Testing the C-O-Ps How?

[BryanB]

After reading all the post and looking around for one I finally found a 1997 Mark VIII with (of course) everything on it. The common off white interior with a cream pear exterior. This thing is really nice!

So far the only things not working is the driver seat heat and the fuel door switch.

I did notice a miss in the engine under a moderate load and it felt like one of my other cars plugs or wires being the problem.

I replaced the plugs and 4 of the boots for the passenger side because of the common oil soak problem. It runs great until it gets warm and it started making the hiccup again every now and then. My question is how do I check the function of the coils? This can't be a hit and miss project of buying one or two and moving them from cylinder to cylinder, could it? Thanks in advance for any help!

 

[kustomizingkid]

If your other boots were ruined by oil then you need to change your valve cover gaskets or the same thing will happend again. For testing cops I just turn on the motor and unplug each cop and listen for a difference in how the engine runs.

 

[Movie Muscle]

If your other boots were ruined by oil then you need to change your valve cover gaskets or the same thing will happend again. For testing cops I just turn on the motor and unplug each cop and listen for a difference in how the engine runs.

Only problem with this is they often work at idle ,but soon as they are under load they breakdown. Plug it in to the scanner and it will give you codes for the cylinders that are not firing. You will need to disconnect the neg terminal for a few seconds to clear the codes from the boots you have already replaced . Then drive it for a while,long enough for it to pick up the codes. Providing this is your problem.

 

[Movie Muscle]

Kid is right do your rocker cover gasket or you will nuke the new boots.

 

[MatthewDavid]

Hey totally... I had the same problem... I have a 97' Mark the valve cover on the driver side is the biggest PITA I've ever seen... it's doable just have to work around the master cylinder... but yeah I went through got new boots and a couple new coils... helped a lot... but it's wierd it's got a little miss ever since the cover leaked oil... mines different now though only chugs at idle runs fine under stress... but the best way is to listen to the engine and go around and unhook the coil and listen to it... it'll change a lot if it's a good one... not so much if it's bad

 

[kustomizingkid]

Unplugging them is not ideal, but tracking a cop problem isn't fun either. I had to spend a couple hours on my 00 vic one night with a cop problem.

 

[Movie Muscle]

Often the problem is not the coil but the COP"s boot. Look for cracks and grey areas that indicate arcing. Careful not to wipe the trac marks off when you pull them out. It will look almost like light grey cigarette ash marks. I just had to do 3 boots on mine and it now runs mint. When I first got it ran rough and wouldn't make 40mph it ran so bad. If you have a dead coil a quick code check will tell you the story right away. I plugged mine in and wa la gave me all the problem cylinders, and it was just boots on all three. If a boot has been left to long it will take out the coil.

 

[Frat-man-du]

I just did plugs on a 98 LSC 105K - the boots were still perfect and not a drop of oil, except #4 had little tiny drop. I could not beleve it.

 

[kustomizingkid]

I just did plugs on a 98 LSC 105K - the boots were still perfect and not a drop of oil, except #4 had little tiny drop. I could not beleve it.

I just started working on my new motor out of a 93 with 150k on it. Pulled the wires and there isn't a single drop of oil in the plug wells, that amazed me.

 

[chicken]

ok here is "chickens COP testing method"
1) clear codes, pull neg bat cable, etc
2) go get at least 3 new boots (mainly if this is your only car)
3) drive till the check eng light comes on and get the codes pulled (that horrible place, autozone will pull them for free, just dont buy anything, have them pull the code then leave) it should be a po30X, x being what cyl # is misfiring cly # layout is 1-4 pass side and 5-8 driver side
4) heres where you might need the boots, swap whatever misfiring cly cop with a non missing cly, if your valve covers are leaking then the boots will be like oatmeal, if not then you have some spair boots, also swap the spark plug from the misfiring cly with another non missing cly
5) clear the codes again as above, get codes pulled again when the light comes back on and see where the miss moved to, if its the same cyl missing then its a mechanical, of a injector prob if the miss moved to where the cop went then its the cop

 

[BryanB]

No code - No problem!

This car was not bringing up a code & did not have a light on. I bought 4 boots to replace the ones that were even discolored. Then I bought one coil from ebay. Some one has a buy it now for less than $26.00. I started by replacing the #4 coil. Still a miss every now and then. I moved the new coil to the #3 cylinder. Success! This was the one giving problems. I may do some mods now. I have hot rodded plenty of Mopars but never a Ford. This could be fun. First item on the list is the removal of the center converter. If that does not improve the exhaust note then it will get some flowmasters. I heard one last Saturday and it sounded great! Thanks for the help.

 

[BryanB]

No code - No problem!

This car was not bringing up a code & did not have a light on. I bought 4 boots to replace the ones that were even discolored. Then I bought one coil from ebay. Some one has a buy it now for less than $26.00. I started by replacing the #4 coil. Still a miss every now and then. I moved the new coil to the #3 cylinder. Success! This was the one giving problems. I may do some mods now. I have hot rodded plenty of Mopars but never a Ford. This could be fun. First item on the list is the removal of the center converter. If that does not improve the exhaust note then it will get some flowmasters. I heard one last Saturday and it sounded great! Thanks for the help.