Really bad Idle and one time white smoke

[Fender8024]

Hey guys question! My car is being really really weird it’s idling really bad and whenever you try to take off it dies but once the car is warm it gives you a bit of leaway and is drivable just rich and at lights a little bit of shakiness from the motor. It’s popping when it idles as well. I checked my crank harness and redid it so that part is good, did my spark plugs, did vacuum lines, cycling valve is new but the car is driving horrible! Any help would be appreciated. It’s a stock 1986 Porsche 944 turbo…………UPDATE…. Car is now struggling completely to turn on when it is cold you have to put down the gas every time if not the car just dies(never did that before). The car once running is very very rich as well and last night it also shot out a bit of white smoke right after I turned it on and drove off after that no problem because the motor was then warm but still I have never had any smoke issues ever. The first drive of the vehicle tries to buck as well for a second as if fuel is no longer there but then corrects right away. I’m at a loss and I took a couple of videos as well to upload but I can’t find how to on the website help with that would be appreciated as well

[johnb]

Hey guys question! My car is being really really weird it’s idling really bad and whenever you try to take off it dies but once the car is warm it gives you a bit of leaway and is drivable just rich and at lights a little bit of shakiness from the motor. It’s popping when it idles as well. I checked my crank harness and redid it so that part is good, did my spark plugs, did vacuum lines, cycling valve is new but the car is driving horrible! Any help would be appreciated. It’s a stock 1986 Porsche 944 turbo…………UPDATE…. Car is now struggling completely to turn on when it is cold you have to put down the gas every time if not the car just dies(never did that before). The car once running is very very rich as well and last night it also shot out a bit of white smoke right after I turned it on and drove off after that no problem because the motor was then warm but still I have never had any smoke issues ever. The first drive of the vehicle tries to buck as well for a second as if fuel is no longer there but then corrects right away. I’m at a loss and I took a couple of videos as well to upload but I can’t find how to on the website help with that would be appreciated as well

Have you checked the DME temp sensor in the block? If it's showing very high resistance (or unplugged completely) that tells the DME that the engine is cold and will cause it to run super rich.

Testing the DME temp sensor: http://www.clarks-garage.com/shop-manua ... m#dme-temp

[Tom]

How do you know it's rich?

On a hunch, pull the rubber hose off the FPR (canister at firewall end of fuel rail) and see if it smells like gas (or drips gas). If so, the FPR may be bad. Even without gas in that line, I'd test the fuel pressure.

Do you have a multimeter and know how to use it to test resistance and dc voltages? If so, I'd check the voltage on pin 7 of the DME while the motor is idling. And test the resistance of the DME temp sensor.

Have you confirmed the timing belt marks to make sure the belt hasn't jumped?

Does anything change if you disconnect the O2 sensor?

For videos, for right now, you need to host them somewhere like youtube and post the link here. They will play in the post, but we're not set up to host them locally yet.

[Tom]

Hey guys question! My car is being really really weird it’s idling really bad and whenever you try to take off it dies but once the car is warm it gives you a bit of leaway and is drivable just rich and at lights a little bit of shakiness from the motor. It’s popping when it idles as well. I checked my crank harness and redid it so that part is good, did my spark plugs, did vacuum lines, cycling valve is new but the car is driving horrible! Any help would be appreciated. It’s a stock 1986 Porsche 944 turbo…………UPDATE…. Car is now struggling completely to turn on when it is cold you have to put down the gas every time if not the car just dies(never did that before). The car once running is very very rich as well and last night it also shot out a bit of white smoke right after I turned it on and drove off after that no problem because the motor was then warm but still I have never had any smoke issues ever. The first drive of the vehicle tries to buck as well for a second as if fuel is no longer there but then corrects right away. I’m at a loss and I took a couple of videos as well to upload but I can’t find how to on the website help with that would be appreciated as well

Have you checked the DME temp sensor in the block? If it's showing very high resistance (or unplugged completely) that tells the DME that the engine is cold and will cause it to run super rich.

