When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I would try the Deoxit first before anything though since it's so easy.
The car parts store didn't have Deoxit. I got QD Electronic Cleaner, which is made for contacts and is supposed to dry quickly (QD) and completely.
I unplugged the two X59 connectors, sprayed both ends, let them dry for ten minutes, plugged them back in, and started the car. It ran really rough and the coolant temperature sensor was no longer connected, giving me a red light on the coolant temperature gauge.
I unplugged both connectors, aimed a hot blow dryer at them for a few minutes and tried again. Same problem.
I ran the car for ten minutes idling and it started running smoother, but the temperature sensor still has a bad connection.
Inspecting both ends of both connectors, I don't see anything unusual. I'm trying to find which wire the coolant temperature sensor is now to see what I messed up. I think the car is driveable right now and I need it as it's my daily driver!
After driving the car for 20 minutes, the connection to the thermostat returned. The fact that spraying on a cleaner and reconnecting caused a bad connection suggests a reliability issue with the X59 connectors.
I got some Deoxit from Radio Shack today. I'll try it soon.
We spoke a couple of weeks ago about your misfire problem. You said it started about 2 months before, why contact us 2 months later after driving with this problem all this time? You said it's your daily driver. If the engine misfires and it's intermittent it's not a good idea to drive the car until problem is identified and fixed. Driving like this could have already caused internal damage. We have instructed you on what to do and how to look for a problem, since you are not "buying" what we advised you maybe you should have just shipped the car to us and have us look for the problem? You said you have replaced 1 sparkplug and 1 ignition coil, after that your car ran without problem for 2 weeks. This indicates it's not a mechanical problem. If the problem comes back and you kept on driving like that something inside might have already got damaged. Any good mechanic should be able to identify what is causing this problem within 2 hours tops. But I guess instead of directly contacting us when you have a problem you prefer to wait 2 months and spend money on local mechanics. Forum is not going to diagnose your problem, a good mechanic needs to see your car in person and then he will be able to tell you what the problem is. Do you diagnose your illness online when you have a health problem or do you go to a specialist? It's the same thing in this case. I could tell you what the problem is right away, but I'd have to see the car in person.
I am here to help my customers, but if they don't let me know what is going on, drive for 2 months with a problem it's not the way to solve any issues. These engines get damaged very easily, especially when something is wrong. Everyone knows driving a car with such problem is not a good idea.
Last edited by MBMotorsports; 02-11-2016 at 12:14 PM.
We spoke a couple of weeks ago about your misfire problem. You said it started about 2 months before, why contact us 2 months later after driving with this problem all this time? You said it's your daily driver. If the engine misfires and it's intermittent it's not a good idea to drive the car until problem is identified and fixed. Driving like this could have already caused internal damage. We have instructed you on what to do and how to look for a problem, since you are not "buying" what we advised you maybe you should have just shipped the car to us and have us look for the problem? You said you have replaced 1 sparkplug and 1 ignition coil, after that your car ran without problem for 2 weeks. This indicates it's not a mechanical problem. If the problem comes back and you kept on driving like that something inside might have already got damaged. Any good mechanic should be able to identify what is causing this problem within 2 hours tops. But I guess instead of directly contacting us when you have a problem you prefer to wait 2 months and spend money on local mechanics. Forum is not going to diagnose your problem, a good mechanic needs to see your can in person and then he will be able to tell you what the problem is. Do you diagnose your illness online when you have a health problem or do you go to a specialist? It's the same thing in this case. I could tell you what the problem is right away, but I'd have to see the car in person.
I am here to help my customers, but if they don't let me know what is going on, drive for 2 months with a problem it's not the way to solve any issues. These engines get damaged very easily, especially when something is wrong. Everyone knows driving a car with such problem is not a good idea.
WOW Here you are Scolding the OP and then you expect him to ship the car to you so you can try to fix it? I have the same problem I have read most of the posts when it comes to misfire incidents. I have done what I can in my garage just like the OP has, I have taken my car to 1 local Porsche dealer, several Indy mechanics and I still have the same problem, The misfire doesn't happen as often (maybe once every 2-3 months)anymore since I took an old timers advise that only cost me 4.99 at the local autozone. To the OP Good Luck !!!!
I've had this, it varied between misfiring on one or more cylinders.
Short answer, replace all spark plugs and coils.
Also a couple of weeks later a friend with the M97.2 engine had the same. We resolved both with the same remedy.
