Engine "missing"
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Joined: Apr 2001
Posts: 73
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From: Tampa, Florida, USA fl
Engine "missing"
My 93 LT1 recently starting running rough and missing after it is driven in traffic after about 1/2 hour. Iy seems to have started after I filled the tank. Do you think I got some "bad" fuel? I took it to the local Vette shop, but they could not make it miss, but it started again on the way home. I put some injector cleaner in the tank and am still waiting for results! Help!! [IMG][/IMG]
Team Owner
Joined: Nov 1999
Posts: 26,679
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From: This vette goes to 11 Milford MA
St. Jude Donor '03-'05
Re: Engine "missing" (David Joseph)
Engine missing? The first place I would check is under the hood, thats usually where mine is.:D
How old is the Opti-spark and when was it last tuned?
[Modified by Fastguy, 1:32 AM 8/5/2002]
How old is the Opti-spark and when was it last tuned?
[Modified by Fastguy, 1:32 AM 8/5/2002]
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Re: Engine "missing" (David Joseph)
Missing is predominently the spark. At night look at the running engine to see if there is any sparks occurring along each spark plug wire. Also, check each spark plug wire with an ohmeter, they should be about 5k ohms per foot. If it passes these tests, an ignition analyzer will tell you if the optispark is on vacation.
Safety Car
Joined: Jun 1999
Posts: 3,570
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From: Austin, Singapore, Kuala Lumpur, Houston, Dallas, Hong Kong, Elgin, etc.. Texas
Re: Engine "missing" (jfb)
I agree, check the spark plug wires first. Don't assume it needs anything major.
My car had a problem with the high tension lead---the wire from the coil to the Optispark. This runs from the coil bolted on the passenger's cylinder head, along the top of the waterpump, then down to the optispark. The factory adds a slip on insulation over the wire to keep it from grounding out to the water pump but this is not completely effective.
The dark garage technique works really well. You may have to let your eyes adjust for 5 minutes or more to see the problem. Wires that have a glow are OK. This is called carona and is normal. Do not touch the wires when the engine is running as you can get quite a zap.
My car had a problem with the high tension lead---the wire from the coil to the Optispark. This runs from the coil bolted on the passenger's cylinder head, along the top of the waterpump, then down to the optispark. The factory adds a slip on insulation over the wire to keep it from grounding out to the water pump but this is not completely effective.
The dark garage technique works really well. You may have to let your eyes adjust for 5 minutes or more to see the problem. Wires that have a glow are OK. This is called carona and is normal. Do not touch the wires when the engine is running as you can get quite a zap.
Melting Slicks
Joined: May 2001
Posts: 2,143
Likes: 7
From: San Diego CA
Re: Engine "missing" (Mez)
I agree, check the spark plug wires first. Don't assume it needs anything major.
If the miss is regular then it's probably wires or plugs. If it is intermittent and random, start thinking opti. Feel the weep hole under the waterpump (when cool) to see if it's starting to drip. If it's the opti, don't panic <$300 and a weekend (first time) and you'll be good to go.
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Joined: Apr 2001
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From: Tampa, Florida, USA fl
Re: Engine "missing" (David Joseph)
Hey, It is very hot here in Florida- I notice that my AC evaporator is sweating a LOT of water. It is located in front of the Optispark- do you think that it could be dripping on it when the car is in motion? (it only misses when the car has been driven for at least 1/2 hour and only in traffic speeds of 25- 45 mph.) :smash:
Burning Brakes
Joined: Mar 2001
Posts: 1,200
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Re: Engine "missing" (David Joseph)
do the tune up first. plugs, wires, coil, fuel filter. GM says the plugs are good for 100k - i change mine every spring. my 94 missed once and awhile. go buy a good bottle of octain boost, just incase you have bad gas, and don't buy gas from that station any more. I feel it every time i use chevron (bad) i always try to go any where but there. after all the above my cars runs pretty good up to 220 degrees.... so 160 stat and new fan switch. all summer it has run near perfect. Note: FUEL FILTER!! if you have not changed it in a year you need to do this! (easy to forget)
Team Owner
Joined: Aug 2000
Posts: 40,156
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From: San Pedro CA
Re: Engine "missing" (David Joseph)
Hey, It is very hot here in Florida- I notice that my AC evaporator is sweating a LOT of water. It is located in front of the Optispark- do you think that it could be dripping on it when the car is in motion? (it only misses when the car has been driven for at least 1/2 hour and only in traffic speeds of 25- 45 mph.) :smash:
mileage and whether the car was really hit by rain or, if the opti was ever drowned in antifreeze. check the waterpump for seepage.
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Burning Brakes
Joined: Feb 2000
Posts: 824
Likes: 2
From: Camden SC
Re: Engine "missing" (bogus)
Ah, pretty darn sure that fin looking thing forward of the radiator is in fact the condensor. High pressure vapor is condensed to a high pressure liquid.
The evaporator is the big monster over by the passenger side.
Keep the faith.
dlmeyers 90 coupe zf6 3 speed shocks
The evaporator is the big monster over by the passenger side.
Keep the faith.
dlmeyers 90 coupe zf6 3 speed shocks
