Max Miller

So I bought this car last week. P/O replaced dme sensor and relay and computer, and crank sensor. Was told it has sat for a while, so I drained the fuel and checked the strainer. It seems the P/O had already done this. So getting to the issues I'm battling; the car is misfiring and a heavy cloud is coming out of the exhaust. It is not a coolant related issue, seems more like oil smoke. So what I have done so far, drained the fuel and cleaned the strainer. Pulled the fuel rain and cleaned the injectors by running carb cleaner thru them and pulsing with a battery. I verified the pump was working and flowing a substantial amount of fuel when the rail was off. I replaced the FPR, changed the plugs. When I drained the oil there was a mix of gas and amounting to about 2.5 to 3 gallons. Prior to this I ran the car a couple times at the P/O house and a couple times on the trailer. There was a pool of thick oily residue under the muffler. I put it all back together today with fresh oil and gas and new plugs and a new FPR and the smoke persisted. Any ideas where to go next?

Max Miller

update. pulled airbox cover found an inch of oil in the airbox. seemed mostly fresh oil. cleaned that out. I tested compression, approx 150 psi across all four cylinders. I fired it up and ran it for a few minutes until it didn't want to stay running. tested compression again, less than 10psi drop across all 4 cylinders. Plugs were oily both times I pulled them, cleaned and reinstalled after comp test. not sure if I should try to run it out hoping it clears up, or if I need to address the AOS seals, or what next. would really appreciate someone chiming to help. thanks

T&T Racing

I would say the AOS seals are leaking, replace them

Max Miller

Would you think it's necessary to replace the whole air oil separator or just doing the seals would do the trick?

T&T Racing

You need to verify the condition of the AOS, look for cracks, wear where the O-rings seat, etc.

Max Miller

okay, seals are ordered. I will pull the OAS and give it a good inspection when I replace the o-rings. I think it may be worth noting that when I filled the oil it was backing up to the top of the filler tube a couple of times. I think that may warrant some over filling backup thru the AOS but I'm not sure. At this point, the car still will only run for a few minutes before she decides to quit. Should I clean and inspect the MAS. I suspect that I should check my fuel pressure and spark while its running and monitor as it starts to choke off. still misfiring, I haven't been able to isolate on which cylinders yet. I suppose I can pull of the injector wires one at time to find out, and then move the injector of the suspect cylinder to see if the misfire moves with the injector. I also would assume with the amount of oil that was in the crankcase, that the engine was pulling oil up into the intake the first few times I ran it, and the soup thats in the muffler is a combination of raw fuel and oil. Im hoping that I can clean the intake bits and plugs and try to burn some of this stuff out and see some signs of hope that I don't have any major issues. I never was able to verify IF I had a stuck open injector, or IF the FPR was bad, but was lead to assume that initially by the smoke and the gasoline in the oil, along with the volume and viscosity of the oil. I got my fingers crossed that if I can get everything cleaned up and start showing some signs of improvement.

T&T Racing

I would consult Clark Garage website. There are tests to perform to do a systematic troubleshooting process. I believe you are at that point.

If the AOS filled up, there could be a restriction in the lower connection.

Max Miller

So a day or two after I last wrote this, I started the car up for a moment just to see how it would go. Within a minute of running, the misfire quit and the engine began running as smooth as a sewing machine. It idled fantastic and reved up with a couple back fires. The smoke subsided almost entirely. 10 minutes after running and reaching full temperature, it suddenly died. It all at once cut out with no warning signs. It would not start after that. The next day I fired it up, and all previous symptoms had returned. It's worth noting that when she has sat and is cool, she fires right up, even with the misfire. On your recommendation I started doing some test thru Clark's garage. I went thru the fuel pressure tests and leak down tests, all results were right to speck. I tested for spark on all four culinders, and re checked compression. At the temp about 1/4 up the gauge I was reading approx 125 psi and 150 cold. I jumped the dme relay and I also I stalled new remanufactured injectors. The air box lid is off, so I'm sure no oil is entering the intake. I also tested for voltage at the Injector connectors. I swapped dme relays and all. So for a recap, she still is misfiring, smoking out the tail pipe, and won't start back up after running for a couple minitesu. I'm at a loss where to go next. Any help would be appreciated.

T&T Racing

I have had bad luck with remanufactured infectors. Are the remanuf injectors low impedance, high impedance do not work with 944 ECU

Next test, I would install original injectors in the fuel rail. Then place each injector in a glass container, all of identical shape and size. Engage the starter for several seconds. Then determine the volume of fuel collected in each jar. If one or more jars has significantly less fuel collected, then switch the "bad" injector with a "good" injector. Record the previous test results by measuring fuel level in each jar. Dump the fuel and then repeat the test with the switched injectors and determine and record the results. That is two sets of data.

Another test is to install the fuel rail with injectors into the intake manifold. Disconnect the J boot at its inlet. You need two people to do this test. Have all buttoned up except the inlet J boot is open with sufficient gap. One person starts the engine while the other sprays fuel into the inlet of the J boot, if the engine starts, see if it will continue to run. If not, another data point. Try to restart the engine while spraying fuel into the inlet J boot and when it fires, continue to spray fuel into the J boot to see if the engine continues to run.
Another data point.

Post results and I will respond

James Wall

Hi, I am going to be in a similar position soon. I have a 1985 Porsche 944 n/a. Are there any immediate parts that should be replaced before starting up. It has been sat for 11 years now and the brakes have locked up, assuming all of the rulers and hoses will also need replacing but no rust on the body luckily. I have read some articles saying that the timing belt should be done straight away, did you do this with yours? And if so how much did it cost?