94 Has a miss
Thread Starter
Burning Brakes
Joined: Sep 2004
Posts: 1,130
Likes: 19
From: Arkansas
94 Has a miss
My recently purchased 94 has started to miss, like it did for the previous owner. It ran great for a few days, but the problem has returned. At first it was intermittent, now it is constant. It seems to sound pretty good when you rev it up, but has a miss under load.
The previous owner replaced the following items:
Opti
Plugs
Wires
Coil
I have read several threads lately about cars with similar probvlems, but have not seen any solved.
I am going to check the fuel pressure, is there any way to check the egr? EGR seems to have come up a couple of times in the other threads.
Do I need to do a compression check if fuel pressure check out?
Any ideas?
Thanks in advance,
Shawn
The previous owner replaced the following items:
Opti
Plugs
Wires
Coil
I have read several threads lately about cars with similar probvlems, but have not seen any solved.
I am going to check the fuel pressure, is there any way to check the egr? EGR seems to have come up a couple of times in the other threads.
Do I need to do a compression check if fuel pressure check out?
Any ideas?
Thanks in advance,
Shawn
Le Mans Master
Joined: Dec 2004
Posts: 5,789
Likes: 8
From: Myrtle Beach SC
St. Jude Donor '05-'06
You can put a vacuum on the egr to see if it moves but more often than not it does and the intake is clogged around it. It is not that hard to take it out and shoot some carb cleaner in it. Be careful with the gasket and re install. If you replace it make sure you get the correct type. You have to unclip the black hose to get it out of the way and one bolt on it is trcky but doeable.I agree a sticky EGR can do this infact I just shot some PB blaster on my EGR shaft and eleminated my miss. Maybe coincidence but it worked. Good luck
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Defeat the underhood lights and in the dark engine idling, look for sparks along each sparkplug wire. Measure the sparkplug wire resistance, if stock, they should measure about 5000 ohms per foot. Plug wires should not touch metal and the wire looms should be in good condition.
Drifting
Joined: Jun 2010
Posts: 1,853
Likes: 8
From: Westerly RI
Defeat the underhood lights and in the dark engine idling, look for sparks along each sparkplug wire. Measure the sparkplug wire resistance, if stock, they should measure about 5000 ohms per foot. Plug wires should not touch metal and the wire looms should be in good condition.
Miss under load could well be ignition, as a weak spark or an iffy plug/wire would show up first under those conditions.
Team Owner
Joined: Oct 2000
Posts: 96,443
Likes: 9
From: Fort Knox, KY
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Thread Starter
Burning Brakes
Joined: Sep 2004
Posts: 1,130
Likes: 19
From: Arkansas
Update:
I started it up in the dark and didn't see any sparks from the wires.
Today I drove it and it ran pretty good, just a slight miss for about 5 minutes. Then it got worse an died while driving. I coasted to a parking lot and she wouldn't restart. Let it sit for a few minutes and it cranked a long time then finally started for about 2 seconds and died. Seemed like it was starving for fuel, but not sure.
SES light came on once, so I will go back later and run the codes.
Another thread talked about the ICM and coil. My coil is new, what is the ICM and where is it located?
Thanks,
Shawn
I started it up in the dark and didn't see any sparks from the wires.
Today I drove it and it ran pretty good, just a slight miss for about 5 minutes. Then it got worse an died while driving. I coasted to a parking lot and she wouldn't restart. Let it sit for a few minutes and it cranked a long time then finally started for about 2 seconds and died. Seemed like it was starving for fuel, but not sure.
SES light came on once, so I will go back later and run the codes.
Another thread talked about the ICM and coil. My coil is new, what is the ICM and where is it located?
Thanks,
Shawn
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Thread Starter
Burning Brakes
Joined: Sep 2004
Posts: 1,130
Likes: 19
From: Arkansas
Thread Starter
Burning Brakes
Joined: Sep 2004
Posts: 1,130
Likes: 19
From: Arkansas
Just used a jumper to pull codes.
It showed C 12 and H18.
I assume that it current 12 and history 18.
I can't find these codes anywhere. In my 84 it flashes 12 three times to show the beginning and end of the codes
It showed C 12 and H18.
I assume that it current 12 and history 18.
I can't find these codes anywhere. In my 84 it flashes 12 three times to show the beginning and end of the codes
Last edited by shawn 84&92; Oct 17, 2010 at 03:48 PM.
Thread Starter
Burning Brakes
Joined: Sep 2004
Posts: 1,130
Likes: 19
From: Arkansas
Symptoms from yesterday make me think there may be two different problems.
The car has a miss, but yesterday it died while driving and wouldn't restart, but a couple of hours later it started right up. A miss shouldn't cause it to die and not restart should it?
A little more history: I thought it might be a valve, but when I picked it up it ran perfect, but had been missing for the previous owner. So a valve wouldn't be bad then good than bad again. Just thinking out loud.
Pulled the fuel injector wires one at a time last night and found the number 6 didn't seem to make much differenceexcept that there was more labor knock with it removed.
The car has a miss, but yesterday it died while driving and wouldn't restart, but a couple of hours later it started right up. A miss shouldn't cause it to die and not restart should it?
A little more history: I thought it might be a valve, but when I picked it up it ran perfect, but had been missing for the previous owner. So a valve wouldn't be bad then good than bad again. Just thinking out loud.
Pulled the fuel injector wires one at a time last night and found the number 6 didn't seem to make much differenceexcept that there was more labor knock with it removed.
Drifting
Joined: Jun 2010
Posts: 1,853
Likes: 8
From: Westerly RI
Code 12 just means the engine is not running. The only thing I could find about Code 18 is that it is called out as "Crank/cam Error" but I don't know where to go with it. Someone else here will probably have this answer.
Drifting
Joined: Jun 2010
Posts: 1,853
Likes: 8
From: Westerly RI
Symptoms from yesterday make me think there may be two different problems.
The car has a miss, but yesterday it died while driving and wouldn't restart, but a couple of hours later it started right up. A miss shouldn't cause it to die and not restart should it?
A little more history: I thought it might be a valve, but when I picked it up it ran perfect, but had been missing for the previous owner. So a valve wouldn't be bad then good than bad again. Just thinking out loud.
Pulled the fuel injector wires one at a time last night and found the number 6 didn't seem to make much differenceexcept that there was more labor knock with it removed.
The car has a miss, but yesterday it died while driving and wouldn't restart, but a couple of hours later it started right up. A miss shouldn't cause it to die and not restart should it?
A little more history: I thought it might be a valve, but when I picked it up it ran perfect, but had been missing for the previous owner. So a valve wouldn't be bad then good than bad again. Just thinking out loud.
Pulled the fuel injector wires one at a time last night and found the number 6 didn't seem to make much differenceexcept that there was more labor knock with it removed.
Race Director
Joined: Jan 2002
Posts: 12,263
Likes: 86
From: O'Fallon Missouri
Ok, just did a little research. Looks like you tripped code 18 when you disconnected the injector while the car was running.
"If the injector is disconnected and the engine is started, trouble code 18 will set ."
"If the injector is disconnected and the engine is started, trouble code 18 will set ."
Last edited by STL94LT1; Oct 17, 2010 at 04:07 PM.