PROBLEM: I ran the 89 951 today, it was raining but the car ran well without a hitch. Parked it in the garage and camme back out 4 hours later to move it. It now sounds like the car is running on 3 cylinders and light gray smoke is "chuffing" out the exhaust. chuff-chuff-chuff...

Shut it down and looked under the hood. I found a thin loose line (vacuum? Breather?) so I replaced it back into the T-fitting from where it obviously came from. Started the car, no change.

Poked around the rear of the motor near the firewall and found an electrical fitting that had disentigrated due to age and heat. When I touched it the car would die. I undid the connection, which had 3 wires in it, and the connector fell apart. damn. I re-did the connection , inserting the spaded wire ends into the connector...started the car, no change. Thats going to cost all on its own.

Gave up and tried a search here...but its hard to search symptoms.

Any help appreciated. Hopefully this isn't going to cost a fortune. Just to refresh, this car is relatiely new to me. Only had it a month or so.



TIA
John

 

John ; did that 3 wire connector go down to bell housing and into a bracket or did it go to the exhaust.

 

It went to a bracket behind the intake manifold, just to the left (toward passenger side) of the oil filler cap. There is a second 3-wire connection which will probably also need replacement, directly under it in the braket.


Hope that made sense.

 

One side of the wire connection goes into a harness and into the firewall on the passenger side. The other side snakes down the firewall on the driver side and ends in, well I don'rt know what that is, but it looks more like bell housing than exhaust. heh, sorry. I can work on a Datsun fine, and the BMWs go to mechanics most of the time, this Porsche is like a mystery novel.

 

OK , lets do it this way. when the wire connector that was broken is hooked up where does the wire finally go to. ? Under the intake toward the front or down the back of the block to the bell housing into a bracket or to the exhaust pipe .

 

Its going down the back of the block. It is not going tot he exhaust.

I pulled the plug wires (checking to see if I was getting spark to all cylinders) and re-connected them. Now it sounds like I am back on all 4 cylinders, but I am still billowing gray smoke.

 

John; those are ref sensor connections everyone talks about. I would tend to them quickly and they are notorious for going bad. Sounds like your problem was in the plug wires though or a wet dist cap that dried out.

 

What about the smoke though? I am doing a search...head gasket? Its too early to tell if I am losing copious amounts of coolant (doesn't seem so) and the oil looks fine. Still afraid to drive it though...

I will do a search on the ref sensor connections.

Thanks for your help thus far..

Best
John

 

Most likely after a drive, the turbo sat for a while and with old, warn seals in the turbo, it leaked some oil in the exhaust housing. When you started it back up, the manifold heated up and began to burn the oil. It will probably go away if you drive it around (non-boost) for a while.

 

Thanks again guys. Yes, the smoke seems to be subsiding as I let the car idle longer, so hopefully you are right about the smoke Chris. However the car is back on just 3 cylinders. I am hoping its the ref sensors, but they are plugged in, so it should not be the problem. Since the car died when I found the loose connection, I know that the leads shorted themselves. Hopefully the short didn't do damage to the electronics of the car...


The hunt continues. I am going to order the ref. sensor wires and see where that gets me. Any other input though would definitely be welcome.

 

The connector is your o2 sensor - someone disconnected it because the old one was bad. If you connect a shorted o2 sensor, it shorts to fuse #34 and car dies. So he disconnected it.

Problem is that with no O2, your car runs very rich all the time and fouls the plugs and smokes. If you pull your plugs and clean them, it will run smoothly again, until they foul. You need a new O2 sensor.

 

I don't think that is the problem. I know the P.O. and he would not have disconnected anything on purpose.

Heres' the rundown: I went for a drive this morning around the neighborhood to see if the motor would burn off the white smoke. I actually though it was getting better, but when I got home and the car idled again the smole returned. I am getting coolant on the ground now toward the back of the motor. Not sure what that means just yet but at least it didn't find its way into the motor.

so far I have:

Rough Idle
White smoke from the tailpipe and some from the motor under the hood
Slight brownish foam (milkshake) on the oil filler cap. The car was driven in rain yesterday.
NO overheating
Loss of coolant from the rear of the motor. Puddle on the garage floor.

Perhaps related:
ref. sensor conector broken and needs replacement. It did short, killing the motor at idle. Twice. It is currently plugged in and the car runs.

 

Well, NEVER, EVER, EVER believe what the PO says about the car. EVER. Sorry, but look and see what you can with your own eyes and believe nothing else.

White smoke at startup is moisture in the exhaust, humid environments tend to make this show more, shows a lot in the cold here when you first start burning it off. Black/gray smoke is fuel, not coolant. Blue smoke is oil burning. If it's white under driving an hour later, it could be coolant being burned.

I tend to agree that your O2 sensor is messed up and your reference sensors may also be making the problem worse if they are going out. Also check all of the vacuum lines to make sure they are connected properly as well. Old/worn out spark plug wires, cap and rotor are also places where a problem could be coming from.

Is the oil on the dipstick milkshaky or normal? Oil in the overflow tank? If not, that is likely normal on the underside of the oil filler cap when a bit of water gets into the oil. It happens....a good drive usually can help burn it off when the oil gets hot enough.

Coolant....if it's coming from the rear of the motor, coolant hoses to the heater valve.....seems those are neglected by many people and do start to leak. I replaced all of mine, took care of the problem. It could be leaking on your exhaust causing the white smoke from under the hood that you're seeing.

When the O2 sensor isn't working, it will run rich and you may not notice much except for decreased gas mileage. Lots of countries with no cats or O2 sensors installed and the cars would run, but gas mileage was a good bit less and you would see a lot more smoke at idle.

Go over each item carefully.....replace things that are old and worn out. Be careful as there are a lot of "while you're in there items" too Even if those items aren't the direct cause of your problem, they will make the car run better and get better mileage. BTW, while doing all of this, it might be time to change the fuel filter as well back by the gas tank....

I have an armload of things I'm getting ready to do to car in the next couple of months. Luckily I have a mechanic well versed in working on these cars to do a great deal of it with me Be a loooong Saturday, but well worth it.

 

Sounds like.......head gasket. Leak between a cylinder and a coolant passage.