Diagnosing an intermittent D-Jet problem..., Hesitation under load at 2800 RPM but only when cold... |
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Diagnosing an intermittent D-Jet problem..., Hesitation under load at 2800 RPM but only when cold... |
MikeInMunich |
Oct 10 2016, 02:46 AM
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#1
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Member Group: Members Posts: 392 Joined: 19-November 13 From: Munich, Germany Member No.: 16,674 Region Association: None |
Hi again from Munich!
Here are the details. But please see update from Feb. 5th below! I have a D-Jetronic intake. Under load and at about 2800 RPM Im experiencing an intermittent hesitation. Yesterday my son and I took the car out for a drive from Munich, towards Innsbruck and back and we ran into a bit of rain coming along the Aachensee (lake), and this hesitation got worse. Then I remembered the only other time I've had this car out with 100% humidity and that it wasn't running well on that day either, so this is apparently a clue. So what can this be? And why does it happen at all, even when it's not raining, albeit not as noticeably? Is there a cure? Experts / senior gurus out there, thank you for your time and sharing your knowledge and experience, in advance! With kind regards, Mike in Munich (IMG:style_emoticons/default/smilie_flagge6.gif) |
MikeInMunich |
Jun 25 2017, 03:30 AM
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#2
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Member Group: Members Posts: 392 Joined: 19-November 13 From: Munich, Germany Member No.: 16,674 Region Association: None |
Problem solved, it was the air temp sensor!
As the hesitation was only happening in the fall, spring and then on cool nights after warm days, it was quite evident that the problem had to do with air temperature. Auto Atlanta has the part and mentions that a faulty air temp sensor can cause this symptom. Nobody had mentioned that this sensor could be the culprit, but George Hussey seems to have known so. Just sayin'. Yesterday I tested the faulty sensor with an Ohm meter. Resistance at ambient temp was within spec, but after putting it in a fridge for 20 minutes the Ohm meter registered, strangely enough, nothing at all. (IMG:style_emoticons/default/confused24.gif) Even Dr. D-jet over here was a bit bewildered and had never seen that before. I can't be 100% sure until I drive my car again while the temp is under 55 degrees F, but I presume having changed out the sensor will have solved the problem. (IMG:style_emoticons/default/smile.gif) M.i.M. (IMG:style_emoticons/default/smilie_flagge6.gif) Final word, April, 2018... Other bogging / hesitations were happening because my seemingly OK contact at the battery was sub optimal. With the volt meter sometimes fluctuating and engine subsequently bogging slightly at idle, I went back yesterday and tightened the connections firmly. This solved that problem, which may have been contributing to the problem with the slight hesitation which was occurring between 2400-2800 rpm. Despite what I had written above here, changing out the air temp sensor did not alleviate the symptom 100%, albeit oddly enough about 90-95%, seemingly. Last night it was cool and I felt the hesitation once, ever so slightly, but only while the engine was cool. After complete warm up, not at all. So there may actually be more than one culprit. I suspect that the CHT sensor may also be sub optimal / a reason for this symptom, whereby the possible solution may well be the known hack with adding resistance/ a washer or two between the sensor and head. I’m not going to do that though, since the problem seems to be just about 100% gone. |
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