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91 L98 just cranks sometimes starts

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Old Nov 24, 2017 | 09:01 PM
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91 L98 just cranks sometimes starts

So the car has not ran for a while. Anyway, it's mainly just cranking it barely starts. At first it would start for a few minutes, but then die. Then, it would just crank. Sometimes it'll start and die right away. As of right now it's just cranking. It'll start with starting fluid, but die right away. I've replaced the fuel pump, fuel filter, spark plugs, and battery. I pulled out the fuel pressure regulator and there was no signs of tears or anything unusual. What could it be? I've never driven this car and really want to. Thanks
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Old Nov 24, 2017 | 11:07 PM
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From: Fallston, Maryland
Car: 1989 Trans Am GTA
Engine: 350
Transmission: T56
Axle/Gears: 9 Bolt 3.70
Re: 91 L98 just cranks sometimes starts

I know you replaced the fuel pump and filter, but have you verified the engine is actually getting fuel? If it'll only turn over with starting fluid, I would think that its not. Check the fuel pressure at the rail and see if it has any. With the key on can you hear the fuel pump priming?
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Old Nov 25, 2017 | 06:39 AM
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Re: 91 L98 just cranks sometimes starts

Originally Posted by mike_c
I know you replaced the fuel pump and filter, but have you verified the engine is actually getting fuel? If it'll only turn over with starting fluid, I would think that its not. Check the fuel pressure at the rail and see if it has any. With the key on can you hear the fuel pump priming?
I haven't had a chance to get my hands on a fuel pressure gauge, but I will today. Yes, I can hear it prime.
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Old Nov 25, 2017 | 06:39 AM
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Car: 89 GTA ASC Conv., Prev: 89 GTA 6.3L
Engine: 5.7L L98 TPI
Transmission: 700r4 Automatic
Axle/Gears: 3.27:1 w/ JG1 Options:B2L, N10, U1A
Re: 91 L98 just cranks sometimes starts

Have you tested the resistance in each fuel injector?
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Old Nov 25, 2017 | 06:40 AM
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Re: 91 L98 just cranks sometimes starts

Originally Posted by Big&BadGTA
Have you tested the resistance in each fuel injector?
How can I do that? I have a multimeter if that's what I need?
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Old Nov 25, 2017 | 06:50 AM
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From: *member since 1999, I think - just can't remember my old name, and the big site crash...*
Car: 89 GTA ASC Conv., Prev: 89 GTA 6.3L
Engine: 5.7L L98 TPI
Transmission: 700r4 Automatic
Axle/Gears: 3.27:1 w/ JG1 Options:B2L, N10, U1A
Re: 91 L98 just cranks sometimes starts

Yes. Check each injector. Unclip the harness.
Should read 16 ohms at each injector.

Post your results in 15 min when done. Thank
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Old Nov 25, 2017 | 06:57 AM
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Re: 91 L98 just cranks sometimes starts

Originally Posted by Big&BadGTA
Yes. Check each injector. Unclip the harness.
Should read 16 ohms at each injector.

Post your results in 15 min when done. Thank
With key turned or just off?
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Old Nov 25, 2017 | 06:57 AM
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From: *member since 1999, I think - just can't remember my old name, and the big site crash...*
Car: 89 GTA ASC Conv., Prev: 89 GTA 6.3L
Engine: 5.7L L98 TPI
Transmission: 700r4 Automatic
Axle/Gears: 3.27:1 w/ JG1 Options:B2L, N10, U1A
Re: 91 L98 just cranks sometimes starts

Key off

You are reading resistance across each injector pin and pin.,,
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Old Nov 25, 2017 | 07:06 AM
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Re: 91 L98 just cranks sometimes starts

So I'm not any good with this stuff, but I have my multimeter on 20K ohms? There's 2000K, 200K, 20K, and 2000, and 200. Which one is it supposed to be on? It's on the ohm area. Also I'm touching one terminal of the injector with the black lead and the red on the other one if that's how you do it?
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Old Nov 25, 2017 | 07:15 AM
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From: *member since 1999, I think - just can't remember my old name, and the big site crash...*
Car: 89 GTA ASC Conv., Prev: 89 GTA 6.3L
Engine: 5.7L L98 TPI
Transmission: 700r4 Automatic
Axle/Gears: 3.27:1 w/ JG1 Options:B2L, N10, U1A
Re: 91 L98 just cranks sometimes starts

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Old Nov 25, 2017 | 07:36 AM
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Re: 91 L98 just cranks sometimes starts

Driver side
18.0

06.6

03.5

10.5
Passenger side
18.0

10.5

18.0

18.0
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Old Nov 25, 2017 | 07:50 AM
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From: *member since 1999, I think - just can't remember my old name, and the big site crash...*
Car: 89 GTA ASC Conv., Prev: 89 GTA 6.3L
Engine: 5.7L L98 TPI
Transmission: 700r4 Automatic
Axle/Gears: 3.27:1 w/ JG1 Options:B2L, N10, U1A
Re: 91 L98 just cranks sometimes starts

2 of 8 are absolutely toast. 2 more are bad, and 4 are fine

Replace all eight (8)
I've used these on mine:

https://fuelinjectorconnection.com/c...l-injector-set

20% off sale, too.
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Old Nov 25, 2017 | 07:52 AM
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Re: 91 L98 just cranks sometimes starts

Originally Posted by Big&BadGTA
2 of 8 are absolutely toast. 2 more are bad, and 4 are fine

Replace all eight (8)
I've used these on mine:

https://fuelinjectorconnection.com/c...l-injector-set

20% off sale, too.
Thanks for your help. Wish I could afford those might have to go with rebuilds
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Old Nov 25, 2017 | 09:16 AM
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From: Fallston, Maryland
Car: 1989 Trans Am GTA
Engine: 350
Transmission: T56
Axle/Gears: 9 Bolt 3.70
Re: 91 L98 just cranks sometimes starts

I've had 2 sets of rebuilt Bosch IIIs in mine from FIC. I'm very pleased with them. I had stock size and then put in 32lbs when I redid the engine.
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Old Nov 26, 2017 | 01:58 PM
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Car: 1987 IROC-Z
Engine: L98 5.7L
Transmission: MD8 700R4
Axle/Gears: G80 GW6 3.27:1
Re: 91 L98 just cranks sometimes starts

Good info BigBad, thanks for sharing.
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Old Nov 26, 2017 | 03:07 PM
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From: *member since 1999, I think - just can't remember my old name, and the big site crash...*
Car: 89 GTA ASC Conv., Prev: 89 GTA 6.3L
Engine: 5.7L L98 TPI
Transmission: 700r4 Automatic
Axle/Gears: 3.27:1 w/ JG1 Options:B2L, N10, U1A
Re: 91 L98 just cranks sometimes starts

Originally Posted by Bow_Tied
Good info BigBad, thanks for sharing.
You are welcome!! I'm here to help!!
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