Jump to content

Sort Of Stumped

dualscoopinchevy

By dualscoopinchevy
in Ask A GM Technician

Recommended Posts

dualscoopinchevy Enthusiast

dualscoopinchevy

Posted
Posted

Hey guys,

About 2 months back I ordered and installed an accel super tune ignition kit w/bigger coil for my 98 5.7L GMC. I also did some exhaust work right after that (replaced muffler and intermediate pipe with flowmaster super40 and a upgraded dynomax intermediate- still has O2 sensors). A few days after the new upgrades, and it had been running great, it died on me while going down the road one evening. Me and my dad changed the fuel pump....not the problem. Had it towed to the dealership, they said they needed to change the distributor because the holes were stripped where the rotor and cap needed to mount in. After I got it back, I noticed it was lacking the pep it had prior to the breakdown. I had to take it on a long road trip immediately after. after a few hours of driving, it began to act up horrible, no acceleration, surging, wasnt fun. And I was hours away from home. Well it made it the whole trip, and began to get a little better, and is still better now. But, it is still surging or missing some, not accelerating like it should, and the mileage has dropped. It will not throw a code. At all. I have changed spark plugs again, they looked like they had been burnt almost, but they were only a month old. I had ordered a Wait4me tune the day it broke down originally, and ran it for a couple of weeks recently, it improved the truck a little bit, but it still isnt running near like it should. So i have the stock pcm in there now.

 

If I take it to the dealer again, will their diagnostic computers be able to tell me whats wrong even if there is no code being thrown?

 

Do you think the hotter coil is burning stuff up? Ive got accel 8mm wires and ugroove plugs.

Is there some reason the a factory style cap and rotor they put in there with the new distributor cant handle the load that an accel brand rotor could?

 

Any insight on what a dealer can diagnose would help, or if you have any ideas what my problem might be i'd appreciate it. Thanks yall

 

Jeremy

Deichler Enthusiast

Deichler

Posted
Posted
Hey guys,

About 2 months back I ordered and installed an accel super tune ignition kit w/bigger coil for my 98 5.7L GMC. I also did some exhaust work right after that (replaced muffler and intermediate pipe with flowmaster super40 and a upgraded dynomax intermediate- still has O2 sensors). A few days after the new upgrades, and it had been running great, it died on me while going down the road one evening. Me and my dad changed the fuel pump....not the problem. Had it towed to the dealership, they said they needed to change the distributor because the holes were stripped where the rotor and cap needed to mount in. After I got it back, I noticed it was lacking the pep it had prior to the breakdown. I had to take it on a long road trip immediately after. after a few hours of driving, it began to act up horrible, no acceleration, surging, wasnt fun. And I was hours away from home. Well it made it the whole trip, and began to get a little better, and is still better now. But, it is still surging or missing some, not accelerating like it should, and the mileage has dropped. It will not throw a code. At all. I have changed spark plugs again, they looked like they had been burnt almost, but they were only a month old. I had ordered a Wait4me tune the day it broke down originally, and ran it for a couple of weeks recently, it improved the truck a little bit, but it still isnt running near like it should. So i have the stock pcm in there now.

 

If I take it to the dealer again, will their diagnostic computers be able to tell me whats wrong even if there is no code being thrown?

 

Do you think the hotter coil is burning stuff up? Ive got accel 8mm wires and ugroove plugs.

Is there some reason the a factory style cap and rotor they put in there with the new distributor cant handle the load that an accel brand rotor could?

 

Any insight on what a dealer can diagnose would help, or if you have any ideas what my problem might be i'd appreciate it. Thanks yall

 

Jeremy

 

For what its worth, I wonder if your hotter coil and better wires means you should possibly need to open the gap on your plugs. It may be that you need an bigger gap to handle the new goodies. Just an opinion. Also, I think your dealer can get info even if your truck is not throwing a code or at least an SES light. Proof is I took my truck in Sat and today they tell me I need "another" ignition switch. The second one in just over a year. Their code reader pulled it up. I think your factory cap should handle it but maybe you should see if accel offers an alternitive to your truck due to the increase in voltage. Just my .02 worth.

Tucson_02Silverado Senior Enthusiast

Tucson_02Silverado

Posted
Posted

I'd say gap as well....if I remember right, I think the basic 5.7 gap is .035. If the gap is at .035 now, try .040 or .045.

 

Also make sure your wire separators are in very good condition and the right size. Using the stock separators with aftermarket performance wires will squeeze the thicker diameter to a point that cross fire could happen between wires.

dualscoopinchevy Enthusiast

dualscoopinchevy

Posted
  • Author
Posted

thanks for the replies guys.

 

the stock gap is actually .060 or .065, i forget, but i increased it just a hair, maybe I should go a full step up.

 

I've never heard that about the stock wire looms before, I know that I have the new wires shoved in there. I'll check that out.

 

I'll also go ahead and fork over some money to have them check it out so I dont waste to much time and money searchin blindly I guess.

 

Anymore ideas would help!

 

Thanks again

Deichler Enthusiast

Deichler

Posted
Posted
thanks for the replies guys.

 

the stock gap is actually .060 or .065, i forget, but i increased it just a hair, maybe I should go a full step up.

 

I've never heard that about the stock wire looms before, I know that I have the new wires shoved in there. I'll check that out.

 

I'll also go ahead and fork over some money to have them check it out so I dont waste to much time and money searchin blindly I guess.

 

Anymore ideas would help!

