87 930 Smoking/running rough

PORSCHETURBO930 · 08-11-2016, 05:00 AM

My car out of the blue on start up started running very rough and smoking from the exhaust. It has a hard time idling now. It used to run perfect. Any ideas where to start ? Thanks

flat6pilot · flat6pilot's Garage

What color is the smoke? Is it stock? Any modifications to the fuel or ignition?

PORSCHETURBO930 · 08-11-2016, 01:00 PM

Bone stock car. Bluish smoke. Smells rich.

PORSCHETURBO930 · 08-11-2016, 01:02 PM

It happened out of no where. Car has low miles.

Rawknees'Turbo · 08-11-2016, 02:20 PM

Typically, a sudden, very rich condition like you describe (smoke, rough running/idle, etc.) is due to an intake air leak. Check for simple things first - like the large rubber elbow connected to the air metering housing, but could also be an intercooler o-ring that has torn or hardened enough to leak air.

Rawknees'Turbo · 08-11-2016, 02:24 PM

Also make sure that both fuel pumps are running (pull the relays, one at a time, and see if idle changes). The rearmost realay also powers the heating element in the WUR and the Lambda O2 sensor.

PORSCHETURBO930 · 08-17-2016, 08:25 AM

I believe the car is getting way to much fuel. With the ignition on and car not running I can hear both pumps running at full speed and I think the injectors are spraying fuel ? After start up almost smells like wet fuel in exhaust pipe and runs rough. As I recall both pumps were not constant on before?

PORSCHETURBO930 · 08-18-2016, 10:29 AM

The engine is being flooded with fuel. Fuel is coming out of the exhaust. The fuel dist sounds very loud and it seems like the injectors are just spraying away. Thoughts anyone?

Rawknees'Turbo · 11:11 AM

The fuel pumps should not run with just the key on due to the safety switch on the air metering body that prevents that (switch works in conjunction with the movement of the air metering arm/disc), and the only way that fuel reaches the mechanical injectors (baring some kind of big failure in the fuel head - such as a torn/leaking diaphragm), even if the pumps are running, is if the air metering arm moves down, and moves the fuel head piston along with it (aka- if air is being drawn over the arm/disc).

So based on what you've described, the first thing I would do is remove the air cleaner housing, and see what is going on with the air metering arm/disc. I wonder if it is stuck in an "open" position? Maybe take some pics of it and post here . . .

PORSCHETURBO930 · 08-18-2016, 11:21 AM

Quote:

Originally Posted by Rawknees'Turbo

The fuel pumps should not run with just the key on due to the safety switch on the air metering body that prevents that (switch works in conjunction with the movement of the air metering arm/disc), and the only way that fuel reaches the mechanical injectors (baring some kind of big failure in the fuel head - such as a torn/leaking diaphragm), even if the pumps are running, is if the air metering arm moves down, and moves the fuel head piston along with it (aka- if air is being drawn over the arm/disc).

So based on what you've described, the first thing I would do is remove the air cleaner housing, and see what is going on with the air metering arm/disc. I wonder if it is stuck in an "open" position? Maybe take some pics of it and post here . . .

Found somebody had disconnected the switch in the back of fuel list and was causing the pumps to run non stop. I reconnected and now the pumps only run when eng is turned on.

Problem is car seems to be getting flooded with fuel when running the point where fuel is coming out of exhaust. It's like the injectors are on full flow. The sensor plate seems not to be binding and at rest.
I do notice the whole fuel list are is very loud when running. If I dis connect one of the fuel pump relays the car actually seems to run better for a few seconds and then crappy since only one pump. Also if the turn on the pumps without the eng running it seems to flood the thing out.
Thanks and open to any ideas to check

Rawknees'Turbo · 08-18-2016, 11:31 AM

Does the flooding still happen with the aircleaner removed? The reason I ask, is because in OEM set-up, if the diaphragm in the WUR (or, "control pressure regulator"), develops a tear or hole, fuel will leak out of its vent and then enter the air cleaner housing (vent is connected to airbox with small hose) and this can cause the flooding you describe.

