I have a 1987 chevy k5 blazer 5.7L T.B.I. 4x4 , it will randomly shut down like i turned the ignition off while turning right mainly and sometimes while driving straight. i have a check engine light that, the code is loose or defective prom and the steering column is loose at the tilt from years of people using it to get in the vehicle. im lost on where to begin trying to narrow it down. please if you have any info that may help it would be greatly appreciated. thank you for your time!

 

My first thought would be your ignition switch. i know that is a common problem for second gen blazers but im not sure if its also a common problem with a K5

 

Had a similar problem of random shut down while driving.
After months of trouble shooting its was a faulty Votage regulator inside the alternator.Occasionally the voltage regulator would overcharge casing the engine management unit to go crazy ,engine mis -fire and eventual stall.(every dash light and alarm would activate)
During one event I happen to glance at the dash volt meter as it spiked at +19 volts .
Located on ebay a new voltage regulator for a delco remy alt for about $20.
It was an easy replacement.
These altenators are not adequatly ventilated and the hot radiator hose loops past the rear cover , subjecting the regulator to overheating and premature failure especially in hot climates.
I hope this helps .

 

Thank you for the imput! I have been watching the voltage there haven't been any spikes but I have noticed when I crrank it and put it in reverse to back out of the driveway voltage only shows 8 and when I put it in drive it jumps to mid 13. I have also noticed the lower it gets on gas the more it happens. I just changed the fuel pump, the filter and relay but no change!

 

I'm also having a problem with the lock in the back. The key doesn't work, it is the correct key. I can roll the window down from inside but not outside?

 

Look for a junkyard 7747 ECM (VERY COMMON, any 350/700r4 '87-'92 1500 truck). Your motor won't run correctly when code 51 is set, but it will run "acceptably good" (I think prom error is code 51?). Ask me how I know... =)

Sounds like your problem is broken wiring somewhere causing the ECM to turn off unexpectedly. Maybe inside steering column, but most likely a bad ground or bad 12v wiring on firewall, alternator, and/or battery. The delco ECM is pretty resilient, but rapid power cycling could probably damage the circuit board and/or prom chip and cause the code 51

You can replace the bearings in your steering column, I know GM lists the parts on a '91 v3500 (but not on some other trucks, even though it was the same parts).

 

hey guys im having a similar problem, let me explain since ive been driving my 87 chevy c2500 with a 5.7l (not sure if its tbi) motor.
When my truck is in drive, and i stop/slowdown for a light/stop sign, she stalls out, if i slow her down in nuetral she 90% of the time she doesnt shut off, when i reverse she shuts off if i dont keep the gas on her, so parking is hella annoying on double side parking streets,( which i live on) if i have her in nuetral in a o MPH possition, and turn the tires around working the power steering pump, she tends to shut off also, could this be the alternator sencor causing all this? in park she idles fine also she will shut off 80% of the time in park, having headlights on makes it 50% of the time lol, i know its a old thread but thats what we're all here for, helping our chevy family strive! haha thanks for reading
Freddy,

 

Also on my way home from work, i got in the truck started it and took off trying to get the truck to stop at lights/stop signs it would not, at all, untill it got hot and the fan powered on then it started turning off, so in my theory, it only does it when it is Hot if its cold it will not act up,this is leading me to believe it has nothing to do with the fuel pump but im going to change the overcharge thing in the alternator, and change fuel pump and check my grounds hopefully i can find the little trouble maker thanks if anyone reads this, some help would be great, here or just email me it goes straight to my phone, shockey4n1@gmail.com

 

1. Open the hood and identify if you have a carburetor or a throttle body.


Answers will vary depending on what induction type you have.


2. I don't know why you would think the alternator would be causing the problem. Especially since you state that when your headlights are on the stalling decreases from 80% of the time to 50% of the time.

Sounds to me like everything has to do with fuel. Not the fuel pump though... Depending on the type of induction you identify in step one you will have a mechanical fuel pump on the side of the block or a electronic fuel pump in the tank. Those would be something to check but first you should look at the carburetor and/or throtle body.


3. Check for vacuum leaks. Rotted hoses, exposed wires, disconnected connections, anything that is out of place.