The engine builder also suggested doing this. My problem is a little different in that it's cylinder 1 giving me 99% of the misfires. I didn't see how changing the coils and plugs on cylinders 2-6 would fix misfires on cylinder 1, but a few days ago I tried this. It turned out that the coils had not been replaced when the engine was rebuilt.
After installing the new coils and plugs on the left bank (cylinders 1-3), I ran the engine for ten seconds before putting everything back together. It ran nice and smoothly. Great! Maybe the problem was solved! After putting on the new coils and plugs on the right bank, it also ran smoothly.
After putting everything back together, it ran very roughly. Jiggling the wiring going to the cylinder 1 coil did not improve things. The Durametric showed mostly cylinder 1 misfires, with a few more on cylinder 5. After a while the misfire counting stopped, but the engine was still running rough and "rough running" on the Durametric, as measuring in rotational acceleration, was still very different for cylinder 1 compared to the others.
After warming up, the rough running went away. I've seen this same pattern intermittently for a week now: Sometimes it runs roughly when cold, then gets better after warm up. Sometimes it's fine when cold, usually when I have my Durametric hooked up to see the misfires.
The engine builder also suggested doing this. My problem is a little different in that it's cylinder 1 giving me 99% of the misfires. I didn't see how changing the coils and plugs on cylinders 2-6 would fix misfires on cylinder 1, but a few days ago I tried this. It turned out that the coils had not been replaced when the engine was rebuilt.
After installing the new coils and plugs on the left bank (cylinders 1-3), I ran the engine for ten seconds before putting everything back together. It ran nice and smoothly. Great! Maybe the problem was solved! After putting on the new coils and plugs on the right bank, it also ran smoothly.
After putting everything back together, it ran very roughly. Jiggling the wiring going to the cylinder 1 coil did not improve things. The Durametric showed mostly cylinder 1 misfires, with a few more on cylinder 5. After a while the misfire counting stopped, but the engine was still running rough and "rough running" on the Durametric, as measuring in rotational acceleration, was still very different for cylinder 1 compared to the others.
After warming up, the rough running went away. I've seen this same pattern intermittently for a week now: Sometimes it runs roughly when cold, then gets better after warm up. Sometimes it's fine when cold, usually when I have my Durametric hooked up to see the misfires.
Even more circumstantial evidence to replace the MAF...
Hi Flat6 Mine is a little different too, the only misfire I get is cyl #2 NO other cyls. If I baby the car the code P0302 will not come on for weeks, but the moment I spin the tires or punch it hard from a dead stop the code P0302 will come on instantly. I have done a leak test, smoke test, changed coil and spark plug, new injector. Im running out of options so with that being said would this BDMEM 7.8 would that fix the problem and if it does where can I purchase it ? also lately ive been getting P0430 code but it only does it once in a blue moon when I fill up the tank. when I get the codes I erase them with the scan-tool. and then it never comes on again until the next fill up.
But Jake, how would a MAF problem only affect one cylinder?
Because other things come into the equation, like chamber filling thats impacted by intake characteristics. We'd all like to think that every cylinder sees the same volume and velocity of charge air, but it does not. The flow bench proves this, and pitot tubes along the intake tract further substantiate the values.
Also, if you continue to have an issue with a single cylinder, consider mechanical issues that can lead to this, even if the engine runs perfectly otherwise, and is symptomless.
Things like non- conventional bore scope evaluations, coupled to running compression tests can find these issues. Typical diagnostics won't, and neither will a "technician" that believes his scan tool is some form of electronic God. The mind must be engaged, and the engine fully understood to find some of these issues.
Re the MAF, just unplug it and see if the idle smooths out. If it does, it points strongly to a bad MAF. You can also monitor the MAF values (g/s) and voltage at warm idle. Should read ~1.3v and 14~15kg/hr when no accessories are on and idle @~700rpm.
Here are four graphs over two minutes of running just after turning on the cold engine. My Durametric software and hardware take almost a minute start taking readings, so the initial time was not recorded. Graphs and comments:
* Engine speed
* MAF, coolant temperature, oil temperature
* Misfires. Where you can't see a line, the value is zero. You can see that the misfires are on cylinder 1, at 400 to 500 (I'm guessing that this is per minute). Cylinder 5 reads 1 misfire from 0 to 17 seconds.
* Rough running. Even after the DME stops reporting misfires, I still feel the engine running rough. The rotational acceleration for cylinder 1 is way different than for the other cylinders on this graph.
02-08-2016, 12:06 AM
