GT500 Fuel Pump Issues

[ILW84U]

I had Eric Brooks tuning my car yesterday & at about 5000 RPM my fuel pressure was running low. I am running the GT500 dual pumps with a MDM Zone 5 driver module & 60lb. injectors. Pumps duty cycle, MAF etc were not maxed out. We switched out the MDM module for the 2 Ford FPDM system & the issue was the same.

Eric thinks it may be leak in the one of the lines in the pumps or possibly a loose wire at the pump. I remember Ford had issues some time back with the GT500 pumps but I don't recall what the problems were.

I got ahold of another set of pumps to swap out & try but thought if anybody here had ran into a similar issue, it may save me some time diagnosing. I need to get this sorted quick as I only have a couple of days while Eric is here to get my tune completed.

I appreciate any assistance.

 

[bigray327]

Funny you bring this up, I'm at my shop right now dealing with identical issues. Swapped the pumps out last night with no luck. My tuner had turned off load anticipation, which according to a calibrator at SCT jacks with fuel pressure on some cars. He had originally turned it off to deal with the load dropping, which worked, but now it seems it has to be turned back on. It's on the dyno now, so we'll see.

I would ask Eric if load anticipation is on or off.

 

[LASO]

OP- what was your fuel pressure reading through out the pulls? Did you hook up a mechanical gauge during the pulls?

 

[lito]

I would ask Eric if load anticipation is on or off.

Don't do that, leave him alone, he is a professional, he may kick your balls for asking dumb stuff you don't know about, I know I would.

There are many things that can go wrong with the GT500 hat, there is a typical three legged thing that is part of the eductor that sometime opens itself up and leaks, one pump could be giving up under pressure, a leaky hose, etc.

Take that off, check and test.

 

[bigray327]

Don't do that, leave him alone, he is a professional, he may kick your balls for asking dumb stuff you don't know about, I know I would.

Roar. Aren't you nice. The best tuner in southeath Texas didn't know about this, so it's worth asking if EB does. As memory recalls from when he tuned my car, he didn't mess with that.

 

[Eric Brooks]

Funny you bring this up, I'm at my shop right now dealing with identical issues. Swapped the pumps out last night with no luck. My tuner had turned off load anticipation, which according to a calibrator at SCT jacks with fuel pressure on some cars. He had originally turned it off to deal with the load dropping, which worked, but now it seems it has to be turned back on. It's on the dyno now, so we'll see.

I would ask Eric if load anticipation is on or off.

That has absolutely no bearing on fuel pressure. Totally bad information.

Inferred MAP, Fuel Flow, and Commanded Pressure dictate what happens. You also cannot say your car and this car are having the same problems without seeing the data.

The pressure is all over the place and falls hard up top while duty cycle sways from 60-100%. I have seen this many many times, and it is a result of a mechanical / electrical issue. It can be tune related, but after doing this combo a few times ( I tune at least a car or two a week with GT500 pumps) you learn what it takes to do it properly.

Don't do that, leave him alone, he is a professional, he may kick your balls for asking dumb stuff you don't know about, I know I would.

There are many things that can go wrong with the GT500 hat, there is a typical three legged thing that is part of the eductor that sometime opens itself up and leaks, one pump could be giving up under pressure, a leaky hose, etc.

Take that off, check and test.

Thanks Lito. I do believe it to be a leaky hose. Luckily someone has a GT500 pump assembly that is getting swapped in.

Roar. Aren't you nice. The best tuner in southeath Texas didn't know about this, so it's worth asking if EB does. As memory recalls from when he tuned my car, he didn't mess with that.

There was no need to mess with it. Anticipation Logic does not change anything to do with the pumps, and whoever said it did doesn't know what they are talking about.

 

[lito]

Who is the best tuner in southeast texas?

I can say I am the best tuner in my country and sometimes that does not means shit, get me a Mopar and see how lost am I.

You can't be the best tuner in anything if SCT has to tell you what to do and specially if the info is wrong, Eric knows, I do, you don't.

 

[bigray327]

There was no need to mess with it. Anticipation Logic does not change anything to do with the pumps, and whoever said it did doesn't know what they are talking about.

Well we turned it back on and the fuel pressure issues went away.

I have no need to argue with you smart people. I was trying to help. Good luck, OP.

 

[Eric Brooks]

Well we turned it back on and the fuel pressure issues went away.

I have no need to argue with you smart people. I was trying to help. Good luck, OP.

Post the data.

 

[bigray327]

Post the data.

No thanks. Like I said, I'm not interested in a pissing match... was only trying to help.

 

[ILW84U]

Damn, I didn't want to start a pissing match. I was just hoping maybe find an easier way to sort out the problem. I will pull the pump tonight to see if any problems are visible & if nothing shows up, swap the pump & try again.

There are many things that can go wrong with the GT500 hat, there is a typical three legged thing that is part of the eductor that sometime opens itself up and leaks, one pump could be giving up under pressure, a leaky hose, etc.

Take that off, check and test.

Is there a way to test while it is out of the car or are we just doing a visual?

I appreciate the help.

 

[Eric Brooks]

No thanks. Like I said, I'm not interested in a pissing match... was only trying to help.

I'm not pissing, or pissed. Just asking for the data to back up your claim.

 

[lito]

Damn, I didn't want to start a pissing match. I was just hoping maybe find an easier way to sort out the problem. I will pull the pump tonight to see if any problems are visible & if nothing shows up, swap the pump & try again.





Is there a way to test while it is out of the car or are we just doing a visual?

I appreciate the help.

You did not started anything, you have a problem and genuine questions and doubts about it and we all just want to help, telling the tuner what to do (specially when he is a guy that knows what he is doing) is something not recommended (specially when it is an incorrect information).

We make them work inside the tank but slightly off (as long as the eductor hose allow us, without the eductor connected there is a lot of air in the system and there are just bubbles coming out from the orange rubber valve) If your car has at least 1/2 tank, your driver's side tank should be full so is easy to keep the pumps sucking fuel and rest of the system out and see if any fuel comes out of the hoses, parts or connections.

 

[ILW84U]

Thank Lito. I'll give that a try.

 

[ILW84U]

Well I pulled the pumps & everything looked fine. Switched to the other set of pumps & the car started fine. This was with the FPDM's so switched back to the MDM & no go. WTF. Checked all the wiring & found no voltage going to the pumps. POS. Hooked the FPDM's back up & started fine.

Went back on the dyno with the same issues. Eric tried to tune out the issue but to no avail. Hooked up a BAP just to see if some extra voltage would help but no change.

I'm tired of messing with this so Monday morning Jared at Lethal will be getting a call to ship out a return style system to me. Once installed, it will be back on the dyno with Eric doing the tuning remotely.

If anyone has any hints, suggestions etc on doing the return system it would be greatly appreciated.