Engine miss that comes and goes...
Thread Starter
Le Mans Master
Joined: Dec 2000
Posts: 7,515
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From: Naperville, IL ...... On Iowa!!!
Engine miss that comes and goes...
My '94 6sp w/55k miles is like Jekyl and Hyde! 4 out of 5 days she runs strong and sweet, but every now and then she acts up. The last time it happened I was in stop and go traffic and the water temp went up pretty high. I started to get a slight miss under acceleration. The next day she ran great.This has been going on for a month now. I'm about ready to take it in for plugs and wires if anybody thinks this would help. :confused: Thanks!
Race Director
Joined: Feb 2002
Posts: 11,268
Likes: 14
From: Honolulu, HI
Re: Engine miss that comes and goes... (LoFlyer)
I seem to be having the same problem, please read my posts and see if it's relative. I have a '92 LT-1. What I gathered from other opinions are this:
Good news is it could be wires or plugs which are relatively cheap.
Bad news is it could be bad Optispark or bad injectors, which each could run between $1400 and $1800 if you pay for the labor. Otherwise I hear replacing Optispark is a Pain in the ( | ) :cry
http://forums.corvetteforum.com/zerothread?id=300448
http://forums.corvetteforum.com/zerothread?id=297549
also, read this guy's post, he seems to be having the same problem too.
http://forums.corvetteforum.com/zerothread?id=300951
[Modified by vvv90, 9:10 PM 5/15/2002]
Good news is it could be wires or plugs which are relatively cheap.
Bad news is it could be bad Optispark or bad injectors, which each could run between $1400 and $1800 if you pay for the labor. Otherwise I hear replacing Optispark is a Pain in the ( | ) :cry
http://forums.corvetteforum.com/zerothread?id=300448
http://forums.corvetteforum.com/zerothread?id=297549
also, read this guy's post, he seems to be having the same problem too.
http://forums.corvetteforum.com/zerothread?id=300951
[Modified by vvv90, 9:10 PM 5/15/2002]
Pro
Joined: Nov 1999
Posts: 623
Likes: 0
From: Toronto, ON, Canada
Re: Engine miss that comes and goes... (LoFlyer)
Besides the Optispark it could be a bad injector. I had this on my old car and it took me months to figure out the injectors were starting to go bad.
Even still Injectors should only run $300-$400 for a set of 8 SVO type. Easy to swap out and you can do it with simple hand tools in 1-1 1/2 hours.
Even still Injectors should only run $300-$400 for a set of 8 SVO type. Easy to swap out and you can do it with simple hand tools in 1-1 1/2 hours.
Race Director
Joined: Feb 2002
Posts: 11,268
Likes: 14
From: Honolulu, HI
Re: Engine miss that comes and goes... (XTwinTurbo)
That's the other thing that I'd said, the Optispark is a pain from what I heard. I'm hoping it's just the injectors because as you said, it's only $300 to $400 and not nearly as much time to replace.
God I fear the Optispark so! I guess I shouldn't though considering i do eventually want to rebuild the motor, or at least take it out myself. Oh well, It just got nice out and I want it on the road again. :cry :cry :cry
God I fear the Optispark so! I guess I shouldn't though considering i do eventually want to rebuild the motor, or at least take it out myself. Oh well, It just got nice out and I want it on the road again. :cry :cry :cry
Melting Slicks
Joined: May 2001
Posts: 2,143
Likes: 7
From: San Diego CA
Re: Engine miss that comes and goes... (vvv90)
Sorry, sounds like the OPTI is starting to go. BTW, are you dripping any coolant from the weep hole under the water pump? or have you washed the engine right before this all started?
Replacing the OPTI is not difficult. It's a DIY project. The first time it will take you 2 days (you'll probably spend a lot of time staring at the engine thinking "How the FORK do I get a wrench on that?" and more time driving to the parts store for a new tool, Yes you need a 6" extension.). A new Opti is ~$250-$300.
The second time will only take 4-5 hours.
Replacing the OPTI is not difficult. It's a DIY project. The first time it will take you 2 days (you'll probably spend a lot of time staring at the engine thinking "How the FORK do I get a wrench on that?" and more time driving to the parts store for a new tool, Yes you need a 6" extension.). A new Opti is ~$250-$300.
The second time will only take 4-5 hours.
Team Owner
Joined: Oct 1999
Posts: 31,977
Likes: 487
From: Guinness Its whats for B'fast JAWGA
CI 3-4-5-9 Veteran
Re: Engine miss that comes and goes... (John Row)
Like John said look for coolant. When it is cool enough try to feel for water around the bottom of the water pump. Mine started acting the same way when the water pump went, and took the opti with it.
[Modified by 93Polo, 6:43 PM 5/15/2002]
[Modified by 93Polo, 6:43 PM 5/15/2002]
Instructor
Joined: Feb 2002
Posts: 227
Likes: 0
From: Greenville TX
Re: Engine miss that comes and goes... (LoFlyer)
I vote opti.
