1998 Suburban Stalling

rjvrs · September 20, 2006

1998 GMC Suburban/k1500-5.7 vin r While driving truck will stall. Usually at low speed/idle, at stoplights. Sometimes will start up, sometimes not. If truck sets for 45 minutes to an hour, can start and drive away until the next time she stalls. Have replaced fuel pump(twice), fuel filter, ingnition module, clean with carb cleaner. When mechanic has truck,

interminet- he can't get the truck to stall. Not storing any codes,so says the mechanic, Also, check engine light will not come on at all, not when you turn key on, while driving, nothing. Bad bulb? Thanks in advance

1999 Tahoe 4x4 · September 24, 2006

This is a tough one.

If there are no codes the check engine light will not come on. Also professional scanners such as the Snap-On MT2500 have test procedures to toggle on/off the check engine light just to make sure it works properly.

I'm WONDERING but not sure if you have an air leak in your upper intake manifold. Basically the intake manifold consists of two pieces: a plastic upper and aluminium lower . However I'm guessing that if this was the case this would/could turn on the check engine light. So I'm not sure.

Theoretically a defective Passloc System could stall your vehicle as well.

I also suggested at some other post to someone else to check for proper ignition switch operation. In my case (although different symtoms) a bad ignition switch did not produce and codes. Despite having a professional scanner it took me 2 full weekends to find this problem as GM does not have any reference to ignition switch failiure in its otherwise comprehensive service manual. The ignition switch (like quite many other parts) is a piece of sh*t quality on these vehicles. Yet it controls many circuits. So I recommend to everyone to change it no matter what even as a precaution.

- My first question is what repairs of modifications have been done recently on your truck.

- Second try to give more information to stalling. Like is the engine hot or cold etc.

rjvrs · September 28, 2006

This is a tough one.

If there are no codes the check engine light will not come on. Also professional scanners such as the Snap-On MT2500 have test procedures to toggle on/off the check engine light just to make sure it works properly.

I'm WONDERING but not sure if you have an air leak in your upper intake manifold. Basically the intake manifold consists of two pieces: a plastic upper and aluminium lower . However I'm guessing that if this was the case this would/could turn on the check engine light. So I'm not sure.

Theoretically a defective Passloc System could stall your vehicle as well.

I also suggested at some other post to someone else to check for proper ignition switch operation. In my case (although different symtoms) a bad ignition switch did not produce and codes. Despite having a professional scanner it took me 2 full weekends to find this problem as GM does not have any reference to ignition switch failiure in its otherwise comprehensive service manual. The ignition switch (like quite many other parts) is a piece of sh*t quality on these vehicles. Yet it controls many circuits. So I recommend to everyone to change it no matter what even as a precaution.

- My first question is what repairs of modifications have been done recently on your truck.

- Second try to give more information to stalling. Like is the engine hot or cold etc.

<{POST_SNAPBACK}>

More info?

1998 Gmc Surbuban K1500

5.7 Vortec Vin code "R"

At this time, 185,122 miles

Long story made short. Bought the truck in aug,2005. has 185000 miles. New tranny at 107000(replaced at dealership), normal maintance otherwise. Only mods has been a K N filter about two monthes ago and install a brake controller for trailering. Other than that , gas, oil and drive. In the spring(2006), I noticed that occasionally while driving that the engine would misfire?. Would see tach drop, other gages move, general hiccup! Wouldn't stall or leave me wanting a tow truck. First part of June, motor shut off while driving, No hum from tank, bad fuel pump. Several hundred $$$ later(new pump from Chevy store), back to normal. First part of Aug, after drivng 10-15 miles(195 deg. on gage) would stop a bank or store, come out, try to drive away, would notice that she had a hesation from startup. Normally no big deal. Then we progressed to the stalling. Always after a short warm-up drive(10-15 miles). A bank, store, stop lights, construction zones. Stop for anything. Wam!! Stalls. Sometimes start back up . Other times, nope. If I would pump gas pedal, sometime could keep motor running. Sometimes not. Acted like old time vapor lock. Then came the flat beds.

