Cascade Crew

Xophertony · Posted: Wed Jan 25, 2006 1:16 pm Post subject: HELP!!!! FUEL PUMP?

GTA won't start. i suspect fuel pump. i tested the pressur elast week and it was 39PSI at idle and 35PSI while i stomped on it. but it does that thing where if you hit the gas there is like a half second delay before you get any throttle response.

i am going to be swaping the rearend out in three weeks anyway for the brake swap... is there any way to coerce this thing to last until then?

Xophertony · Posted: Wed Jan 25, 2006 1:38 pm Post subject:

well, i got a new pump on order @ the GM dealership... $120. when the hell did they get so expensive!?

and why the hell did GM not put a hatch to access the fuel pump in our cars... A-holes. Very Happy

if anyone has any info that will allow me to not pull my rear end in the rain today i would realy apreciate it.

Dewey316 · Posted: Wed Jan 25, 2006 1:47 pm Post subject:

you dont' need to completely pull it, just move it out of the way. Make sure you disconnect the exaust. at the cat, and move it all out of the way as much as possible.

BTW, how long are you waiting for that pump? For the same price, you could have gotten a Walbro 255.

Twilightoptics · Posted: Wed Jan 25, 2006 1:51 pm Post subject:

No doubt, walbro man. Factory pump from Napa is only $70.

You need to disconnect the rear fully, but don't have to move it from the car.

The dropping to35psi when on the throttle shows something's wrong with it. Did you check the pressure with the vacuum line off? That's your base pressure and what you typically go by. It should be 5-10psi higher than with the vacuum line on.

Did you get the fuel pressure gauge back on it to test now? Did you check voltage at the pump?

Yeah... that's one of the "hot" mods on TGO. Cut a big hole in your well to get to the fuel pump. Rolling Eyes

Soulds like it could be fuel pump. Good luck man.
Your exhaust is going to be your biggest hassle.

Edit: One more thing. BE CLEAN!!!!!!!!!!!!!!!!!!!!!!

Xophertony · Posted: Wed Jan 25, 2006 2:02 pm Post subject:

where do i get this "walbro255" and what model number is it. the guy said he will have the GM pump in by 4PM, but i can always call and cancell, they normally stock it anyway.

Xophertony · Posted: Wed Jan 25, 2006 2:05 pm Post subject:

Dewey316 · Posted: Wed Jan 25, 2006 2:31 pm Post subject:

BTW, I'm not working friday. If you can find garage space, I'll be more than willing to pack the coveralls with me to work tomorrow, and swing by and help you rip into her. I'm not all that keen on helping in the rain though. Wink

Xophertony · Posted: Wed Jan 25, 2006 2:46 pm Post subject:

no garage

driveway @ my dads. his racecar is in the garage Crying or Very sad

Xophertony · Posted: Wed Jan 25, 2006 3:01 pm Post subject:

went to check the voltage at the pump.... can't get to it without a jackstand Mad

. all i succeded in doing was getting the ass of my pants all wet. but i can say that the pump is not priming when i start the car. where on the ALDL do you bridge ti get it to turn on?

Xophertony · Posted: Wed Jan 25, 2006 3:34 pm Post subject:

ok.. so NAPA does not carry walbro, where do i get one. i need to order this soon because i need to do it tomorow.

and why does this shizzle always happen like the week of dyno. last time my fuel pump went it was during inventory week at my video store. that baisically means i was working a 50HR week. and all of the sudden i have no way to get to work Rolling Eyes

it's murphy's law. "if it can go wrong, it will." AKA the dyno curse. Twisted Evil

thanks for the quick help guys.

alloy · Posted: Wed Jan 25, 2006 3:35 pm Post subject:

As I recall, you supply 12 volts to terminal G. I just used a small jumper wire off the battery and stuck it in the terminal when I pumped my tank out to change my pump. Worked like a charm to empty my tank.

Twilightoptics · Posted: Wed Jan 25, 2006 3:35 pm Post subject:

What year is your car? I don't think you bridge the ALDL... forget though. You need to pull the connector from the engine block that's right above the oil filter. It's the oil pressure switch/gauge lead.

