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Topic: Running ok then not

in Forum: C4 Fuel, Emission Control, and Exhaust Systems


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Running ok then not (1/9)
 8/11/18 2:47pm
Tony B
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Massapequa, NY - USA

Vette(s):
1990 Dark Red Metalic hardtop convertible


Joined: 10/29/2017
Posts: 17

Drove my 90 vette L98 yesterday to work, no problems. Coming home went to take off from a stop and out of the blue car started to sputter when giving it gas no acceleration. Stalled a few times, was able to restart it after a few tries. When restarted couldn't get it to move faster than about 15-20 mph. Finally it wouldn't move without stalling and needed a tow home. Changed the IAC today no change. Installed new fuel pump last November.

I have been getting a service eng soon light when driving it after about 20 min  to 1/2 hr. Ran the ALDL only code coming up is 44, O2 sensor, lean exhaust. Any connection to the current problem?
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Re: Running ok then not (2/9)
 8/16/18 10:37am
Black Shark
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Vette(s):
Black 1979 L-82 Black 1996 LT1 Black 1999 Coupe


Joined: 3/20/2009
Posts: 611

To be honest; there is a lot more that needs to be done/checked for a proper diagnosis of what could be the problem.
 
Bad fuel can cause similar probs you describe, so can a fuel cap that don't vent.
Re: Running ok then not (3/9)
 8/18/18 2:55pm
Tony B
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Massapequa, NY - USA

Vette(s):
1990 Dark Red Metalic hardtop convertible


Joined: 10/29/2017
Posts: 17

Ok, thanks
Re: Running ok then not (4/9)
 8/19/18 12:38pm
rtslt4
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Huntington Station, NY - USA

Vette(s):
1996 Black Cpe., Lt. Beige Int., LT4, 6 Spd., Corsa Exh., K & N, & Chrome Replc. Wheels.


Joined: 7/2/2013
Posts: 51

I recommend checking the fuel pressure first.  When is the last time the fuel filter was replaced?

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Re: Running ok then not (5/9)
 8/23/18 12:06pm
Robert
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Joined: 10/14/2015
Posts: 2

Replace the EGR electric / VAC senser. And the computer (ecm) . All problems will go away. Ecm first. You may have trouble finding the sencer. If needed.

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Re: Running ok then not (6/9)
 9/5/18 11:56am
Barn find
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Lakeville, MA - USA

Vette(s):
1987 convertible


Joined: 4/19/2014
Posts: 23

I replaced my fuel pump and shortly after the car would die on me while driving, but once off the road it would restart. Turns out the sending until wires were corroded and the movement of the car would cause the connectors to lose contact. Just saying, you did the pump last fall. You may want to take a look.
Re: Running ok then not (7/9)
 9/5/18 1:27pm
Phat98
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Crystal Springs, MS - USA

Vette(s):
1973 Mille Miglia Red LS5 1981 Claret Red 1982 White 1985 Silver Metallic 1988 Yellow 1993 Torch Red ZR-1 1994 Torch Red Coupe LT1 1996 Dark Purple Metallic LT4 2000 Torch Red 2001 Light Pewter 2003 Z06 Millennium Yellow 2009 Atomic Orange


Joined: 7/29/2011
Posts: 33

All good recommendations, above. Handshake

Your lean condition, unless it was pre-existing, should be your clue. I had a brand-new Delphi fuel pump fail within six months...uncommon, but it happens. Fuel pressure would be my first check, then fuel filter, injectors, etc.

Also, clogged catalytic converters can cause the exact issues you described. Dead




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1973 Mille Miglia Red LS5 - SOLD
1981 Dark Claret Metallic - SOLD
1982 White
94 Torch Red LT1
96 Dark Purple Metallic LT4
02 Black Convertible - SOLD
03 Millennium Yellow Z06
09 Atomic Orange Z51
 
Re: Running ok then not (8/9)
 9/11/18 11:32am
destoy
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Virginia Beach, VA - USA

Vette(s):
1992 Coupe Z07 Black Rose Metallic


Joined: 8/10/2018
Posts: 1

I had a very similar symptom. In prep for Corvettes at Carlisle 2017 (last year) I took my '92 out on the expressway and went full throttle. Immediately it started misfiring. I limped home on what felt like 5 out of 8 cylinders were firing. Would not maintain idle without nursing the throttle. Check fuel delivery; good. Read a lot on this and corvette forum. Called fuelinjectionconnection.com. The injectors were original and they said it was probably shorted coils. It turns out that factory injector's coil are cooled the with gas. And with only four days before departure to CAC I decided to purchase a set of Bosch 3 24# (stock are 22#) injectors with over night shipping. Install took ~ an hour. Starting and drivability were instantly improved. Full throttle performance was way improved. Scared me at first but have certainly gotten use to that kick in the pants (so to speak). In addition to the fix I learned more about wet coil injectors, BTU of ethanol vs pure gas and why the 24# injectors seem to improve full throttle, corrosiveness of ethanol, etc. I also read somewhere that you can use a multimeter and measure the resistance of the injector coils. Most likely that info came from the corvette forum or the folks at fuelinjectionconnection. Happy troubleshooting!

|UPDATED|9/11/2018 8:32:45 AM (AZT)|/UPDATED|


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Re: Running ok then not (9/9)
 9/22/18 2:36am
Hot Rod Roy
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Mission Viejo, CA - USA

Vette(s):
Yellow '84 Coupe


Joined: 3/18/2015
Posts: 74

Robert said: Replace the EGR electric / VAC senser. And the computer (ecm) . All problems will go away. Ecm first. You may have trouble finding the sencer. If needed.

This is called "shotgun troubleshooting".   No analysis needed.   Just keep throwing money at the problem, and maybe you'll get lucky!

Sick

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