Compression test 01 Navigator

[Fordgirl01]

I posted in my original thread below but it’s an older post so I thought I’d start a new thread for this question.

I’m attempting to do a compression test but I’m not sure what I need to do to disable the vehicle from starting. I first found the ignition fuse and removed it. The vehicle started so I immediately shut it off. I looked at the fuse diagram again and watched some YouTube videos. I found there is a second ignition fuse so I pulled that. The videos said to remove fuel pump fuse, so I did. Now with both ignition fuses (111 and 113 I think) and the fuel pump fuse removed, it won’t even turn over.

Do I put the ignition fuses back in and just leave the fuel pump fuse out?

Persistent #8 misfire, 01 Navigator
https://r.tapatalk.com/shareLink?sh...-#8-misfire,-01-Navigator.38944/&share_type=t


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[Atman246]

My first question is why the compression test? As for the cranking without starting,the easy way,although a pain in the ass is to hook a remote starter directly to the starter. It's a momentary contact switch with large gauge wires that connects between the battery positive and the starter solenoid. Still chasing misfires?

 

[Fordgirl01]

Misfire on #8. I bought it this way and I’m just getting around to working on it. A dealer supposedly changed plugs and coils on that side, charged the former owner almost $1000, then told her it needed a new motor (probably also selling her a car in the process).


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[Atman246]

I just read the other thread. You've already got half the plugs out so just unplug the rest of the coils and remove the fuel pump fuse.You should be good to go then. Like I said in the other thread,good luck,you're doing awesome.

 

[Atman246]

I saw the number 8 plug. It looks like it's not firing at all which would lead me to think electrical. Problem is,like the one report said,fuel washing the cylinder from not firing could cause scoring on the cylinder walls or broken rings. Either means an engine teardown or replacement. Once you've done your compression test,see about having a look down in the cylinder. I have a camera /monitor for that kind of thing. Nowadays,you can get them to plug into smart phones for like 40 bucks. Handy tool. I'll try to find the link I saw.

 

[Fordgirl01]

I do have a camera-bought it when I changed plugs on my 04 and had a piece of plastic in one of the holes!!

I’ll put the ignition fuses back and leave the fuel pump fuse out and try again. Thanks and I’ll update later.


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[Atman246]

https://www.thift.co/products/endoscope

 

[Fordgirl01]

I got the tester threaded in #8 (I thought I did-it felt threaded in), put ignition fuses back in and cranked it over 5 times is so. Tester read zero. I cranked it again maybe 8-10 times and the gauge still was sitting at zero. So I decided to check the other 3. I couldn’t get the GD tester threaded into any of them so I’m thinking (hoping) it wasn’t really threaded into #8 either. I can feel it hitting the plug hole but it won’t thread in. The adapter looks to be the correct size-it’s just a cheap HF set. I’m looking for a better tester-any suggestions?

For the heck of it, I stuck the camera down on the #8 hole. I don’t really know what I’m looking for, but it looked way gunkier in there than the plug hole next to it.




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[Fordgirl01]

Am I going to need something like this? I did notice the threads on the compression tester adapter are much shorter than the plug threads. This adapter says for 04 and newer but this 01 seems to be the same as my 04 I just worked on-same plugs.




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[Atman246]

Looks like you will need the adapter. As for the pics,it's really hard to see anything other than the gunk you see. Does the camera have a light on it? Hard to tell. If you can,try bending the camera neck and have a look for the valves. If the valve is hanging down,it'll be like Moose said,possibly a broken valve spring. There was another thread in the third gens I think where the guy found that. That would be a relative easy fix if thats the case. How's the weather for this? It's hot and sticky up here. I need to work on my daughters Honda and aren't feeling too motivated.. Haahaha.

 

[Fordgirl01]

Looks like you will need the adapter. As for the pics,it's really hard to see anything other than the gunk you see. Does the camera have a light on it? Hard to tell. If you can,try bending the camera neck and have a look for the valves. If the valve is hanging down,it'll be like Moose said,possibly a broken valve spring. There was another thread in the third gens I think where the guy found that. That would be a relative easy fix if thats the case. How's the weather for this? It's hot and sticky up here. I need to work on my daughters Honda and aren't feeling too motivated.. Haahaha.

I did order the adapter-it should be here Thursday. The camera does have a light and it was on so I guess that’s as bright as it can get. I wasn’t really able to get it at any better angles but I’ll mess with it again sometime and see if I can get a better shot.

The weather is hot and sticky here too but luckily I have a garage that at least gets me out of the sun. It stays somewhat cooler in there.

Thanks for the suggestions. I’ll post again after I get the adapter.



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[TobyU]

Just get a piece or rubber hose that will fit into plug hole tightly or a screwdriver handle to act like a stopper to put against plug hole and have someone crank it.
it should only blow blow blow and forcefully. A valve (mainly rocker) problem would create a suck condition when piston goes down (if intake) or a double hard blow (if exhaust) not opening.
It's not really worth all the time and extra money (though you will use the adapter in the future) when you can just slap a new plug in there and put a known good coil on #8 and run it too see if the miss is gone. Then if it is you can pull the plug in a few miles to read it.

 

[Fordgirl01]

Normally I would just replace plug and coil to see if it fixes the misfire. But, this is the vehicle I picked up from someone who already had it at a dealer for the same problem. The plugs and coils were already replaced (at least they were supposed to be) and the misfire remained.


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[rjdelp7]

Do you have a CEL light? Does it say misfire #8 code? You are skipping the basic steps. Did you pull the valve cover and check the cam followers? They can come off.

 

[Fordgirl01]

Do you have a CEL light? Does it say misfire #8 code? You are skipping the basic steps. Did you pull the valve cover and check the cam followers? They can come off.

Yes-original post covered all of the history (CEL, #8 misfire that did not go away with plug/coil replacement). I have not yet pulled valve covers.


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[Atman246]

FordGirl,you're on the right path. A compression test is the next step. Blowing air into the cylinder wouldn't do anything unless you crank the engine to get number 8 to tdc on compression stroke. That way the valves should be closed and the cylinder is sealed. If after the compression test and you still have 0,then pulling the valve cover is the next step to look for a broken spring. Just as a side note,the cam followers falling out would only cause the valves to close,not hang open. And another side note,pulling the valve covers is a nasty task. Especially on these cause of all the accessories. Been there done that. Good luck,you go girl.

 

[Fordgirl01]

Well that’s disappointing. I finally did the compression test after borrowing someone’s kit that had an extension that actually worked (the one I ordered was too fat). I was so hoping the dealer has not bothered to change that PIA plug in the back and that’s why it was still misfiring (a gal can dream-right).

I will attach my test results. I’m assuming this is very bad[emoji3525]

Is there any hope?

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[Fordgirl01]

 

[JExpedition07]

Is this supposed to be layed out like we are looking at the front back? If so that’s not a healthy engine, generally a cylinder should be able to manage 100 psi to be considered a ‘good’ one.

 

[Fordgirl01]

That’s disappointing-it only has 115,800 miles on it.


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