My 'Bird died over the weekend, loss of fuel pressure. Figured it was the pump, so I put in a Walbro 255 in tank pump. No difference, turn key on for the 2 second prime and it spikes to 40PSI, immediately drops to 28030 for the primimg period, and drops to ZERO within a second or two of the pump shutting off. Way tooo fast a drop and never reached correct pressure. So I changed the filter, no change. Tried pinching off the return hose from the regulator to see if it would hold pressure - no change. Tried pinching off the feed line during the 2 second prime, no change. Drops all pressure with a second or two of the pump shutting off.

So now I'm thinking a stuck open injector. Will OHM them all tonight, but that won't tell me if one is stuck open. So I wonder, the ECM provides the ground to fire the injectors, right? What would happen if you manually applied the 12 volts and ground to each injector? Should you be able to hear them "click"? Just trying to find an idea before pulling the fuel rail on the MR.....

 

I don't think its a stuck injector, If one was stuck open it would not bleed pressure off that fast, and you would have an engine full of fuel if it did.

Does it have any fuel pressure when its cranking over?

 

Yep, about 30 PSI.

Anyone ever seen the inside of a TPIS adjustable FPR? Or taken one apart?

 

Did you use SAE 30R10 spec fuel hose when installing the Walbro pump? Did the pump come with a short section of that type hose? Regular FI hose will melt when submersed in gasoline and will give the symptoms you're describing. The same as a pump with a bad check valve.

 

I didn't have to use any hose when I installed it in my tank. ALthough I do still have it. Maybe that's where I went wrong? I just fit it on the platform and plugged it into what I think is called the "pulsator"......

 

Vern, keep us updated on how it's going.

 

Anyone know the purpose of the pulsator, and if you should be using it with a Walbro 255 pump?

 

the pulsator was problem prone at best.
its main job was to dampen the pressure pulses from the fuel pump.
it also helps some in pump noise reduction.
the best thing to do with it is find a nice place for it in the trash can, i have put many there.

 

That's where mine is going tomorow - Thanks for the reply. As usual, I should have done a search before posting this. Did one earlier this afternoon and found lots of references to the pulsator. And at least 95% of them said to throw the SOB away!
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By the way - it looks like my problem was the AFPR. Replaced it and the pressure is back up in the realm of where it shoudl be.

 

UPDATE - car is running fine again. I put the Walbro in the tank, deleted the pulsator and used the hose section that came with the pump, and put on another AFPR since when I disassembled my TPIS AFPR while it was still on the car the spring took off for parts unknown. Running fine now, holding 46 PSI at idle with vac line disconnected. Appreciate all the inputs and ideas.

 

Clutch foot working good?
Zoom, Zoom, Zoom...

 

Not yet. I said it was running, not being driven

I'm still restricted to an automatic tranny until at least Wednesday when I see the doc again <sigh>

I did sneak out on one little 5 minute drive to the gas station though....

 

30PSI was a dead giveaway- too bad I didn't see the thread sooner.

 

I knew the fuel pump was bad the minute a saw 6 PSI as it's max. The 30 PSI was while the regulator was missing the spring that took off for parts unknown...

Then I removed the pulsator based on restriction posts due to it I found in a search here on TGO.

 

I too left the pulsator off when I installed my Walbro 255, and I wondered at the time if I was committing some sort of sacrilege by not using it. It just made sense to me when I was looking at the assembly that a short piece of hose with two worm gear clamps would be much better pressure-wise than something that just pushes on with no clamps. I did a search on here after I had put it back together without the pulsator, and was relieved when I saw how many other guys eliminated it too. Hell, I even spent $20 for a new pulsator from AZ, and now it's sitting right next to the old one in a drawer out in the garage. Lol.