4.3 Chevrolet won't start

[bigz1001]

A 1998 Chevrolet Blazer with the 4.3 running fine, sputtered out then just died and will not restart. After checking all the fuses they are fine, and a shot of starting fluid didn't even make it hit, what else can I do to trouble shoot this engine? Does anyone else have any ideas?

[grass_cuttin_fool]

4.3 are very famous for the distributor cap going bad, most of the time they start by running ruff or It might be the module in the distributor

[Eric 1]

How long did it run rough before it died, how many miles are on it, have you ever tuned it up, did it run bad hot or cold or both.give us more info.

My guess would be coil, dist. cap , fuel pump, MAS air sensor, or map sensor.

[bigz1001]

How long did it run rough before it died, how many miles are on it, have you ever tuned it up, did it run bad hot or cold or both.give us more info.

My guess would be coil, dist. cap , fuel pump, MAS air sensor, or map sensor.

The vehicle has 80,000 miles on it, it had ran rough the day before. The engine has never ran hot or cold, it has always made it to normal operating temp and just stayed there. The engine has had new spark plugs, recent oil change, and a new fuel and air filter.

[grass_cuttin_fool]

I would start with a new dist cap, fairly cheap and easy to do and at 80,000 miles its about due

[riches139]

I had a gm motor that the rotor cracked and grounded through the distributor shaft.
Might check and replace both at the same time.
Control module won't make it run rough. It either works or not.

[bigz1001]

New dist cap didn't fix the problem, bought the rotor as well but was not able to install it because I didn't have the right size star with me, going back to change it now. Any other ideas?

[Eric 1]

By "rough" was it surging or fees like it is going to stall? and did it do it at all RPM's .

If you can, get a timing light and put it on the coil wire to see if you have spark, if you do then put it on a plug wire to see if it is coming out of the dist.

If there is no spark at the coil then put a test light on the coil power wire to see if it is getting power there, if so you need a coil.

If there is spark, at the coil but not the plug, then something in the dist went bad.

If there is spark at the plugs, then it is a fuel problem.

This will help you greatly narrow your problem instead of just throwing parts at it hopping for the best.

[bigz1001]

Thanks for the help, new dist cap and rotor button with no luck so far.

[xcopterdoc]

If no spark, check coil, ign module and crank postion sensor. All are known to be problems on the 4.3. Just a matter of narrowing it down, next to impossible to troubleshoot here. Easy in the shop with a test light and dvom.

[TJLC]

Maybe a little off subject but my Chevy 4.3 runs ruff from a cold start. The real problem occurs after it is fully warmed up, shut down for about a 1/2 hr or so and then restarted and ran. It then spits and sputters and dies until it runs for about 10-15 min and then it runs OK but ruff. This senerio happens almost everytime. Thanks for any help you can give me on this.

[Eric 1]

TPS
MAS air
MAP
Temp sensor (acts as choke)
Coil


Take it to a shop. they hook it to a scan tool and in 10 min tell you exactly whats wrong.

[TJLC]

TPS
MAS air
MAP
Temp sensor (acts as choke)
Coil


Take it to a shop. they hook it to a scan tool and in 10 min tell you exactly whats wrong.

I took it to the shop and they hooked it up and said 3 codes came back. Egr, o2 sensor and rich exaust. They replaced the o2 sensor but it's still doing the same thing. I called them and told them it was still messed up and I would bring it back in as soon as I could. I had hoped for the $200.00 they charged me to hook up, test and replace the o2 sensor it would have been fixed.

[Eric 1]

See thats info we needed in the first place. :)

My dads 4.3 did the same exact thing, it is the EGR. it gets plugged up with carbon and stuck open. you have to remove it and clean it out. Ours was noticeable immediately, there was a huge chunk stuck in the valve. We had to do this proses repeatedly for about a week till it stopped. i got to were i could do it in about 20 min totall. 1 thing is DO NOT do it when the engine has been run, you will be burned. i would not recommend replacing it just yet, clean it and see what happened.

