Montana

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)
Fuel Pump showed 4v
Battery 13v
ALT 14v (on idle)

Ground test:
12v (no leaks)

Vacuum test:
no leaks

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)

Does the PCM gives voltage directly to the pump or it has to pass by the FPDM first? How does electricity goes to the pump so i can check more things.

How can i check the PCM fuel pump wire that goes to the pump and FPDM?

Any ideas what else should i check please?

Thank you.

Glenn

What is the voltage suppose to be at wot? Silly question did you change the fuel filter too?

antdog

What mods do you have on the car?

Montana

12-14v
filter changed 2 times
its an electrical issue that im having, i think its the PCM not getting / sending enough voltage to the pump

Montana

The car is stock, no mods at all
its an electrical issue that im having, i think its the PCM not getting / sending enough voltage to the pump

texastboneking

Pcm is a ground controlling device. It doesn't send power. The fdm takes care of the fuel pump. The pcm has little input on it. I'd be looking at maybe a new fdm. If your voltage is dropping at high rpms your alternator is probably going out. Its common for alternators to quit at high Tom's due to weak brushes.

Montana

Attached is the FPDM photo with wires im checking (i wrote colors of wires).

I did some electricity tests with a VOM:
FPDM shows 12v on idle (tested pink+ black # 1 wire)
FPDM ground 12v on idle (pink + a bolt)
---> FPDM voltage not stable at all , up/down between 1-4 Volts (Yellow + Black # 2) <-----

ALT shows 14.01v on Idle / 13.88 on electric load (AC & all lights on)
Battery shows 12.60v with key on
Inertia switch is ok (i joined the wire and tested it)
Some Ground tests shows 12V but
-Valve cover ground shows 10V- I wonder if its normal?

I need to be instructed by details how to follow wires to the PCM by colors, which connectors to check on the PCM or in between, also some photos of those wires / connectors can help me following them.

Lime GT

Did you turn Off the TC switch just to the left of the 4-way switch? Tire spinning will engage traction control.

There may be a PID to check (TQ-Cntrl) that indicates if the PCM is reducing fuel/spark due to ABS, VSS and OSS sensors.

Montana

Can you check those pids and see if its an electrical issue or no please?
im using livelink v.2 latedt version

Lime GT

I have no scan tool access to verify but I would think a pid would be on a scanner for vss and oss. Watching the your video over again I think it's other than the traction control but always worth trying to see if it's related.
Sorry I no other answers other than using the PC/ED manuals troubleshooting without codes section.
If there was previous work done to the vehicle I would go over all the connectors unplugged and recheck for damaged pins, poor connections aka broken lock tabs.
Good luck

Montana

Thats what im looking for now, how to check the wires and pins of the PCM which goes to the FPDM and Fuel pump. im a newbie in wiring diagrams ican only check by wires colors.Thank you anyway

cdynaco

Are you getting any codes?

cdynaco

btw, reading through the manual (08) something simple caught my eye. Have you checked the fuel cap to make sure it seals tight?

Also, you are prob aware that driving too much with intermittent fuel pressure could damage your pistons because of a lean condition.

cdynaco

Do you have this site for the S197 manual? Its kind of cumbersome w/pdf's but it works.

http://iihs.net/fsm/?dir=41

Montana

My problem is im not familiar with diagrams i need photos or exact instructions by wire colors on how to follow fuel pump wires from PCM to the pump and check them for faults.
Today the issue went bad, the car felt on its face at 3000-3500 rpm, it was 5000-5500 before and with sct i got P0148 - P1000 codes bur no check light on the cluster.

cdynaco

From what I gathered in the manual is there is no break of the wiring harness from the FPDM to the PCM. So you have the colors on the FPDM, now look at the plug to the PCM for those same colors. Right?

Montana

PCM has 3 connectors, top, middle, bottom. Which one to check for color match?

cdynaco

Not sure if the diagram is laid out like the PCM plugs are, but it says #922 WH-RD (circuit #, white-red) and #928 LB-RD (light blue-red) go direct from FPDM to PCM. It appears to be the lower plug.

However, are these circuit numbers stamped on the plug or PCM to help identify? The connections to the PCM also have 21 (FP Monitor - the WH-RD wire) and 12 (FP Control - the LB-RD wire) listed. Are these two numbers stamped on the PCM?

Searching for those error codes...

cdynaco

Found these. btw, have you tried unhooking your battery for 5-10 mins to reset the PCM? Wouldn't it be great if it was something easy. lol

P1000 - OBD-II Monitor Testing Incomplete


P0148 -Fuel Delivery Error - At least one bank lean at wide open throttle. Fuel System: ·Severely restricted fuel filter ·Severely restricted fuel supply line

Montana

No nothing stamped on connectors nor on pcm, this is why we need the PCM sheet paper that explains numbesr with wire colors. The FPDM positive wire is Pink-brown and the negative is black (both think wires) + 1 yellow thin wire and 1 white-red thin wire.