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Does anyone have any experience with the intake lettering from Jager Engineering (Garage 9)? I'm debating whether to go with that, or try to paint it by hand. I don't really trust myself with a brush, but I got a silver paint pen for the raised bits, and then someone suggested putting paint (probably red) in a big syringe and filling the inset lettering that way, which seemed like a relatively easy way to do it. I worry about the durability of the stickers, plus I think I'd have to buy two sets of the lettering which annoys me lol...
My goal for today was to get the car all put back together and running properly. I achieved half of that
It's all back together. I smoke tested it, and saw no smoke, so that's a good sign. I also jumpered the fuel pump and there were no fuel leaks, another good sign. Initially, it wouldn't start, then I realized I had disconnected vacuum from the front fuel damper to inject the smoke, and failed put it back....I don't know if that would cause a no-start, but I fixed that and it started. Rough at first, but then it smoothed out....but damn, did I NOT fix my high idle. It's "idling" at over 2K.
Now, I have no idea where my idle adjustment pot is set, but if I understand it, that's not the solution if you're this high. Something is wrong.
When it was apart, I tested the idle switch electrically, and it seemed fine. Now that it's back installed, if I manually move the throttle rod I hear the idle switch click as I would expect. It's definitely in the idle position, when it's supposed to be idling.
Actually, closer to 3K. Jumpered pins to bypass LH idle control and tried twisting the screw on the throttle body but it did nothing, really. I'm at a loss.
Another clue, FWIW. When I start it, it starts right up, and momentarily sounds like it is going to settle into a reasonable idle (VERY momentarily) before it revs up to 3K or a bit under and stays there. If I blip the throttle, it revs higher, then drops down (again, VERY briefly) to what seems like it may be a reasonable idle speed, before immediately revving up again.
I don't think it's idling at all, when it's exhibiting this "high idle." But what, other than the throttle, can make it behave this way? Because the throttle mechanism is not doing this. I once had the cruise control cable get hung up, which caused it to "idle" around 2K because it was maintaining tension and holding the throttle open....but idle never dropped momentarily...it couldn't. And the cruise cable is disconnected anyway...
My cruise control cable did something similar after the same job.
Can't idle so high without a lot of extra air coming from somewhere. Vacuum leak (ruled out?), throttle cable awry, throttle plate awry, ISV doing something wrong - I think that's the exhaustive list of sources. The behavior you just described sounds like a control problem - ISV? Hopefully someone with greater experience and knowledge will chime in.
Is there an upper limit on how high it will "idle" based purely on extra unmetered air? I would think so
Regarding the list of possibilities below, the ISV is newish...replaced within a year or so. It never really fixed the problem I had, which was a high idle (~1100) although there were some off-throttle behaviors that changed.I suspected that the hoses to the ISV were the culprit, which is why I did the intake refresh. I suppose the ISV could be bad? These are mysterious to me...I've seen where people test them off the car and they seem to work but they still end of being the root cause of a problem. If I jumper B and C on the diagnostic connector, I think that bypasses LH idle control, meaning the ISV, correct? So unless the hypothetical ISV problem is a massive leak, wouldn't that remove it as a potential cause here?
The throttle cable and throttle plate seem to be working as I would expect. When I activate manually, it feels right, clicks in the right place, etc. When it was off the car, it seemed to be working well.
Looking back at what I did, I think my smoke test was maybe a little perfunctory. Barring any other ideas, I think I'm going to do that again, as my next step.
Originally Posted by Adk46
My cruise control cable did something similar after the same job.
Can't idle so high without a lot of extra air coming from somewhere. Vacuum leak (ruled out?), throttle cable awry, throttle plate awry, ISV doing something wrong - I think that's the exhaustive list of sources. The behavior you just described sounds like a control problem - ISV? Hopefully someone with greater experience and knowledge will chime in.
I had no reason to suspect my ISV. I don't automatically consider new parts to be better than old, so I left mine in after testing and inspection. I have not yet been punished for this heresy.
Again, let's hope a real expert chimes in, but my vague notion of how idle is controlled is that the computers conspire to know RPM, and one of them delivers a corrective signal to the ISV. I think it is a pulse-width-modulation signal to a coil working against a spring, twisting the spool open. It is open a little even without a signal.
I've always wanted an oscilloscope, and just got one for no particular reason. It will actually give a measurement of a PWM signal, percent "on". It would be educational to hook it up to the ISV circuit....
A while back I would occasionally scan local classifieds looking for surplus lab equipment for cheap. I never really found anything, but this would actually be a good thing to have, I may have to resume that search.
Given than my ISV wasn't doing THIS before the refresh, I suspect. regardless of whether it's actually working properly or not, it's not causing me to have a 3K idle (I do have the old one, which was never definitively proven bad, just in case). I also didn't replace anything that's particularly functional...just hoses and stuff. Common sense dictates that whatever is wrong now, that is different from before is related to what I did. That pretty much leaves air leak or incorrect assembly. I wonder if there is anything in the vacuum routing that could conceivably cause this if hooked up wrong?
Originally Posted by Adk46
I had no reason to suspect my ISV. I don't automatically consider new parts to be better than old, so I left mine in after testing and inspection. I have not yet been punished for this heresy.
Again, let's hope a real expert chimes in, but my vague notion of how idle is controlled is that the computers conspire to know RPM, and one of them delivers a corrective signal to the ISV. I think it is a pulse-width-modulation signal to a coil working against a spring, twisting the spool open. It is open a little even without a signal.
I've always wanted an oscilloscope, and just got one for no particular reason. It will actually give a measurement of a PWM signal, percent "on". It would be educational to hook it up to the ISV circuit....
Hi Curt!
Question for point of clarity: I thought the S3 ISV signal from the LH2.2 was ON or OFF? To my knowledge, the S4 ISV signal from the LH2.3 is PWM.
The S3 ISV's wear out because they are constantly banged full wide open, then right back to full close. Over and over as required to maintain idle speed.
A stuck ISV is just that, stuck.
On the S4 ISV's, it is adjusted open or closed as required to maintain idle speed. A stuck ISV eventually causes the driver to burn out in the LH2.3. It overloads trying to move that which will not.
The S4+ ISV has a 2 pin connector, right? S3 has 3....I think it gets 12V to either side causing the little motor to slip from one side to the other.
Originally Posted by skpyle
Hi Curt!
Question for point of clarity: I thought the S3 ISV signal from the LH2.2 was ON or OFF? To my knowledge, the S4 ISV signal from the LH2.3 is PWM.
The S3 ISV's wear out because they are constantly banged full wide open, then right back to full close. Over and over as required to maintain idle speed.
A stuck ISV is just that, stuck.
On the S4 ISV's, it is adjusted open or closed as required to maintain idle speed. A stuck ISV eventually causes the driver to burn out in the LH2.3. It overloads trying to move that which will not.
Yep. S3 ISV has three pins. +12VDC fwd, common, +12VDC rvs. Motor runs to spin the valve full open, or runs the opposite direction to spin the valve full closed.
Update: I reran the smoke test on the compressor this time, and made sure plenty of smoke was in there...no obvious leaks. I've had plenty of vacuum leaks with this car, and they typically cause idle to be in the 1100-1400 range. If it's even possible for a vacuum leak to cause it to run at 3K, of which I am doubtful, then it would have to be a pretty massive leak, ie I would have seen a ton of smoke. So whatever is going on, I don't think it's a leak.
It seems so much like something mechanical with the throttle but I just don't see how. Everything seems fine with that...TPS is in the "idle position" (and btw I didn't remove the TPS from the throttle body).
05-31-2018, 02:21 PM