P.M me and i can give you extreme details if you like.

[Eric 1]

I had hoped for the $200.00 they charged me to hook up, test and replace the o2 sensor it would have been fixed.

Wow thats alittle steep. :dizzy:

Hey BIGZ, did you get it fixed yet, I am curios to see what the prob was.

[bigz1001]

As a matter of fact I did, but this leads me to another question. After replacing the distributor and rotor button with no luck I took the advice of the timing light and determined it was the ignition coil (Thanks a bunch). And I have it hooked up and zip tied in there right now and it started with no hesitation. My question is, how am I supposed to mount the new one? It came with 2 metal straps and 4 nuts and bolts. The other one is however made into a "bracket" and held in with studs, do they want me to drill the studs out and make other holes for the new coil, or am I missing something much easier? Thanks again!

[xcopterdoc]

Sometimes bigz thats what ya have to do , depending on the aftermarket maunfacturer. Just make it work best ya can. Glad ya got it fixed. These engines are work horses and very easy to diagnose in person.. ie. HANDS ON!
Just because my old uncle Ed's 92 did the same thing dont mean squat! Throwing parts at a problem has never and never will be a diagnostic tool. On the same hand, all the diagnostic equipment dont mean squat if Joe Bob cant read or doesnt want to believe what he's reading. ANYWAY! lol!
Our next class will be on EGR systems.. Pm me for that one if ya wanna know!

[bigz1001]

Yeah, this thing doesn't seem like it was engineered with repair in mind. I drilled the rivets out and things went smoothly from there. Replaced it and re-bolted that bracket and the 4 others that I had to take off to remove this one. Woulda saved some money to try more diagnostics on the thing before throwing parts at it, but I figure taking it to the shop and letting them figure it out woulda cost me more than the $40 in parts that weren't needed(the rotor button was a little messed up on the end and the distributor cap had some corrosion on it, might be money ahead to have went ahead and replaced them. Anyone ever replaced a hub assembly on one of these?

[Eric 1]

Sometimes bigz thats what ya have to do , depending on the aftermarket maunfacturer. Just make it work best ya can. Glad ya got it fixed. These engines are work horses and very easy to diagnose in person.. ie. HANDS ON!
Just because my old uncle Ed's 92 did the same thing dont mean squat! Throwing parts at a problem has never and never will be a diagnostic tool. On the same hand, all the diagnostic equipment dont mean squat if Joe Bob cant read or doesnt want to believe what he's reading. ANYWAY! lol!
Our next class will be on EGR systems.. Pm me for that one if ya wanna know!


Hey now,

I was just trying to help him, he said what the shop told him and that they did every thing but the egr, thus leading me to believe thats what it was. It then reminded me of the incident of the same nature on out 4.3.

Sure i will take a class on EGR systems i like to lern all i can. :cool:

[Eric 1]

Bigz, glad to here you got her going! nothing like the truck being broken down. :cry:

Glad i was able to help to. :cool:

[grass_cuttin_fool]

LOL , when I said to try a dist cap and rotor button I wasnt really throwing parts at it. 80,000 miles and not replaced I thought it was a possablity they were bad and a quick fix. Some times you have to look at the obivious and not over think your self. GlaD you got it running and yes please comment on the egr system, Im willing to learn anything I can

[bigz1001]

I am with you on the 80,000 miles. As I mentioned the cap did have some corrosion and the rotor button was a little boogered up on the end, just looking it was a definite option. I really think that I am money ahead to have went ahead to replace them both. Thank you all!

[xcopterdoc]

Sorry Eric... wasnt talking about you or anyone personally.. just some people in general. It happens all the time, even in the repair shops. Check engine lights are a prime example. Pull the codes and it says something about an O2 sensor.. first thing they do is order a sensor.. no troubleshooting, just order a 100 dollar part and hope for the best. Bad way to do business!

[mike green]

90 percent of the time its the distrubuter mod,