for a few seconds, your fuel pressure is low/no fuel present. If not, start looking at ignition timing or a mechanical failure.

Was there any symptom of a pending failure, or did it just happen? Does the engine sound the same as it always has while cranking? If it sounds like its spinning faster than usual (no load on the starter), its possible you lost a timing chain and have no compression.

Unfortunately, its hard to point you in the right direction without any testing equipment.

[kl3vr]

Hey, thanks for the reply.

The timing chain was recently replaced and yes there were known compression issues. It has ran for years with low compression. As far as I recall, it just happened.

I can't discern any difference in the sound of the cranking between now and before.

The starter fluid sounds like a good place to start.

[j cAT]

Originally Posted by kl3vr

Hey, thanks for the reply.

The timing chain was recently replaced and yes there were known compression issues. It has ran for years with low compression. As far as I recall, it just happened.

I can't discern any difference in the sound of the cranking between now and before.

The starter fluid sounds like a good place to start.

with a sudden engine shutdown this can be the fuel pump. being carefull to not spray too much starting fluid into the intake see if it does start up for a time if so the fuel pressure need testing. with no codes this is what it could be.

if you operate the vehicle with low fuel level this is common failure..also at this age .

[kl3vr]

Thanks all for participating. A mechanic came last weekend and checked it out, we tore the engine apart and appear to have found the culprit. I figured I'd post our findings for future readers.
We started with investigating the timing chain, as it was recently worked on. Taking off the timing chain cover, we saw that the plastic tensioner had been chewed up and a piece had broken off. He determined that the timing was off and that the chain had most likely skipped a tooth on the sprocket. After a few attempts trying to adjust the timing and get the motor started, with no success we were back to square one. Some more fiddling around and we came to the conclusion that there wasn't any compression.
With the timing chain off and with cylinder 1's valves closed, and with a pressure gauge screwed on, rotated the cam and thus compressed the cylinder, which proved there was zero compression. Grrr.
So we moved on to removing the head to inspect the valves, look for leaks. With the head off, it became obvious that all 4 cylinders had collided with the intake valves and bent them.
What we also noticed is that the upper gear from the timing chain had chewed up inner gears. There was also a wear pattern on the back plate holding the gear showing that the gear wasn't perfectly straight! Also, the chain doesn't align with the tensioner, it sticks out past the plastic.

So, what we're looking at is a full rebuild to inspect the cam shaft and bearings. We could just replace the valves and re-align the timing and it might run fine, but this being the second time I've had a timing chain issue, I'm afraid it'll only get worse. This mechanic has given me a $300 estimate in labor to do an upper and lower rebuild, plus parts at cost from an online supplier. What do you guys think? Is a full rebuild my best chance? any suggestions or stuff I should look out for?

[j cAT]

get a scrap yard engine. 1995 is too old to rebuild an engine with this much damage. see if you can find one used in good shape.

[kl3vr]

If I do an engine swap, I'd want to put in some more power!
Will the v6 4.3L be a drop in? How would I go about finding a compatible motor that will be as simple as possible, plug and play?

Does anyone else think that doing a complete rebuild is a waste of time & money if we can do it for under 700$?