My First Compression Test

[MadDog]

I am so sort of proud of myself. I actually managed to do something engine related without inadvertent flames, explosions, or loss of life (knock on wood, all disclaimers apply).

A friend was kind enough to show me how to do a compression test and I tested the front 3 cylinders (passengers side to drivers side is 5-3-1, right ?) - 190, 200, 200 (all dry tests).

I looked at the back 3 plugs. I looked again. I looked from both sides of the car. I thought to myself... "seriously, Ford ? You couldnt add another 2 inches to the engine bay so I could actually see the freaking plug heads ?"

So, is the best bet to remove the hood and then do I have to remove the coil pack (is that the correct term ?) to have a decent chance of getting the rear spark plugs out ?

I did have a bit of a scare. I put the #5 plug back in, put the boot back on, and when I started the car, it idled roughly. I immediately turned it off and decided to not to panic (too much). I removed the spark plug, cleaned it and put it back in. This time it seemed to work.

Mad Dog

 

[BrApple]

the front bank passanger to driver side is 4, 5, 6.


you don't have to remove the coil pack to get to the rear plugs, but it helps. There is plenty of space to work. Just duct tape the sparkplug socket to the extension.

 

[B3NN3TT]

Put the spark plug socket on a 6-inch extension, and drop it down into the hole and onto the plug. Put a 3-inch extension on the ratchet, and use that to take the plug out. You don't have to remove ANYTHING to access the rear bank. All three plugs are perfectly clear to reach with this technique. You DO have to work blind, but everybody knows what's back there, since it's exactly the same as the front bank - just facing the other direction.

 

[blu_fuz]

I use a 1' extension when doing the rear plugs. It gets your wrench just above the wiper cowl but below the hood enough to wrench on it . Take your time and DO NOT install spark plugs into a hot motor. You could easily cross thread the spark plug holes in the heads and damage them. Antisieze on the spark plug threads is your friend.

 

[Smokinjoe]

All great info. Changing the plugs in the Contour is MUCH easier than changing plugs in the Lightning. Oh my god what a nightmare.

 

[MadDog]

How could it possibly worse ? I dont know if I can even reach my hand in to pull the boots off (short fingers). The upper manifold was apparently designed to have razor sharp, finger-biting edges. At least with the lightning, the engine bay has lots of room, being a pickup truck, right ? : )

I made sure the engine was cool (sitting overnight). I was warned about that.

Do I have to put the coil pack back on before trying to crank ? Is it grounded to the mounting points ?

Using a flashlight, I can see the piston heads. Ug. 208K miles of carbon build up.

thanks,

Mad Dog

 

[BrApple]

yes reinstall the coil pack.

It is grounded by the metal strap. The valve cover is isolated from the head by the gasket/seal.

 

[MadDog]

I think the best way to go is to remove the coil pack. However, it appears that I cant get to the rear bolts that fasten it. So, if I remove the wire and plugs form the coil pack, are there any gotchas I need to know about ?

Alternatively, maybe I need a better set of tools.

thanks,

Mad Dog

 

[BrApple]

they are very easy to get to .... I use a quarter inch ratches, short extension, swivel and socket. It not hard at all ... just don't loose track of the ground wire.

 

[MadDog]

I decided to remove the plug heads from the coil pack. I dont need any of them on while doing a compression test, right ? Will I damage anything if I dont have the plug heads on ?

Sorry for being paranoid, but this is my daily driver. If I had a second car, this process would be angst-free.

Mad Dog


Edit: wait a minute... since I unplug the master plug (electrical connector), I dont have to worry about damaging the coil pack sockets. No current goes there. Duh. Well, since I am in edit mode, it looks like the coil pack sockets have some sort of grease on them... what is this, and should I apply some when I plug them back in ?

 

[MadDog]

Finally ! I did it ! I finished the compression test on all 6 cylinders. Assuming the cylinders are
(passenger) 1-2-3 (driver)
(passenger) 4-5-6 (driver)
(front end of car)

195-200-205
190-200-200

All dry tests. I guess thats pretty good for a motor with 208K on it.

I also replaced the spark plugs which is a first for me. I was sweating bullets the whole time, just waiting for something to go really wrong. For what its worth, to get to the 3 rear sparkplugs, I removed the plugs from the coil pack. With these out of the way, I could get to sparkplugs 1 and 2. To get to #3, I had to remove the coil pack, which , as it turns out, is pretty easy. The whole unit pulls out (I had assumed it was hardwired) easily. I also did 1 sparkplug at a time, and started the car each time to make sure if something was wrong, I knew where the problem was. Advice for newbs like me, I guess.

I took a picture of one of the dirtier looking plugs. Is this telling me anything unusual ?



I wouldnt of dreamed of doing this without the great advice here, and all the car videos (Eric the Car Guy, for example) on youtube.

thanks,

Mad Dog

PS: now that I have thoroughly jinxed myself, I have a horrible feeling all 6 sparkplugs will come shooting out the engine when I drive to work tomorrow.