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Discussion Starter #1
Hey Guys, Coming back from a vacation my 95 sub 2wd 144k, took a dump on me three
hundred miles from home with 5 kids and my mother in law and wife, at a rest stop for seven hours, looooong story.... The truck ran great for 1700 of the 2000 miles trip.
About 300 miles into the last day I had to pay a toll when I went to go it kinda died but I
gave it some gas and it recovered it did it again within 50 feet then it was fine. About 200 miles later my wife tells me that the tach is going up and down from 2k to 3 k. not good.
We get off at a rest stop. Before she turned it off I noticed what looked like black smoke from the exhaust. It would not start, I checked for spark and had one and heard the fuel pump working. Still no go and had to get it towed 145 miles. More fun. I went back the next day to the garage(Sunday) it hesitated a bit but started, did it a few more times and it started okay, maybe a tad rough on the idle but could be me over analyzing . I left it there the mechanic has a very good rep. It starts up Monday AM, they let it sit and try again a few hours later, it will not start. They went to lunch and came back and it started fine. They can't figure out what is wrong. Any ideas this truck has been well maintained and taken care off. I have had some minor electrical gremlins that I solved by running a jumper wire to the wipers. Also at times the orange dot by the prndl will flicker if the a/c is on high etc...
Any suggestions would be great, we are in a bind and need it back in good shape. We have other trips planned but I would be hesitant to take it again until I have a diagnosis.
And it is the only vehicle we have that can hold our family. Thank you in advance for you two cents,
Regards,
Pat
 

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Well, your mechanic should first check for codes (did they? If so, what code or codes did they find?) Next, consider doing a tune up or have them check the following: rotor, cap, plugs, maybe wires, O2 sensor, fuel filter, air filter. Black smoke usually means too rich of a fuel/air mixture. An air filter that is clogged can cause this. Have them inspect carefully the TBI intake. It can get clogged inside with sediment. They can take it apart to check it out. Your injectors may be clogged at times then releasing the wrong amount of fuel (but if they are clogged it should lead to a lean condition, not rich.) Your computer may be acting up and giving the wrong signal for the amount of fuel (very unlikely.) Anyhow, there are procedures to follow in the Diagnosis GM manual that will narrow it down if they are patient and follow the steps.
 

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Discussion Starter #3
I picked up the car yesterday and it ran fine, the guys could not find
any codes, no check engine light on,
my buddy thought maybe crank sensor? Another friend said that perhaps the temp
sensor thought it was very cold and dumped tons of fuel.
I'll keep driving it but man I wish I knew what was up. Thank you for your advice!
Pat
 

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Bad timing.... Could be a crank sensor, also map sensor could cause it too. My buddy has a 93' k2500 with a 350 and it was doing something similar to that and we replaced the MAP sensor and it was fine. The fact that sometimes its working and sometimes its not is kinda odd. I would hate to say its an ECM prob. but that would be WCS. I know the MAP sensor for that truck should be about 50$ because my 95' 4.3L uses the same MAP sensor and I had to replace it. I dont know if there would be a fuel pressure regulator on that.. if there is it could be that as well. I would make sure that the ecm is working by jumping the pins with a paper clip and making sure that you get code 12. That means that the ecm is working correctly. it will flash like this.... flash.........flash.. flash..... long pause.... then repeat if no other codes if you dont get code 12 then it could be an ecm prob. the SES light wont need to be on to get this code. it should always flash code 12 first to verify that the ecm is good.


Good luck hope its an easy fix

Let us know what it is when you find out
 

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If you jump the A and B pins it will flash the CEL for the codes. It can't be running but the key needs to be all the way on.


Click on the pic to make it bigger. This is for the OBD1 system which you should have. It should be located under the dash on the driver side. obd1pinout2.gif
 

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Discussion Starter #6
The truck has been running great, my guy thinks the problem was fuel related, that the gas in the lines may have gotten so hot that they boiled and
then it started when it cooled down, I'll take it in in a week or so and keep you posted.
thanks again for all the advice!
Pat
 

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Could be a fuel reg going bad. They can be intermittent.
So can fuel pumps and you need full pressure, not enough to just hear it working. They can also do the intermittent thing.

The cooling sensor is the one on the neck. It is not the sensor your gauge reads so it's possible you see one temp and the pcm see's another.-possible.
You would think the PCM would read the O2 sensors and shut the fuel down, But it doesn't happen. I've see that myself.
 

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Discussion Starter #8
Thanks for the info, I'll have it checked out in a few weeks and see what we can find.
I'll report back.
Pat
 

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Discussion Starter #9
It died on me again, this time after on the road for 10 mins, I stopped 5 mins in and when I turned it off it began to dieseling for
a few secs, five mins later my hood was up in traffic, the verdict was bad temp sensor, part of the housing was broken off
and it was not contacting well, my mechanic said it thought it was like 20 below and dumped way too much fuel.
100 bucks out the door. I will be putting some good miles on it soon, we'll see if that was the cause. Thanks again for everyone who
chipped in with advice!
 

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Replace the ignition coil(they are like $40 for a performance one) and replace the distributor cap and rotor. Just because it's getting a spark, doen't mean it's getting a strong enough spark. My truck was doing exactly like yours for a while, until I replaced that ignition coil, then no problems whatsoever.

Also, check the two wires grounding to one of the bolts on the thermostat housing on the manifold, if they are loose, blob some solder on them, if those two wires don't have a good ground, the truck will not run.
 

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As Ethan said, check grounds first.
Easier too do...and it will cause you ignition and timing problems if the ground is loose.
He is the ground for your ECM.....so if he is acting up, so will your engine.
 

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Discussion Starter #12
The Plot Thickens

Hey Guys,
Thanks again for all the advice! I have an update, I was about 250 miles from home with my family and I'm driving etc...
and it just dies on me, out of the blue, keep in mind I had the temp. sensor replaced. So I do the basic shadetree stuff and
I happen notice that the ignition coil wire is ruined, the wires to all the plugs are fine but the one covering the coil looks like it
melted or something from the inside out. I cleaned the crap off it and pushed it down good and it cranked right up,
I went to autozone and bought a knew wire just slightly longer than the old one and it ran great. Any ideas? Bad Coil? Can I keep using the longer cable?
Also just a shoutout to a guy named Keith who helped me and my family for two hours after he saw me pushing the burb in traffic! I'm sure helping us was not on his to do list for a day off but stepped up big time!
He drove us to a playground (in his 1994 Chevy Truck), took me to the autozone twice etc... and refused to accept any money. I know most
people hear just the bad about people but there are some great great people out there!(Driving Gms of course)
Hope to repay the favor to anyone who needs it soon.

---------- Post added at 07:18 PM ---------- Previous post was at 07:03 PM ----------

Me again, just read a post somewhere that said if the wire melts it is not due to a bad coil but the wire not being pushed in all the way
any ideas on that one?
Thanks again!
 

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That could very well be your problem. If the wire is not pushed in all the way, it could cause arcing, causing extreme heat to build up in the wire due to the extra volts and amps it'll be pulling to jump the arc.

It wouldn't hurt to replace the coil though, they are cheap, and it's an easy upgrade.
 
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