1993 S-10 Blazer 4.3 no start

[tire_doctor]

My son has a 1993 s-10 blazer with 4.3 vortec when the engine is cold it will start and run fine. After it has warmed up (2 miles or less) when the engine rpm drops below 1800 it will die and will not restart unless you jump start it,(sometimes it will start) (sometimes start with starter fluid) ( sometimes wont start at all) even though the engine cranks normally. It acts like it isnt getting fuel.we have tested for and it is getting spark, Sometimes the starter solinoid just clicks, before engaging, we have noticed the alt. gets very hot, (alt. was taken off and tested by shop cold, passed all tests) and now the battery wont hold a charge (new battery). Now for what has been replaced within the last 2 weeks new fuel pump, fuel pump relay, TPS sensor, Ignition control module, battery, battery cable ends, computer(local shop said no injector pulse, bad computer) didnt cure problem, we are at a loss the problem began 3 weeks ago, when it died you could start it right back up, but has gotten so now its undrivable. What am I missing, high voltage draw, a short, bad alt. Help

[ricksza]

First, if you are constantly running the battery down trying to start, the alternator is constantly charging which will cause it to get hot. If it's hot without running, it's a short in the alternator. You will kill the battery if you keep running it dead and recharging. If it has enough power to crank normal speed, the battery and alternator won't keep it from running.
The next time it won't start, you need to verify if it has spark, injector pulse and actual fuel pressure before it cools down. This will point you in the right direction.

[jsgold]

Just went through something similar ( I also have a 93 S-10) and I ended up replacing the fuel pump (needlessy) then discovered my ignition module and / or coil were putting out weak spark. I was fooled into thinking it was a fuel problem because when mine stalled it would hit on starting fluid. So, I ASSUMED the pump was bad. So much for that. Did not help and left me stranded. I ordered a CPI and nut kit but discovered the spark problem before I replaced that. I ended up replacing the ENTIRE distributor, and coil. So far, so good. But if you have replaced the ignition module already perhaps the coil then?? And as the previous post suggests, double check the fuel pressure. Could be a bad pump - right out of the box. These things take a LOT of pressure to run and stay running, more than I thought. I now have a new fuel pressure tester and a cheap spark tester to hopefully not make these mistakes in the future. Would suggest cleaning EGR, AIC, and, if all else fails, pull the plenum and check for a bad regulator. It is prone to failure as well and could be your problem when pressure and spark are known to be good. Be prepard to spend about 275-300 dollars for a CPI unit, gasket, and nut kit (hose kit).

[tire_doctor]

Originally Posted by ricksza

First, if you are constantly running the battery down trying to start, the alternator is constantly charging which will cause it to get hot. If it's hot without running, it's a short in the alternator. You will kill the battery if you keep running it dead and recharging. If it has enough power to crank normal speed, the battery and alternator won't keep it from running.
The next time it won't start, you need to verify if it has spark, injector pulse and actual fuel pressure before it cools down. This will point you in the right direction.

The battery isnt going dead due to cranking, it is going dead over night with no activity, as for the alternator, our outside tempature in Alaska right now is 0 and after 10 min of the engine running the altenator is hot enough to blister your finger when you touch it. My thought is when the engine rpm drop to idle position, the altenator cant provide enough voltage to run the electronics????? Im lost here

[Fireplug]

With key off does the alt get hot?? Did you check the engine grounds??? all of them??

[ricksza]

If the battery is bad, you can't run the engine off the alternator alone, too much draw between lights, fuel pump, etc. The alternator could be getting hot because it's putting out full amperage trying to charge a dead battery. This will distroy the alternator.

[jsgold]

It seems like there are two issues here. One, the truck stalls/ won't start etc., and two, the battery is not holding charge. If you have stalled out a lot and it is that cold, you may have overdone the battery, even if it is fairly new. I assume that the truck is even running enough to keep it charged??? Get that checked first. May have voltage but no amperage left. If that turns out OK then you will need to check voltage drain. unsure of most practical way to do that. Starter may be dragging as bit too, pulling life out of it.
Second problem, check my previous suggestion.

[Fireplug]

I have seen alternators short out and drain the battery. I have also seen ign switches short out and do some crazy things.
The first thing I would do is to get a load test on (volts and amps)the battery just to make sure its good.
Then I would check my fuel pressure to make sure its with in specs. If that all checks out I would look at the ign switch on the lower steering coloum and check for melted wires , loose wires anything that looks bad , wiggle them and see what happens.
Look for melted wires on the alternator and starter loose wires on both,
I have seen frozen belt adjusters cause pressure on the alternater bearing causing it to heat up fast.
Does it start ? do you have a dvom to test the voltage output??? when running>

[BlazerLT]

This sounds like a bad alt to me or a dead short going from the alt to the battery.

Check all cables going to and from the battery to the alternator and to the starter.

[tire_doctor]

Finally after hours of testing, guessing, and parts throwing, we found that the ignition control module that we had replaced was bad. We reinstalled a new one and it started right up. It is now up for sale, so who ever buys it will also get a new ECM, Fuel Pump, Fuel Filter, TPS, and Battery. Thanks for everyones help and responses

[BlazerLT]

Originally Posted by tire_doctor

Finally after hours of testing, guessing, and parts throwing, we found that the ignition control module that we had replaced was bad. We reinstalled a new one and it started right up. It is now up for sale, so who ever buys it will also get a new ECM, Fuel Pump, Fuel Filter, TPS, and Battery. Thanks for everyones help and responses

I don't get it, you get it finally fixed and running right and you SELL it?

Shoulda done that in the first place.

Now all this help was for nothing.