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Fuel pump activates when manual trans is in reverse

Old Oct 20, 2023 | 02:15 AM
  #1  
Je90GTA's Avatar
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Joined: Jan 2009
Posts: 11
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From: Fort Mcmurray
Car: 90 T/A GTA
Engine: LB9 305
Transmission: 5 speed
Fuel pump activates when manual trans is in reverse

ok so,
Prepared the harness for terminator x. Wanting to maintain factory dash.
Installed harness, and now when I put the t5 in reverse. The fuel pump along with engine light and security light comes on. Even without a key.
I've changed the key and successfully bypassed vats. I will start there tomorrow. It looks like power comes from the signal lights.
left works very slowly. Right stays on..
I have a constant 12v on the green.
I'll also look for grounds while I'm searching.

thanks on advance

UPDATE

Verified problem still exist .
- Turned on left indicator and the fuel pump comes on with it ( on/off/on/off). (Back up light plug is not connected at this time. Transmission is not in reverse)
-Pulled steering wheel off . Everything looks good. Looked at fuse box - nothing appears out of sort. All fuses good.
- turned on hazard light switch - dash lights dimmed , did not blink. Stayed on.
- Pulled hazard fuse out - indicators functioned perfectly.

-checked Reverse light. Blinking with signal light.

- plug headlight module back in. Headlight function ( previously they did not- one thing at a time) . Check Reverse light. On - soli. Ok good.

plug in fuse for hazard flashers. Back to fuel pump issue/ no signal light function/fuel pump issue.

Update
I've searched everywhere for anything .still nothing

hazard lights (by themselves)- function
Turn lights (by themselves) - left stays on/right side function
put it in reverse... turn lights dont function. Hazards dim, then blink slowly.

Battery gauge gauge jumps with hazards lights blinking
oil pressure goes up to max
Engine temp jump up and down slightly.
This happens with or without key in run position.


Last edited by Je90GTA; Oct 21, 2023 at 02:58 PM.
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Old Oct 21, 2023 | 02:37 PM
  #2  
Chris 84TA's Avatar
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25 Year Member
 
Joined: Jul 1999
Posts: 363
Likes: 59
From: Poteau, OK, USA - Age: 44 - AKA 84TAVeRT
Car: 1984 Trans Am Convertible
Engine: 355
Transmission: WCT5
Axle/Gears: 3.73
Re: Fuel pump activates when manual trans is in reverse

check the ground strap from the engine to firewall. we found out that we had no body ground on my son's car after the transmission was replaced. it may be that the signals are grounding the body when the relay flashes.

Thanks,
Chris
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Old Oct 21, 2023 | 03:02 PM
  #3  
Je90GTA's Avatar
Thread Starter
Junior Member
 
Joined: Jan 2009
Posts: 11
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From: Fort Mcmurray
Car: 90 T/A GTA
Engine: LB9 305
Transmission: 5 speed
Re: Fuel pump activates when manual trans is in reverse

Yes sir, checked and confirmed. It's there.
Cleaned contacts and still no improvement

I'm thinking its a ground issue as well . Just can't seem to figure it out.
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Old Oct 24, 2023 | 05:24 PM
  #4  
Je90GTA's Avatar
Thread Starter
Junior Member
 
Joined: Jan 2009
Posts: 11
Likes: 0
From: Fort Mcmurray
Car: 90 T/A GTA
Engine: LB9 305
Transmission: 5 speed
Re: Fuel pump activates when manual trans is in reverse

Well, you were correct. I found the ground issue...there's a ground wire by the hatch release and it wasn't connected to the body. I never thought it could ever cause the fuel pump but there you have it.

thanks for the help!
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Old Oct 25, 2023 | 04:23 PM
  #5  
Thirdgen89GTA's Avatar
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20 Year Member
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Joined: Sep 2004
Posts: 5,906
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From: Chicagoland Suburbs
Car: 1989 Trans Am GTA
Engine: LT1, AFR 195cc, 231/239 LE cam.
Transmission: M28 T56
Axle/Gears: 3.23 10bolt waiting to explode.
Re: Fuel pump activates when manual trans is in reverse

I quickly learned when I bought my GTA going on 20 years ago, that yeah, missing grounds will cause ALL sorts of issues.

PO had cut a ground all the way back to the loom, so I didn't know it was even missing.

If I turned on the parking lights, the instrument lights would come on, but all the needles dropped dead. If I opened the driver side door, everything worked as it should.

It wasn't until I found an unmolested car and could look at the wiring that I tracked back the missing ground.
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