Also, another guy here (JFairman), recently had a deal where one of his injectors was spraying constantly and it turned out that the main diaphragm in the fuel head was messed up from ethanol exposure. That's not something easy to deal with though, so before assuming that is the problem, hopefully he, or others with more CIS troubleshooting experience than I have, will see this thread and offer some "tests" you can do.

PORSCHETURBO930 · 08-18-2016, 11:43 AM

Quote:

Originally Posted by Rawknees'Turbo

Does the flooding still happen with the aircleaner removed? The reason I ask, is because in OEM set-up, if the diaphragm in the WUR (or, "control pressure regulator"), develops a tear or hole, fuel will leak out of its vent and then enter the air cleaner housing (vent is connected to airbox with small hose) and this can cause the flooding you describe.

Also, another guy here (JFairman), recently had a deal where one of his injectors was spraying constantly and it turned out that the main diaphragm in the fuel head was messed up from ethanol exposure. That's not something easy to deal with though, so before assuming that is the problem, hopefully he, or others with more CIS troubleshooting experience than I have, will see this thread and offer some "tests" you can do.

Yep that vent line from the WUR is clean and dry. I ran it without the air cleaner and same thing. It starts right up just blowing smoke and raw fuel from exhaust. This happened out the the blue. Car was running perfect.
The car is all stock no mods.

PORSCHETURBO930 · 08-18-2016, 12:53 PM

An update is that I pulled out the #6 injector and turned on the fuel pumps. The injector was not spraying fuel. When I depressed the metering plate it sprayed as it should.
I re installed and started the car and it is smoking badly and the fumes sting your eyes. Obviously running very rough.

Norm K · 08-18-2016, 01:20 PM

Have you inspected the plugs to see which are fuel-fouled?

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icemann427 · 08-18-2016, 02:30 PM

Taking it one more step from what Norm said, you most probably have some fouled plugs. Buy a new set and install them...Before you install them, though, turn the engine over for 10 seconds with NO plugs installed to get any excess fuel out of the cylinders.

If the new plugs don't make it run well, you may want to check to see if your injectors are spraying fuel, correctly.

PORSCHETURBO930 · 08-18-2016, 02:40 PM

The plugs I have in there have maybe 100 miles on them. Like I said out of the blue on start up it stated running what I think is very rich and smoking, and fuel coming wet out of exhaust. I can put new plugs in but I would imagine they would be ruined if it runs like this. I have looked at various connection for a vacuum leak but don't see any.

icemann427 · 08-18-2016, 04:01 PM

You probably either have a fuel head/injector problem or fouled plugs...Or fouled plugs because of a fuel head problem. I would change the plugs and do what I said about removing any fuel from the cylinders. Just because the plugs have 100 miles on them doesn't mean some haven't already gone bad. My .02.

PORSCHETURBO930 · 08-19-2016, 08:06 AM

Pulling the plugs and so far are looking like this...

T77911S · 08-19-2016, 10:31 AM

could be a fuel head problem as in one port is leaking fuel all the time.

there are several ways you can approach it.
you can compare plugs to see if any look worse than the others,

start it cold and run it for a minute then check the exhaust ports to see if any are colder than the others,

you can pull all the injectors and turn the key on (run the pumps) to see if any are spraying with the engine off.
or less work than above just turn the key on and run the pumps and listen to see if any injectors are spraying. (none should be).

JFairman just went thru the same thing basically. he had one port that sprayed all the time. his problem was the head but it could also be the injector.
if you find out what port is doing it, swap injectors before rebuilding the head.

it could also be rich due to a bad warm up reg. (WUR). make sure you have power to it first.

maybe even a bad plug wire. first you need to figure out if it is just one cylinder or all

PORSCHETURBO930 · 08-23-2016, 11:07 AM

Put new plugs in it and restarted had same problem.
Pulled all the injectors and left them hooked up to the lines. With the pumps running the number one injector is pouring out fuel and does not stop. Swapped injectors to #1 and still same problem. Seems like a bad fuel dist head ?