Those plugs are wasted, they aren't the ones in the car now are they?
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Low power at low rpm's
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cchase
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Originally Posted By: Scott_Tucker
Those plugs are wasted, they aren't the ones in the car now are they?
They were replaced a few weeks ago when I pulled them. Three of them look fine, three look like the one on the left, with no tip left on the electrode.
The cameras quality is making both look different than they actually look - I suppose it's the downside of good lighting and a decent camera.
Those plugs are wasted, they aren't the ones in the car now are they?
They were replaced a few weeks ago when I pulled them. Three of them look fine, three look like the one on the left, with no tip left on the electrode.
The cameras quality is making both look different than they actually look - I suppose it's the downside of good lighting and a decent camera.
cchase
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Just an update.
I just used a multi-meter and vacuum pump to test the MAP sensor at 0, 5, 10, and 20 inches vacuum and compared values - everything there seems to be normal. It was also reporting realistic values through OBD, so I wasn't expecting much there.
I also disconnected spark plug wires briefly, one at a time. They all seemed to have the same effect - the engine started misfiring and the idle speed dropped slightly while it was unplugged. I didn't notice any kind of variation in the change, they seemed about the same everywhere.
I just used a multi-meter and vacuum pump to test the MAP sensor at 0, 5, 10, and 20 inches vacuum and compared values - everything there seems to be normal. It was also reporting realistic values through OBD, so I wasn't expecting much there.
I also disconnected spark plug wires briefly, one at a time. They all seemed to have the same effect - the engine started misfiring and the idle speed dropped slightly while it was unplugged. I didn't notice any kind of variation in the change, they seemed about the same everywhere.
cchase
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I replaced the knock sensor this afternoon, mostly because it's not that expensive of a part.
I took it out for a long drive afterwards since the weather was not that great anyway. And I noticed it is occasionally misfiring, sort of a hiccup every once in a while, on the highway. I do not believe this is connected with the knock sensor replacement, and I'm hopeful that it's connected to the source of the problem. At this point I'll gladly take being stranded on the side of the road if it means that whatever is causing the issue finally fails completely.
Any chance this is somehow fuel injector related? I still don't understand why my fuel trims look fine, but a lean misfire would at least make sense for some of the symptoms.
I took it out for a long drive afterwards since the weather was not that great anyway. And I noticed it is occasionally misfiring, sort of a hiccup every once in a while, on the highway. I do not believe this is connected with the knock sensor replacement, and I'm hopeful that it's connected to the source of the problem. At this point I'll gladly take being stranded on the side of the road if it means that whatever is causing the issue finally fails completely.
Any chance this is somehow fuel injector related? I still don't understand why my fuel trims look fine, but a lean misfire would at least make sense for some of the symptoms.
cchase
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Originally Posted By: The_Eric
Did you ever listen to all the injectors with a mechanic's stethoscope or a long screwdriver/extension?
There are a few problems with my trying this. One is that, sitting at idle, I don't think it's misfiring. So what would I be able to hear?
The other problem is that you can't actually get at the injectors - the upper intake plenum is pretty much completely in the way. I might be able to get on one but that's it.
I'm open to creative suggestions to try it, but I can't figure out so far, how to do it.
Did you ever listen to all the injectors with a mechanic's stethoscope or a long screwdriver/extension?
There are a few problems with my trying this. One is that, sitting at idle, I don't think it's misfiring. So what would I be able to hear?
The other problem is that you can't actually get at the injectors - the upper intake plenum is pretty much completely in the way. I might be able to get on one but that's it.
I'm open to creative suggestions to try it, but I can't figure out so far, how to do it.
Not necessarily. Just because you don't notice it, doesn't mean that there isn't a quantifiable issue at idle. Sometimes you can a mechanic's stethoscope under the upper intake and listen to them. One may sound just a bit different than the others- it could be plugged or sticking. The "clack" that it makes may be different. Not enough to cause perceivable issues at idle, but under load.
Alternatively you could disco the wiring harness and read the resistance of each injector via the harness connector. If you find one or two different than the others, then you have something to go by. Readings can vary hot to cold with bad injectors, so keep that in mind.
Alternatively you could disco the wiring harness and read the resistance of each injector via the harness connector. If you find one or two different than the others, then you have something to go by. Readings can vary hot to cold with bad injectors, so keep that in mind.
cchase
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I used a stethoscope on all the injectors (finally went out and splurged the $4 to buy one) this morning. It's kind of hard to tell what I should be listening for - but I could hear all of them clacking away. The only "anomaly" I really noticed was that #6 sounded like a very loud stopwatch with a noticeable "click" and #4 (the easiest to compare since it is next door) sounded more like an idling diesel truck with a loud "clack" noise, which was representative of the way most of the other 5 cylinders sounded. But having no experience trying to diagnose injectors I really don't know what to take from that. My truck's injectors have close to 390,000 miles on them and are easy to diagnose operation anyway - just remove the air filter housing and watch...
