S10 2.2L Cuts off while driving, then won't start

[NovaRod]

I've been working with a friend who has a problem with his 96 Isusu Hombre 2.2L (same as S10). Runs fine, then intermittantly cuts off. He pulls to the side of the road, and tries to start it. It cranks but won't fire. He waits about 10 minutes or so, then he starts it up just fine. No computer codes.

Now, I've read over a dozen threads on this forum about this specific bug, but noone has yet been able to document a fix.

Come on now, the one who documents a fix will win the prize!! Please help these poor souls who are struggling with this bug. It is obviously a common problem with S10's.

Thanks and Happy Motoring!

PS: I'd fix my buddy's problem, but I'm in Alabama and he's in New York.

NovaRod
72 Nova 2-door Coupe
4 speed BW ST10
406 small block
chevy 12-bolt 3.73 gears Auburn posi

[SD45]

Thank you Rod for posting my problems. I thought I'd add a bit more info. Starting the vehicle is a more common problem then quitting while running, with similar symptoms to other's problems that I have been reading here. Something different with my Hombre is that the problems starting appear to be weather related. They happen in times of drastic temperature change, in the Fall, Spring, and Winter. I've never had a problem in the Summer.

The following work has been performed- new fuel filter, 2nd ground put in, spark plug wires have been replaced, the relays replaced and a crank case sensor has been replaced. The next step is (was) to have ICM replaced but from reading other posts this does not fix the problem.

Hopefully we'll have an answer soon.

Joshua

[blu night]

Had the same problem on a 3800 olds replaced cam sensor and ran fine after. Hope this helps.

[mjfdesigns]

I have a post here as well
I ran the diagnostic test and found that
I have a bad coolant temperature sensor.

10 bucks and change at autozone

have not had time to put it in yet.

- Mike

[NovaRod]

I'm guessing the cam sensor is the same as the crank trigger? Anyway, that has been exchanged. No fix.

I like the thought of the coolant temperature sensor because if the sensor is defective, the engine would think it's cold (when it's hot) and not adjust itself correctly. I had a '93 Ford F150 that had that problem and what a problem it was!

Has anyone considered the coil pack or ECM?

How about the possibility of a fusable link that is intermittantly failing?

Josh, you may want to check the fuel pump when this failure surfaces. When it cuts out and you go to start it, do you hear the fuel pump prime itself?

I think it's important to keep this thread going so we can capture this problem. Thanks for your replies!
NovaRod

[SD45]

Rod,

Josh says he hears the fuel pump prime before he cranks it both when it starts and when it fails.

Relays in back of glove box dropping out (but not always!) suggest a voltage drop somewhere - bad connection, high resistance link?. Couldn't that throw everything off and the ECM would tell "DON'T START"?

mjfdesigns post which resulted in coolant sensor reads like a different problem, IMHO.

Oil pressure sensor and fusible links sound like low cost things to try next.

Also need to confirm (with tester) if spark continues present when failure occurs.

[bj126821]

My s-10 is doing the same thing once a week, I 've changed the ignition switch, crakshaft sensor, ignition mod. This is very frustrating. I to will send a prize to the person who has a fix for this.

[xtremetrk]

Originally Posted by bj126821

My s-10 is doing the same thing once a week, I 've changed the ignition switch, crakshaft sensor, ignition mod. This is very frustrating. I to will send a prize to the person who has a fix for this.

It's the fuel pump cutoff switch. Located on the right side of the engine. The dealer will be able to tell you where. Do i get a prize?

[NovaRod]

OK everyone, go out as fast as you can and find the fuel pump cutoff switch!

Can you elaborate any on this? Is it an overload type of switch, or did the dealer who originally receive the truck forget to turn it on and these poor folks have been wandering aimlessly trying to find out why life was so mean to them?

Also, (I am a bit thick here) is it to the right as you face the engine or as you sit in the driver's seat?

[xtremetrk]

If your looking into the passenger side wheel well. Its the oil pressure sensor. Its also the fuel pump cut off switch

[NovaRod]

Just slap my forehead!!!!
I had a 74 Corvette that I put an electric fuel pump on and wired it to cut off when I lost oil pressure.

A good catch. You are truely a gifted gearhead!

Thanks for the post. It looks lie a good piece of intel.

[bj126821]

Does the fuel pump cut off switch cause the relay clicking noise from the glove box???(don't want to sound stupid) and why would it only cut out once in a while and not all the time ?

[xtremetrk]

The clicking noise your hearing is the fuel pump relay clicking. That means its working. I think becuase it shuts off once in a while is that maybe your oil pressure is dropping.

[NovaRod]

My guess would be that the oil pressure sensor (i.e. fuel pump switch), if defective, may fail not only intermittantly, but could drop from the normal 12 volts to something less, thus causing relay chatter. The relay chatter is caused when the pick voltage is less than needed. The theory behind relays is that it takes more to pick a relay than hold the relay closed.

This is classic failure, imho.

The reason many mechanics and dealers fail to find this type of failure is that they are weak in the electrical skills necessary to troubleshoot electrical/electronic problems. Their skills are strong mechanically, but not in electrical theory (i.e. trace a ladder diagram, understand loop and nodal analysis to isolate a complex circuit loop, etc.).

Nova Rod

[NovaRod]

xtremetrk is on to something. Look at two things here: is the oil pressure dropping or is the oil pressure good and the pressure switch defective?