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> Last night I unplugged my intake temp sensor..., does that make me a bad person?
drewvw
post Jun 6 2006, 07:29 AM
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There's a current thread about hunting idle and somebody (I forgot who) mentioned that they yanked the plug on their intake temperature sensor and the car ran much better, due to the slightly richer mixture.

Well after consulting the Brad Anders d jet bible, I decided to run a little test myself. I went out for a drive with the wife, got it warmed up, and did a bunch of runs with it plugged and unplugged.

It runs fine, but it does run just a little better with the sensor unplugged.

Normally, I am not a fan of doing stuff like this but I have clamped down EVERYTHING and fought the good fight with vaccum leaks...and I've still found it runs just a tad too lean and you can't richen the mixture any other way through the throttle range right?


what do you think? In principle it feels so wrong but when the 914 and I are alone and gunning the throttle...it feels so right!!!

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good morning!
Drew
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jim_hoyland
post Jun 6 2006, 07:59 AM
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Doesn't disconnecting the temp sensor cause some cars to not run at all when hot ? Seems like this was in a previous thread.
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drewvw
post Jun 6 2006, 08:10 AM
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I think that's the CHT...this is the intake temp sensor on the plenum.

Supposedly, the ITS only has a slight effect on mixture and unplugging it causes only a slightly richer mixture, a "common mechanic's trick" as the d jet bible says...

I'm really torn about this...on one hand I hate the fact that the sensor is unplugged but on the other hand, the car does run better due to the slight adjustment.


come on people....I know you have opinions. Feel free to lambast me.
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mike_the_man
post Jun 6 2006, 08:18 AM
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This is a old trick that mechanics used to use, or so I've heard. If it runs better, then go with it. Better to run a little rich than lean. Less likely to run hot and all that bad stuff. So, if it works better, then run with it.

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drewvw
post Jun 6 2006, 08:41 AM
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That's my line of thinking right now too. While fundamentally not the best practice, I'd rather have my car running a bit too rich than a bit too lean.
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Dr Evil
post Jun 6 2006, 09:23 AM
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Are you sure the sensor was not kaput to begin with? Maybe it was too low in value all of the time causing it to be lean (opposite of infinite value and rich when unplugged).

I say; check your spark plugs before and after a period of time with it unplugged, and check your fuel economy.

If you need another sensor I think I have a good one lying around, just PM.
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drewvw
post Jun 6 2006, 11:31 AM
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yup I did consider that evil...the long term plan would be to slot a temp sensor in there and see what it does.

PM sent...
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bd1308
post Jun 6 2006, 11:35 AM
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i got somthing...

what if you got a resistor of a regular operating temp value, and see what your FI does...

b
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r_towle
post Jun 6 2006, 11:37 AM
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you missed something else.

What are the symptoms...
Have you checked your MPS, and does it hold 15kg for 5 min of vacuum?
Have you removed, cleaned, and regreased your dizzy advance plates?
Is your dwell set correctly?
Is your timing correct?

Rich
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drewvw
post Jun 6 2006, 11:43 AM
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I do need to check the MPS but the car drives and idles pretty well. Only a slight hesitation at times
(tracking down a mytivac to test the MPS)

need to do dizzy advance plates, its on the list

I have a pertronix so no dwell and the timing is dead on.

also acts worse in colder outside temperatures...which is what tipped me off to the intake temp sensor in the first place.


I'm not saying I'm done looking, just saying its running better now!
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2-OH!
post Jun 6 2006, 01:14 PM
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Told you so ...

No scarcasm meant, but It solved my problems in one swift "Unplug"...

If I had not sold the car, my next move was to slave in another sensor...The problem was how to know whether the slave was any good or if it was in the same condtion as the original...

There must be a test to check and see if the sensor is working properly...It's got to be simple...

Perhaps it's something in the ECU that does not like the sensor input anymore...Could be a burned (or tired) component in the ECU...

Does anyone know if the sensor is a situation of open or closed ???

2-OH!
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drewvw
post Jun 6 2006, 01:21 PM
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LOL....he's baaaaaack. (IMG:style_emoticons/default/biggrin.gif)
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