Fuel trims really high and no boost leaks?

[EagleTalonTim]

Yeah, I spent an entire weekend tearing down the TB and intake to fix all possible boost leaks. I got a log a few minutes ago and I will have to post it as soon as I get it on my computer. One question I do have is.... is there a math formula to calculate the air/fuel ratio by the O2 voltage readings? I know 14.7 is dead in the middle but I am unsure of the range that the O2 can read.

 

[91tizzy]

I need information on this ground strap thing to downpipe! Tim mine and your cars are almost identical and if that helped your problem I gotta get this on my car....i need pics on where its supposed to be etc. Car never had one on it. About to just just say to hell with it all and get my keydiver setup.

 

[EagleTalonTim]

I just took some 12 gauge industrial wiring and bolted it to the O2 dump where the heat shield used to be and run it straight down to the frame. Since I have the stock O2 dump, there is a bolt hole right above the waste gate flap where the heat shield used to bolt to. For the connection on the frame, I found a bolt hole that was already tapped right next to the front motor mount, so I cleaned it up really good and bolted the wire down to it. I left about 6 inches of play in the wire incase the motor happened to move since my motor mounts have been slowly deteriorating. I also found that my O2 had become loose since the last time I changed it, the engine was cool when I put it back in. The heat probably caused the O2 to loosen up enough to rattle and cause strange knock problems which was posted in another thread I started. Everything has been good so far

 

[spyderturbo007]

I just put a ground wire on the O2 dump to the frame and it looks like that may have sort of fixed my problem. Instead of a 139% with the SAFC at 0% correction, the Low trim is now around 108%. With the SAFC set at +4% it floats right around 100%. Another problem I am running into is that even with a 192° t-stat, my engine temp hardly ever gets over 182°. What would cause this?

Perfect. I knew something had to be going on with the O2 sensor to cause those problems with the FT's.

 

[matthewdesigns]

Another problem I am running into is that even with a 192° t-stat, my engine temp hardly ever gets over 182°. What would cause this?

T-stat stuck open. I had a "never hot enough" issue a couple months back and a new t-stat solved it. I could only get up to normal temp in stop and go traffic, and on the interstate it hardly got above 170*...on cold nights it was more like 130*.

 

[EagleTalonTim]

I just put the second 192° t-stat in and still have the same problem. I am just going to get me a 100 ohm potentiometer to splice inline with the ECU signal to be able to offset my temp.....kind of like the DSMlink temp offset feature.

 

[91tizzy]

Hey Tim, do you plan on installin the 550s with 2g maf soon? Im assuming your trims are still staying good now? As for your deteriorating motor mounts....take them off and fill the stock gaps and all cracks with some loctite black and a hand pump....makes a big difference. I dont have any boost leaks anymore either and my trims are maxed out lean at anything below 50psi base fuel pressure. Im thinking maybe our stock auto ecu may help to offset this till I can get the rest of my keydiver chip funds saved up.

 

[DJ23GSX]

I had similar problems with my 680's and 2g maf. Fuel trims almost always maxed out even after adding a ton of fuel with the safc and a new o2 sensor. Turned out to be a couple things. First my fuel pressure gauge was wrong. It was reading 8psi higher than the real pressure. So when I thought I was running 38psi bfp it was really only 30psi. A new liquid filled gauge set to 40psi bfp helped my low and mid trims but my hi trim was still way off and I was getting knock at 6k rpms no matter how much fuel I added on the safc. The second problem was my rewired walbro 255 was dying. After putting in a brand new high pressure 255 my trims are almost perfect with the safc set to 0 and the keydiver chip compensating for the 680's and 2g maf. My knock issue at 6k is gone as well. I purchased the keydiver chip first thinking that would help this issue but it didn't.

Good Luck