no compression

[SixFtUnd]

bronco not getting compression on 4 of the 5 cylinders I checked took valve cover off every thing looks like its moving correct

what could cause that and how do I diagnose it

easiest thin first HAHA


:confused: :(

[eighty3bronco]

What engine is in it?

[SixFtUnd]

351

[94Dodge Truggy]

Did you check compression with a compression tester and read 10 psi. or ? I thought you had a 302 motor in the black bronco. So the bronco will not run?

[SixFtUnd]

yeah I used a compression tester and it didn't move out of the red not enough to even register but it did move slightly

yeah I have the 351

[race4fn]

Have you checked your timing with a timing light?

If it is way off I would say your timing chain has stretched or tensioner broke.

Take the plugs out and move the crank using the bottum pulley and see if you can rotate it back and forth, and feel sloop in the chain.(as soon as it moves it should move the cam shaft and you should be able to see the lifters go up and down)Any sloop in the chain and you need to replace it.

I cant think of anything besides the timing chain that would cause more than two cylinders to loose compression.

[94Dodge Truggy]

Have you checked your timing with a timing light?

If it is way off I would say your timing chain has stretched or tensioner broke.

Take the plugs out and move the crank using the bottum pulley and see if you can rotate it back and forth, and feel sloop in the chain.(as soon as it moves it should move the cam shaft and you should be able to see the lifters go up and down)Any sloop in the chain and you need to replace it.

I cant think of anything besides the timing chain that would cause more than two cylinders to loose compression.

I agree!

[KargoMaster]

Have you checked your timing with a timing light?

If it is way off I would say your timing chain has stretched or tensioner broke.

Take the plugs out and move the crank using the bottum pulley and see if you can rotate it back and forth, and feel sloop in the chain.(as soon as it moves it should move the cam shaft and you should be able to see the lifters go up and down)Any sloop in the chain and you need to replace it.

I cant think of anything besides the timing chain that would cause more than two cylinders to loose compression.

He came over Monday... I have a light, but there's NOTHING on that pulley that resembles a timing mark... (We did adjust it, but what good without a reliable mark... I didn't see any unusual phasing of the pulley while the light was on it... which I might expect from a stretched pulley??) I'm looking at my 302 on the Jeep frame, and it's got a mark that you could cut your finger on as it comes around... Even his Haynes manual had a pic of a "typical" setup that wasn't what we were looking at.

I meant to get a socket on the crank, but forgot... :(

Hoping it's a chain issue at this point...

[race4fn]

It almost has to be the timing chain, if it was only loosing compresion in two cyl. than I would say blown head gasket, cracked head or block. But having
no compresion in more than two cyl. its the timing chain. Get new gears and double roller chain set, gasket for the water pump and timing chain.

My 79 bronco with 400m did the same thing. It killed 3 ignition modules than I replaced the chain and it was fine.

Junior

[SixFtUnd]

I think it is the Timing chain
I tore it apart tonight and the chain was very loose
the chain and gears I got fron Auto zone Look diferent so i'm not sure if I got the right thing
I was hoping to get it back up for tomorrow but not going to happen :(

defenitley better than replaceing a motor