4.8 lsx swap ecu problems
Thread Starter
Staging Lane
Joined: Apr 2013
Posts: 82
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Thread Starter
Staging Lane
Joined: Apr 2013
Posts: 82
Likes: 0
So I checked the bolt that is the ground on the little mini harness at the tank.
Bolt and wire on top of the frame.
Didn't take it out but just looked at it and checked it out.
Looked fine. Didn't volt meter anything, too dark.
Is that the one bolt/ground that could be causing the issue?
Do I need to take it off, and like clean it, put it back on?
And is there a way for me to check other things like clogged fuel lines without dropping the tank?
Or anything that I CAN do in the driveway?
Bolt and wire on top of the frame.
Didn't take it out but just looked at it and checked it out.
Looked fine. Didn't volt meter anything, too dark.
Is that the one bolt/ground that could be causing the issue?
Do I need to take it off, and like clean it, put it back on?
And is there a way for me to check other things like clogged fuel lines without dropping the tank?
Or anything that I CAN do in the driveway?
Thread Starter
Staging Lane
Joined: Apr 2013
Posts: 82
Likes: 0
I know that I need to get the ECU tuned with a non-automatic straight drive.
So my question is no longer involving the ECU but more alone the lines of,
What would cause the fuel pressure to drop 30~40 pounds randomly at WOT (sometimes at the same RPM intervals.)???
Fuel filter has been replaced.
I pulled the vacuum hose off of the FPR, while it was running and gasoline didn't spill out so im guessing its not the problem? (maybe it is?)
The only non replaced fuel lines are from the filter to the tank, (along with return), everything was replaced with custom made lines.
Connection? clogged lines? Im so confused.
I can't remember if you checked fuel pressure at the rail with key on, no start? Also, what is fuel pressure with it idling? This should tell you if your regulator is working properly.
If all is good there, I would unhook the fuel line from the fuel rail and route to a 2 liter bottle or something, and cycle the key to check for flow. Pressure can be fine but if you have low flow, as the injectors squirt fuel, if the system can't keep up the pressure will drop. With it unhooked, you should have a solid stream of fuel coming out of the hose when you cycle the key, if not, somethings wrong.
Are you confident the pickup in the tank is staying covered with fuel? Low fuel? what hoses did you use to connect the new pump? I have seen problems there.
If all is good there, I would unhook the fuel line from the fuel rail and route to a 2 liter bottle or something, and cycle the key to check for flow. Pressure can be fine but if you have low flow, as the injectors squirt fuel, if the system can't keep up the pressure will drop. With it unhooked, you should have a solid stream of fuel coming out of the hose when you cycle the key, if not, somethings wrong.
Are you confident the pickup in the tank is staying covered with fuel? Low fuel? what hoses did you use to connect the new pump? I have seen problems there.
Thread Starter
Staging Lane
Joined: Apr 2013
Posts: 82
Likes: 0
I can't remember if you checked fuel pressure at the rail with key on, no start? Also, what is fuel pressure with it idling? This should tell you if your regulator is working properly.
If all is good there, I would unhook the fuel line from the fuel rail and route to a 2 liter bottle or something, and cycle the key to check for flow. Pressure can be fine but if you have low flow, as the injectors squirt fuel, if the system can't keep up the pressure will drop. With it unhooked, you should have a solid stream of fuel coming out of the hose when you cycle the key, if not, somethings wrong.
Are you confident the pickup in the tank is staying covered with fuel? Low fuel? what hoses did you use to connect the new pump? I have seen problems there.
If all is good there, I would unhook the fuel line from the fuel rail and route to a 2 liter bottle or something, and cycle the key to check for flow. Pressure can be fine but if you have low flow, as the injectors squirt fuel, if the system can't keep up the pressure will drop. With it unhooked, you should have a solid stream of fuel coming out of the hose when you cycle the key, if not, somethings wrong.
Are you confident the pickup in the tank is staying covered with fuel? Low fuel? what hoses did you use to connect the new pump? I have seen problems there.
Already did the flow thing when I changed the filter.
So either pump connections or pump pick up?
But even with half a tank it still does it.....
Any misfire DTC's?I had a similar condition,turned out to be a broken #5 injector wire,broke off at the pin inside the connector so it would make an intermittent connection.Solved that problem,now if I could only clear up my P0327,332 codes...
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Staging Lane
Joined: Apr 2013
Posts: 82
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I want to do a crank sensor relearn procedure.
Injectors (SEEM) fine but I guess I will check them.
Will also hook the guage back up and record the pressures.
You have already identified low fuel pressure, low fuel pressure will cause it to behave exactly like it's behaving. If it were me, I wouldn't waste time chasing anything else until the fuel pressure is resolved.
Thread Starter
Staging Lane
Joined: Apr 2013
Posts: 82
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I could care less about the missfire untill I figure out the fuel pressure dropping issue.
I mean, the pressure isnt low when Im cruising or light load, only when gunning it does it stay at like 50 pounds and then randomly drops to twenty for half a second and then goes back
Sounds like it's sucking air at the pump. I would fill the tank and try again. If that fixes it, the problem is in your tank. If that doesn't fix it, it could be electrical or fuel line path.
Thread Starter
Staging Lane
Joined: Apr 2013
Posts: 82
Likes: 0
Thread Starter
Staging Lane
Joined: Apr 2013
Posts: 82
Likes: 0
Thread Starter
Staging Lane
Joined: Apr 2013
Posts: 82
Likes: 0
The lines going from the filter to rails are soft, fuel injection hose and they are like clamped/molded and can't take them off.
And I cannot drop the tank to check like baffles or electrical connections yet.
Or is there another way I can electricly check everything without dropping the tank?
Well I ran into a problem.
The lines going from the filter to rails are soft, fuel injection hose and they are like clamped/molded and can't take them off.
And I cannot drop the tank to check like baffles or electrical connections yet.
Or is there another way I can electricly check everything without dropping the tank?
The lines going from the filter to rails are soft, fuel injection hose and they are like clamped/molded and can't take them off.
And I cannot drop the tank to check like baffles or electrical connections yet.
Or is there another way I can electricly check everything without dropping the tank?
I would fill it up and try it first, that would be easier, if that don't work we can go further. Right now I am leaning towards either sucking air somewhere or a restriction in the line.
Still would like to confirm actual fuel pressure with key on engine not running and running.
Staging Lane
Joined: Feb 2013
Posts: 55
Likes: 0
From: Miami, FL
I'd agree with the pump sucking air under hard accel, happens on my little toyota from time to time when i'm below a half tank. Try it with a full tank and see if it improves. Possibly an issue with the tank internally or the fuel pump basket not allowing in enough fuel to sustain WOT operations.