Changing it is evil, but the only real catch was the harmonic balancer. If I could have gotten the hub and balancer separated, then the whole job would have been much easier.
Odd tools you will need:
U-joint for one water pump bolt
Harmonic Balancer puller
7/16" bolts to use with HB puller
If you need to assemble/disassemble opti:
T8 torx bit
E4 reverse torx socket
There is a good writeup of the job floating around here. I don't think it has been added to the tech tips, but it needs to be.
Changing it is evil, but the only real catch was the harmonic balancer. If I could have gotten the hub and balancer separated, then the whole job would have been much easier.
Odd tools you will need:
U-joint for one water pump bolt
Harmonic Balancer puller
7/16" bolts to use with HB puller
If you need to assemble/disassemble opti:
T8 torx bit
E4 reverse torx socket
There is a good writeup of the job floating around here. I don't think it has been added to the tech tips, but it needs to be.
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Pro
Joined: Nov 1999
Posts: 623
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From: Toronto, ON, Canada
Re: Engine miss that comes and goes... (vvv90)
God I fear the Optispark so! I guess I shouldn't though considering i do eventually want to rebuild the motor, or at least take it out myself. Oh well, It just got nice out and I want it on the road again. :cry :cry :cry
Race Director
Joined: Feb 2002
Posts: 11,268
Likes: 14
From: Honolulu, HI
Re: Engine miss that comes and goes... (XTwinTurbo)
ooooo, that's a good point, I guess considering even if the optispark isn't the problem right now....and I do want to do an s/c, I should replace it regardless. Especially considering the optispark on my model vette (92) is a POS anyway.
Thanks for waking me up :smash:
Thanks for waking me up :smash:
Melting Slicks
Joined: May 2001
Posts: 2,143
Likes: 7
From: San Diego CA
Re: Engine miss that comes and goes... (vvv90)
It's a later model cap and rotor on the early opti base along with a vacuum hose kit. You could drill an early cap (there's a write up in tech tips).
The later cap has a connection for a vacuum line. I had heard that Pep Boys had a kit for this but never looked for it.
The RIGHT way to do this would be a complete upgrade to the 95/96 Opti. You need to replace the timing cover as well and the complete opti.
The later cap has a connection for a vacuum line. I had heard that Pep Boys had a kit for this but never looked for it.
The RIGHT way to do this would be a complete upgrade to the 95/96 Opti. You need to replace the timing cover as well and the complete opti.
Burning Brakes
Joined: Mar 2002
Posts: 844
Likes: 11
From: Il
Re: Engine miss that comes and goes... (John Row)
If its any consolation my 94 is having the same symptoms. If been through Everything except the opti. (plugs, wires ect.) It mostly happens when I let it get over 200*. My Idle usually goes to crap to. If I keep it cool I can break the tires in second at 35mph. I'm checking around for a opti and figure I'll change the water pump to. :rolleyes: I also got all the info on venting vs. going the timing cover route. Doing the upgrade to the old opti makes more sense to me. :yesnod:
[Modified by abigfoot, 3:51 PM 5/16/2002]
[Modified by abigfoot, 3:51 PM 5/16/2002]
Melting Slicks
Joined: May 2001
Posts: 2,143
Likes: 7
From: San Diego CA
Re: Engine miss that comes and goes... (vvv90)
I bought a Meziere (Heavy Duty) pump from Speed Demon for about $220. I've heard that Internet Racers Supply had them on sale for <$200. You'll need another fan relay or equivalent and a 20amp fuse holder. The rest of the parts are part of the Meziere kit.
The pump uses the same housing as the stock. It replaces the front cover. It's a pretty simple installation. If you decide to do it. I'll try to give you a detailed explaination. It seems to me that there is a URL that does a pretty thorough explaination, but my CRS is peaking at this point in the day.
The pump uses the same housing as the stock. It replaces the front cover. It's a pretty simple installation. If you decide to do it. I'll try to give you a detailed explaination. It seems to me that there is a URL that does a pretty thorough explaination, but my CRS is peaking at this point in the day.
Melting Slicks
Joined: May 2001
Posts: 2,143
Likes: 7
From: San Diego CA
Re: Engine miss that comes and goes... (abigfoot)
On a recent run from Barstow to Laughlin (desert country for you easterners) with ambient temps in the 90s (and at least 5 continous minutes at around 120 way:cool: ) the temps never got above 224. My normal temps around town are usually between 198-209.
The only time my temps start to climb is when my wife is hill climbing in the mountains in 2nd gear above 3000'. My theory is that the air is moving too slowly (she hates it when I say that :p: ) and there is less air.
The only time my temps start to climb is when my wife is hill climbing in the mountains in 2nd gear above 3000'. My theory is that the air is moving too slowly (she hates it when I say that :p: ) and there is less air.
