96 Tahoe dies while driving and won't start

[Snowbound]

Just throwing a few things out there to check.

Could the distributor been moved at all? If cam/crank correlation isn't within spec it won't fire. Doesn't explain the reason it shut off in the first place but if you've made any repairs that fixed the original problem but accidentally turned distributor while replacing cap and rotor, it would explain why it's not firing now. Maybe just try to turn it by hand, if it doesn't move with just slight force, don't try to force it.

Could you have gotten bad fuel? Is it even fuel? Kerosine? I'm sure you've smelled it while you've been checking fuel pressures and such but try siphoning some into a clear jar and let it sit without disturbing. Check to see if it seperates like there's water in fuel. You never know!!

Is there any possible way the catalytic convertor is clogged so bad that it can't push the exhaust out?

Last thing coming to mind at the moment, did you try to clean your plugs? They are platinum plugs and should never attempt cleaning with wire brush or anything. I know a guy that worked on his truck for over a month until he listened to me and changed plugs. Fired right up after that. He was convinced they were giving him defective crank sensors.

Speaking of sensors, you say you replaced one. Does your scanner give you a reading on crank and cam sensors while cranking? Check into that. I'll check back later as I'm off to bed, if I think of anything else I'll chime back in.

 

[east302]

Backing up just a bit, does your check engine (Service Engine Soon) light come on and stay on when the ignition is on?


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[Nightflyer]

Servus,

I've replaced the distributor an cap...the chevy runs very good a few months...until it dies..

The fuel is okay...checked.

Every sensor is working correct. my scanner-program shows it to me.

@east302: yes, the ses light goes on and stays on when the ignition is on. When i'm starting the engine it's going off. I think this is normal.

Germanys beer is the best beer. Specially here in bavaria. My city (Bamberg) has 9 brewerys (Schlenkerla, Mahrs, Zwergla, etc)...

 

[Nightflyer]

@Snowbound: i'll think moving the cap (rotor) by hand is not so easy....

 

[east302]

.

@east302: yes, the ses light goes on and stays on when the ignition is on. When i'm starting the engine it's going off. I think this is normal.

Was the CMP offset set (-2 to 2 degrees) when the distributor was replaced?

The check engine light is normal, was just making sure you had that coming on in case it was an issue with the computer.



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[Nightflyer]

hi east302,

sorry, i explained it not correct: I've only changed the distributor-cap and the rotor. Not the whole distributor...

 

[JonnyTahoe]

hi east302,

sorry, i explained it not correct: I've only changed the distributor-cap and the rotor. Not the whole distributor...

I have a 95 Tahoe 5.7 TBI that did the exact same thing that yours did. I was driving at highway speeds and it just died "Like someone turned the ignition off". Keep in mind I have had this truck for many years and this was the first time something like this ever happened. I coasted off the highway and into a parking lot where I parked the truck so I could work on it. I started with a new cap and Rotor which was about nine years old, It had been so long since I replaced the rotor I actually had a little trouble getting it seated properly. Would not start. Next I replaced the Coil because It may of been the original and I figured that had to be the problem, would not start. I had the truck towed home because I needed to be home too. You mentioned you did replace the ICM, also know as the Ignition Control Module. This ignition part you are not replacing in a parking lot and are lucky if you even have a small enough wrench to get the tiny screws off. I had replaced this Module nine years prior as a security measure because they are known to fail with little or NO warning. I replaced this ICM while sitting in the engine compartment on a 90 degree afternoon. I figured it had to be a Ignition issue since I had fuel in the tank and I could hear the fuel pump when I would turn the key. I started with the cheapest parts and worked my way to the more expensive parts hoping for the best as it turned out the last part and the most expensive part was the problem. The only thing I did not replace was the advancer with the small colored wires which can also fail if the wires get old, loose or break off the connector. In my case after installing the new Ignition Control Module the engine started right up.

 

[the_coroner2002]

I ran into the same thing. Did you say that you replaced the Crank Position sensor? When mine failed the truck had the exact same symptoms. As soon as the crank sensor was replaced the tahoe started right up. it was showing no codes on the scanner just wouldn't spark. I sure hope this helps.

 

[Nash]

My truck quit the same way on I-81. I changed all the ignition parts and others also. It would crank but never start. I finally found the knock sensor went bad.

 

[Gmc lovin75]

Just because the fuel pump is new doesn't mean that it can't go bad on you

 

[wolfeman2120]

The key here is to make sure you have fuel and spark.

based on what information was provided, here's what I would do. Check to make sure you have spark at the end of each plug wire. Use a test light for this and have someone crank the engine. If you have spark at all 8 cylinders then its likely a fuel supply issue.

