Hello everyone, I'm hoping to get some help with my truck. It's been a great beater and I'm hoping to keep it running for at least a few more years. Currently, it has ~240,000 miles on it.
For starters, here's the list of things I've replaced since I've had it:
Part Replaced
plugs 2018
wires (ac delco) 2018
coolant temp sensor 2020
distributor cap (Oreilly, brass pins NOT AC Delco) 2020
Fuel filter 2020
rotor 2020
spider injector (mpfi conversion, Oreilly's) 2020
thermostat (195°F) 2020
Water pump 2020
I've also recently flushed/replaced coolant, the #4 spark plug with an AC Delco. It doesn't lose coolant (that I can tell), and the exhaust seems ok. I'm far from an expert but I'm pretty handy and good with data/numbers. I have this: https://bafxpro.com/products/wifi-obdii-reader-scanner-for-ios-devices, and an app called OBD Fusion. I don't think this app has the ability to tell me misfire counts or detailed data, but if someone knows how to do that with this tool I would love to hear it.
For the last few weeks I've been tuning this truck up in preparation for deer season, and overall it runs great. Especially since replacing the thermostat, it now heats up fast and holds at around 190 and gets about 17 mpg on short trips. Not too bad, and an improvement from the 14-15 it was getting with the old thermostat ( I don't know what specs were).
The truck sat for awhile this summer, was hard starting when I needed it but would ultimately always start. Never really noticed hesitation or anything until I got the code reader and read the codes and noticed the P0304 and P0300. It also throws a P0440 sometimes, but I think that's the gas cap. When I replaced the injector assembly, i found fuel in the electrical connector ( leaking by the seals on the solenoids) which now makes me suspect the harness (maybe corrosion). Problem is, if I start it and immediately put it in gear and go it won't throw the code and it seems to run fine. From my view, fuel trims and all other data look good. Please let me know if you see something different here. I'm including a couple of charts from a recent 15 minute drive that may be helpful.
The things I know I need to check:
Long term fuel trim averages (approximate):
Bank 1: -3.0%
Bank 2: 5%
Short terms (approximate):
Both ~0.3%
I've also been running Marvel Mystery Oil in the crankcase, and Seafoam in the fuel tank. Fuel is premium (not ethanol free though).
I'm at a loss, but would like to keep the check engine light off if possible. Seems to be quite difficult though, with this truck. Previous owner had a piece of tape over it. Got a heck of a deal on the truck, PO thought it had major problems but replacing cap, rotor, wires, fixed it right up a few years back.
I've been browsing these forums for awhile, trying to find similar situations and I know there's a lot of information out there. Now hoping for some personalized advice. What would your next step be?
Thanks!
-Trent
Edit 10/11/20: Removed irrelevant maintenance items from the list, I originally copy pasted everything from my personal list of things I've replace
For starters, here's the list of things I've replaced since I've had it:
Part Replaced
plugs 2018
wires (ac delco) 2018
coolant temp sensor 2020
distributor cap (Oreilly, brass pins NOT AC Delco) 2020
Fuel filter 2020
rotor 2020
spider injector (mpfi conversion, Oreilly's) 2020
thermostat (195°F) 2020
Water pump 2020
I've also recently flushed/replaced coolant, the #4 spark plug with an AC Delco. It doesn't lose coolant (that I can tell), and the exhaust seems ok. I'm far from an expert but I'm pretty handy and good with data/numbers. I have this: https://bafxpro.com/products/wifi-obdii-reader-scanner-for-ios-devices, and an app called OBD Fusion. I don't think this app has the ability to tell me misfire counts or detailed data, but if someone knows how to do that with this tool I would love to hear it.
For the last few weeks I've been tuning this truck up in preparation for deer season, and overall it runs great. Especially since replacing the thermostat, it now heats up fast and holds at around 190 and gets about 17 mpg on short trips. Not too bad, and an improvement from the 14-15 it was getting with the old thermostat ( I don't know what specs were).
The truck sat for awhile this summer, was hard starting when I needed it but would ultimately always start. Never really noticed hesitation or anything until I got the code reader and read the codes and noticed the P0304 and P0300. It also throws a P0440 sometimes, but I think that's the gas cap. When I replaced the injector assembly, i found fuel in the electrical connector ( leaking by the seals on the solenoids) which now makes me suspect the harness (maybe corrosion). Problem is, if I start it and immediately put it in gear and go it won't throw the code and it seems to run fine. From my view, fuel trims and all other data look good. Please let me know if you see something different here. I'm including a couple of charts from a recent 15 minute drive that may be helpful.
The things I know I need to check:
- Fuel rail pressure (though this wouldn't explain one cylinder misfire with new injectors)
- Compression: but if there was a stuck valve or broken spring wouldn't this show up in performance too? the truck runs strong, no performance issues that I can tell.
- Distributor cap: I bought one of the bargain ones with brass pins, maybe a mistake. I hear crossfire could be a problem, any way to check for this without buying more parts?
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Long term fuel trim averages (approximate):
Bank 1: -3.0%
Bank 2: 5%
Short terms (approximate):
Both ~0.3%
I've also been running Marvel Mystery Oil in the crankcase, and Seafoam in the fuel tank. Fuel is premium (not ethanol free though).
I'm at a loss, but would like to keep the check engine light off if possible. Seems to be quite difficult though, with this truck. Previous owner had a piece of tape over it. Got a heck of a deal on the truck, PO thought it had major problems but replacing cap, rotor, wires, fixed it right up a few years back.
I've been browsing these forums for awhile, trying to find similar situations and I know there's a lot of information out there. Now hoping for some personalized advice. What would your next step be?
Thanks!
-Trent
Edit 10/11/20: Removed irrelevant maintenance items from the list, I originally copy pasted everything from my personal list of things I've replace
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