 

Thanks again

Good Idea to get it scanned. You never know it just might need to be cleared and you are good to go. You stated that your plugs looked burn't already, maybe purchase a fresh set of platnums, (your choice of man.), and set the gap to .65-possibly.70 and see what you get. Maybe like I said since you have all accel ignition you may want to check into a distributor cap. There may be some differences compared to stock, I don't know worth checking in to I guess. Again just my opinion. Hope it helps.

dualscoopinchevy Enthusiast

dualscoopinchevy

Posted
  • Author
Posted

i've thought about putting the stock stuff back on, but i'm not sure if i can put the stock coil back on since I had to cut the bracket to put the bigger one on. im not sure off hand how big of a job it'd be to put on another bracket. anywho....

 

I took it in this morning to the dealership, apparently they couldnt do much with a computer since it wasnt throwing a code. I figured they'd have a computer that could tell me more than that. But he was able to drive it with the scanner hooked up, and picked up some random misfiring. Primarily #5, also 3, 7, and a little from 1 and 4. But by far more from 5. He said he thought since the ignition was pretty much all new, that it could be the injectors, since they've never been cleaned (it's a 98). So i may try that monday morning. He said if that isnt it, they may check to see if a regulator in the throttle body (tryin to remember what he said) could be the problem if it's not spraying properly.

 

Should I have the injectors cleaned?

 

Could any of this be a result from switching to a higher octane gas? My dad ran 87 in it for years, and upon anticipation of a tune from wait4me, I started running 89 then 93. Could this have caused a problem. As of now, I have gone back to 87 until I can get things figured out.

 

I'm going to take the wires out of the stock looms tom. morning and see if the crossfire idea may be happening (between school and work not a lot of time to do stuff lately)

 

Thanks for continuing to help guys. If you have any ideas about the new info please let me know!

 

 

Jeremy

-Devil- Enthusiast

-Devil-

Posted
Posted

with changing the fuel pump you may have stirred up some trash which clogged the injectors ...

 

if it still doesn't feel just right, and is missfiring some .. i would check the dist that they installed to make sure there isn't to much play in the shaft .. and that the rotor fits on snuggly and doesnt jump around.

atboley Enthusiast

atboley

Posted
Posted

in california, because of our bad gas, we have a special policy for those injectors, they are coverd for 10 yrs or 200000 miles for free replacement, they clog all the time on those motors, and if it werent for all the aftermarket stuff i would say that that is definetly your problem... If your regulator is leaking then you would have a problem with long cranking to, if you dont have long cranking then i doubt that is a problem... but even tho they cleaned the injectors, they still may not be performing like they should and may need to be replaced...

 

but now u have more info, if it keeps doing it at least you know that #5 is your biggest problem cylinder, so consetrate on checking that cylinder for ignition problems that you may have caused with the tune....

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Latest Articles

  • Posts

    • Tyler Gibbs
      Travel Trailer 2024 2500 HD 6.6 Gas Engine ?

      By Tyler Gibbs · Posted

      The curb weight on a 1 ton crew cab long bed is around 7k lbs.  Now, I don't know where you went to school but 9k is not more than 2x 7k lbs. More than 2x 7k lbs would be 14k+.   With that said, obviously yes you're going to feel a 9k lb trailer when slowing down.  I already said, when accelerating.  When changing lanes?  No.  But if you look at the context of what was quoted, the original person said, "after a mile or two..." which means that would be after the accelerating portion and you're driving a generally steady pace.  Please do learn to read and comprehend.
    • sFrank
      2026 Silverado Range AFM DFM ECU loaction

      By sFrank · Posted

      So I purchased the Range unit for my 2026 and I am seeing different locations suggested for the ECM . Can anyone confirm wither under hood, left side or right side or behind the wheelwell?
    • No F-bdy Bs
      Dave's Auto (custom engine builder) tear down of L8T

      By No F-bdy Bs · Posted

      Like I've said before. Di and Carbon buildup is not that big of a concern. Engine had minimal buildup, and that engine was obviously not super well maintained. Do regular oil changes, and you're gtg as long as the rest of the truck lasts. Also, the High Pressure FP that people ****** about, but can't tell you why.  Now, I wish they'd trash the variable oil pump. No real world issues with them, but I'll gladly eat whatever miniscule MPG it's saving me in favor of more oil at all RPMs.    Curious to see his assessment of the 7.3 compared to the 6.6. I expect he'll praise the port inj, but from a structural standpoint, the 6.6 is as robust as any engine out there.    Not to take away from the 7.3. I feel it's equally as good as the 6.6.     As to heat on the rear cyls, I'd have to see numerous examples before I'd say it's an issue. Especially not knowing the history of that engine. For all is known, they could have blown a rad hose, and ran it hot, and the 2 rear cyls may be the first to get hot in a low coolant situation, but not be an issue aside from that. 
    • Donstar
      Navigating senior years.

      By Donstar · Posted

      "Life is getting back to normal."    I'm driving again and all new joints are operating as expected for this stage of recovery.   My most recent joint replacement still requires a lot of attention but experience has taught me that time will quiet the remaining pain.  I joked with my surgeon that another joint replacement would take my mind off my most recent surgery and he responded by saying the next will be a hip!  There are no plans for another surgery but, unlike me, I don't think he was joking!  I certainly wouldn't refuse further replacement  if required but hope to spend time out of the "post-op"  period.  I can't stress enough that if you have been recommended for total hip, knee or shoulder replacement that you welcome the offer.  Post-op "recovery" may sound daunting and painful, however, this is far better than the insidious erosion of mobility you are currently experiencing.  Imagine what it would feel like to wake up most mornings feeling better and more mobile than you did the previous day!  Prior to my first surgery in June 2025, even getting out of bed was becoming a formidable task.  Since the day after my first surgery, I get out of bed everyday easily and unassisted.  Making the switch to feeling a little better each day rather than a little worse, is hugely motivating!
    • Coastie05
      ‘25 Silverado purchase- back to dealership for bumper/radio issue

      By Coastie05 · Posted

      Hope it all works out for you. 

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...