Fuel gremlins
Fuel gremlins My cousin is having problems with his fuel system in his '99 TA. When he goes WOT it leans out and surges a bit like it's starving for fuel. He tunes with HPT himself and has logged every run with a wideband. Here is his setup.
Iron block 404 stroker 11.15 CR
TEA Ported TFS 225cc heads
FAST 102/102
Weisco -2cc pistons
LS2 rails
42lb green top injectors
Walbro 255 with factory bucket mods
The only think I can think is fuel lines kinked or restricted OR the fact that he doesn't have the hot wire kit on his 255 yet. I'm thinking it is line related as he didn't have this problem until he toasted a tranmission in testing and installed the new one. Since then it has intermittenly had a fuel problem. Any ideas would help us track this down ASAP!
Iron block 404 stroker 11.15 CR
TEA Ported TFS 225cc heads
FAST 102/102
Weisco -2cc pistons
LS2 rails
42lb green top injectors
Walbro 255 with factory bucket mods
The only think I can think is fuel lines kinked or restricted OR the fact that he doesn't have the hot wire kit on his 255 yet. I'm thinking it is line related as he didn't have this problem until he toasted a tranmission in testing and installed the new one. Since then it has intermittenly had a fuel problem. Any ideas would help us track this down ASAP!
recently completed a 404 LQ4 Stroker build and was getting the car dialed in nicely Thanks, Neal.
I also posted this over at the HP Tuners Forum:
"I recently completed a 404 LQ4 Stroker build and was getting the car dialed in nicely when I started having an issue that seems to be fuel related. The car was running awesome and then things went the other way all of a sudden. I checked my walbro fuel pump and everything seems fine with it. My fuel filter is not clogged either. Before the mysterious problem emerged I was running about 20 degrees of timing at WOT, commanding (and getting) right at 13.0 AFR. The car was slipping the tires at 70+ mph when it went WOT. Then...... the problems began. The AFR started going to around 14.0 at WOT with no changes to the tune and it subsequently lost a ton of power. The strange thing is that I can sometimes get 12.9 AFR and it still acts like its not getting enough fuel. I had heard of fuel starvation problems (at low fuel levels) related to the modified fuel bucket/Walbro pump modification. With this in mind, I topped off my tank and the problem didn't go away. I'm thinking that my best move is to look into a different fuel system setup with new lines and a different pump but I want to be reasonably sure that this is where my problem is coming from. Another thought that I had was to install a "hotwire" kit. I'm also thinking of installing a fuel pressure gauge to verify what's going on at WOT.
I thought that I would post my tune to have you folks take a look first. Is there anything in the torque management or traction control that could cause something like this to occur? The Scan file is very short with a WOT pull in the middle. Can anything be determined from the injector data?
Anyway, I'd appreciate any help on this project.
Here's my complete setup:
1999 Transam with Performabuilt 4L60 and TCI 3500 stall
404 iron block with Trick Flow Heads ported by TEA, FAST 102/102, 42 lb FORD green top injectors, LS2 fuel rails, Yella Terra 1.7 Roller Rockers, Custom Pat G cam, 1 7/8" long tubes with off road y and magnaflow catback, no MAF (speed Density Tune), Walbro 255lph Fuel pump, NGK TR6 plugs (yes they are a bit too hot) and lots of other stuff that probably won't help in this diagnosis."
I also posted this over at the HP Tuners Forum:
"I recently completed a 404 LQ4 Stroker build and was getting the car dialed in nicely when I started having an issue that seems to be fuel related. The car was running awesome and then things went the other way all of a sudden. I checked my walbro fuel pump and everything seems fine with it. My fuel filter is not clogged either. Before the mysterious problem emerged I was running about 20 degrees of timing at WOT, commanding (and getting) right at 13.0 AFR. The car was slipping the tires at 70+ mph when it went WOT. Then...... the problems began. The AFR started going to around 14.0 at WOT with no changes to the tune and it subsequently lost a ton of power. The strange thing is that I can sometimes get 12.9 AFR and it still acts like its not getting enough fuel. I had heard of fuel starvation problems (at low fuel levels) related to the modified fuel bucket/Walbro pump modification. With this in mind, I topped off my tank and the problem didn't go away. I'm thinking that my best move is to look into a different fuel system setup with new lines and a different pump but I want to be reasonably sure that this is where my problem is coming from. Another thought that I had was to install a "hotwire" kit. I'm also thinking of installing a fuel pressure gauge to verify what's going on at WOT.
I thought that I would post my tune to have you folks take a look first. Is there anything in the torque management or traction control that could cause something like this to occur? The Scan file is very short with a WOT pull in the middle. Can anything be determined from the injector data?
Anyway, I'd appreciate any help on this project.
Here's my complete setup:
1999 Transam with Performabuilt 4L60 and TCI 3500 stall
404 iron block with Trick Flow Heads ported by TEA, FAST 102/102, 42 lb FORD green top injectors, LS2 fuel rails, Yella Terra 1.7 Roller Rockers, Custom Pat G cam, 1 7/8" long tubes with off road y and magnaflow catback, no MAF (speed Density Tune), Walbro 255lph Fuel pump, NGK TR6 plugs (yes they are a bit too hot) and lots of other stuff that probably won't help in this diagnosis."
Just to finish this out he found his problem. One of his injectors came unplugged. Someone at the HPT site looked at his logs and suggested checking all his injectors. Running like a beast again and back to tuning. I can't wait to see some numbers from this beast!
