fueling issue? or something else?
fueling issue? or something else? So I feel this issue has been going on for quite some time. Car is 2002 trans am. Car was completely stock and I've always that in the higher RPMs it was kind of gutless. Anyways since then I've upgraded injectors, new filter same issue. I also installed a cheaper aftermarket pump that still has the venturi boost jet but still had the same issue with fuel pump hotwire kit.
Recently installed rebuilt LS2 engine with factory LS6 intake manifold so the fueling didn't change, also installed some wideband sensors and sure enough the car is still leaning out under WOT. I just installed new racetronix pump and now fueling issue is even worse, during this time I also ran a fuel pressure gauge and it only dropped 2-3 PSI under WOT... a little frustrated so I spent the big bux and bought new A/C delco unit and got that installed and still same issue. AFR under WOT is going to 20:1 or worse. I pay for remote tuning service and he's certain its a fueling issue and we've even tried a SD tune with the same results. I'll list things below that I've done to try to fix issue.
Checked fuel lines for kinks, was unable to check about 1' of line above fuel tank.
New A/C delco pump assembly
New Fuel filter
Fuel pump receiving 14.4V while car is on
Pressure is 57-60 PSI, I think it may have even been slightly higher with the racetronix pump
replaced MAF, Also ran SD tune with same issue
I'm $470 into this issue with a car that I can't floor... Any Ideas? do I just need to change out all fuel lines and fuel rail?
Recently installed rebuilt LS2 engine with factory LS6 intake manifold so the fueling didn't change, also installed some wideband sensors and sure enough the car is still leaning out under WOT. I just installed new racetronix pump and now fueling issue is even worse, during this time I also ran a fuel pressure gauge and it only dropped 2-3 PSI under WOT... a little frustrated so I spent the big bux and bought new A/C delco unit and got that installed and still same issue. AFR under WOT is going to 20:1 or worse. I pay for remote tuning service and he's certain its a fueling issue and we've even tried a SD tune with the same results. I'll list things below that I've done to try to fix issue.
Checked fuel lines for kinks, was unable to check about 1' of line above fuel tank.
New A/C delco pump assembly
New Fuel filter
Fuel pump receiving 14.4V while car is on
Pressure is 57-60 PSI, I think it may have even been slightly higher with the racetronix pump
replaced MAF, Also ran SD tune with same issue
I'm $470 into this issue with a car that I can't floor... Any Ideas? do I just need to change out all fuel lines and fuel rail?
Take the tank down and check for any kinks in the plastic lines. While you have it down, inspect inside as well. I have dropped the metal tank in my 1998 twice (that one is a PITA due to the non-removable filler neck) and I just put a new plastic tank in my car after pulling it out from a junkyard car. The plastic ones are not too bad. The only hard part is getting the bolt on the straps started when you push it back up there--it probably helps to have someone to hold it for you, or use a jack (lightly).
If the plastic lines seem okay, it may be time to start blowing an air compressor through the metal lines under the car to check for restriction. Obviously, take everything off the ends so that it is just a straight shot through.
If the plastic lines seem okay, it may be time to start blowing an air compressor through the metal lines under the car to check for restriction. Obviously, take everything off the ends so that it is just a straight shot through.
Take the tank down and check for any kinks in the plastic lines. While you have it down, inspect inside as well. I have dropped the metal tank in my 1998 twice (that one is a PITA due to the non-removable filler neck) and I just put a new plastic tank in my car after pulling it out from a junkyard car. The plastic ones are not too bad. The only hard part is getting the bolt on the straps started when you push it back up there--it probably helps to have someone to hold it for you, or use a jack (lightly).
If the plastic lines seem okay, it may be time to start blowing an air compressor through the metal lines under the car to check for restriction. Obviously, take everything off the ends so that it is just a straight shot through.
If the plastic lines seem okay, it may be time to start blowing an air compressor through the metal lines under the car to check for restriction. Obviously, take everything off the ends so that it is just a straight shot through.
Good idea on blowing compressed air through the lines, I'll try that.