You checked the fuel pressure at the schradar valve so you know the pump isn't suspect yet. The likely culprit is either the injectors or the fuel pressure regulator. Since its one unit, your better off replacing the whole thing. Also replace your fuel filter and flush the fuel lines when you do it.

Since the vehicle is over 20 years old with the CPI I would blame that as they are known for clogging with carbon. The injectors themselves could be fine, but the inside is likely full of crap preventing it from working right. And if that regulator is bad then it won't open the injectors.

Its also possible that injectors 1 and 4 are not closing correctly and leaking fuel into the cylinder when it is pressurized. Overnight you might see that fuel pressure drops.

 

[muncie21]

I had a Tahoe that would crank and not fire, however come back an hour or day later and it would start no problem. It did this intermittently, with no discernibly pattern. I tested/replaced most of the things that have been suggested in this thread.

After exhausting all other possibilities, I was left with only the PCM. I purchased a used PCM however the truck didn't give me any problems from that point until I sold it about 4-6 months later.

 

[Beechwood]

I had the same problem on my '99. After changing $500 worth of sensors and ignition components, I brought it to my mechanic.

It was the wire harness touching the exhaust manifold behind the motor I couldn't see. One wire was grounded out.

Was a $1 fix....

 

[muncie21]

I had the same problem on my '99. After changing $500 worth of sensors and ignition components, I brought it to my mechanic.

It was the wire harness touching the exhaust manifold behind the motor I couldn't see. One wire was grounded out.

Was a $1 fix....

That's a very great (observant) mechanic. Keep him on your Christmas card list!!

 

[bayviewnick]

Hello Matthias,
I don't know where you are in your plight and have not yet read all of your responses. To save time, I'll get to the point. I had a 1999 Tahoe with a 5.7 (350) TBI that used to stall out and not start. Wait anywhere from a few hours to two weeks and it would restart only to do the same a few days later.
Four garages changed: spark plugs (twice), coil, fuel pump, wires and cap. Two suggested the fuel spider was bad. As it turns out my problem was the crank sensor. The crank sensor doesn't need replacing to trouble shoot, it can be ohmed out. I hope this helps you.

 

[nathanhanover]

Hey Guys,

I'm Matthias from Bamberg, Germany. I've an 96 Tahoe (350 Vortec TBI) and a real big problem:

My car died three weeks ago while i'm driving (it was like, someone cut off the ignition) and won't start again. Nobdy in Bavaria and Germany knows why.....

- the battery is in a very good condition
- the car cranks very well but won't start
- the chevy has very good sparks
- the fuel pump is running and new
- fuel pressure at schrader-valve (is that the name?) is about 61psi and 63 while cranking
- changed the distributor cap, rotor, plugs and wires
- changed the ICM
- changed the CKP-sensor
- it misfires whit starting fluid (one time)
- the plugs are sometimes wet and you cann (sometimes) smell gas
- the timing chain is okay (tested with turning the crankshaft and look at the distributor..the rotor moves

sometimes it seems like, that the chevy would like to start. it sounds like, that there is no pulse to the injectors.

btw: there are no codes stored in the PCM and all cables ok.

Please: could someone help me? what can i test and look for?

Best regards from Bavaria/Germany

Matthias

p.s.: soorry fpr my bad english..

 

[nathanhanover]

had the exact same thing with my 1996 2 door 2wd, replaced the Distributor cause it had 200 k, still wouldn't fire. Kept checking found that the Brand new rotor cap had a short. Replaced it and wallah!

 

[JonnyTahoe]

had the exact same thing with my 1996 2 door 2wd, replaced the Distributor cause it had 200 k, still wouldn't fire. Kept checking found that the Brand new rotor cap had a short. Replaced it and wallah!

As many of us have found out working on these Distributors in the limited space you have is a real pain. The stories people have shared are interesting I never would have suspected a Crank Sensor or Knock Sensor and certainly not a wire grounding out on a Exhaust Manifold. These are very dependable trucks and when they stop running we all go back to the Basics to find the cause and start "Throwing Parts" at them. Sometimes we get lucky sometimes we don't.

 

[JonnyTahoe]

I had the same problem on my '99. After changing $500 worth of sensors and ignition components, I brought it to my mechanic.

It was the wire harness touching the exhaust manifold behind the motor I couldn't see. One wire was grounded out.

Was a $1 fix....

 

[JonnyTahoe]

And I was upset about a hundred.