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93 Suburban Idle And Stalling

studibel

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studibel Enthusiast

studibel

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Newbie here! Have a 93 'Burb 2wd with 210,000+ miles. Had no previous issues but one evening about 2 weeks ago, experienced the following issues. Noticed that the tach would spike up when driving about 40 mph. Got home and parked in driveway and had to go somewhere about 1 hour later. It wouldn't start...just turned over and over. Good battery so turns over fine, but no fire. Checked the spark by removing coil wire from cap and grounding...good spark so put wire back in cap. Fired right up. Next day, head to work and get same tach spike. Stopped by store on the way, get back in and it wouldn't start. At noon that day, went back to where it was (Walmart) and it fired right up. Pulled off the dist cap and rotor and see little knobs of carbon and rotor looked somewhat burned. Cleaned fouling on both, reinstall and fires right up, so drove it to work. Get home OK, a couple of RPM spikes, but made it. Pulled in front of house and put in drive to just straighten wheels...dies and won't start. Sits a day or so and it starts back up...seems to be that pattern at least. Leave it for a couple days, fires right up. Checked the OBD1 and saw codes 32 (egr) and 35 (idle air control). Checked EGR by depressing diaphragm and engine stalls some...figure it is OK. Changed IAC with a new one, didn't make much diff. Things done thus far: Changed dist cap/rotor; coil; fuel filter (thought it to be fuel originally). Still will fire right up and run OK, but get the RPM spike and today 11-10-09, on way to work, it dies...stranded. So, tow it home and pour fuel into TBI but no fire. Have read many other issues similar on web saying that Ignition Control Module can heat up and get these symptoms. Got me stumped...and frustrated..could it be this ICM? Stu

 

I should also add that when it does get that spike in the RPM, you do feel it in the drivetrain. I don't think I'm feeling that sharp of a spike, but definitely, it does act like it misses or just runs rough...on the way to stalling and then not starting.

davidw450@sw.rr.com Enthusiast

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Posted
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Newbie here! Have a 93 'Burb 2wd with 210,000+ miles. Had no previous issues but one evening about 2 weeks ago, experienced the following issues. Noticed that the tach would spike up when driving about 40 mph. Got home and parked in driveway and had to go somewhere about 1 hour later. It wouldn't start...just turned over and over. Good battery so turns over fine, but no fire. Checked the spark by removing coil wire from cap and grounding...good spark so put wire back in cap. Fired right up. Next day, head to work and get same tach spike. Stopped by store on the way, get back in and it wouldn't start. At noon that day, went back to where it was (Walmart) and it fired right up. Pulled off the dist cap and rotor and see little knobs of carbon and rotor looked somewhat burned. Cleaned fouling on both, reinstall and fires right up, so drove it to work. Get home OK, a couple of RPM spikes, but made it. Pulled in front of house and put in drive to just straighten wheels...dies and won't start. Sits a day or so and it starts back up...seems to be that pattern at least. Leave it for a couple days, fires right up. Checked the OBD1 and saw codes 32 (egr) and 35 (idle air control). Checked EGR by depressing diaphragm and engine stalls some...figure it is OK. Changed IAC with a new one, didn't make much diff. Things done thus far: Changed dist cap/rotor; coil; fuel filter (thought it to be fuel originally). Still will fire right up and run OK, but get the RPM spike and today 11-10-09, on way to work, it dies...stranded. So, tow it home and pour fuel into TBI but no fire. Have read many other issues similar on web saying that Ignition Control Module can heat up and get these symptoms. Got me stumped...and frustrated..could it be this ICM? Stu
davidw450@sw.rr.com Enthusiast

[email protected]

Posted
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a rebult dist. assy from o rileys auto parts will fix the problem. it,s in the dist shaft pick up coil signal. high mileage one loose the magnetic signal, sounds like a load of crap but i have seen many of these fail

studibel Enthusiast

studibel

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Does it seem like its missing at all? Like throttle response off or anything? And another question does it smoke at all?

After it has a spell of not starting, can go out and it will fire right up. It does not sound like it misses or hesitates through the throttle range. Some others are suggesting distributor/pickup coil and/or that ICM. If I do replace the distributor with a rebuilt one, does it come with new pickup coil and ICM? Kind of at a loss here. Don't exactly know where to turn. It has been a really decent vehicle for me for going on 10 years now! If it is ICM or distributor, could it throw those same 32 or 35 codes?

studibel Enthusiast

studibel

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Could be the ICM....but...

