Register or Log In To remove these advertisements. |
|
|
|
Thread Tools | Display Modes |
|
05-11-2017, 08:51 PM | #1 |
Registered User
Join Date: Aug 2011
Location: Dallas TX
Posts: 563
|
1999 Suburban 2500 454 misfire
OK my new to me daily driver / tow rig is killing me. A couple days after I started driving it I randomly started getting a misfire. Over a few weeks it started getting worse and I watched it while driving on a scanner and its coming from #4. To get a base line I did a tune up with plugs, wires, cap , rotor and new 02 sensors. Fixed!! Drove like a dream for 3-4 days then started to get a occasional miss again Over the coarse of about 3 weeks its gone from occasional to 15000 misfires on a 20 miles commute home. It's still #4.
Start looking deeper. Misted water on the wires in the dark no arcing. Pulled #4 plug looks great but replaced anyway with no change. Replace wire with another new wire.. no change. Compression test on 2, 4, 6, both hot and cold all 135-138 psi. Injector balance test... all 8 with in 2psi. It makes no sense to me! What the h##l am I missing? Anyone have any idea? I have an injector on order and hope to have it in over the weekend but if that does not fix it my next step might be a match and a can of gasoline. |
05-11-2017, 09:38 PM | #2 |
Registered User
Join Date: Mar 2013
Location: Marquette michigan
Posts: 828
|
Re: 1999 Suburban 2500 454 misfire
A friend complained of the same thing on a 97 454 in a suburban and i remember something in a tsb (technical service bulletin) about exhaust valve guides either being too tight and valves dragging 9misfire) or too sloppy and the stems getting hard carbon and then dragging (misfires).
My friend also said it only happened after a hour or more pulling a trailer. |
05-11-2017, 10:46 PM | #3 | |
Registered User
Join Date: Aug 2011
Location: Dallas TX
Posts: 563
|
Re: 1999 Suburban 2500 454 misfire
Quote:
|
|
05-12-2017, 08:30 AM | #4 | ||
Registered User
Join Date: Oct 2009
Location: .
Posts: 2,180
|
Re: 1999 Suburban 2500 454 misfire
Quote:
The vortec 454 is known to have injector problems. Its a good idea to replace all of the injectors. I recommend replacing the fuel pressure regulator when you do the injectors. TSB for reference: Quote:
|
||
05-12-2017, 10:46 PM | #5 |
Registered User
Join Date: Mar 2013
Location: Marquette michigan
Posts: 828
|
Re: 1999 Suburban 2500 454 misfire
God i hope the Alzheimer isn't starting already. Thanks for finding the tsb 95 s trucker!
|
05-16-2017, 11:59 PM | #6 |
Registered User
Join Date: Aug 2011
Location: Dallas TX
Posts: 563
|
Re: 1999 Suburban 2500 454 misfire
For anyone following this I am 98% certain I have found the problem. The light blue wire with black stripe is the #4 injector wire. Yes that is copper you are seeing.
|
06-12-2017, 09:16 AM | #7 |
Registered User
Join Date: Oct 2006
Location: Southern Kalifornia
Posts: 3,066
|
Re: 1999 Suburban 2500 454 misfire
Ive been dealing with Random misfires on my 98 K1500 5.0. I ended up pulling the heads for a valve job, dropped them off Friday and last night I went out and just for sh*s and giggles I flipped the intake over and saw the intake gasket was leaking in #6...where the misfire was!
__________________
------------------------------------------------------ -Lance 2000 Chevy C2500, 5.7, 4L80e 1999 Suburban K2500, 7.4, 4L80e 1980 Camaro..son's car...PROJECT |
Bookmarks |
|
|