Two of those wires are fuel pump, no oil pressure, no fuel. That switch could be bad also. Turn the key on, and jumper the two wires with a paperclip.. if the pump turns on you're golden.

Use your chilton to figure out which wire goes to the gauge, and jumper the other two.

You can also jumper the relay on. Give 12v to the Green/white wire on the fuel pump relay. Relay is located on the firewall. There are probably 2-3. DO NO play with the one that has BLUE wire going to it. It's the MAF Power and or MAF burn off relay (should you still be a MAF car)

Twilightoptics · Posted: Wed Jan 25, 2006 3:38 pm Post subject:

Well, that will jumper the relay on! Which is part of what you need to know lol. If fuel flows, then it's something else... IE that oil pressure switch.

Napa carries stock replacement. For local, you'll need to call some place like Baxter and ask for a Walbro 255 in tank GM.

If they don't have it... I've got a napa replacement in my car, and it does fine to 300RWHP.

-----------------------
--| F | E | D | C | B | A |--
| |-----------------------| |
--| G | H | J | K | L | M |--
-----------------------
North American ALDL connector pinouts

Schultzy89GTA · Posted: Wed Jan 25, 2006 9:05 pm Post subject:

ahhhh... another right of passage Tony. This is what we refer to as 'The Dyno curse'. We can tell all sorts of tales when we get together. Press through it.

You can do it! /Rob Schneider

Very Happy

-Schultzy

iansane · Posted: Wed Jan 25, 2006 9:40 pm Post subject:

Isn't there a red wire near that mess of relays by the booster meant for testing the pump? Apply 12v to it and it should turn the pump on?

Xophertony · Posted: Wed Jan 25, 2006 10:03 pm Post subject:

i'll be getting into this more tomorow. i'll be up bright and early to have the car towed to my dads house so i can work on it. or drive it if it actualy starts. then i will take his truck to go get parts (fuel pump, strainer and gasket). if all goes well i'll be done by noon. if not.... well i hafta leave by 4:30pm at the latest to get to class on time. so if it's not done by then i guess i will finish it up on friday morning.

Twilightoptics · Posted: Wed Jan 25, 2006 10:36 pm Post subject:

Xophertony · Posted: Wed Jan 25, 2006 11:46 pm Post subject:

do you mean test the new pump or make sure the old one is not bad before i drop the tank?

i will be checking before i remove a single bolt:
1. voltage at the pump. if it's bad jump to step:5
2. bridge ALDL "G" lead.
3. relay
4. oil pressure switch
5. fuse
6. ground below the rear seat.

is there anything else i should check?

also how do i check the oil pressure switch?
does anyone know where the relay/fuse are on an 88? i think they are on the passanger side fender.. but specifics would of course be helpful. thanks again guys for all the help. i gotta get this car on the road by dyno Smile

EDIT: if i do have to pull the tank (knowck on wood) it is going to suck because it is FULL!!!

also i found this post on TGO quite helpfull http://thirdgen.org/techbb2/showthread.php?s=&postid=2715752#post2715752

Twilightoptics · Posted: Thu Jan 26, 2006 12:39 am Post subject:

Checking the oil pressure switch.... Like I listed before, jumper the switch. Turn the key on... if the pump... pumps... start the car. If it runs fine, then it's your oil pressure switch. Unlikely, but the tank is a big job and I'd rather not do it without being certain.

Heh Full tank, that's going to suck. I'd figure out a way to syphon drain it first. Even at the price of gas, I'd waste 10gallons before bench pressuing a few hundred pounds of gas shloshing around.

Xophertony · Posted: Thu Jan 26, 2006 1:02 am Post subject:

oh, bypass the switch:duh: i feel silly.

Rolling Eyes

you just run the pump (even a busted ass pump will drain a tank) into a gas can or other vehicle. it took an hour on my 86 pumping at 10-20PSI.

also our tanks have a syphon blocker that prevents a hose from being inserted down the fuel neck... that or i am realy bad at it Very Happy