Thanks for the great leads Blazer Forum members. Have removed the fuse panel from the firewall, this morning, and discovered it was very lubricated with some sort of fluid (tar? oil? or?) at the receptor connectors. Not yet sure if this could be it, but also ran a code diagnostic yesterday which came back fine. Seems like the only the left at this point. I appreciate the advice about the ground at the battery. I think the end connecting to the negative post actually IS corroded. I will repair and retest.

 

sounds like disty module gone bad just did mine 2 weeks ago hasty but did the trick and a new coil ? how many miles on carb and is carb electrical cause i have 83 no o2 sensor or electric carb

 

Thanks for the tip about the ground wire. I did remove both cables from the battery, and although they were clean, I wire brushed the side mounts, terminals, and side mount bolts. However, I did not clean the other end that mounts to the frame. I am going to bundle up and venture out into the snow to take care of that this afternoon. I'm also going to look into the oil pressure gauge sending unit as mentioned here. I have been told that as a safety feature designed to save the engine, power to the fuel pump is cut off if the vehicle thinks there is no oil pressure. We'll see what happens...

As always, thanks for the tips, hints, and suggestions... much appreciated!

I did replace the ignition module in the distributor cap last year. Similar symptoms... was running fine, shut off while driving, would crank but wouldn't start. However, I still had power to the fuel pump, but no spark at the plugs. This time around, I have spark at the plugs, but no power to the pump... The trials and tribulations of process of elimination... lol

 

I did go out and clean the thicker ground wire that goes from the negative battery terminal to the engine block, and the thinner ground wire that goes from the negative battery terminal to a bolt right beside the socket for the passenger side headlight. Neither connection showed any signs of corrosion, rust, dirt, etc., but I cleaned them anyway. This had no impact on any of the problems.

I read in a different post that there are three grounds on the vehicle. 1. Battery to frame. 2. Engine to firewall. 3. And what was described as a ground underneath the vehicle in the area where the passenger's feet would rest.

As I already mentioned, I have two negative cables coming off the negative terminal of the battery. Thick one goes to the engine block to the passenger side of the water neck/thermostat. Thin one goes to a bolt near the socket of the passenger side headlight. I can not locate a ground wire/strap that goes from engine to firewall, or anything resembling a ground wire/strap underneath the vehicle near the passenger footwell as mentioned in the other post. Possibly a difference in years?

Trying to locate oil pressure gauge sending unit: I have read other posts, and checked suggested locations for the oil pressure gauge sending unit, but I have yet to locate mine. I have nothing near the remote oil filter that resembles a sending unit for the oil pressure gauge. Nothing with connectors, tubes, or wires. The nearest thing is two black ""modules/relays/sensors/???", each about the size of an ice cube, mounted side by side on the driver's side fenderwell, but closer to the master cylinder than the remote oil filter. I have nothing on the firewall that appears to be an oil pressure gauge sending unit. Now keep in mind, I am used to carbs and mechanical fuel pumps... the days when you could take the hose at the opposite end of a mechanical fuel pump, stick it in a drywall bucket full of gas, and be on your way... As far as computers, relays, sensors, modules, correct current, correct pressure, etc. etc. etc., I find that to be a little unfamiliar and a lot frustrating. Any... my point... I have found two things that in my mind resemble a sending unit... One is a "plug" with two wires coming out of it to the passenger side of the water neck/thermostat, right beside where the negative battery cable connects to the engine. The other is a "plug" on the passenger side of the engine block with one wire coming out of it. It is mounted in line with, and between, two spark plugs, and has a hard plastic boot around it. When researching oil pressure gauge sending units in other posts, I did not see either of these mentioned. So if anyone has any ideas, please let me know. We actually have some sun today, and it might get out of the 30's, so it might not be a half bad day for wrenching on the Blazer. I really don't want to take her to the scrap yard, but zoning is very strict about vehicles that don't run, so my time is running out... open to any and all ideas...

And if anyone comes across this without seeing my original post...

1989 s10 Blazer, 4.3, 4x4, Auto.

 

Found that the wires that supply power to the fuel pump, fuel guage, and the rear tail lights all run under the carpet by the drivers feet. Now my Dozer-bot is from Washington where moisture is THE main car-killer. The wires to the fuel pump were COMPLETELY fried and had partially melted the power supply wire (always hot) causing power to be transfered from the fuel pump to the tail lights! Re-routed the wires from the floor-board to the A-pillar and over the drivers-side door, down inside the panel for the seat-belt, then aft to the fuel pump, etc... AFTER finding this, the truck STILL didn't run. Dropped the tank AGAIN to find the short in the floor had melted my 2nd fuel pump. Replaced with a 3rd fuel pump and DOZER is back to kicking Decepticon tail once again.

 

have a 1986 s10 blazer the fuel runs all the time pulled the realys on the wheel well but it still runs any segs.

 

Billygoat, I am a little confused by your post, but I will toss a few things out there in case something helps. You mentioned pulling the relays on the wheel well. On my 1989 s10 Blazer, the fuel pump relay is located on the firewall. It is black, about three inches by three inches square, and about 1/4 inch thick. If you are standing in front of the vehicle looking at the engine compartment, it is a little to the left of the windshield wiper motor. You may have pulled the wrong relay.

 

Are you still having problems with the interior lights and the fan blower? I know whenever I blow my Horn/DM fuse that it kills the interior lights, horn, and rear hatch button among other things. I'm sure you checked the fuses but I thought I should mention it anyway. As for the blower working in every speed but high, it might be your high speed blower relay if your truck is similar to mine in that sense. I had the same problem and replacing that fixed it.

 

I'm also having issues with the cranking but not starting. I've replaced the fuel pump, the cap and rotor.. changing the fuel filter out tomorrow. I don't know what's going on with it. Came out from work one evening and it just wouldn't start. Strange. I'm hoping it's not an electrical issue, as I know Jack Squat about things like that.

 

In many ways electrical troubleshooting is easier than mechanical troubleshooting. The first thing you should do to troubleshoot a fuel pump issue is find the fuel pump test port. Run a test lead from the positive terminal of the battery to the test port. Check and see if the fuel pump comes on when you apply power to the test port. If it comes on when you apply power then you know that your fuel pump is getting power.