97 expo dont run right

[strokin393]

If I were to do a leak down test, what would I set the gauge to and do I put motor on tdc?

 

[Racenut]

Yes you would need to put the motor on TDC of the compression stroke for every cylinder that you are testing that way you know that all of the valves are in the "closed" position.

As far as pressure, I have always used between 90 - 100 psi. Fill it up shut off the air supply and see how long it takes to drop and if it is droping quickly then try and listen to your intake, exhaust, and pcv port to see where the air is coming from ( if the leak is bad enough you may need to turn on the air supply and let it run till you can find where the air is going ).

**Note** With the pressure from this test you may need to have someone holding the harmonic balancer bolt with a socket ( the same one you use to put the motor at TDC for each cylinder ) to keep the motor from turning. As the bearings / rings get old ( high milage ) the force of the air can be enough to "turn over" the motor.

 

[strokin393]

Ok, when I go to do the compression test, do I start the truck or just turn it over? Can you give me step by step please? Thanks

 

[Racenut]

Here is a good video of How to do a Cylinder Compression Test - For the Expedition instead of trying to disable all of the coils, just pull the fuel pump fuse/relay that way you are not filling the cylinders with gasoline ( and this way it wont start ) also while you are cranking the engine over make sure you hold the gas pedal to the floor so that the engine can pull in it's maximum amount of air.

http://www.youtube.com/watch?v=X_tbksFYhl4&feature=related

And here is a good one for the Cylinder Leak Down Test - It is pretty long at 27 min, but it has all of the information that you will need.

http://www.youtube.com/user/EricTheCarGuy#p/u/23/WgrfT0LFMhc

Hope this helps out a bit! By using these two tests you should be able to find out exactly what the problem is if it is a mechanical problem.

 

[strokin393]

Here is a good video of How to do a Cylinder Compression Test - For the Expedition instead of trying to disable all of the coils, just pull the fuel pump fuse/relay that way you are not filling the cylinders with gasoline ( and this way it wont start ) also while you are cranking the engine over make sure you hold the gas pedal to the floor so that the engine can pull in it's maximum amount of air.

http://www.youtube.com/watch?v=X_tbksFYhl4&feature=related

And here is a good one for the Cylinder Leak Down Test - It is pretty long at 27 min, but it has all of the information that you will need.

http://www.youtube.com/user/EricTheCarGuy#p/u/23/WgrfT0LFMhc

Hope this helps out a bit! By using these two tests you should be able to find out exactly what the problem is if it is a mechanical problem.

So, do I take all 8 plugs out or just the 4 on the side that I want to test and how do I test the coil packs with a volt meter? Thanks

 

[Racenut]

So, do I take all 8 plugs out or just the 4 on the side that I want to test and how do I test the coil packs with a volt meter? Thanks

You can either take out all of the plugs and test every cylinder ( recomended ) or you can pull one plug at a time it will work either way.

Here is a very breif breakdown on how to test the coils:

http://www.ehow.com/how_5910271_check-coil-pack-ford-engine.html

 

[strokin393]

Just wondering if the pass side harness to the coils could be bad, not work but the driver side work if pass side don't? I don't have a way to test and see because I can't keep truck running and its just me here. Like I said b4, I had it running and it wasn't running good so I unhooked the injectors 1 by 1 to see what was going on and the whole pass side made no dif.
If I were to try and test it with a volt meter, does engine need to be running?
If I were to use a test light, the engine needs to be running, right?
I'm just trying to figure out the est and easiest way to find out if my coil packs are getting power to them before I go out buying tools and stuff. I ordered a coil tester, but it hasn't got here and I don't want to wait any loner. I thought it would only take 3 days to get here and I really didn't want to wait that long.
A friend of mine is letting me use his compression tester, so do I cut fuel off while doing this and how? Thanks for all the help
I'm sorry if I'm asking the same questions over, I'm just not thinking straight and this stuff is getting to me, I just want to get this truck fixed.

 

[Racenut]

You should be able to test the coils wiring harness with a volt meter or test light WITHOUT the vehicle running. With the key on you should have a constant 12v + the way the coils work is the computer will " pulse " the ground side of the coil to get the field to colapse causing the spark.

As far as the compression test goes. In order to shut off you fuel supply, just pull out the fuel pump RELAY from the UNDER HOOD FUSE JUNCTION BOX. This will keep the engine from starting.

 

[strokin393]

Thanks a lot for all the help

 

[strokin393]

Ok, I see that I'm getting power to that side of plug, now how do I test to see if I'm getting the pulse?