960 hard start, wont idle, P0301, P0300, P0304, P0305, P0306

hondamonster · Post by **hondamonster** » 03 May 2010, 15:46

I have a 1997 960 which has ran well until yesterday. My son tried to drive through a deep and long "flash flood." The car died, so I pulled it home. This morning (5/3/2010) I took the igniters off, took the plugs out to make sure there was no water in the cylinders (turned over the engine-nothing came out), checked the plugs to make sure they were firing (they were). Then put everything back together. After numerous times I finally got the engine to run, but it ran very rough (almost like the connecting rods were hitting the block) and wouldn't idle. About 1/2 - 1 pint of water came out of the tail pipe at this time. I let it set for awhile. Retried it about 30 minutes later, water was still coming out of tail pipe, drips and sputters now. Took the hoses of the air inlet off and checked inside the throttle body, it was about half full of water, so I vacuumed it out (prior to all this the air filter was removed and we cleaned out the filter "box" also). I finally crank it up again holding down of the accelerator to keep it running. When the engine got below 500 rpm the engine would die. I took it out on the road and ran about 1/2 mile out and 1/2 mile back (I realize I probably shouldn't have done that now, but its too late) still ran very rough. Ran the OBM check and found the following error codes: P0301 #1 misfire, P0300 multiple misfire etc., P0304 #4 misfire, P0305, #5 misfire, and P0306 #6 misfire. The only thing that I can think of is its possibly be out-of=time, which is fairly easy to fix, I think. But is there more problems that I don't know of? Are they fairly easy DIY fixes?

DanR · Post by **DanR** » 04 May 2010, 06:12

You may still have some water shorting out spark plugs. Take the intake duct off at the throttle body and open the throttle plate and look down and see if there is still water on the bottom of the ball shape part. Dry it off with long narrow strips of cloth. Then run the engine until it is very warm. If that doesn't help, look at the connection to the power stages, dry them out with an air blast.

Also check for a proper fitting or missing rubber hose to the idle speed motor. Impact from water splash may have dislodged it.

If it still running poorly after that, then do a compression test. If that is not right, then check timing, but I would suspect a bent valve and not mis timing, if compression is bad in one or more cylinders.

Keep us in the loop on what developes

DanR '94 964 350,000 miles (116,000 on the new engine)

hondamonster · Post by **hondamonster** » 04 May 2010, 09:44

What and where are the power stages? Where is the idle speed motor? When it comes to old cars I know how to fix them but these new ones, because of all the computers they are rough to say the least. LOL.
I took the throttle body off then took a towel and dried out the manifold. Cranked engine, this time the engine did run, somewhat, better today (5/4). It would idle @ about 1000 rpm with noise emanating from the intake side of the engine (drivers side). Could not isolate the noise though.

Post by **billofdurham** » 04 May 2010, 11:41

hondamonster, welcome to Matthew's Volvo Site.

The power stages are also called the ignition discharge modules. There are two of them, both mounted on the intake manifold, one at the front and one at the rear. The attached shows their locations.

960 engine sensors.pdf: (81.81 KiB) Downloaded 377 times

I believe the idle speed motor that DanR refers to is #7 on the attached.

Some of the codes you have pulled also mention possible damage to the catalytic converter.

Bill.

hondamonster · Post by **hondamonster** » 04 May 2010, 14:44

Okay Bill, I've found both "power stages" could those be causing the "hard knocking" sound I'm hearing. Also the engine sounds as if there is a lot of "back" pressure. Not just the knocking sound but a, lack of a better term, stuffed up. There is exhaust coming out but I wonder if there is enough. Is there a way to check the exhaust air pressure (amount of air coming out of the exhaust). The catalytic converter could be damaged.

Post by **billofdurham** » 04 May 2010, 15:35

In simple terms the power stages replace the old distributor points, opening and closing the current through the ignition coil(s). Each power stage handles 3 cylinders. I doubt if the knocking you hear is caused by the power stages.

To test the back pressure in the exhaust you need a pressure gauge. This link will take you to an article dealing with this.

Bill.

DanR · Post by **DanR** » 04 May 2010, 16:36

hondamonster wrote:What and where are the power stages? Where is the idle speed motor? When it comes to old cars I know how to fix them but these new ones, because of all the computers they are rough to say the least. LOL.
I took the throttle body off then took a towel and dried out the manifold. Cranked engine, this time the engine did run, somewhat, better today (5/4). It would idle @ about 1000 rpm with noise emanating from the intake side of the engine (drivers side). Could not isolate the noise though.

So there was water still in the intake manifold, I know if the engine is running on three cylinders, it will make quite a racket, and sound as though it will be throwing a piston. Check the rubber intake for any splits, have you checked for the idle valve motor hose? If that is missing all you will hear is an loud rushing air sound.

Rather than check for exhaust pressure, it would be easier and more enlightening to do a compression test, if you need a gauge, the auto parts stores will loan them free with a deposit.

Prepare for the worst though, it very well may have damaged so valves.

DanR