Would call tow in, be towed to the house, pay off driver. Next morning, starts right up and away we go. Until she warms up. Then the kids start to whine and cry about getting left on te side of the road. Took truck to mechanic I been using for 15 Years. Only code showing was a egr failure. Replaced. He checked around, could find nothing else out of place. Two days later, on side of road again. Hmmm, Let the thing sit for awhile. 45 minutes later, started right up, drove home. Next day, same thing. Took back to shop, replaced fuel filter. Day later, side of the road again. Cools off, drive home. Next Monday, had pump removed and replaced under warrenty. Checked all wiring while there. Nothing out of place. Two days later,you guessed it. Side of the road again. Was suggested that maybe ignition module bad, replaced that. No better. Maybe coil, Nope. Bought a scanner, Had a tps sensor failure,Not that. Then a crankshaft sensor(intermittent),unplugged connectionto that,dry no burnt spots. Cleared code. Wamm. On the side of the road again. Half hour later,home.

Finally broked down and took it to the Chevy dealer. They went thru the normal,scanner,checking plugs to sensors, taking a 30 miles test drive. Nothing.

Got it back yesterday, drove it home, okay. They said that maybe a connection(plug)was maybe loose, not making good contact. Drove to work last nite. 28 miles there, 28 back, no problems. Went to town this morning, bank parking lot,Start up motor,back out of parking spot, shifted to drive,applied some gas, stalls. Starts right back up, drove to grocery store, watched gages on the way,tach was boucning(motor shutting down) and gas gage was doing 360's.

Got the grocery, bought stuff. Started up, drove home, some stuttering on way home. That is where we are at as of this moment. A few parts replaced(list below) money wasted being hooked to scanners, test drives, and techs saying that there is nothing wrong will your truck! (Want to trade<oh nooo)

Any help,suggestions would be appreciated.

Thanks Ron

Air filter

Ignition module

Egr valve

Coil

Tps sensor

Fuel pump 2x's

Fuel filter

RaysZ71 · September 28, 2006

This is a tough one.

If there are no codes the check engine light will not come on. Also professional scanners such as the Snap-On MT2500 have test procedures to toggle on/off the check engine light just to make sure it works properly.

I'm WONDERING but not sure if you have an air leak in your upper intake manifold. Basically the intake manifold consists of two pieces: a plastic upper and aluminium lower . However I'm guessing that if this was the case this would/could turn on the check engine light. So I'm not sure.

Theoretically a defective Passloc System could stall your vehicle as well.

I also suggested at some other post to someone else to check for proper ignition switch operation. In my case (although different symtoms) a bad ignition switch did not produce and codes. Despite having a professional scanner it took me 2 full weekends to find this problem as GM does not have any reference to ignition switch failiure in its otherwise comprehensive service manual. The ignition switch (like quite many other parts) is a piece of sh*t quality on these vehicles. Yet it controls many circuits. So I recommend to everyone to change it no matter what even as a precaution.

- My first question is what repairs of modifications have been done recently on your truck.

- Second try to give more information to stalling. Like is the engine hot or cold etc.

<{POST_SNAPBACK}>

More info?

1998 Gmc Surbuban K1500

5.7 Vortec Vin code "R"

At this time, 185,122 miles

Long story made short. Bought the truck in aug,2005. has 185000 miles. New tranny at 107000(replaced at dealership), normal maintance otherwise. Only mods has been a K N filter about two monthes ago and install a brake controller for trailering. Other than that , gas, oil and drive. In the spring(2006), I noticed that occasionally while driving that the engine would misfire?. Would see tach drop, other gages move, general hiccup! Wouldn't stall or leave me wanting a tow truck. First part of June, motor shut off while driving, No hum from tank, bad fuel pump. Several hundred $$$ later(new pump from Chevy store), back to normal. First part of Aug, after drivng 10-15 miles(195 deg. on gage) would stop a bank or store, come out, try to drive away, would notice that she had a hesation from startup. Normally no big deal. Then we progressed to the stalling. Always after a short warm-up drive(10-15 miles). A bank, store, stop lights, construction zones. Stop for anything. Wam!! Stalls. Sometimes start back up . Other times, nope. If I would pump gas pedal, sometime could keep motor running. Sometimes not. Acted like old time vapor lock. Then came the flat beds.

Would call tow in, be towed to the house, pay off driver. Next morning, starts right up and away we go. Until she warms up. Then the kids start to whine and cry about getting left on te side of the road. Took truck to mechanic I been using for 15 Years. Only code showing was a egr failure. Replaced. He checked around, could find nothing else out of place. Two days later, on side of road again. Hmmm, Let the thing sit for awhile. 45 minutes later, started right up, drove home. Next day, same thing. Took back to shop, replaced fuel filter. Day later, side of the road again. Cools off, drive home. Next Monday, had pump removed and replaced under warrenty. Checked all wiring while there. Nothing out of place. Two days later,you guessed it. Side of the road again. Was suggested that maybe ignition module bad, replaced that. No better. Maybe coil, Nope. Bought a scanner, Had a tps sensor failure,Not that. Then a crankshaft sensor(intermittent),unplugged connectionto that,dry no burnt spots. Cleared code. Wamm. On the side of the road again. Half hour later,home.

