Fuel tank issue?
Joined: Dec 2001
Posts: 9,937
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From: Chicagoland
Car: 1989 IROC-Z. Original owner
Engine: LB9. Dual Cats. Big Cam
Transmission: World Class T-5
Axle/Gears: BW 3.45
Joined: Apr 2000
Posts: 3,938
Likes: 99
From: Huntsville AL
Car: 88GTA
Engine: 5.7TPI
Transmission: Auto
Axle/Gears: 3.27
Joined: Dec 2001
Posts: 9,937
Likes: 636
From: Chicagoland
Car: 1989 IROC-Z. Original owner
Engine: LB9. Dual Cats. Big Cam
Transmission: World Class T-5
Axle/Gears: BW 3.45
Re: Fuel tank issue?
Last edited by chazman; May 23, 2017 at 11:18 AM.
Joined: Dec 2001
Posts: 9,937
Likes: 636
From: Chicagoland
Car: 1989 IROC-Z. Original owner
Engine: LB9. Dual Cats. Big Cam
Transmission: World Class T-5
Axle/Gears: BW 3.45
Thread Starter
Moderator

Joined: Jun 2000
Posts: 8,459
Likes: 215
From: Florida
Car: 87 IROC-Z, 82 Pace Car
Re: Fuel tank issue?
I've tried multiple gas options. I've been running 89 ethanol free gas for the past two years. No change. I've been busy doing other things lately, so I haven't had time to do basic things to the car. I want to blow out the vent line from the tank to the canister, and I want to replace the vacuum lines just in case there's a hairline crack that I don't see when inspecting them. Both of those can cause this issue.
Supreme Member
Joined: Nov 2003
Posts: 1,629
Likes: 17
From: Somewhere
Car: 88 IROC
Engine: 305 TPI
Transmission: 700R4
Axle/Gears: 10 bolt 3.73
Re: Fuel tank issue?
I have not had access to BP fuels in over 10 years. No BP gas here in the AZ. Only SHELL, CHEVRON and QUICKTRIP. All 91 octane
In my dragstrip testing my car can run a solid two tenths of a second quicker on Shell premium compared to the Chevron and Quicktrip. I have duplicated this result in multiple drag strip tests and also on other TPI Thirdgen's here in AZ.
Peanut cam 88 Iroc. 305 TPI.
CHEVRON 91 - 15.21
Quicktrip 91 - 15.22 and 15.23
Shell 91 - 14.96 ( same time I get running 100 octane race fuel). Makes me wonder if the octane is higher then they are advertising on the Shell.
Testing done at Wild Horsepass dragstrip in Chandler AZ roughly 1/2 tank of fuel.
I would love to test the BP premium but no way to get it here. Back in IL that was the gas to run.
In my dragstrip testing my car can run a solid two tenths of a second quicker on Shell premium compared to the Chevron and Quicktrip. I have duplicated this result in multiple drag strip tests and also on other TPI Thirdgen's here in AZ.
Peanut cam 88 Iroc. 305 TPI.
CHEVRON 91 - 15.21
Quicktrip 91 - 15.22 and 15.23
Shell 91 - 14.96 ( same time I get running 100 octane race fuel). Makes me wonder if the octane is higher then they are advertising on the Shell.
Testing done at Wild Horsepass dragstrip in Chandler AZ roughly 1/2 tank of fuel.
I would love to test the BP premium but no way to get it here. Back in IL that was the gas to run.
Joined: Dec 2001
Posts: 9,937
Likes: 636
From: Chicagoland
Car: 1989 IROC-Z. Original owner
Engine: LB9. Dual Cats. Big Cam
Transmission: World Class T-5
Axle/Gears: BW 3.45
Re: Fuel tank issue?
One interesting note on the screeching fuel pump on my '85. I put a bottle of Techron in once and it completely quieted it down within 5 minutes.
Joined: Aug 2013
Posts: 4,808
Likes: 905
From: MICHIGAN
Car: 1988 Trans Am
Engine: L03
Transmission: 700R4
Axle/Gears: 10 Bolt 2.73 Open
Re: Fuel tank issue?
Well it was pretty much 95 100 degrees here today, i drove the car from like 10:30 till like 4, not 1 issue of boiling gas or hard start problem after sitting for like 20 minutes or so. No noise what so ever outta the pump, its freaking amazing. So im pretty sure this 10 year old problem is solved
Supreme Member
Joined: Nov 2003
Posts: 1,629
Likes: 17
From: Somewhere
Car: 88 IROC
Engine: 305 TPI
Transmission: 700R4
Axle/Gears: 10 bolt 3.73
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Joined: Mar 2001
Posts: 14,293
Likes: 195
From: Doghouse ······································ Car: 1989 Formula 350 Vert Engine: 350 L98 Transmission: 700R4 Axle/Gears: B&W 3.27
Car: 87 Formula T-Top, 87 Formula HT
Engine: 5.1L TPI, 5.0L TPI
Transmission: 700R4, M5
Axle/Gears: Sag 3.73, B&W 3.45
Re: Fuel tank issue?
Funny thing, in my area there is a station that will sell you pure gasoline for a premium. Regular gas is $2.00, they sell pure gas 89 octane for $3.50. but one day, 2 hours away from me I found a station that had 87 gas no Ethanol for only 30 cents more.
Joined: Aug 2013
Posts: 4,808
Likes: 905
From: MICHIGAN
Car: 1988 Trans Am
Engine: L03
Transmission: 700R4
Axle/Gears: 10 Bolt 2.73 Open
Re: Fuel tank issue?
Got it.
State-by-state list of ethanol free gas here (links at bottom of page). Don't know if that helps anyone.
http://pure-gas.org/
I think there's a phone app too.
State-by-state list of ethanol free gas here (links at bottom of page). Don't know if that helps anyone.
http://pure-gas.org/
I think there's a phone app too.
Re: Fuel tank issue?
The Bosch unit for these cars is a turbine pump. Walbro and that holly pump are gerotor designs. Both heat fuel up more. The holly pump looks suspiciously like a Walbro. After running a turbine pump when tuning my turbo Audi back to back with a Walbro I will never use a Walbro or non turbine style pump again. You get a better more "laminar" fuel flow, and the car is easier to tune, at least in my case with a super picky 1.8L 5v motor and a 60mm turbo.
I am currently doing a fuel tank, sender and new lines plus a new pump. I'm either retrofitting a low mileage stock turbo Audi A4 1.8T turbine pump that flows enough for 300AWHP at 20psi of boost and 60psi rail or just buying a bosch meant for this car.
I'm probably going to retrofit the Audi pump into the new sending unit. It is for a 1998 A4 1.8T and at 3 bar rail with no forced induction it would flow fine for decent power, it is larger in size to shed heat and not heat the fuel up as much, etc. Benefits to it plus I have it sitting here with 5000-10000 miles on it.
I am currently doing a fuel tank, sender and new lines plus a new pump. I'm either retrofitting a low mileage stock turbo Audi A4 1.8T turbine pump that flows enough for 300AWHP at 20psi of boost and 60psi rail or just buying a bosch meant for this car.
I'm probably going to retrofit the Audi pump into the new sending unit. It is for a 1998 A4 1.8T and at 3 bar rail with no forced induction it would flow fine for decent power, it is larger in size to shed heat and not heat the fuel up as much, etc. Benefits to it plus I have it sitting here with 5000-10000 miles on it.