However, it is fairly hard to do direct A to B comparisons since it takes a few seconds to get to the back injectors.
I also measured the resistance of the injectors when I shut the car down. The Haynes manual says the resistance should be 11 to 14 ohms. I got ~14.3 to 14.5 ohms on all 6 of them, but the engine had just been shut off so it was hot. I'm not sure whether hot injectors have a higher or lower resistance and I am waiting to let it cool down to find out how they measure cold. I'm also uncertain as to whether them being 0.3 to 0.5 ohms high is "something" or not.
However, it is fairly hard to do direct A to B comparisons since it takes a few seconds to get to the back injectors.
I also measured the resistance of the injectors when I shut the car down. The Haynes manual says the resistance should be 11 to 14 ohms. I got ~14.3 to 14.5 ohms on all 6 of them, but the engine had just been shut off so it was hot. I'm not sure whether hot injectors have a higher or lower resistance and I am waiting to let it cool down to find out how they measure cold. I'm also uncertain as to whether them being 0.3 to 0.5 ohms high is "something" or not.
Trav would be the go to guy on the resistance specs, but IMO the small variation from spec is likely no big deal- in fact it could be your test equipment.
The key to listening to the injectors is consistency. Place the tip of the stethoscope on the same part of each injector, or they will sound different. If after doing that, you still have one that sounds muted or muffled, you may have one partially plugged or getting weak/lazy.
The key to listening to the injectors is consistency. Place the tip of the stethoscope on the same part of each injector, or they will sound different. If after doing that, you still have one that sounds muted or muffled, you may have one partially plugged or getting weak/lazy.
cchase
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Well, at any rate, when the engine cooled down the injectors all read 12.3 ohms which is within spec.
cchase
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I'm bringing this back to the light.
Since I last posted, I've replaced the 7X crankshaft position sensor and purchased one of those little Harbor Freight inline spark testers. And fully come to terms with the fact that I'm basically throwing parts at the problem.
The crankshaft position sensor looked fine but measured slightly out of spec for resistance, so I decided that for $30 it was at least worth a try. No difference, however.
The most annoying current symptom, beyond that acceleration at 3000 RPM, is the occasional misfire (or at least it feels like a misfire) while driving down the highway. Almost like the car is hiccupping.
For what it's worth, the spark tester did not show any missing spark events. And the car still starts just about instantly when you turn the key. And is returning decent (although not as good as it once was) gas mileage.
Since I last posted, I've replaced the 7X crankshaft position sensor and purchased one of those little Harbor Freight inline spark testers. And fully come to terms with the fact that I'm basically throwing parts at the problem.
The crankshaft position sensor looked fine but measured slightly out of spec for resistance, so I decided that for $30 it was at least worth a try. No difference, however.
The most annoying current symptom, beyond that acceleration at 3000 RPM, is the occasional misfire (or at least it feels like a misfire) while driving down the highway. Almost like the car is hiccupping.
For what it's worth, the spark tester did not show any missing spark events. And the car still starts just about instantly when you turn the key. And is returning decent (although not as good as it once was) gas mileage.
cchase
Thread starter
Okay, the final follow-up.
It ended up being a plugged catalytic converter. Not sure what was in the converter, looked like small whitish chunks.
Day and night improvement, power is back, gas mileage is back, no hesitation on acceleration.
It ended up being a plugged catalytic converter. Not sure what was in the converter, looked like small whitish chunks.
Day and night improvement, power is back, gas mileage is back, no hesitation on acceleration.
Originally Posted By: gregoron
Try disconnecting the battery for a minute or two to reset the ECU if that helps
While just disconnecting the battery to reboot the ECU didn't work with my situation, after I had a terrible hesitation problem on acceleration, the car idled fine, and seemed OK when cold, but as soon as the engine would reach normal operating temperature the car literally would stall when taping the gas pedal. I looked at all the obvious issues with temp sensors, distributor, rotor, cap, ect...finally I was focusing on the fuel pump. Well before I threw down 400$ for a new pump I was playing with my basic read and clear universal OBDII scan tool. I accidentally left the ignition in accessory position (not supposed to do this when plugging in the code reader to the port) and saw the reader oddly show something it shouldn't have (reseting all ECM values to factory) and it automatically proceeded. Well right after that I went to start the car and viola, no more hesitation problem. I don't know what happened but it solved the problem and that 13$ scan tool is NOT supposed to be able to do a reset of all ECM parameters to factory values. But it did, and it worked...anyone else have an experience like this? Car was a 1996 VW Golf 2L.
