Intermittent starting/stalling

Okay, so I have had this 92 Blazer 4.3 since September 2004. It ran great for a month, like a dream. Before I describe the problem/s, I would like to say I do not have the vortec. The first problem I noticed was a shimmy at 60 mph, from reading the posted messages I found I should check the U joints but, since I cannot keep it running, this is hardly an issue at this point. I drove it for about an hour and stopped for a red light, it died when I started thru the intersection when the light turned green. It started right back up again and I drove it home. The next day I drove it about a mile away, stopped and waited at a light, same thing happened. Later that day I drove about a mile and was stopped in traffic and it died. No warning, it just died. It would not start so I had it towed to a mechanic I thought I could trust. He was 99.9 percent sure that it was the ignition control module, about $300 for that, parts and labor. I wish I had done that repair myself. Same problem the day after I picked the Blazer up, he changed out the same part. Took it home, next morning it would not start. All winter it would start when the temp got around the mid 30's but not anything below that. Changed out the ECM on advice of mechanic friend, same problem. Temp here finally in the 40's during the day so I drove it to work today, it started fine this morning. Different story this afternoon. Now what should I do,? I cannot afford to keep throwing money at what MIGHT be the problem. The original mechanic said he was 99.9 percent sure the third time I took it in that it was little box he called the spark control module. I took this to the local dealer and they called it the knock sensor and told me that it could not possibly cause the problems I am having. Please help, I need this vehicle and cannot afford any more bad advice. :banghead:

change the distributor cap/rotor, sparkplugs&wires & coil wire. i'm pretty sure this tune up will cure the problems also check the coil for any cracks or excessive rust where it mounts to the bracket.

Maybe I should note that I was having a bit of a power problem, replaced plug wires that were in bad shape, replaced distributor cap and rotor before anything else.

Also Checked Coil, bought a new one, checked to make sure they tested the same, thank you for trying to help.

Forgot to mention that mechanic wasn't getting any codes. Not only that, it kept erasing his stored codes.

How about the plugs?

Sorry I did not mention. Tuned up late August, Champion plugs.

Have the fuel pressure checked.

Will not start today, started yesterday. Checked fuel pressure. 12 psi. Just a tad low <~~ sarcasm. Changed filter, pressure reading 7. Guess I tackle the pump next, what fun... Will also check sending unit while I'm in there. Advice?

Do you have the TBI or CPI 4.3L?

TBI, thought I had mentioned that in my first post.

I believe 12psi is actually good for a TBI.

Okay, now pressure is next to nothing after changing fuel filter. Do you have any suggestions on what I should try next? Should I change out the pump? Some days the little bugger will start and some days it will not. I don't know where to go next so any suggestions would be greatly appreciated.

sorry, but im lazy, your first post is to long, but my jist of it is your havein a fuel problem and you dont know if your pressure is right, go get a hayns (sp) manual for your truck, it will have all those kind of specks in it for you, and b4 i would go to the work of changing a fuel pump, i would make sure my ground was a good solid ground, all relays have good contact, and (i see youve already done both of these) fuel pressure regualtor and fuel filter
Edit: got board and read your post, the dealer would of corse tell you it cant be a problem, that way you say what is it? and they respond with o i dont know, we can put it on the machine for (here 72 usd) and tell you what 300 doller part we would like to install for you, or they will say other then that you can TRY and they will give you a list, especally if your machanicly inclined or female... and another note from doug, seince it doesnt want to run right when cold, how about throwing some dri gas into her, it is "throwing money at her" but only a couple of bucks, i suggest you go get some heet or peak dry gas and put it in the tank, a bottle for a tank should be plunty, if your real low, you need to put gas in b4 the dry gas, (its bad to have a bunch of that stuff in a small amount of gasolien) the fuel pump gets warm when working, specally on half a tank or lower, that causes condencation and vwala you have water in your gas tank causing you to run like shit

Okay, now pressure is next to nothing after changing fuel filter. Do you have any suggestions on what I should try next? Should I change out the pump? Some days the little bugger will start and some days it will not. I don't know where to go next so any suggestions would be greatly appreciated.

You will have to cycle the key to the on position (not started) for 3 seconds and back off for 10 seconds about ten times so the fuel pump can remove the air from the fuel system and regain the prime.

You will have to cycle the key to the on position (not started) for 3 seconds and back off for 10 seconds about ten times so the fuel pump can remove the air from the fuel system and regain the prime.


