# HB Idle



## Oldnissanguy (Jan 6, 2005)

I bought my 97 HB automatic with 190,000 miles. It idled too fast when hot. I checked the tempature with an external gage and it was correct. I cleaned the throtle body and the idle went back to normal, for a while. Then I set the idle as per the service guide and it idled normally, for a while. Now it's back to around 1200 - 1500 and I'm at a loss as to what to try next. Any ideas out there? I do notice that sometimes when I start it while it's still hot it will idle normally.


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## dvdswanson (Nov 6, 2005)

v-6 or 4 cyl?


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## Oldnissanguy (Jan 6, 2005)

2WD - 4 cyl.


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## SPEEDO (Jun 9, 2003)

I believe your problem is a "thermo element" (nissan pt# 16391-12G00) it's on the throttle body. When mine went out the idle stayed high. Replaced it and all is good...


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## Oldnissanguy (Jan 6, 2005)

The only thing I can find somewhat like that on my 97 is the EGR temperature sensor, nothing on the throttle body other than the postion sensor. Does this sound like what you replaced?


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## SPEEDO (Jun 9, 2003)

Hmmm, how to explain this.. you know where your TPS (throttle position sensor) is, the 
thermo element is on the opposite side! should be a "U" shaped bracket holding it in, if your close to a stealership give them the part number and they should be able to bring
up a picture (see if they will print it out for you) I dont believe its very hard to change on a KA motor. Or see if they have the part in stock so you can see it!
Let us know what happens...


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## Oldnissanguy (Jan 6, 2005)

Ahhhhhhh. I was looking for somthing plugged into a wire. The investigation continues. Factory service guide is rather vague on this item.


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## dougstruck (Sep 21, 2006)

I have my 91 HB in the stealership (I like that phrase) for a shift prob and idle issue. Be interesting to see what they do...I'll get back to you.


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## SPEEDO (Jun 9, 2003)

yeah... let us know!


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## Oldnissanguy (Jan 6, 2005)

There doesn't seem to be any way to attach a picture to this and I don't have a picture host site, so here goes. I don't have any kind of U shaped bolt. On the front of my throttle body is the TPS/Closed Throttle Position Switch. On the left side is the IACV-AAC valve and the IACV-FICD solenoid. On the right side is the Mass Airflow Sensor. On the right rear is a plunger device that controls the fast idle cam and appears to be setting in the coolant that flows through the TB. Is this what I'm looking for? It's the only thing left!


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## SPEEDO (Jun 9, 2003)

the thermo element controls the coolant flow for the fast idle.. sounds like you found it!


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## Oldnissanguy (Jan 6, 2005)

You had it pegged right down to the part number. Local dealer wanted $104.87 + tax. Ordered it from Pinnacle Nissan (Scottsdale) online for $73.54 shipping included. If anyone can find genuine Nissan parts cheaper than them I would be interested in knowing where.

Gee, I hope this fixes my idle.


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## Oldnissanguy (Jan 6, 2005)

Follow up: On Pinnacle's web site '16391-12G00' indicates an X-Terra fuel tempature sensor and '16391-12g00' indicates the thermo element. Beats me???


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## dougstruck (Sep 21, 2006)

*Shift probs and idle wierdness*



dougstruck said:


> I have my 91 HB in the stealership (I like that phrase) for a shift prob and idle issue. Be interesting to see what they do...I'll get back to you.


As a follow-up...turns out the braintrust that replaced the throttle position sensor rung off the set screw making it impossible to secure the TPS and adjust it correctly. Now the shift points as well as the erratic idle and wierd shifting probs when warm are gone. Hate that I spent the $$$ at the stealership, but at least it's fixed. For those of you handy enough to take care of this kind of thing yourself, maybe make a note for your files.

Thanks for all the suggestions regarding this issue. Working on my next 188k miles now.


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## SPEEDO (Jun 9, 2003)

Oldnissanguy said:


> You had it pegged right down to the part number. Local dealer wanted $104.87 + tax. Ordered it from Pinnacle Nissan (Scottsdale) online for $73.54 shipping included. If anyone can find genuine Nissan parts cheaper than them I would be interested in knowing where.
> 
> Gee, I hope this fixes my idle.


I found my reciept (ABC Nissan) list was $83.23 and they sold it to me for $62.42


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## Oldnissanguy (Jan 6, 2005)

That's close to what I paid plus the shipping, but thanks for the heads up. I'm really cheap so always looking to save a buck. I'll give them a try on my next project, whatever that turns out to be.

BTW, I tried to get on their web site. Boy does it suck. Some of the pages wouldn't come up and you can't actaully order parts. You have to send them an email telling what you want. Probably works best to just call.


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## GolfmanSpeck (Oct 4, 2006)

*Idle problems*



dougstruck said:


> As a follow-up...turns out the braintrust that replaced the throttle position sensor rung off the set screw making it impossible to secure the TPS and adjust it correctly. Now the shift points as well as the erratic idle and wierd shifting probs when warm are gone. Hate that I spent the $$$ at the stealership, but at least it's fixed. For those of you handy enough to take care of this kind of thing yourself, maybe make a note for your files.
> 
> Thanks for all the suggestions regarding this issue. Working on my next 188k miles now.


hey did the erratic idle also happen when you were at speed and take your foot of the accellerator (it makes my truck lurge forward when I apply a constant brake)? I think I have the same problem. Is that is the throttle position sensor that I need to replace?

Thank you


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## dougstruck (Sep 21, 2006)

GolfmanSpeck said:


> hey did the erratic idle also happen when you were at speed and take your foot of the accellerator (it makes my truck lurge forward when I apply a constant brake)? I think I have the same problem. Is that is the throttle position sensor that I need to replace?
> 
> Thank you



It might be worth taking a look at the TPS and making sure its not loose. Before mine was replaced (and it was loose) everytime I hit bumps or accelerated like other than an old lady, the idle would become erratic, try to shift out of gear and all kinds of stuff.


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## Oldnissanguy (Jan 6, 2005)

SPEEDO,

Part arrived yesterday. Any pointers on installing it? The pidgin english instructions that came with it are mostly clear, I think.

I was quite impressed with the spring loaded holder it came in. There must be a post installation use for that thing somewhere.


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## SPEEDO (Jun 9, 2003)

yeah, the packaging looks a little intimidating.... I havent done one on a KA motor (I have the Z24) I believe there is a bracket held in by a screw that keeps it (thermo elem) in the throttle chamber, it should just be a slide the old one out (maybe some reisistance to do vacuum) and slide the new one in!


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## Oldnissanguy (Jan 6, 2005)

Well I installed the thermo element a while back. I reset everything to factory specs and it worked OK for about a day, then back to the fast idle. I've been trying ever since to determine if there is any pattern but nothing is emerging. It does seem to idle a little slower if the heater is on (water flow probelm?) but it may be my imagination. Once in a while (very rare) it will idle properly if I start it after it's hot and has been trurned of for 10 or 15 minutes. One time I left it idling in the driveway for a few minutes and when I came back it was idling normal?

It seems that whatever I do it fixes the problem for a short period of time. It's almost like the computer is resetting itself to idle fast to compensate for any adjustments.

At this point I'm pretty much open to any more ideas.


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## Oldnissanguy (Jan 6, 2005)

Need some help here guys and gals. Any ideas?


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## GolfmanSpeck (Oct 4, 2006)

Not sure, it turns out the problem I had was a poor connection with the... I think it is called the ECR control valve. The electric connector was loose. You might check that!


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## Oldnissanguy (Jan 6, 2005)

Thanks. That gives me something else to check.


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