To this day I have no answer for this and no it's not a joke. Ford, GM ect don't count this should be basic engine principles.
We had this car in our shop for about a week. Customer complained about not running right at idle but was fine driving down the road. After a few days one technician gave up on it. I got the car ran some test. Put map sensor in it.. no change. New computer no change. Compression on all four cylinders were at 170-175 with in specs. Timing looked good. Our service manager drove the car up to 100mph no problems but still ran like poop at a stop. So I decided on a cylinder leak down test. Of course we didn't have prober tool for it so we came up with our own. I thought I heard air from exhaust on cylinder 2 and air on cylinder 4. So I called another tech to listen and started running the test again when the engine locked up. He told me I was crazy until he tried. We looked down in the spark plug hole and noticed a valve. We pulled the head and amazed at what was found. 4cyl 16V. Cylinder 2 dropped both exhaust valves and one was in bedded in the top of the piston. cyl4 had dropped intake valve and beat a exhaust valve.
tech 1 8yrs, tech2 30yrs Me 6yrs and service manager 20yrs. All theroy knowledge and experience went out the window. In theory the car should have never been able to run... So If you ever here me say in theory it should do this, its because since this day I don't have much faith in theory just beleive in reality. Explain that to a customer Hello mam we found your problem. You need a new engine
Anyone else have any unexplained events? Or any thoughts on how a why it ran for as long as it did

 

That is crazy, how would something end up like that?

 

That is strange!!! It also means it could've done 200 mph if all 4 cylinders were working, instead of just 2.

Steve

 

Can you post some pics, I'd like to see this

 

an interference (sp?) engine can do this if the timing belt slips even one or 2 ribs. my brother had a tallon that had bent valves because his timing belt jumped. it wasnt as bad, but it ran like crap at idle and like a champ when moving.

 

I'm not at all surprised that it ran. Go up to a four banger and start pulling plug wires and see what happens. As for what caused the problems on the vehicle being serviced, my first reaction is customer abuse in the form of improper lubrication or a customer that flat out ran the heck out of it, redline plus, valve float, etc etc etc. Maybe she didn't do it, but a husband/kid/boyfriend did. On the slipped timing belt thought, I'd assume that you'd find that during your course of dissasembly. Any galling on the valve guides?

 

Wish I would have some pics but this happened a few months back.

You would have thought the engine would have made some noise with peices of a valve laying in it. It was easy to start. One of the valves I beleive on 4cyl was just hangin lose. We have no explaination other than timing, but why didn't it show in compression? At idle vacum was erratic but off idle stabilized. Another thought we had is we thought maybe a valve spring lock but nope. somehow the cylinder was sealing don't know the answer to that either.
Boy I got harrassed over this one for a good month

 

Well I am not a mechanic but just a thought. If you have a 4 valve per cyl engine and something jams one of the intake or exhaust valves in the seated position. the engine would still have compression and could run (probably not well) with the other valve still working, until it also dropped down and jammed everything to an abrupt halt...

 

Did you guys watch the data stream for the the fuel map? If you had a dead cyl the fuel map would show and increase of fuel to compensate for the lean 02 readings then lean out then go high again. The damage had to happen in the shop could be a by product the one of the tests run on the engine but who knows. The poor idle could have been caused by a number of things what kin of car was this? I might be able to give you somthing more definate if I you let us know make/engine. When I worked in my parents shop I seen all kinds of strange stuff but I always found out the cause, not knowing why drives me nuts.

 

If I remember right it was a grand prix. I know it was 2.4L dohc basicly a quadfour. O2 reading were with in specs. Map sensor was the only thing really out of normal range.

 

This is the sort of fault-correcting technology that will enable the machines to take over!