Fuel pressure dropping when pressing throttle, whats going on...

[jboyle83]

After 2 years and a lot of patience I started my Supra for the first time today. Upon starting it it idled for a few seconds and died. I restarted it again, same thing over and over... I watched the fp guage on my DM AFPR and as the car idled the fp dropped to 0psi until it died and then returned to about 40 psi after dying (hose off). As I'm running a Walbro 255 on stock wiring I decided to jump the resistor. With it jumped the pressure held stable at 40psi at idle, but the moment I hit the gas pedal the pressure started dropping until it sputtered out and died as it was before.

I have came up with a couple possible scenarios, let me know what you guys think so I can take this beauty for its first drive.

Here are the possibilities I have came up with...

1. Bad pump-- Walbro purchased on Ebay (possibly got screwed with a knock off stamped with the Walbro name)

2. Some sort of issue with AFPR

3. Blockage in lines between tank and AFPR (car has not been driven in 6+ years, and sat without an engine in it for 4+ years)



Other key info... Egr was removed, no VSV's, tank was cleaned and new fuel filter installed when pump was put in.

Any help would be great, thanks in advance guys.

 

[89supracrazy]

I would check the pulsation damper on the fuel rail. I had one on a fuel rail in my basement and it was rusted up solid. Even on the inside.

 

[NashMan]

hate to ask this qestion is there gas in it

and last but not lest sounds like a pluged fuel filter

if you wana test fule reg clamp the return line and see if rasies if not the pump or fuel filter is were I would start

then go from there

 

[Poodles]

If it sat that long, you might have a rusty tank. Will very quickly clog the sock on the fuel pump.

 

[supraguy@aol]

I thought he said he replaced the fuel filter, and cleaned the tank?
Did you do these things two years ago, or just recently?
In any event, I would consider blowing out the feed line from the pump outlet to the fuel rail.
See how strong the flow of compressed air is at the end of the fuel line.

 

[jboyle83]

Thanks for the replies guys...

From what I understand the pulsation dampener should have nothing to do with flow, only there to smooth the pressure from the pulse of the injectors... (Of course correct me if I'm wrong)

Yes there is between 4 and 5 gallons in the tank.

Tried clamping the return line the day I started it, same problem with it clamped.

And the tank was cleaned and filter installed about a year ago or so.

I am planning on blowing out the feed line on monday, but I would think a restriction there would keep pressure from building and staying consistent even at idle...

 

[NashMan]

well if ya clamped the line it should build up rather high so fule pump is most likly the issue

if there is plug in the line the pump would run louder

 

[shipkiller]

trowing a bone here but
what if the pump still run on 9v and 12V, if it doesn't switch to 12V the fuel pressure will drop as the car will consume de fuel in the rail?

 

[NashMan]

not that fast and the stock pump does not run that low or it would burn out over time I think it low setting is like 10.8 to 11

but easy way to cheak is with volt meter in the hatch and remove the cap and test the leads

 

[jboyle83]

Thanks for all the help guys. There was a restriction in the line. Once I blew the line out she reved just fine... Purred like a kitten for the first time in 7 years!

 

[supraguy@aol]

Yay Me !!! lol

Oh, and congrats to you too.