Author Topic: AAZ won't pump fuel...  (Read 3053 times)

June 18, 2018, 05:56:02 am

Patrick

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AAZ won't pump fuel...
« on: June 18, 2018, 05:56:02 am »
Haven't posted in a long time. Swapped an AAZ into a 92 Jetta this weekend, pulled out an AAZ that's getting tired (low compression). Engine I swapped in ran when pulled  from another car a lot of years ago but was tired. Had a start issue that I traced to the input seal on thr pump, kept losing it's prime. new seal, went through the whole engine. Rings, bearings, head studs (plans for the future), water pump etc. Been on the shelf for a lot of years. Finally put it in the car this weekend. No luck getting the injection pump to move fuel. Currently sitting overnight with fuel/ATF mix in the filter and the pump. I'm assuming the vane pump is stuck from sitting around.... Anyone got any suggestions?



Reply #1June 18, 2018, 08:17:30 am

Tmarkle

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Re: AAZ won't pump fuel...
« Reply #1 on: June 18, 2018, 08:17:30 am »
May seem like a stupid question but do you have 12v to the shut off solenoid?


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1985 Jetta 1.6 NA, Project
1981 Rabbit 1.5 diesel SOLD
1980 Dasher, also a project
1993 Passat GLX VR6 (daily driver)
1992 Toyota Pickup, 350 V8 swapped
1997 Jetta TDI, engine donor for a diesel powered Toyota!
1986 Toyota Custom Cab

Reply #2June 18, 2018, 10:23:50 am

Patrick

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Re: AAZ won't pump fuel...
« Reply #2 on: June 18, 2018, 10:23:50 am »
Good thought but there's power and I hear a click at the pump when rhe key is turned on.

Reply #3June 18, 2018, 07:45:27 pm

libbydiesel

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Re: AAZ won't pump fuel...
« Reply #3 on: June 18, 2018, 07:45:27 pm »
You filled the fuel filter and pump entirely with fuel before trying, right? My favorite way is to pull a vacuum on the return fitting.  With clear supply and return lines do you see fuel move at all?  It should move regardless of stop solenoid activation/function.  If it is not moving fuel when cranking, then the vane pump vanes are stuck or the pressure regulator is stuck flowing all fuel back to the supply.  Smart money would be on the vanes being stuck. 

Reply #4June 18, 2018, 08:17:06 pm

Patrick

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Re: AAZ won't pump fuel...
« Reply #4 on: June 18, 2018, 08:17:06 pm »
Thats my guess too... pump and filter full.

Reply #5June 18, 2018, 08:46:17 pm

ORCoaster

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Re: AAZ won't pump fuel...
« Reply #5 on: June 18, 2018, 08:46:17 pm »
Since he provided this for context:

Engine I swapped in ran when pulled  from another car a lot of years ago but was tired.

And he already replace the front seal.

I would put my dime on the vanes being stuck as well.  They do that if they sit for a few months. 

You might have luck with some Diesel Purge and not have to pull the pump apart. 

Reply #6June 18, 2018, 10:00:25 pm

Patrick

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Re: AAZ won't pump fuel...
« Reply #6 on: June 18, 2018, 10:00:25 pm »
I'm hoping so. If I have to I can pull the pump off the engine I just pulled but would rather not. Need that engine complete for another project.
« Last Edit: June 19, 2018, 05:24:24 am by Patrick »

Reply #7June 19, 2018, 05:39:12 pm

Patrick

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Re: AAZ won't pump fuel...
« Reply #7 on: June 19, 2018, 05:39:12 pm »
It runs. Left it sitting for about a day with 1/2 diesel 1/2 ATF in the pump. Looks like that was enough to free up the vane pump. Made sure everything was full, cranked until I had fuel at all 4 injectors. Fired! Still some detail work to do but should be on the road again this week.
« Last Edit: June 19, 2018, 05:45:52 pm by Patrick »

Reply #8June 19, 2018, 07:21:00 pm

libbydiesel

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Re: AAZ won't pump fuel...
« Reply #8 on: June 19, 2018, 07:21:00 pm »
Excellent!  Glad to hear that worked. 

Reply #9June 19, 2018, 08:42:03 pm

ORCoaster

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Re: AAZ won't pump fuel...
« Reply #9 on: June 19, 2018, 08:42:03 pm »
I love simple fixes that take care of themselves overnight while you snooze on it. 

Reply #10June 19, 2018, 09:18:13 pm

Patrick

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Re: AAZ won't pump fuel...
« Reply #10 on: June 19, 2018, 09:18:13 pm »
Excellent!  Glad to hear that worked. 
ME TOO!   Old truck driver's trick, using ATF to clean up fuel systems. Don't know if you'll find it in a repair manual anywhere....

Reply #11June 23, 2018, 11:03:59 am

Patrick

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Re: AAZ won't pump fuel...
« Reply #11 on: June 23, 2018, 11:03:59 am »
On the road again....