Good evening!

I have a 1991 GTA with an L98 350. 4 years ago, I had the motor pulled. I completely redid the ignition, replaced all the sensors, replaced some cooling system components, upgraded the oil pump, added a racing oil pan, and replaced the harmonic balancer, timing chain, and timing chain cover. I’m sure I’m forgetting a few things.

It turns out the shop I used sucked. I upgraded to solid motor mounts; they lost the bolts. In driving it off the lot, I noticed the oil pan seal and/or rear main seal were leaking. I also had the rear differential seal replaced, that was also leaking.

This was four years ago. Out of frustration, I parked the car and let it sit since then.

My new mechanic is working on it now. He says my fuel pump is bad. I know ethanol eats 3rd Gen fuel pumps. I always used non-ethanol gas when it was available, but it wasn’t always available. Perhaps 4 years of ethanol killed the pump.

I’m having him flush the fuel system since the fuel is old. I don’t need it gumming up my new Southbay fuel injectors.

Since he has to drop the fuel tank to replace the pump, I’m also asking him to treat it. He uses GB products. Has anyone ever heard of this brand?

Since the pump has to be replaced anyway, what pump do you recommend? My Southbay fuel injectors flow stock numbers, but I’d like to be able to add more air/fuel in the future. Do aftermarket options come with new hoses and an in-tank harness like the OEM GM replacement? Do they hold up better to ethanol than the OEM pump? Can they flow less fuel to match my stock-flowing injectors?

I already have new fuel injectors and a fuel pressure regulator. Besides treating the tank, upgrading the fuel pump, and replacing the fuel filter, what other maintenance, service, and or upgrades can I perform at this time?

(I am aware of the modification to cut a fuel pump access port in the trunk. There’s a ghetto way and an awesome kit made for TTAs.)

Since the previous mechanics sucked, what should I ask my mechanic to look for when he checks their work?

Thanks for your help!
Bill

 

If I was going to replace the fuel pump I would either go GM OEM from the dealer or Bosch. I’ve researched this a bit and they are likely your best bet for durability and performance IMO. I would also really think of replacing or rebuilding the sending unit in tank, it’s likely in rough shape.

An adjustable fuel pressure regulator might not be a bad idea if your going to be working on the fuel system, it’s nice to be able to experiment with pressure to see what your car likes. Holley makes a nice one with the easiest adjustment dial out there.

If he is dropping the tank it would be an ideal time to replace the rear springs and shocks if they are worn out.

 

Thank you! I already have an adjustable fuel pressure regulator installed.

I like the idea of going OEM. My only concern is that I won’t be able to boost fuel delivery in the future.

Good call on the fuel sending unit. Also, good call on the springs and shocks. (I’m already running Koni yellow shocks.)

I appreciate your reply!

 

I just installed this pump https://www.summitracing.com/parts/dwk-92011028 it's quiet, future proof, and went in pretty easy.

I've got a 5.0 and it seems to be working fine from my minimal testing so far. Just got the car back on it's wheels earlier this week so extensive testing has yet to occur.

But it was suggested by someone else on this forum.

 

Good choice, If I wanted a pump with more power than stock that is the one to get. I would take that over the Walbro any day. The reliability of that pump is also supposed to be great.