j0n

iTrader: (1)

First some background:
I purchased an '88 iroc with a 305tpi, 5-speed and procharger p600b with a 13psi pulley. I bought it knowing that the fuel pumps wouldn't prime and now that the car is home I'm trying to diagnose the issue.

With the key in the "on" position nothing happens. After cranking a couple times something primed out back(i was working alone so im not sure which pump was priming) and then started spraying fuel out of a leaky hose so that ended the night. Today I went out and directed the leaky hose into a fuel container in order to try and empty the tank. Now with the key "on" and cranking nothing primes.

The individual I bought the car off of believes it to be a wiring issue so can anyone give me an idea where to start looking for problems?

Also, I was contemplating doing something like a single or double walbro 255 in-tank and eliminating the fmu and auxiliary pump. Any thoughts on that?

AC

iTrader: (3)

Jon, first check the pump fuse (near battery I believe). Secondly, if you're at the point of being able to or considering putting in a 255 pump do it. That's my

j0n

iTrader: (1)

thanks i completely forgot to check the fuses im going to go out and do that in a second. also, the car makes just under 400whp as it sits and my plans for the car won't surpass 500whp(~600 at the crank) for at least the next couple years. I don't know if the dual walbro is warranted at that power level?

j0n

iTrader: (1)

fuses are all good...any other ideas?

FSTFBDY

iTrader: (33)

get yourself a multimeter and prob the power wire going to the tank.
Remove the rear backseat rest.

There are 3 wires. there a ground a gauge and the power wire.
see if you have power even going to the pump and how many volts.

Id say just guy the GSS340M and hotwire kit.
http://www.racetronix.com/product/RX..._Pump_Kit.html

That should solve your problem.

86Z

iTrader: (4)

you can access the harness just above the rear end on the outside of the car, check for voltage going to the pump, could be the fuel pump relay, a dual walboro 255 will not take the place of an FMU the fmu is there to bump the fuel rail pressure up under boost, unless you run a boost sensing ECM.

j0n

iTrader: (1)

Thanks im going to go probing with a multimeter tomorrow. What kind of boost-sensing ecms are available and what kinda pricetag do they carry?

also does anyone run the "GSS340M and hotwire kit"? Any complaints with it?

vwdave

You dont need a multimeter, just a test light.

Unplug harness under car near rearend, check for power and ground.

If power/ground is present, take the tank out and replace pump.

If power is missing, time to goto the relay. At the relay, there will be a wire with constant power. There will also be a wire with switched power. When you turn the key into the on position, it will come on for about 5 seconds then shut off. When you turn the key into the start position it should come back on and stay on. Thats your trigger.

If there is no constant power, check the fuse.

If the trigger doesnt work, I think that goes to the computer. Its been awhile ok?

If all that works, replace the relay.

j0n

iTrader: (1)

I'll follow that exact procedure tomorrow...pardon my n00bness but....wheres the fuel relay?

firstfirebird

iTrader: (3)

I got MegaSquirt, MS1 with knock sensor and spark circuits for $240 from KingEFI...

I don't have it installed yet, but even if I did I couldn't help you with tuning since I have a V6. It comes with a 2bar MAP that will sense up to 21PSI, and they have an available 4bar MAP as an upgrade.

vwdave

On mine its in the engine bay between the fender and brake booster. Its bolted to the firewall. There should be two relays, it should be the furthest towards the fender.

AC

iTrader: (3)

joN, as far as boost sensing ecm go into the DIY-PROM forum and read,read,read,read,read,read (you get the idea) of using (or getting to atleast) at what those users are doing with 730 ecms running 749 code and a 2bar map sensor. Can be done realtively cheap but the hidden cost is the time you'll invest learning to tune. From what I've learned / read over the last 1.5 years diy-tuning is invaluable.

vwdave.....good info in your post as far as procedure. 8)