superbling

I replaced the fuel pump and screen in my wife's mazda mini-van but now I can't get it to start/run without the use of starter fluid then it dies. I unplugged the lines while starting it and gas shoots out the nipple on the pump assembly. I blew compressed air through the intake line and gas blew out the return line so I don't think the lines are clogged or that the new pump is bad. Pump is located in tank.

Does priming the lines take THAT long? I've run the battery down twice trying to start it without starting fluid. I also tried the "flooded engine" proceedure in the owners manual.

Background: The car was sporatically hesitating on typical acceleration and occasionally on even throttle but never on full throttle. I tried fuel injector cleaner first, then running it completely out of fuel (thinking bad gas/water) and adding known good gas but neither solved it. So I thought it was a clogged filter and/or bad pump. 46k miles.

HELP

kai ju

Does it continue running once you get it started on starting fluid ?
Have you checked fuel pressure at the rail ?
Can you hear the pump run when you turn the key on ?
If it doesn't continue running then you don't have sufficient fuel pressure, which you can verify with the pressure gauge.
Listen for the pump running when cycling the key.
BTW all of the above holds true for motorcycle fuel injection systems but should apply to any fuel injection system, regardless of vehicle.
Kai Ju

superbling

Kai,

I can't really hear either pump since they sit so far down in the tank. What I've done is disconnect the lines and watch the outlet. Upon switching the ignition on, they both pump out one good shot then stop. Then while cranking they both pump fuel as long as I continue to crank.

I kept the engine running with starter fluid for up to 2 minutes at a time. That should be more than sufficient time to purge/fill the lines.

Next I kept the outlet connected and disconnected the return line while I started and ran the engine with starter fluid. I have yet to see anything come out of it except for the time I purged the lines with an air compressor.

What I don't understand is why the old pump assembly, which worked 98% of the time, doesn't work at all now. When I ran the tank dry thinking I had some bad gas, the engine started within about 3 seconds of cranking after refilling the tank with 2 gallons of gas.

kai ju

It sounds to me like you don't have sufficient fuel pressure.
Most modern FI systems have a running fuel pressure of at least 35 psi to as high as 50psi.
The fact that nothing comes out of your fuel return line suggests that not enough is going into the inlet.
FI engines will not run with low pressure.
Do you have access to a fuel pressure gauge ?
Kai Ju

superbling

Yeah, a local guy says to check the pressure too. I'll have to get a guage.

But what I don't understand is why, now all of a sudden, the stock pump won't run the engine either. AFAIK, nothing else is different. GRRRRR......

Thanks for your help.

superbling

Well I got a guage and have zero at the port just before the intake manifold. I kinda knew that since I tried pushing in the shrader valve and didn't hear or see anything.

The 1 ft or so fuel line to the port comes from the fender and what looks like a filter or regulator. I unplugged the line and fuel shoots out of this item while cranking. So I'm guessing there's total plug in that short line although I don't see how it suddenly failed when I replace a pump way back at the tank (sigh.......)

I'm giving up and having it hauled to the shop.

kai ju

Try backflushing that component, what likely happened is that the partial blockage that you were trying to eliminate moved to that component with pressure from the new pump.
If it's a filter just replace it.
If it's a pressure regulator you might be able to backflush it.
Use low airpressure if you can regulate it, i.e. no more than you pump can generate.
Kai Ju

superbling

I tried compressed air both ways on it and it felt like no obstructions at all on that "filter". It really looks like a filter so I'll call it that for now. I reinstalled the intake line from the tank to it and cranked. Gas blew out the outlet 1/2 way across the engine bay so I think it's OK. From there, it's a short 1 ft line to the fuel rail/test port which is reading zero psi.

I tried to find something at two auto parts stores that I could use to bypass it but it has special, no standard, nipples (insert crass joke here).

kai ju

Depending on what that short line is made of you should be able to blow it out as well.
I have to assume that it is a piece of debris ( rust etc. ) that you might be able to dislodge with a coat hanger if it's rubber ( Make sure you round off the end of the coat hanger into a sherical shape so that you don't damage the inside of the hose.
If its a hard line use an old clutch cable or something similar with the end soldered so that you can chuck it into a drill or Dremel tool.
Good luck.
Kai Ju

Scooberhawk

Oh, the oddball posts that we come across when searching..

Did this ever get solved?

superbling

LOL!!! yeah, it got resolved: I traded that POS in on a new car two weeks ago! Lesson learned: Don't own a vehicle that doesn't have a local dealer unless you have lots of spare time and money.

Long version: fuel pump was never the problem yet I still don't know why the original would not come up to pressure when reinstalled. Independent shop then replaced spark plugs (only 50K miles) and also wanted to replace wires but I said no. Bill: $400+ Check engine light never resolved (local auto parts stores didn't have the mazda code reader) and months later the original problem reappeared (poor running). I believe it was emmissions related (egr valve etc). Tranny began shifting hard/erractically, front suddenly began pulling to the left, both sliding door handles broke off in my wife's hand, and rear A/C switch stopped working. All of this AFTER the warranty expired of course. sigh.......

superhawk22

Yep, don't you know they have a little timer in the car that goes off as soon as the warranty expires. Then the car goes into self destruct mode.

Scooberhawk

Glad that got worked out. It's a shame it abused your brain for another 9 months before you could get rid of it. Hopefully the new car treats you a lot better!

sprhawk neil