Finally broked down and took it to the Chevy dealer. They went thru the normal,scanner,checking plugs to sensors, taking a 30 miles test drive. Nothing.

Got it back yesterday, drove it home, okay. They said that maybe a connection(plug)was maybe loose, not making good contact. Drove to work last nite. 28 miles there, 28 back, no problems. Went to town this morning, bank parking lot,Start up motor,back out of parking spot, shifted to drive,applied some gas, stalls. Starts right back up, drove to grocery store, watched gages on the way,tach was boucning(motor shutting down) and gas gage was doing 360's.

Got the grocery, bought stuff. Started up, drove home, some stuttering on way home. That is where we are at as of this moment. A few parts replaced(list below) money wasted being hooked to scanners, test drives, and techs saying that there is nothing wrong will your truck! (Want to trade<oh nooo)

Any help,suggestions would be appreciated.

Thanks Ron

Air filter

Ignition module

Egr valve

Coil

Tps sensor

Fuel pump 2x's

Fuel filter

<{POST_SNAPBACK}>

The problem is electrical, a fuel problem would not make your gauges act like that. I am wondering if your having a problem with the PCM ( power train control module) Its a computer with a processor kinda like your PC. If they overheat they can shut down, lockup and be unstable. If the PCM is the problem, it would not throw a code either.

Just a thought. I am a PC tech, this kinda reminds me of a AMD cpu that over heats.

Steady Eddie · September 28, 2006

"1998 GMC Suburban/k1500-5.7 vin r While driving truck will stall. Usually at low speed/idle, at stoplights. Sometimes will start up, sometimes not. If truck sets for 45 minutes to an hour, can start and drive away until the next time she stalls. Have replaced fuel pump(twice), fuel filter, ingnition module, clean with carb cleaner. When mechanic has truck,

interminet- he can't get the truck to stall. Not storing any codes,so says the mechanic, Also, check engine light will not come on at all, not when you turn key on, while driving, nothing. Bad bulb? Thanks in advance"

==================

Ron--

I just ran thru this problem, all the symptoms were the same.

Was a bad grounding point where the minus (-) battery cable

was grounded to the Chassis/Frame.

Drove me nuts!!

The battery always tested good.

I was worried that a problem like this could co$t a lot of

money by throwing parts and labor at it.

If your problem is battery or cable related, having the

battery self-dis-connect from the Main Circuit is a very

bad thing. The battery acts like a buffer and softens the

spikes from the alternator output and it is very hard on the

PCM/ECU to see these power surges...good luck...

rjvrs · October 11, 2006

STEADY EDDIE, YOUR THE MAN!!! BAD CABLE ON NEGATIVE SIDE!

AFTER THE MECHANICS HEARD, TALK ABOUT KICKING THEMSELVES IN THE BUTT!

REPLACED BOTH POSTIVE AND NEGATIVE CABLE JUST TO BE ON THE SAFE SIDE. PROBLEMS ARE GONE. THANKS FOR ALL THE HELPFUL REPLIES.

RON

bradjamesward · August 19, 2007

STEADY EDDIE, YOUR THE MAN!!! BAD CABLE ON NEGATIVE SIDE!
AFTER THE MECHANICS HEARD, TALK ABOUT KICKING THEMSELVES IN THE BUTT!

REPLACED BOTH POSTIVE AND NEGATIVE CABLE JUST TO BE ON THE SAFE SIDE. PROBLEMS ARE GONE. THANKS FOR ALL THE HELPFUL REPLIES.

RON

Let me tell you about how thankful I am for steady Eddie and his post...rjvrs too! 1AM at work...working on Saturday night...d**n, I hate writing Thesises! 60 miles from home...where my new 8 week old Lab is probably crying her eyes out because I am not there. Jumped the 99 Chevy Tahoe (same exact symptoms above in this post too!)...didnt work...noticed when I wiggled the negative battery cable the lights would come on...read this post...clamped down the ground wire that is connected to the negative terminal and bam...it starts...heading home!