C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

poor acceleration

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Old Jun 7, 2011 | 05:48 PM
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From: Troy Al
Default poor acceleration

My 93 wants to die at rapid acceleration. Also, it takes 3 tries to start. Unusual for this car, as previously it would start with only a bump of the starter. No codes. Recently replaced the opti with a new AC/delco w/ MSD cap and rotor. I torque down the rotor, and added lock-tight, but I am suspicious of the rotor. The very first thing I'm thinking is poor fuel pressure. What is a source for a good cheap gauge, that I can trust?
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Old Jun 7, 2011 | 06:12 PM
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I had to go to O'Reillys and pay $40 for a good fuel gauge that would read over 40 lbs. I asked why no one else carrys those and the guy said `cause everyone round here still uses carburetors. Make sure when you do the test you tape the gauge to the windshield and go for a drive to watch it when the problems come up. pressue should stay steady at around 38-43 lbs.
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Old Jun 7, 2011 | 08:24 PM
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I could not find a cheap pressure gauge either. Sometimes you just have to pay for good tools but it pays in the long run because you usually use it more than you think.

While you looking for a gauge, check the vacuum line to the FPR. If it is leaking fuel back into the manifold over night as it bleeds down, it will be real rich in the morning and hard to start. It could also be the cause of an acceleration problem.
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Old Jun 7, 2011 | 09:44 PM
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Originally Posted by choopes
My 93 wants to die at rapid acceleration. Also, it takes 3 tries to start. Unusual for this car, as previously it would start with only a bump of the starter. No codes. Recently replaced the opti with a new AC/delco w/ MSD cap and rotor. I torque down the rotor, and added lock-tight, but I am suspicious of the rotor. The very first thing I'm thinking is poor fuel pressure. What is a source for a good cheap gauge, that I can trust?
I had a hard starting issue with my 93.
replace tons of parts in ignition system except for optispark.
the thing that ended up fixing all the issues was a set of FIC Fuel Injectors. ( Thank You Jon @ Fuel injector connection)
The FI in our Corvettes are junk multech and is 75% of the problems with hard starting and misfires.

I would OHM test your FI cold and hot if they are not in spec wich is 12-16 ohms replace them and I will to bet that will fix your issue.

BTW..I had one FI that read 10.4 ohms hot (thats bad, ohms should be higher hot if anything where resistance would go up hot not down )


GL

Last edited by Repzard; Jun 7, 2011 at 09:47 PM.
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Old Jun 7, 2011 | 09:57 PM
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Although, ohming the injectors only tests the coils, and won't tell you the condition of them mechanically. When I replaced my injectors it really woke up that car. If you do decide to replace them, jon is a good guy and will treat you right. I don't recomend just throwing parts at it like this though. Make sure you've eliminated every other variable.
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Old Jun 8, 2011 | 05:52 AM
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did u pay 169 for each injector or all 8 , from jon ?
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Old Jun 8, 2011 | 10:55 AM
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$169 for all 8.
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Old Jun 8, 2011 | 11:05 AM
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From: Troy Al
Default One thing at a time

Some guages I looked at call for an adaptor for GM products. Can anyone give me a model that has worked good for them "out of the box" they have recently bought, preferably one cheap, as I'll likely never use it again
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Old Jun 8, 2011 | 11:11 AM
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I believe (years ago) I bought my gauge at AutoZone. It is a dedicated GM gauge with the fitting on the hose, no adaptors. Took it out to the car to try it first. Not much room to get the hose in there to get the threads started, but is was OK.

Last edited by pcolt94; Jun 8, 2011 at 06:42 PM.
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Old Jun 8, 2011 | 11:28 AM
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Originally Posted by tehcarguy
$169 for all 8.
Jon is awesome FIC
I got all 8 injectors for 179 and where made just for the 92-93 LT1 only.
Corvette runs better than it ever has with his FI.

Jon is a great member and vendor.
He has my business and also pass his info onto a friend who just bought FI for his Grand national.

If OP is having a problem with FI , I wouldnt want to send him to anyone else but FIC
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