:redface: Thank you, I will try that first thing tomorrow, did not realize I had to 'prime' it before checking again, stupid mistake I suppose. Will let you know what I find. Again, thanks.

dmbriskit51

She runs great when she starts, maybe a little slow to kick in passing gear but is probably related to whatever problem keeps her from starting. Have to get the starting problem addressed before I worry about overall performance. Thanks for the advice anyhow....

You will have to cycle the key to the on position (not started) for 3 seconds and back off for 10 seconds about ten times so the fuel pump can remove the air from the fuel system and regain the prime.

Primed, checked. 12 psi. Now I have no clue what to check next. On the bright side, I don't have to change out the pump but now I am back to step 1. What the bleep is wrong with this thing? Please, any suggestions or many suggestions. I need help. :banghead:

Took out spark plug and found not getting any spark. Already tested coil so maybe the pickup unit. Would this possibly cause the intermittent problem? What else may need checked?

Are you getting spark from the wire coming from the coil to the distributor cap?

Are you getting spark from the wire coming from the coil to the distributor cap?

Yes. Now what?

test it with a multimeter

test it with a multimeter

:eek: I don't think a voltmeter can take 40,000volts.

it honestly depends on the meter, a general perpous one, no, my g pa has one that he an only use on the ignition system because anything less and it wont come up with a reading, its an old style one with a needle, im not sure about new ones, im sure that you can get it

:eek: I don't think a voltmeter can take 40,000volts.


BlazerLT, I would be interested in hearing from you of any sequence of things that I could check, I am really stumped. All of this began with changing out some very worn plug wires and installing a new distributor cap and rotor. I don't think it has anything to do with the problem I am having now but she ran fine until then, and now I have no clue where to go from here. This Blazer is stumping every mechanic I have had look at it.

Forgot to mention that mechanic wasn't getting any codes. Not only that, it kept erasing his stored codes.

Alright, what do you mean here? He would intentionally make a code come up, and it would set the SES light on, it would stall, you restart it and the stored code is gone?

BlazerLT, I would be interested in hearing from you of any sequence of things that I could check, I am really stumped. All of this began with changing out some very worn plug wires and installing a new distributor cap and rotor. I don't think it has anything to do with the problem I am having now but she ran fine until then, and now I have no clue where to go from here. This Blazer is stumping every mechanic I have had look at it.

I would reseat all the plug wire connections and make sure you connected the right plug to the right wire.

You aure you didn't cross wires?

Have you checked all connection to make sure they are tight?

I used masking tape and marked each connection and each wire. There is no way they can be wrong, they are, in fact, still marked. Each connection is tight and has been checked numerous times.

Alright, what do you mean here? He would intentionally make a code come up, and it would set the SES light on, it would stall, you restart it and the stored code is gone?

No, he hooked her up, it showed no codes and erased the stored codes he already had on his machine. My Blazer never actually stalled for him, it even started every time he tried to start it. He let it run for hours and never got her to stall (after he replaced the ignition control module for the second time and we started having the problem with starting her consistently). He then wanted us to pay another $300 to have him change out what the dealer called the "Knock Sensor" and he called the "spark control module". The dealer told us that this could not possibly cause intermittent starting trouble.

I would check the coil.

Check at night and look for blue sparks coming from it.

It has been a while, a very long while. We finally found a mechanic that did not want a staggering amount per hour to look at the blazer. The ignition control module that we already had changed out twice was completely burned up, despite the fact that we have not actually driven the vehicle since we got it back from the mechanic and only start it ocassionally. He told us that it looked used to him. I do not know if this would cause a cold start problem or not but it is currently too warm here (in Alaska) to check. Anyhow, he charged us less than $100 so we now have a new mechanic. Going to go pick my Blazer up now and hope that it starts when the temperature gets below 30 as it often does here. Thank you, BlazerLT, for all of your time and help.

It has been a while, a very long while. We finally found a mechanic that did not want a staggering amount per hour to look at the blazer. The ignition control module that we already had changed out twice was completely burned up, despite the fact that we have not actually driven the vehicle since we got it back from the mechanic and only start it ocassionally. He told us that it looked used to him. I do not know if this would cause a cold start problem or not but it is currently too warm here (in Alaska) to check. Anyhow, he charged us less than $100 so we now have a new mechanic. Going to go pick my Blazer up now and hope that it starts when the temperature gets below 30 as it often does here. Thank you, BlazerLT, for all of your time and help.

You aare very welcome and I applaud you coming back here to tell us the conclusion.

You don't know how many people will use your info to fix their situation.

BRAVO! :D