Testing the DME temp sensor: http://www.clarks-garage.com/shop-manua ... m#dme-temp

I think it's time for a carpokes-style test DIY for the temp sensor....

[Fender8024]

Alright so off the bat I’m going to check the DME temp sensor I do have a multimeter and have played with the DME before to test resistances and such so I’m sure it’s very similar according to Clark’s garage. For the being rich part I believe it is so becuase there’s a massive smell of gas from the inside of the car when there wasn’t before and the exhaust is a bit smellier as well plus the popping seems like unburnt fuel. To that though disconnecting the O2 sensors could be a way to check on this if the car stays the same once disconnected is that good or bad? There should be a change right as soon as you disconnect the car should run sluggish right? Speaking of O2 sensors could an old Cat be an issue? I’ll check the FPR as well I was going to switch that out regardless because I was going to do some upgrades but this stumped me a bit The timing belt is on time but I do notice it’s very flimsy so I will be doing that with the water pump as well but it hasn’t skipped.

[Tom]

Alright so off the bat I’m going to check the DME temp sensor I do have a multimeter and have played with the DME before to test resistances and such so I’m sure it’s very similar according to Clark’s garage. For the being rich part I believe it is so becuase there’s a massive smell of gas from the inside of the car when there wasn’t before and the exhaust is a bit smellier as well plus the popping seems like unburnt fuel. To that though disconnecting the O2 sensors could be a way to check on this if the car stays the same once disconnected is that good or bad? There should be a change right as soon as you disconnect the car should run sluggish right? Speaking of O2 sensors could an old Cat be an issue? I’ll check the FPR as well I was going to switch that out regardless because I was going to do some upgrades but this stumped me a bit The timing belt is on time but I do notice it’s very flimsy so I will be doing that with the water pump as well but it hasn’t skipped.

I'd still check the fuel pressure, and pin 7 on the dme. Disconnecting the O2 was just a thought in case it's pegged rich, but even that probably would explain the severity of your symptoms. Does it smell like rich exhaust or like raw gas?? Upload the video to youtube and post the link here. You can leave it 'unlisted' if you don't want it to appear on your channel...

[Fender8024]

Alright so O2 is kind of last case then! And I can do that i need to make a YouTube channel first so once that’s done I’ll share the link on the website but I’m irritated because now i try to take a video and the car is literally fine warm it’s only when it’s cold

[Tom]

Alright so O2 is kind of last case then! And I can do that i need to make a YouTube channel first so once that’s done I’ll share the link on the website but I’m irritated because now i try to take a video and the car is literally fine warm it’s only when it’s cold

I'd go through the basics first, but a friend of mine had a bad KLR that was telling the DME to run on the full-throttle maps 100% of the time. When the car was cold, it was being enriched as designed while it warmed up, and was getting extra fuel from the WOT maps, causing it to run terrible when cold but seemingly fine when warm. A bad TPS could do the same thing by constantly triggering the WOT mode. Your issues sound more severe though, but the video might help gauge that. You can also email it to me at [email protected] and I can post it later from youtube if easier...

[Tom]

Saw your video on FB and would definitely check the DME temp sensor. I'm going to make a carpokes how-to on that, but if you need help in the meantime, let us know.

[Fender8024]

Thank you so much for being on this Tom sorry I stopped responding I was just working and barely had time to catch up once I got home I spaced out the internet and just started checking everything that was mentioned….. and boy oh boy I had so much waiting for me under the hood I started checking the sensors mentioned and to my concern every harness on this vehicle needed some love from my knock sensor, tps, icv and just everything lol but I noticed one and just dug deeper and so now the intake is off and to find out the last mechanic who worked on this car ruined the vacuum like routing… I seriously don’t know how this car was running let’s just say but new harnesses are on the way and new hoses I’m excited to feel the car afterwards!


Since I do have the intake off anything you would mention to touch up or can see from the photos that need attention? Every hose for the vehicle has been ordered vacuum, fuel, and coolant and the Venturi delete as well I’m going to be cleaning all the grounds and the bay and changing the necessary harnesses but now it’s just waiting patiently for parts