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Hummer H3For the Hummer driver who wants the rugged look and off road capabilities of the Hummer, but in a smaller size and with a more fuel economy friendly engine.
That was going to be my next stop as I'm still misfiring despite all the stuff. Cylinder 1 looks like already had the connector and wire replaced at some point.
haha no rodents, but the wire conduits around the car just crumble. I've been replacing them where I can.
Just traced the wire from cylinder 5 coil, don't see any exposed copper, not to say there's isn't an intermittent break somewhere inside the wire. That damn air box sure keeps things snug in there and could have potentially pinched a wire, saw a few sharp bends. I'm about to rip that thing out and install something more practical that gives me easy access to wiggle the wire around while the truck is running.
Did more digging today to try and pin point when I get the misfire. Looks like I only start to misfire once engine is at full temp, in park, AC off. If I turn the AC on or put the truck in D misfire goes away, in other words engine load at 20% = cylinder 5 misfire, engine load between 25-30% no misfire. LTFT and STFT normal, manifold pressure normal, I couldn't tie engine RPM to misfire, but it seems to fluctuate between 660-690
Did more digging today to try and pin point when I get the misfire. Looks like I only start to misfire once engine is at full temp, in park, AC off. If I turn the AC on or put the truck in D misfire goes away, in other words engine load at 20% = cylinder 5 misfire, engine load between 25-30% no misfire. LTFT and STFT normal, manifold pressure normal, I couldn't tie engine RPM to misfire, but it seems to fluctuate between 660-690
To me it appears to be sticking valve I've corrected on my 3 with induction cleaning & only refilling with TOP TIER™
Still misfiring in cylinder 5 - bought a pair of gauges to do a leakdown test, cylinder 5 leaking 40% mostly via rings as I can feel air more noticably blowing from the PCV and oil dipstick tube, hardly anything from the intake and exhaust. Which further confirms my wet/dry compression test I did earlier that strongly pointed to rings not sealing well.
Gonna try another b12 and mmo soak to try and free things up, otherwise I'm probably going to sell the darn thing. I thought about buying a crate engine and swapping that in, but kinda over it at this point.
As a last resort/Hail Mary, you could change the oil, try a slightly thicker viscosity (10W-40 for instance) and add in a can of Engine Restore.
For the I-5 I would try the 6 Cylinder formula. This might seal things up enough to restore some lost compression and rid the Misfire, but then again it might not.
As a last resort/Hail Mary, you could change the oil, try a slightly thicker viscosity (10W-40 for instance) and add in a can of Engine Restore.
For the I-5 I would try the 6 Cylinder formula. This might seal things up enough to restore some lost compression and rid the Misfire, but then again it might not.
That's the plan, luckily the misfire is not terrible only triggers CEL once in a while, but shows up on the scanner nevertheless. I did read about engine restore and some folks used it with good results, but idk about using higher viscosity oil, it does get very hot around these parts during the summer so maybe it won't be so terrible.
0W-40 oils are recommended by automakers for many types of European vehicles, including Mercedes-Benz, Porsche and Volkswagen. The viscosity is gaining popularity with American automakers for high performance engines in both cars and pickup trucks.
In this viscosity, we offer Mobil 1™ FS 0W-40 or Mobil 1™ ESP Formula 0W-40. They can be used in either gasoline- or diesel-powered engines.
If your diesel-powered engine requires an oil meeting the CK-4 specification, then choose Mobil Delvac 1™ ESP 0W-40. Note: We don’t compare diesel engine oils with motor oils formulated for gasoline-powered vehicles.
Mobil 1 ESP Formula 0W-40 carries the dexos®2 approval specified for General Motors vehicles.