Try disconnecting the battery for a minute or two to reset the ECU if that helps
While just disconnecting the battery to reboot the ECU didn't work with my situation, after I had a terrible hesitation problem on acceleration, the car idled fine, and seemed OK when cold, but as soon as the engine would reach normal operating temperature the car literally would stall when taping the gas pedal. I looked at all the obvious issues with temp sensors, distributor, rotor, cap, ect...finally I was focusing on the fuel pump. Well before I threw down 400$ for a new pump I was playing with my basic read and clear universal OBDII scan tool. I accidentally left the ignition in accessory position (not supposed to do this when plugging in the code reader to the port) and saw the reader oddly show something it shouldn't have (reseting all ECM values to factory) and it automatically proceeded. Well right after that I went to start the car and viola, no more hesitation problem. I don't know what happened but it solved the problem and that 13$ scan tool is NOT supposed to be able to do a reset of all ECM parameters to factory values. But it did, and it worked...anyone else have an experience like this? Car was a 1996 VW Golf 2L.
Originally Posted By: cchase
Okay, the final follow-up.
It ended up being a plugged catalytic converter. Not sure what was in the converter, looked like small whitish chunks.
Day and night improvement, power is back, gas mileage is back, no hesitation on acceleration.
Besides the repair bill, that's great news! I'm glad you finally have an answer.
Out of curiosity, what made you replace the cat?
Okay, the final follow-up.
It ended up being a plugged catalytic converter. Not sure what was in the converter, looked like small whitish chunks.
Day and night improvement, power is back, gas mileage is back, no hesitation on acceleration.
Besides the repair bill, that's great news! I'm glad you finally have an answer.
Out of curiosity, what made you replace the cat?
How did you determine it was the cat?
cchase
Thread starter
Originally Posted By: The_Eric
Besides the repair bill, that's great news! I'm glad you finally have an answer.
Out of curiosity, what made you replace the cat?
A few months ago (I think I wrote about it in this thread) I pulled the O2 sensor out and drove around and "thought" the car seemed faster. But, I am also aware of the potentially false sense of additional power that comes from additional noise. And I was not convinced enough (particularly considering both the potential cost if I was wrong and the condition of the exhaust flange in front of the converter) to throw a converter at the problem.
After my last post here, I decided to just bring it to the local dealer and ask them to look into it. The tech, although friendly and willing to respect the work I had already done, basically told me that it felt fine to him and that another tech (whose wife supposedly has the same car) went out with him and also claimed it felt normal.
Slightly discouraged, I decided to bring it to a local mechanic. His method of diagnosis was the same as mine but he was more convinced that it felt better with the O2 sensor removed. I didn't get the feeling that he wanted to throw parts at the problem, so I trusted his judgement and told him to replace it.
He actually did a very nice job with the work. I do not typically ever bring vehicles to mechanics but I felt more comfortable having someone else make a $600 judgement call.
The difference is night and day, as I mentioned before. Based on the way it feels now, I think this repair has been due for quite some time. I'm not sure if the LIM gasket failure ~45k miles ago did the original in or what. Driving the car has gone from being a chore to being a pleasure, once again.
Besides the repair bill, that's great news! I'm glad you finally have an answer.
Out of curiosity, what made you replace the cat?
A few months ago (I think I wrote about it in this thread) I pulled the O2 sensor out and drove around and "thought" the car seemed faster. But, I am also aware of the potentially false sense of additional power that comes from additional noise. And I was not convinced enough (particularly considering both the potential cost if I was wrong and the condition of the exhaust flange in front of the converter) to throw a converter at the problem.
After my last post here, I decided to just bring it to the local dealer and ask them to look into it. The tech, although friendly and willing to respect the work I had already done, basically told me that it felt fine to him and that another tech (whose wife supposedly has the same car) went out with him and also claimed it felt normal.
Slightly discouraged, I decided to bring it to a local mechanic. His method of diagnosis was the same as mine but he was more convinced that it felt better with the O2 sensor removed. I didn't get the feeling that he wanted to throw parts at the problem, so I trusted his judgement and told him to replace it.
He actually did a very nice job with the work. I do not typically ever bring vehicles to mechanics but I felt more comfortable having someone else make a $600 judgement call.
The difference is night and day, as I mentioned before. Based on the way it feels now, I think this repair has been due for quite some time. I'm not sure if the LIM gasket failure ~45k miles ago did the original in or what. Driving the car has gone from being a chore to being a pleasure, once again.
cchase
Thread starter
I will do that - it's a good idea.
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