Tony_m

First i am in Beirut/Lebanon i have GT 2005 with 117k on it that was shipped from the US. I have a major problem on acceleration and on WOT with the fuel delivery as shown in the video here:

I shipped a new FP and installed it but the problem remains the exact same one.
I sat in the back of the car with a friend driving it and tested the voltage coming to the pump on load, it reached maximum 9V (thats a problem) .

I did some pids logs :
Fuel rail pressure on WOT: fluctuating severely between 0 and 60psi
Fuel pump voltage: between 5-9V maximum (problem)

VOM tests with key on:
TPS showed 5v
FRPS showed 5v
FPDM 12v (i read that it should be 10.5v)

VOM test on idle:
---->Fuel Pump showed non stable voltage (up & down 1v to 4v) <-----

---->FPDM test non stable voltage (up & down 1v to 4v) <----- dunno if its the correct way to test it (Pk wire + outside 2nd black wire on the connector)

Battery: 13v
ALT: 14v (on idle)

Ground test to strut bolts 12v,
<----- Ground test to coil covers 10V <-----

Vacuum test:
no leaks, no fuel smell

Inertia switch test passed (i connected the 2 wires and car runs)

MAF cleaned also.

I logged battery voltage pid and it goes down to 10-11V on load, something is sucking power (here is the problem)

How can i check the PCM pin/wires/connectors that goes to fuel pump and FPDM?

Any ideas what else should i check please?

Thank you.

hammeron

if the car is stock, i would start by loading in a stock tune
from a reputable tuner like brenspeed, or american muscle.

moosestang

I don't now what to make of that video. Is the check engine light on?

117k miles, the alternator probably needs replacing. They have a bad habit of leaking AC current into the electrical system and causing all kinds of sensor malfunctions.

I think the fpdm should see 12v and the fuel pump voltage is regulated by the pcm I believe, so that could just be a system of the real problem.

The way the rpms jump up and down is really strange, like you are hitting the rev limiter. the car could be in fail safe mode for all we know.

moosestang

Is the throttle body stock?

mapitts

I don't think his engine in fail safe mode. At least it does not act like with the throttle surge. I have never personally seen or heard of them surging like that in fail safe mode. Not saying that it won't. Does your A/C work. If it does, then you are not in true fail safe mode. moosestang brought a very valid point with the high mileage alternator. hammeron did too with the stock ECM reflash. The throttle jump is just really weird. I have never seen it to that degree ever. Your car is wanting it to go and does for a second.

Nuke

What's not stock? A little more info would help.

I agree with checking on a different tune and making sure the alternator is healthy. The S197 charging system is barely marginal and has been a chronic issue.

Have you looked here for info?: http://iihs.net/fsm/?dir=1

Tony_m

Tune is stock, Everything is stock, no mods at all.
Brand new fuel pump Motorcraft original.

The car now stalls at 3000-3500 RPM it was on 5000-5500 RPM last week.
I could reach the rev limit on WOT while car is parked, now i can only reach 3000-3500 RPM
If i floor it slowly in park mode i can reach the rev. limit, if i WOT it fast it stalls on 3000-3500 RPM but engine never shut off.

I have a PA 130am + 4g wire that i shipped from the US, it has 4k miles on it now only.
Changed to a new battery today, no changes.
Changed back to the old Alt. today, no changes.

Ran a voltage test on battery and PA Alt: 13v on key on, 13.88v on idle, 14.1v on 2000 rpm.
Ran a PCM to FPDM wire test (#12,#21) both wires pass ok.
Ran an FPDM test, 12.66v on idle, voltage fluctuates between 13v & 13.33V on WOT.
Ran a wire directly from FPDM to FP, 12v on key on. / fluctuates between 3v-5v on idle. / fluctuates between 4v and 7v on WOT ---> rpm never reached more than 3500 on WOT<-----

Im totlay lost in my country, what else should i check any ideas?

Tony_m

Tune is stock, Everything is stock, no mods at all.
Brand new fuel pump Motorcraft original.

The car now stalls at 3000-3500 RPM it was on 5000-5500 RPM last week.
I could reach the rev limit on WOT while car is parked, now i can only reach 3000-3500 RPM
If i floor it slowly in park mode i can reach the rev. limit, if i WOT it fast it stalls on 3000-3500 RPM but engine never shut off.

I have a PA 130am + 4g wire that i shipped from the US, it has 4k miles on it now only.
Changed to a new battery today, no changes.
Changed back to the old Alt. today, no changes.

Ran a voltage test on battery and PA Alt: 13v on key on, 13.88v on idle, 14.1v on 2000 rpm.
Ran a PCM to FPDM wire test (#12,#21) both wires pass ok.
Ran an FPDM test, 12.66v on idle, voltage fluctuates between 13v & 13.33V on WOT.
Ran a wire directly from FPDM to FP, 12v on key on. / fluctuates between 3v-5v on idle. / fluctuates between 4v and 7v on WOT ---> rpm never reached more than 3500 on WOT<-----

Im totlay lost in my country, what else should i check any ideas?

hammeron

ok i think it's time to give the throttle body a good cleaning, there is
a brenspeed video on youtube that shows how to do it. seems to me
it is not a fuel related problem but air related.

BlackBetty

Fuel filter needs changed?