01 running rich

01_GT

Member
Oct 6, 2020
7
1
13
30
Santa fe NM
So about 2 months ago i bought this car that i felt was a steal for the price. 01 gt with longtubes, o/r x pipe, CAI, act clutch (it was an auto but was swapped to a tr3650) steeda tri ax, flowmaster cat back, sct tuner, lowered with eibach springs. The engine is rebuilt with heads from 2010 crown vic that were milled .010. New timing chain with billet chain guides and new tensioners (have paperwork for everything listed). Now that i listed everything done to the car on to my issue. The car is running rich, i dont have a a/f guage BUT i can defines smell the gas in the exhaust, iv checked plugs and changed them because they were fouled, about a week later they were fouled again and smelled like gas, all 8 plugs looked the same and about 6 smelled of fuel. Iv put a fuel pressure guage (MAC if that matters) and at idle its steady around 37-40 psi. Iv tried using the tuner to read fp while driving but it only gives me an option for FPDC. LTFT seems to be adding fuel when driving tho. It can go from 1.3% to about 1.8% while driving. So my understanding is the pcm is adding fuel based on the parameters it sees. There is no CEL light and the car runs kinda sluggish. Iv been thinking that timing is where my issue is at, because of the milled heads and the fact that the tuner only has provisions for 87 and 93 octane and we only have 86 and 91. Iv tried both tunes with 86, 88, and 91 Octane and have had similar results. Would anybody care to help me out in figuring this out? Again i want to say timing is my issue but even tho i have done a lot of research i cant figure out which way to go with it or what to change since there is settings for global spark, spark 2k-4k and 4k-6k and WOT.
 
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01_GT

Member
Oct 6, 2020
7
1
13
30
Santa fe NM
Well just an update. I went with the 87 tune and put 91 octane in the tank and started messing with the spark adjustment at WOT. I so far have added 3* to WOT spark and am seeing some results showing my ltft drop to 1.2-1.4% and no pinging/knocking yet. And less smoke for sure when i step on it. It went from a big puff of smoke to something just slightly visable. Iv added 1* at a time and drove it for a while. Not sure if i should keep adding until it pings/knocks then back it off. Im not even sure if im in the right track in what im doing. Wish someone would chime in!!!
Oh and before someone gets upset and says “get it tuned stop messing with it” thats out of the budget at the moment, definitely planned for the future tho.
 

McFly2

New Member
Nov 21, 2020
3
0
1
63
Cincinnati
Hey 01_GT
I have a 2001 Bullitt. I have a fuel air code P0174 bank 2 lean, that causes PCM to add fuel. so I have been studying the subject.
You stated that LTFT can go from 1.3% to about 1.8% while driving. Plus or minus 5 in the LTFT and STFT's are normal at idle and at RPM. When you idle up, or for accelerate; you should see the STFT go up instantly if fuel is adjusted by PCM, but should stabalize to + or-5 quickly at cruise speeds. I wish you had stated what your fuel trims are at idle, and 1500rpm and 2500 rpm. Your LTFT and STFT should be at + or - (5) at idle for bank 1 and bank2; would be perfect. [no more than + or - (10) max.
When rpm go up, trims should stabilize to the same fuel trim data, as idle. Your results showing your ltft drop to 1.2-1.4% are of no consequence. They are still in perfect range. I'm not sure why you suspect timing or why you would adjust timing. I need more data [ Your LTFT and STFT at idle for bank 1 and bank2; would be a start. Smelling gas could be cause by PCM adding gas for a lean condition. Because the problem is not reaching thresh hold to send a MIL code, all you have to lean on is fuel trim data, 02sensor data, fuel pressure, maf data, etc. Data that can be read by Innova 3040RS OBD2 scanner $89. Auto zone lets me use theirs. That is how I learned what my code is. Then I learned how to get into Live data and Freeze frame. Then to interpret data I watched Schrodinger's Box
"Secret of Engine Problem Diagnosis- Fuel Trims Pt.1 YouTube video.
IF your fuel trims for Bank 1 are the same as bank 2, that means a part or symptom that effects all cylinders (example: vacuum leak after MAF sensor / to throttle body).
If you just have abnormal Bank 1 data, that would indicate problem on cylinders 1-4 (ex. vacuum leak on passenger side of engine bay.) Im a new subcriber here. Im not an auto mechanic. You will have to watch the videos out there. Get your hands on a scanner.
I used Innova 3040. I just ordered ThinkOBD 100 for $30. It supposedly has the fuel trim data etc. I dont have it yet. You will have to get your hands on a scanner. Then do a scan. Try to interpret. Watch videos and read more. Do another scan. You have to go through the motion. send me your fuel trim data
( Your LTFT and STFT at idle for bank 1 and bank2; at idle and for 2000 rpm. I will tell you what I know.
McFly2