I posted previously about stalling/won't idle.

I have a 2001 dodge ram 1500 laramie v8 5.2l 189k

I did a compression test and got 145 psi #2.

Then checked #4, 6, and 8 cylinders and it sounded like the engine wasn't cranking. Instead of going waa waa waa it just went waaaaaaaaaa and read 0 psi.

I checked #1 and I got 130psi.

#3 did the same as cylinders 4, 6, and 8.

#5 130psi.
#7 170psi.

I bought the truck from a guy who said the timing chain broke and he replaced it. I can get the truck to drive around the block so i find it very hard to believe that 4 of 8 cylinders are bad! It doesn't drive really well but it will drive.

Any help or suggestions? I unhooked the fuel relay and the ignition coil when I did the compression test.

it sounded like the engine wouldn't crank when i tested the cylinders with no compression.

 

If the chain actually broke, the valves may have hit the pistons and bent them. Do a cylinder leak down test. You apply air to the cylinder at TDC on the compression stroke. It tells you the % leakage and you should hear where the air is leaking. Intake, exhaust or crankcase.

 

What kind of shape is your battery ( battery cables) in? If your saying it sounded like the engine wasn't turning over, it might not have been (at speed anyway). You need to have a full charged battery to get accurate results. Did you have the throttle plate propped open when doing the test?

 

Well I think the damage is beyond a leakdown test. The engine will have to be torn apart I suppose. When the engine was running i would throttle the engine from under the hood and it sounded like suction from inside the throttle.

 

The battery showed 12.5 volts before cranking. It a newer battery. Well it sounded like it was cranking ONLY when I had the pressure gauge screwed into certain cylinders. #2, 1 ,5, and 7. It wasn't happenstance because i tested the cylinders with no compression more than once and it made the no compression sound. I guess it changed because I had that cylinder closed off with the gauge.

Could it be the plenum gasket or head gasket bad? I thought these were no interference engines.

 

And no I didn't have the throttle plate open. Was I supposed to? 4 of the cylinders got 0 compression.

 

The engine was backfiring sometimes when running before.

I just find it very hard to believe that I was driving the truck on four cylinders.

 

Cool, i wasn't sure if you meant literally zero compression, or just really low.