Sounds like a Cam or Crank position sensor problem to me.

 

I've read some about that too, but thought that these sensors were only after 1996...and OBDII? Is that wrong?

studibel Enthusiast

studibel

Posted
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a rebult dist. assy from o rileys auto parts will fix the problem. it,s in the dist shaft pick up coil signal. high mileage one loose the magnetic signal, sounds like a load of crap but i have seen many of these fail

 

Forgive the dumb question, but is that where the tach gets its signal for the gauge? That freaky spike in the tach concerns me. You can definitely feel it start its stalling/hesitating when it does that spiking. If it doesn't do that, it feels like it just purrs! Do you know if the rebuilt distributor assy would come with new ICM? Thanks for the help!

studibel Enthusiast

studibel

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a rebult dist. assy from o rileys auto parts will fix the problem. it,s in the dist shaft pick up coil signal. high mileage one loose the magnetic signal, sounds like a load of crap but i have seen many of these fail

 

Checked the reman dist at OReilly and it DOES come with new ICM. The only thing i'm worried about (since I've never pulled/replaced distributor) is getting the gear lined back up with cam for proper timing and making sure the shaft lines up properly with the oil pump shaft. Is there a link to a good video that shows all of the steps in R/R distributors?

Nytemare Senior Enthusiast

Nytemare

Posted
Posted

I don't have a video for ya...

 

But, basically you want to set the truck at TDC and set the new distributor to point at or just before #1. You can buy a tool to turn the oil drive shaft....but I usually pop the center out of an old distributor and take the Cam drive gear off it, so it doesn't get in the way. Than you can use this shaft to turn the oil drive shaft a little at a time until its where you need it for the new distributor to fall in place....this may take a "few" tries.

 

After the distributor is seated, you should rotate a full 720* of engine rotation to make sure the distributor is still pointing at #1 when your done. If its just off by a couple of degrees you can adjust it by turning the top of the distributor...if its more than a couple degrees, your gonna need to pull it out again and try to get it closer to #1.

 

This process can be a real PITA...or it can just drop in and not give you grief at all. Depends on how Karma is going to treat you. :D:)

studibel Enthusiast

studibel

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I agree with davidw450, just replace the whole distributor it comes with everything, icm,rotor,cap. I got mine from Autozone, lifetime warranty.

 

Thanks. I got one from O'Reilly...appears to be same brand as AZ. Put it in last night and went like a dream. Now, I'm struggling to get the dang dist cap on...one screw or the other won't exactly line up. Got frustrated (and dark) so quit...will go out and try again this a.m. Will need to locate that single wire disconnect for timing with light. but, should be pretty close as had timing marks at TDC and rotor pointing to #1 when took out the old one...new one went right back in the same way. Hoping..!!!

studibel Enthusiast

studibel

Posted
  • Author
Posted
a rebult dist. assy from o rileys auto parts will fix the problem. it,s in the dist shaft pick up coil signal. high mileage one loose the magnetic signal, sounds like a load of crap but i have seen many of these fail

 

I could use some help for this.

 

Dropped in the reman distributor and it went right back into the same position I removed it from. Had the timing marks at TDC and had the rotor pointing to #1...which I also mentally marked with the coil tower terminal since it directly lined up with that. When I dropped in the new dist, it went right back in the same position. I attached the dist cap and seated all the wires, double- and triple-checking the firing order for the wires. Put back on the coil wire and it fires right up.

 

But, now I have what seems like a dead miss. Very rough idle. Not backfiring or anything, but a dead miss. It did that from the first start up after dist install. I disconnected the single wire connection for timing, checked it with light and set to TDC which is spec. Shut down, reconnect wire and disconnect neg battery cable to clear codes. Started back up and still dead missing.

 

I feel like the dist is installed correctly. It went right back in and located where the old one came out. It all seems right, but why the miss now?

 

Before I pull the dist back out and try to do it all over, can someone offer some help?

 

One other note: after letting it run while missing for a while, it throws the 35 (Idle Air Control) trouble code.

Nytemare Senior Enthusiast

Nytemare

Posted
Posted

Check the timing with the base timing wire hooked up...it should be 10*BTDC @2000 rpm...It will be marked on a sticker on the rad support.

 

You may have also separated a plug wire...check them all with a multimeter.

 

 

That code will set because it cannot get the truck to run properly in a set amount of time...once the miss is fixed that code should subside.

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