Started my intake refresh...
06-15-2018, 03:51 PM
#91
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I think for me the question is between put my old one back in or buy another one. I don't think I could pull off that fix, and I don't really want to replace it multiple times.
I'm curious about what really failed, though. It seems to be passing way more air than it should, even when not under LH control.
I'm curious about what really failed, though. It seems to be passing way more air than it should, even when not under LH control.
06-15-2018, 03:54 PM
#92
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The cone shaped plastic piece is actually shown in the 3rd photo, sitting at the bottom. Notice the o-ring as well at the top, take this out and wipe it off before reassembly. I also smeared some silicone lube on the o-ring.
06-15-2018, 03:59 PM
#93
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The ISV internals are free to rotate with changes in engine vacuum (revving) when not under LH control, I noticed this when I unplugged the electrical connector with ISV still installed in the car. There's nothing to stop it from moving by itself (if it's not stuck somehow).
06-15-2018, 04:08 PM
#94
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All I can figure is that it won't work properly if the commutator and brushes are worn or rough. The electrical connections have to be good on all contacts with no increased resistance on any of them.
Also, with the diagnostic pins bridged, the ISV is still under LH control. It's supposed to close completely when doing this. That's when you adjust the idle screw on the TB, which provides minimum air for the engine to run.
Also, with the diagnostic pins bridged, the ISV is still under LH control. It's supposed to close completely when doing this. That's when you adjust the idle screw on the TB, which provides minimum air for the engine to run.
06-15-2018, 04:44 PM
#95
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Interesting. It closes when the pins are jumpered? I thought it opened. Hmm...
06-18-2018, 03:55 AM
#96
Burning Brakes
After intake refresh had idle problems.....smog test, checked for leaks changed y connector from intake to brake booster,brake booster vacuum line ... I bench tested the original isv and worked good. Idle was variable from 500 up to 2k. Changed isv with a Lowe # 51101. Never had a good idle like this, before. Theo jenniskens tool stated a steady 663 rpms idle. End of troubles.
06-18-2018, 10:12 AM
#97
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Here's hoping my intake refresh ends up the same way!
After intake refresh had idle problems.....smog test, checked for leaks changed y connector from intake to brake booster,brake booster vacuum line ... I bench tested the original isv and worked good. Idle was variable from 500 up to 2k. Changed isv with a Lowe # 51101. Never had a good idle like this, before. Theo jenniskens tool stated a steady 663 rpms idle. End of troubles.
10-03-2018, 01:40 PM
#98
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Thread Starter
So, I finished this intake refresh job a couple months ago. After some struggles with the ISV, everything seemed finally to be working. However, the following issues are happening (some intermittently) which are likely, but not definitely, connected:
- On a couple occasions (this seems to last a couple days and then clear up, at least it did the first time) the idle has been low, and there are irregular "hiccups," for want of a better word. When it's not low, you can sort of still hear it (this predates the intake refresh) but during this period of lower idle you can feel the car shudder when this happens. I don't know how to explain it...maybe I'll be able to get an audio recording of it. Once I get on the throttle, it's all good.
- When letting off the throttle (to come to a stop, for instance) the RPMs drop precipitously and dip well below the idle speed. This doesn't ALWAYS happen, but it does more often than not. This also predates the refresh but I thought the ISV would take care of it. Since the refresh, this is not usually a problem, but during the period where the first problem is occurring, it will often stall when coming to a stop. I can prevent it usually by goosing the throttle ever so slightly as the idle drops past 1000 or so, but that is a PITA.
- I seem to be losing coolant. I don't see it on the ground, I do occasionally smell it, and once when I had perhaps overfilled it, I saw steam coming from between the hood and windshield, on the passenger side, and I could hear a gurgling. I pulled the airbox, expecting possibly a leak around the heater valve or the thermoswitch (I replaced it during the refresh) but there was no obvious leak there. However things felt wet and greasy, and reaching down to the bottom of the V at the back there I came back with some of that chocolate milkshake-looking stuff which is usually coolant and oil. WTF? I cleaned the sludge out of there, although I didn't go nuts like some of you folks
I need to get my endoscope down there to see if I can see more but that thing is never as clear as I had hoped it would be. I'm concerned I may have leaks around my oil fill neck and water bridge, which will really **** me off...
Anyway, the plan is to try and get a better view into potential leaks...certainly there does not seem to be enough liquid there to account for all that has gone missing.
Regarding the first problem, am I looking at Yet Another ISV issue? I'm getting really sick of that thing... maybe I need to spring for the actual Porsche/Bosch unit after all? What a waste.. :-(
- On a couple occasions (this seems to last a couple days and then clear up, at least it did the first time) the idle has been low, and there are irregular "hiccups," for want of a better word. When it's not low, you can sort of still hear it (this predates the intake refresh) but during this period of lower idle you can feel the car shudder when this happens. I don't know how to explain it...maybe I'll be able to get an audio recording of it. Once I get on the throttle, it's all good.
- When letting off the throttle (to come to a stop, for instance) the RPMs drop precipitously and dip well below the idle speed. This doesn't ALWAYS happen, but it does more often than not. This also predates the refresh but I thought the ISV would take care of it. Since the refresh, this is not usually a problem, but during the period where the first problem is occurring, it will often stall when coming to a stop. I can prevent it usually by goosing the throttle ever so slightly as the idle drops past 1000 or so, but that is a PITA.
- I seem to be losing coolant. I don't see it on the ground, I do occasionally smell it, and once when I had perhaps overfilled it, I saw steam coming from between the hood and windshield, on the passenger side, and I could hear a gurgling. I pulled the airbox, expecting possibly a leak around the heater valve or the thermoswitch (I replaced it during the refresh) but there was no obvious leak there. However things felt wet and greasy, and reaching down to the bottom of the V at the back there I came back with some of that chocolate milkshake-looking stuff which is usually coolant and oil. WTF? I cleaned the sludge out of there, although I didn't go nuts like some of you folks
I need to get my endoscope down there to see if I can see more but that thing is never as clear as I had hoped it would be. I'm concerned I may have leaks around my oil fill neck and water bridge, which will really **** me off...Anyway, the plan is to try and get a better view into potential leaks...certainly there does not seem to be enough liquid there to account for all that has gone missing.
Regarding the first problem, am I looking at Yet Another ISV issue? I'm getting really sick of that thing... maybe I need to spring for the actual Porsche/Bosch unit after all? What a waste.. :-(