92 s10 blazer (W) Problems

[117mph1999]

For about two months my blazer was really hard to start and sometimes it would start right away even when cold but not a lot. About a week ago it start to stumble and what sounded like missing, a lot during acceleration so I quit driving it completely. Then I had to go stay with my girlfriend for a couple weeks so I decided to chance it and drive it over there so I could continue working on it. Got about 15 miles down the road and just died, and I have not been able to get it to start since. I was just pulling away from an intersection when it happened so was at a dead stop. Haven't seen any noticeable drop in fuel economy but it does seem like it was lacking a small amount of power during the time before it started stumbling. Haven't performed any tests yet but plan to do a fuel pressure test and possibly remove the upper plenum and check out the regulator and such.
I've replaced the sending unit and fuel pump, o2 sensor, fuel filter, cap and rotor and plugs.
Noticed the other day that the metal tips where the wire plugs into the spark plug is already rusty after only being on there for maybe 6 months and yes they are AC Delco.
Any ideas and let me know if you need further info.

[old_master]

If you squirt a shot of carb cleaner in the air intake will it start?

As for the rust.... when replacing plugs and/or plug wires, always put a dab of silicone dielectric grease in the plug boots, (both ends). It prevents rust by keeping moisture out, makes the boot easier to remove next time, and helps with the electrical connection. When replacing the distributor cap, put a dab on each terminal of the cap, inside and out.

[117mph1999]

Tried spraying starting fluid in the intake but no start at all.

[old_master]

Pull the coil wire out of the distributor cap, prop it up about a half inch from ground, (don't hold it) and crank the engine.... is there a good blue, not orange, spark?

[Rick Norwood]

I had this problem with a '93. Mine died when it was hot and basically would not start again. It turned out to be the Module in the Distributor. Before you pull everything apart, TEST. The Module can be bench checked at AutoZone.

[117mph1999]

Got a blue spark.

[old_master]

Ok, that's good! Plug the coil back in and check for good blue spark at each plug.

[117mph1999]

Forgot to add that I took off the distributor cap and there was build up on the inside part of the terminals as well as on the rotor tip. So I just picked up a new cap.

[old_master]

The "build up" is supposed to be there. When the cap and rotor are replaced, there should be a dab of silicone dielectric grease added to each terminal, inside and out, of the cap, (it helps conduct the current). When the engine is running, the current passing from the rotor to the cap causes the grease to crystalize.

[Rick Norwood]

Have you checked the fuel pressure yet? Can you hear the fuel pump 2 second prime cycle when you turn the key on? Stand by the gas cap door and have someone turn the key on and listen for it. When was the last time you changed your fuel filter?

[117mph1999]

Changed my fuel filter about 9 months ago. Checked fuel pressure and it was at 59psi. Since I've owned it it has always had a leak down problem which never seemed to prevent it from starting, unless it has become worse now but didn't look like it went down any faster and this last test I did. Checked everything underneath the plenum and it doesn't appear to be leaking in there. Yea I can hear the priming when the key is turned on.

[old_master]

Pressure is fine for 92 CMFI. Provided the pressure remains above 53psi for 5 minutes after the pump shuts off, it should be fine as well.

[117mph1999]

Forgot to mention that when I took off the upper plenum it was oil covered everywhere inside. And there was a 2 or 3 areas where it had a few drops of oil that had pooled. Could this have anything to do with my problem. Took some pictures when i removed the plenum.

[viggy58]

i dunno for sure, but i'd say that's normal, especially for the age. i did the lower intake gasket on my '01 last year and the manifold/plenum were caked with carbon/oil buildup.

[old_master]

Normal, although there does appears to be slight "washing" near the fuel pressure regulator. A fuel pressure and leakdown test would tell for sure if it's leaking fuel.