Possible bent con rod with normal compression test?

What are they supposed to read.

Was more concerned with balance, but might have answered my own question, as book says between 350min and 450max @200rpm no fuel

Best do compression test again I think....

Lee

That's pretty low numbers for a diesel. Try again with the engine hot. A leakdown test might be a better way of determining whether it's engine wear or bent rods. I'm not sure why or how all four rods got bent though and apparently by exactly the same amount.

Bending all 4 seems unlikely :-) Are you sure the cam timing's right?

what engine exactly is it?

Was running perfectly before ecm shorted out, taking two injectors with it. Although timing is on the list to check again.

YD22 dci (euro 4 spec) in an X-Trail. All waveforms and sensors seem to check out and it's not throwing any codes. Rail pressure has been checked and pronounced ok.

Lee

It was running perfectly before the ecm blow-up though. Got to agree with you, and I'm thinking a bent rod was suggested because there doesn't appear to be any obvious electronic or mechanical faults anywhere else.

Lee

Forgot to add, did remove injectors and checked to see if maximumm height of each piston was the same. Which it was, as far as such a test is useful.

Lee

ignoring the compression figures, the symptoms may point at maf sensor. try running with the maf disconnected and see if it improves.

Without lifting the head it will be tricky to be totally sure, but a dynamic compression test i.e. with an amps clamp on the starter feed, and scope will clearly show if one pot is lagging behind the other 3...

If this is a VAG car, i;ve known cam lobes to spin on the shaft, as they are merely pressed on....

Tim..

Diesel "expert" who suggested bent rod clearly wasn't so expert after all... Just come back from having the new (not recon) injectors independently tested, two have excessive leak back and 1 of those also has a 0.1ms delayed injection response. Mate has had to order another two injectors and I sense a warranty argument looming....glad it's not me, as these are piezo injectors and they aren't exactly cheap :(

Lee

You still have to resolve the low compression test numbers. Either it was an invalid test because the engine was cold or there are other problems to sort. Most engine problems aren't a single fault but a combination and it's easy to forget one part of those when something obvious rears its head but turns out to be a red herring.

That's a good point. I did manage to convince him to repeat the test hot and he got 320 psi. Mate maintains that engine was running fine before and so is not at all concerned about the compression numbers, apart from them being balanced.

We shall see.... :)

Lee