only running on 3 cylinders?

99_xc70 · Post by **99_xc70** » 15 Dec 2011, 05:40

I swapped the entire fuel rail and injectors from my other good running car, still had the same 1 and 2 cylinder not working. I did finally get a engine light on for misfire on #2. Swapped coil from #3 and drove it around the parking lot. The engine light came back on with random misfire now.

I'm going to swap all coils and plugs from the other car today and see what happens. What about limp mode, what goes on when it's stuck in limp mode? Does it shut down cylinders?

Post by **Ozark Lee** » 15 Dec 2011, 07:19

You have pretty much reached the "fool the guesser" stage. I do have a '99 XC that I bought thinking it had a bad head gasket, which it did, but it also has two broken pistons. I have never driven it so I don't have experience with limp modes. The only limp modes any of my 850s or the S70 have is with the automatic transmissions where the up arrow flashes and it is stuck in third gear. The engine computer will go into an open loop mode where it makes its best guess on fuel mixtures when various sensors fail or limit out but it still runs on all 5 cylinders.

From your postings you have made all of the correct diagnostic moves and I am stumped. The only things you need for an engine to run is compression, fuel, and spark and you seem to have all three.

The only thing that remotely comes to mind is that perhaps there is a massive leak in the intake manifold gasket at the front of the engine.

...Lee

99_xc70 · Post by **99_xc70** » 15 Dec 2011, 07:32

Yes I just came to the conclusion that maybe I have a vacuum leak in the intake manifold, either the gasket or a hose somewhere. I will swap coils anyway and check for any leaks.

99_xc70 · Post by **99_xc70** » 15 Dec 2011, 17:52

Alright so any update I guess, swapped coils from my other car and still the same dead cylinder 1 and 2.

195-200psi in both cylinders
with noid light on injector harness clip it is pulsing
I have abouth 50-55psi a the rail while running
with spark plug in coil, ground against valve cover bolt it has a good spark

With the engine running I can unplug either coil or injector to just cylinder 1 and 2, not get a change in running condition, do that the cylinder 3,4 and 5 and it stumbles and almost stalls(normal).

I pull all the brand new plugs out and cylinder 1 is wet and clean, #2 is sooty black and 3,4 and 5 are black on one side and are not soaked in fuel but are definately not buring properly. I have cleaned and checked all grounds, swapped out every part possible from my other car and do not have any change in running condition.

Just for fun though I did a charging system test and have a charging problem. It says excessive ripple under load. It also says good charging but I guess under load it's not?? Could this cause this insane almost ready for the junkyard dead cylinder problem? I'm running out of ideas? I want to swap ecu's but that involves a program relearn.

only running on 3 cylinders?

Re: only running on 3 cylinders?