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Rereading your IP, so you are saying fuel pressure is a healthy 57-60 psi at rest, and under WOT it only drops 2-3 psi? I don't know much about tuning, but that sounds perfectly within the normal range for our cars. If the A/F ratio is leaning out to 20:1, that is something in the tune not running the injector pulses long enough, or the injectors themselves. If you rule those two out, then it is somehow not reading the air intake properly.
If I am understanding that correctly, I don't think it is a fuel supply issue.
If I am understanding that correctly, I don't think it is a fuel supply issue.
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Verdad Gallardo See that's what I was thinking. My tuner is reputable and is a sponser on here... he says he's having to add a lot more fuel than he should and its giving him "red flags" he says I'm running about 25% less fuel than I should. He provided me a SD tune and i had the same issue.
This morning I was thinking about my MAP sensor and i'm thinking maybe there could be an issue with that? I feel it'd have to be pretty far off to cause this much of an issue though. I can post up some of my log files if that would help.
I appreciate your responses eb110americana.
I picked up a fuel gauge pod and waiting for the adapter so i can keep a better eye on the pressures.
This morning I was thinking about my MAP sensor and i'm thinking maybe there could be an issue with that? I feel it'd have to be pretty far off to cause this much of an issue though. I can post up some of my log files if that would help.
I appreciate your responses eb110americana.
I picked up a fuel gauge pod and waiting for the adapter so i can keep a better eye on the pressures.
Since you replaced the MAP sensor, and your problem is only at WOT, that is not likely. However, if you want to test, you can unplug the MAP, start the car, let it settle for a few minutes, and then go drive it (a check engine light will come on, but it will clear itself after a few miles of driving with the MAP plugged back in later).
If the problem does not change, you can rule out the MAP. If it runs much better, then you have a faulty MAP or possibly faulty MAP tune.
Otherwise, yes, realtime fuel pressure with your new gauge will hopefully shed some light on the issue. Are you sure you have the right injectors for the tune his giving you?
If the problem does not change, you can rule out the MAP. If it runs much better, then you have a faulty MAP or possibly faulty MAP tune.
Otherwise, yes, realtime fuel pressure with your new gauge will hopefully shed some light on the issue. Are you sure you have the right injectors for the tune his giving you?
I have not replaced it yet, but since vacuum is at its lowest during WOT maybe the MAP sensor readings are off. I'm still running the LS6 intake manifold and I know before I ran the LS6 PCV and catch can the LS1 PCV was flowing a lot of oil into the intake. so maybe? its also the factory one with 106k miles. I ordered one and it'll be here Friday.
I did have realtime fuel pressure reading when I had the gauge taped to the window lol. but a digital one will be easier to read.
Yes I'm sure the injector data is right, I put in that information before the tuner. Also I was having the issue before the injectors.
I did have realtime fuel pressure reading when I had the gauge taped to the window lol. but a digital one will be easier to read.
Yes I'm sure the injector data is right, I put in that information before the tuner. Also I was having the issue before the injectors.
So here's an update.
I've installed a fuel pressure sensor and gauge into my gauge pod so I can keep a closer eye on what the fuel pressure is doing, but here's the strange part. The car has good AFR's under WOT when cold. I did a couple WOT pulls a couple of minutes in to the being and it AFR was right about 11.5 and then another pull was even 11 and 10.9. As the car warmed up though I was getting leaner and leaner AFRs until WOT would be as high at 16:1. Also note the fuel pressure was behaving exactly the same at cold as it was at hot. So now I need to figure out what is causing this.... If interested I've attached my log file that shows good afr at start then leans out towards the end.
https://drive.google.com/open?id=0B2...kzRXkwRDVRUTlZ
I've installed a fuel pressure sensor and gauge into my gauge pod so I can keep a closer eye on what the fuel pressure is doing, but here's the strange part. The car has good AFR's under WOT when cold. I did a couple WOT pulls a couple of minutes in to the being and it AFR was right about 11.5 and then another pull was even 11 and 10.9. As the car warmed up though I was getting leaner and leaner AFRs until WOT would be as high at 16:1. Also note the fuel pressure was behaving exactly the same at cold as it was at hot. So now I need to figure out what is causing this.... If interested I've attached my log file that shows good afr at start then leans out towards the end.
https://drive.google.com/open?id=0B2...kzRXkwRDVRUTlZ
