GT500 pump issue?

[stang910]

Had my car dyno tuned today and it put down right at 500 rwhp on a dynojet. Around 6500 rpm my pumps went flat in the datalog. I don't know what the duty cycle was because my tuner just showed me the graph where the pumps were no longer able to support anymore fuel. So we didn't even attempt to pull more power out of it. My MAF also pegged at the same time. This is the first time I've seen GT500 pumps max out at 500 rwhp so I'm kinda concerned. Does the MAF have anything to do with this or do I have a mechanical/electical issue somewhere? I'm using 52lb injectors.

 

[lito]

Have you changed your fuel filter lately?

 

[stang910]

Thats the first thing that went thru my mind when it happened. This slipped my mind while I was getting the car ready for the dyno. Its the first place I was gonna start looking for the problem, but I didn't think a clogged fuel filter would limit the pumps that much which is why I posted here. I assume you think thats what my problem is.

 

[lito]

Not necessarily but is a place to start. The filter has to be replaced anyway someday.

On the MAF I suggest changing the sensor instead of buying a MAFia.

Would be nice to log you pump DC at idle before you do anything so you will now if you are getting any improvement out of the changes/test you perform.

 

[stang910]

I already have a mafia but my tuner said to leave it off until he seen what the MAF was doing. Never made another comment about it. The datalogging is a great suggestion so I'll make sure I do that. Have you ever seen correctly working gt500 pumps max at 500rwhp?

 

[lito]

No problem on using a MAFia, I commented just in case you had to buy something.

No, usually they go to 600 and depending on some conditions and config they do go further. AFR, injectors, boost, type of FI and more things determine when they get maxed.

 

[lito]

Your pumps should idle around .2xx (or .4xx depending on what is logged) duty cycle.

 

[stang910]

Thanks! Gonna pick up a filter tomorrow.

 

[stang910]

Your pumps should idle around .2xx (or .4xx depending on what is logged) duty cycle.

Just checked it with the handheld and it was showing .209-.210

 

[lito]

that is where it should be.

 

[JeremyH]

Some 60 lb inj would help, also i would change out the gt500 pumps for 2 ford gt pumps. I am currently running 540rwhp 62lb injectors, 2 ford gt pumps on the single oem fpdm 75% duty cycle, stock maf/ mafia set at 3.

 

[lostsoul]

Some 60 lb inj would help, also i would change out the gt500 pumps for 2 ford gt pumps. I am currently running 540rwhp 62lb injectors, 2 ford gt pumps on the single oem fpdm 75% duty cycle, stock maf/ mafia set at 3.

Dont forget that fpdm wire upgrade from lethal you told us about..

I just finished installing it.. here is what I posted in their section.. haha




"BTW: thanks for the instructions from the FPDM wire upgrade. Those were easy to read and understand.. step for step.. I wish all were like that. The only thing I would say that would help more is if you guys added another 2-3 feet of wire.. it was a close fit.. other then that I was good to go.

I almost shit my pants and learned something.. After I was done with it I had the car up on jacks all 4 sides.. I was just going to crank it over to see if it would start.. when I did I heard the most horrible sounding noise. I thought it was the fuel not making it or something with the wiring. I tried it again for a second and then said this cant be right.. It was a grinding noise.. I look under the car and found out you cant start your car that way or the crank pulley will rub on that cross bar!! HAHA.. Why did't you have that in your instructions?? ahaha Fuck I'm sad "

 

[one eyed willy]

i had a very similar experiance, tuner told me my pumps were maxed out at 450hp.....i was like "WTF?", he said i should upgrade the power wire to the back, so i went to a 12 gauge power wire....pulled the pumps out to make sure it wasnt a connection issue.....all to find out it was the tuners fault, he never put it in the tune that i had gt500 dual pumps, so the ecu only saw 1 pump and figured up the duty cycle as ALOT higher than what it actually was.fixed REAL easy after i had the correct tune!!...and the bad part was he KNEW i had gt500 pumps, we discussed the wiring and everything....i guess he just had a brain fart?