High fuel trims problem
11-18-2013, 05:29 AM
#1
High fuel trims problem Ok, I've been chasing what I thought was an injector setup/tune problem for a couple of weeks now. I can get the truck to start and idle, but will die when you put it in gear. From the first time I got then engine to start and run, I was getting some misfires on the right side (Bank 2) that were causing the short term and long term bank2 fuel trims to go extremely high. I thought it was just a problem with the injector data I had in the tune for the SD80 injectors I have. From everything I've read online, they are a hard injector to get dialed in. So I just assumed that was what my problem was. After much research, I'm pretty confident that I have that part of the tune setup correctly, but I still have the problem on the right side.
So last night I decided to do some trouble shooting to try and eliminate as many possible causes as I could. First, I swapped the O2 sensors from side to side, but no change. Next, I swapped the fuel injectors from the passenger side to the drivers side, still, no change. Finally, I swapped the the coil packs from side to side, but still, no change. The only other thing I can think of is that the the wiring to the coil packs on that right side is messed up. The engine sounds like a couple of plug wires are crossed on that side. It's probably been doing that since the first time I fired it up, but its been hard to detect because of the open headers. I even tried unplugging the individual coil packs on that side to see if you could isolate the miss, but it almost seems random. All of the headers pipes on that side are getting hot, so I know everyone of them are firing. This is very frustrating and I've got to figure this out first before I go any further with the tune. Sorry for venting.
Rob
Trouble codes:
[] P0174 - Fuel Trim System Lean Bank 2 (Immature)
[] P0300 - Engine Misfire Detected (Old) (Immature)
[] P057C - (SES) (Pending) (Old) (History) (Current) (Immature)
[] P0621 - Generator L-Terminal Circuit (Pending) (History) (Immature)
[] P219A - Fuel Trim Cylinder Balance Bank 1 (Old) (Current) (Immature)
[] P219B - Fuel Trim Cylinder Balance Bank 2 (Old) (Current) (Immature)
[] P2537 - Ignition Switch Accessory Position Circuit Low (Pending) (Old) (History) (Current) (Immature)
[] P057C -
Continuous Tests
Misfire: Complete
Fuel System: Incomplete
Comprehensive Component: Complete
So last night I decided to do some trouble shooting to try and eliminate as many possible causes as I could. First, I swapped the O2 sensors from side to side, but no change. Next, I swapped the fuel injectors from the passenger side to the drivers side, still, no change. Finally, I swapped the the coil packs from side to side, but still, no change. The only other thing I can think of is that the the wiring to the coil packs on that right side is messed up. The engine sounds like a couple of plug wires are crossed on that side. It's probably been doing that since the first time I fired it up, but its been hard to detect because of the open headers. I even tried unplugging the individual coil packs on that side to see if you could isolate the miss, but it almost seems random. All of the headers pipes on that side are getting hot, so I know everyone of them are firing. This is very frustrating and I've got to figure this out first before I go any further with the tune. Sorry for venting.
Rob
Trouble codes:
[] P0174 - Fuel Trim System Lean Bank 2 (Immature)
[] P0300 - Engine Misfire Detected (Old) (Immature)
[] P057C - (SES) (Pending) (Old) (History) (Current) (Immature)
[] P0621 - Generator L-Terminal Circuit (Pending) (History) (Immature)
[] P219A - Fuel Trim Cylinder Balance Bank 1 (Old) (Current) (Immature)
[] P219B - Fuel Trim Cylinder Balance Bank 2 (Old) (Current) (Immature)
[] P2537 - Ignition Switch Accessory Position Circuit Low (Pending) (Old) (History) (Current) (Immature)
[] P057C -
Continuous Tests
Misfire: Complete
Fuel System: Incomplete
Comprehensive Component: Complete
Last edited by Hart_Rod; 11-18-2013 at 05:55 AM.
11-18-2013, 12:13 PM
#4
I've got one ordered. Open loop seems a little better, but you can still tell there's a miss on the right side.
Fuel pressure is 58 PSI. I'm running an A1000 pump, 10 AN feed, 8 AN split to the rails, Aeromotive Boost referenced FPR, with an 8 AN return. Siemens SD 80 injectors. What voltage are you talking about? Here's a link to more specifics on HPT's web site:
http://www.hptuners.com/forum/showth...S1900-1968-C10
Fuel pressure is 58 PSI. I'm running an A1000 pump, 10 AN feed, 8 AN split to the rails, Aeromotive Boost referenced FPR, with an 8 AN return. Siemens SD 80 injectors. What voltage are you talking about? Here's a link to more specifics on HPT's web site:
http://www.hptuners.com/forum/showth...S1900-1968-C10
11-18-2013, 01:49 PM
#5
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My fuel pressure is never exactly what I set it to. I am wondering is that your fuel pressure now or has it dropped for some reason? Specifically the ECM voltage but battery voltage is close enough. An issue with either of these could throw you into a lean condition.
11-18-2013, 02:08 PM
#6
Both voltage and pressure seem to hold pretty steady while it's running. Don't you think it would affect both banks instead of just one, if it were the fuel pressure or battery voltage? I'll pay more attention to it the next time I data log.
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11-28-2013, 08:41 AM
#8
After checking everything possible and not finding anything obvious, I figured I would make some progress by having the exhaust put on. Once that was done I fired it up just to check it. Guess what fixed the problem.......I feel like an idiot....I guess the open headers were causing the fuel trims to go in opposite directions....go figure. Now everything appears to be working correctly and I need to start working on dialing in the MAF table.
