Chevy Impala SS Forum banner

241 - 245 of 245 Posts

·
Registered
Joined
·
8,047 Posts
QUOTE: "All posts on the web pointed to the Opti."

NOPE. Not on this forum it woont have. With just your second two prior sentences I immediately thought FP. Now that you've joined up it might save you some $$$. Like it has the rest of us. lol
 

·
Registered
Joined
·
2,327 Posts
Sorry, didn't read all 13 pages so this may have been mentioned but I have personally worked on two B bodies where the cause of misfires was from a bad injector pigtail which I diagnosed with a simple noid light. One car had an intermittent misfire that would be very obvious when it was acting up. On the other car, it wasn't as noticeable (just like pulling plug, some will have more of effect). If you're getting a strong misfire, put your fingers on each injector and you could feel if it is functioning or not. The noid light will let you know if it is the harness and not just bad windings in the injector. Don't forget to wiggle the harness around while testing it. On both cars I had the problem with, the loose connection was at the pigtail itself and was easily fixed by soldering in a new pigtail.
 

·
Registered
Joined
·
2,327 Posts
Also,as far as the web is concerned, all problems always lead to the opti LOL. I can't say I wasn't victim of this myself. I swapped two optisparks once figuring out why my car was misfiring under load so bad it would barely move after a race. Ended up finding 3 bent up pushrods under the valve covers when the optisparks didn't fix the issue haha
 

·
Registered
Joined
·
1,720 Posts
Sorry, didn't read all 13 pages so this may have been mentioned but I have personally worked on two B bodies where the cause of misfires was from a bad injector pigtail which I diagnosed with a simple noid light. One car had an intermittent misfire that would be very obvious when it was acting up. On the other car, it wasn't as noticeable (just like pulling plug, some will have more of effect). If you're getting a strong misfire, put your fingers on each injector and you could feel if it is functioning or not. The noid light will let you know if it is the harness and not just bad windings in the injector. Don't forget to wiggle the harness around while testing it. On both cars I had the problem with, the loose connection was at the pigtail itself and was easily fixed by soldering in a new pigtail.

When doing my intake gasket R&R I found that the 5/7 injector pigtail had worn through to the copper from just rubbing up against other wires in the harness. That area is where all the wires for the engine harness bundle together in to the main loom.But yeah.../I just discovered it by chance. It could have easily progressed until it started arcing or something.
 

·
Registered
Joined
·
11 Posts
Couple years ago I wrote this down in my maintenance log, had an intermittent issue that put me into limp mode and kept me down for weeks.


"Comprehensive Research performed. Solenoids in Trans targeted first due to Impala SS Forum research. EFI Fuse (#4) repeatably blowing, shutting down everything associated with that circuit. First out DTC is reliably #83, TCC Circuit Failure followed on the very next data resolution point, TDC #48 MAF Sensor Fault. Next out is #84, 3-2 downshift fault. SS only has 3rd gear for forward motion, reverse also works. From the three GM service manuals, pieced together that loss of power to the 1-2 and 2-3 can put the trans in one gear and keep it there and also the 3-2 downshift controller will cause a soft landing into 3rd gear and keep it there. DTC 26, 27, 29 also appear after awhile, which makes sense cause they all route through the #4 (EFI) Fuse.
Tested new solenoids for appropriate resistance, SAT, removed old and tested, SAT for resistance values however the 367B did not cycle when mechanically agitated. The 394 (3-2 control sol) was not pushed in all the way, which was weird but I'm undecided if it was making a difference. Check engine light still on, reflashed PCM with a delete of the Air Pump DTC check and set the Air Pump Enable to 154 Deg C minimum. Ran diagnostics again (in garage 2, 2/3/2018). SAT

(24 hours later)Failed again, moved on to the rest of the circuit. Since the O2 Sensors have been replaced recently, took a look at the canister purge valve. Unplugged it and tested it for several days. Failure did not repeat. Reflashed computer with cansiter purge deleted. Running satisfactory at this time."

Its been running SAT ever since. That canister purge valve was the true root of the problem.
 
241 - 245 of 245 Posts
Top