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Resolved fuel pump not turning on *im an impatient idiot*

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ThunderChild

Supporting VIP
3,755
1,140
Jan 5, 2012
Rathdrum, Idaho
k guys, did some searching and havent come up with an answer, basically i need some more advanced diagnosis options.

just finishing my 92 tsi awd build, and i am having some issues with the fuel pump not turning on in the proper order. ive gone though THIS thread, and the only circuit thats not functioning is pin 9 on the relay. i have proper voltage on all other pins, and can jump the fuel pump at my rewire in the back and the car will run.

i have an aeromotive 340 stealth pump, it is rewired, and i did swap out the abs fusible link pack where the battery used to be, for a non-abs one.

the 4 pin connector back at the fuel pump gets the following readings when turning the key:
YL/GR- 12.6v with key on, MPI relay in or out
BLK- 0v "
YL- 6v "
BLK/WHT- .09-.10v "

the BLK/WHT wire doesnt change if i turn the key to the start position with clutch depressed (car cranks over).

any insight would be helpful, just want the fuel pump circuit to work like its sposed to instead of bypassing it or rigging it otherwise. i will upload some pics of the fusible link and MPI pins ive tested
 
Did the car run before the fuel pump swap? Do you have voltage at pin 2 on the mpi relay which is the power for the fuel pump(trigger for fuel pump rewire)? Heres a diagram to check
 

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Did the car run before the fuel pump swap? Do you have voltage at pin 2 on the mpi relay which is the power for the fuel pump(trigger for fuel pump rewire)? Heres a diagram to check

unknown. the car was bought with bent valves, so i did all the work to it before ever attempting to fire it.

im assuming this is at the ecu? the pic is hard to see all the writing. ill check, tho.

im also going to rewire the 4 pin connector at the fuel pump, its giving me some wierd residual/crossover voltage when i back probe it. stock connnector is covered in oily residue and cleaning it hasnt solved that issue
 
Pin 2 on the mpi relay. Its next to the ecu.

Are you sure the rewire was done correctly? Where was the rewire signal tapped into? The black/white wire on the fuel pump gets power from pin 2 on the mpi relay which is a blue/green wire.
 
Pin 2 on the mpi relay. Its next to the ecu.

Are you sure the rewire was done correctly? Where was the rewire signal tapped into? The black/white wire on the fuel pump gets power from pin 2 on the mpi relay which is a blue/green wire.

i got it figured out. combination of my own stupidity and a bad connector. i got ahead of myself when testing and was getting a poor reading on the FP side of the connector in back, so i thought i wasnt getting power. also, i wasnt pushing the clutch down the first time i tested it, and after re-reading, saw my error. fires up good now, no excuse by my own haste, haha.

now i just need to figure out why the fans arent turning on. but ill wait till i get the rest of the interior back together, im wondering if theres a loop through the ac circuit, cuz i dont have any of the hvac connectors hooked up currently.

there are several other things in need to sort out at as well. lean idle, fans, fuel gauge not working, and what looks like a small amount of oil weep around the cam gears or timing cover somewhere.
all the little stuff now that it actually runs :rolleyes:
 
Happy to hear you figured it out. The main engine fan (pass side) has no connection to the ac side. Its a simple circuit using the sensor on the bottom of the radiator to trigger a relay turning on the fan.

The oil leak... Good luck LOL its a dsm
 
thanks for the responses and info!
after some more searching thats what i found. my thermo switch is bad, ordered a couple new ones. going to wire the a/c fan to run in parallel with the main.

yea, its not alot, just a small mist, looks like it might be from the valve cover corners right behind the cam gears. ill monitor it for the time being as its very small. just want to make sure its not hemoraging anywhere whille i break it in and run it through the paces.

everything else is just teething issues
 
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