dr_latino999

iTrader: (12)

I was midway through a cross country drive (11 hours) last month and out of the blue I picked up an Intermittent P0170 code that I haven't been able to escape. I've attempted to troubleshoot this myself, but I'm not having any luck what so ever. My historical data logs have shown that my Fuel trims are progressively getting worse which is worrisome.

What left do I have to check to see what is causing this?



Is it possible the addition of a -10 AN fitting added to my intake pipe after the MAF for my recirculative catch can system is throwing off fuel trims at all? It was added in early February of this past year which fits in the time frame of the fuel trims going south.

Troubleshooting done as of yet in the past month.

1. Changed out Oxygen Sensor for new Denso 234-4741; no change.
2. Switched out FIC 1250's for new set of 1250's incase of E85 gunk buildup - Texas has relatively dirty E85; no change.
3. Check the four vacuum lines for a leak - FPR, Zeitronix MAP, BOV, Brake Booster, all good; no change.
4. Check exhaust manifold for leaks, find cracks. Replace MAP Shortrunner with FP Cast manifold; no change.
5. Changed out Oxygen Sensor for new NGK/NTK 23500; no change. It was a slight possibility that the previous one was bad, but I doubt both are bad.

Pertinent Modifications
Tephra v7 - Rom 96530706
Zeitronix ZT-2 Wideband in place of rear oxygen sensor - disabled rear O2 for over 15 months.
FIC 1250cc Bluemax
E85

legacydestroyer

Bump for this. I am having the same issue with my fuel trims. I have also tried to no avail the same things you have to correct this. I'm running the same injectors but no e85. Car had been running fine since 9/14 after my last tune. About a month ago after running a can of torco octane boost through the tank, I got the p0170. Now this was almost two tanks of 93 later and the car ran fantastic with the stuff in the tank. No signs of fuel mileage increase or decrease. Just keep pegging -12.5% after a 100 miles of driving or so after resetting the trims. Even went back to my tuner for some help. Took twice as long this time, but the code still set. Haven't called him back yet. Could really use some ideas. Could a map sensor cause this?

dr_latino999

iTrader: (12)

My original ROM was ignoring the MAP sensor, creating a SD one on the side to tie into it.

I made the logical assumption after boost leak testing, MAF cleaning, logging, that the recirculating catch can line into the intake was the source of my unmetered air throwing off my trims. I ended up logging like mad, plugging my evoscan logs into a quick Access file I constructed to isolate fuel trim (+/-) average for each Hz value measured, and made the necessary modifications to the MAF scaling maps.

Later this summer I'd like to switch to Speed density to remove this issue all together, but it is currently driveable and the fuel trims are within specs.

dothacker81

wish i could learn how to do this :P. I had this today and all I did was to reset the SES by disconnecting the battery... and issue never came back after that

dr_latino999

iTrader: (12)

Wait 200-300 miles once the fuel trims balance back out to a state of