Gear head question

[W2VW]

I'd at least get a book and read up on OBDII.

[The Slab Bacon]

I wonder if I just pull the sensor out and plug up the hole.  It's worth a shot to see how it behaves.

Bob,
       If you pull the IAT sensor out of the hole, try to put it somewhere where it will not pick up the engines heat, or you have not accomplished anything. I like Bill's idea better.
                                             The Slab Bacon
     

[W3SLK]

Bob said:

Then there's a graph which I'll describe: At  -4 degrees F the approximate resistance is 18kohms.  At approximately 248 degrees F the resistance is 200ohms.  It's almost linear (a very slight curve) with a negative slope.

Bob you can check this out by hooking up a decade resistor box and adjusting the resitance IAW the temp curve. Some themal elements will use thermocouple wire which is pretty accurate or if there are three to four wires, it could be a RTD. The extra leads are usually compansation leads for lead length.

[W1RKW]

I found the sensor on the ass-end of the plenum.  Picture included.

I guess what I need to do is determine what the intake temp actually is once the car is warmed up.  I'll try  doing a resistance check on the sensor this weekend after a good drive to give me a rough idea of what I'm dealing with.  I can't imagine that the intake temp will actually be the ambient temp considering the curve stretches out to 250 deg F.  I don't know if coolant is sent through the plenum.  And temp will probably vary somewhat depending on throttle position too.

Mike,
The picture doesn't show it but it turns out the temp sensor only has two wires.  Very simple it looks like. 

I wonder if I just pull the sensor out and plug up the hole.  It's worth a shot to see how it behaves.

Bob,
       If you pull the IAT sensor out of the hole, try to put it somewhere where it will not pick up the engines heat, or you have not accomplished anything. I like Bill's idea better.
                                             The Slab Bacon
     

[W2JBL]

ah- i see the problem now: the engine is installed sideways.

[W1RKW]

Yeah, I know it's front wheel drive...   Can't tell that it's FWD when driving though. It's very neutral steering wise.  No torque steer whatsoever.

[W2JBL]

just a funnin' ya son...  my Ford is down on power this week with the hot humid weather. even with the hotrod flash programming etc, it's a bit off. was up on the roof of a 48 story building in Manhattan yesturday and could not see the Statue of Liberty for the smog! if you go after your problem looking for bad sensors be a ham about it- use you DVM and test the parts, instead of replacing them. and do check out the "tuner" websites. after you filter out the tons of obvious BS on them you will find a few folks who really know your car's system.fooling sensors with series resistors and voltage dividers sometimes works, but eventually gives trouble codes or bad mileage. i tried all that years ago on GM products and found the best way to go is with programming. the programmers for you car offer more tuning options than most domestic systems. you can really do a lot- and you have an excellent engine there to work with.

[W1RKW]

Hi Chris,
Yeah, I knew you were poking fun.  No problem. I'm pretty thick skinned and easy going.

I have an older Ford Ranger with a 4.0L V6 and it doesn't like the hot humid weather either and I don't think it likes this gasahol crap their peddling as gasoline. I feel like I'm dragging a block of cement at times. I load the back of that truck up during the winter with maybe 250 or so lbs of firewood for weight in the back for when it snows.  I swear the truck is much faster with all that weight during the winter than when it is unloaded during the summer.

I did a little research on reprogramming the Honda at a couple of "tuner" sites.  From what I have found the OBDII computer would actually have to be replaced with an OBDI computer in that car then reprogrammed and fitted into the car.  I'm not exactly sure what they use for the computer chip-wise in the OBDII computer but from what I understand that particular computer cannot be reflashed or reprogrammed. I don't know if I want to go down that road with retrofitting another computer in such a new car at least not just yet.  What I have considered doing though is making my own intercooler so to speak by trying one of those pelteir solidstate coolers on the intake.  The thing I don't know is if they have enough BTU's to provide constant cool air as air is being pulled across the heatsink fins. Then I would also need to deal with condensation if it did provide enough cooling.

I though I would dick around with the sensor this weekend but I found out today that I have a last minute business trip to go on this Saturday so tinkering is off the radar screen this weekend.  I've wondered what I could expect if I mess around with the sensor.  I sort of expect to get the result  you did with your tinkering with resistors and dividers.  I guess I'll find out once I get in there.

[The Slab Bacon]

Guys,
        here is one more thought to ponder. Sometimes things are not as they seem. I was thinking about this the other night and came up with another scenario.

Many of these cars have an intake air preheat stove to warm the incoming air to the engine. (Sucks hot air off of the exhaust manifold.) If the thermostatic actuator for that is stuck on, you could easily have too high intake air temp on a warm day. Thus causing the compooter to compensate for what it thinks is an extreme operating condition.

I dont know whether or not your buggy has one, but if it does it may be worth looking into. If it does, the simple pulling and plugging of 1 vacuum hose should tell the difference.
                                                The Slab Bacon

[WA1GFZ]

Bob,
I see they finally raised thge price of gas on Main St. $3.82 full service.
Maybe a selector switch under the dash for strap / normal with a series resistor in or out.  I was walking through the parking lot at work the other day and noticed many cars have black pipes. My truck is also black when I run 87 craptane. It is interesting that my truck runs fine on 87 this year but never did in the past It would ping a lot.
Maybe after 75K of mobile 1 the thing is finally broken in. I used to get best gas mileage on 89 but 87 is about the same now. 93 worked the best but went through the motor like crap through a goose. fc

[W1RKW]

SB,
I thought about that too.  Though I'm not sure this car has one.  However, I never really looked close to see if there is any plumbing that is taking heat off the engine and passing it to the intake.   If I do have one I don't think that's malfunctioning.  One thing I've noticed is the warmer it gets outside the louder the intake noise becomes which is telling me that air flow to the intake plumbing is being controlled somehow. I 'll have to look into that.

Frank,
Yes, that Sunoco in town is out of control with their gas prices.  Why they haven't gone out of business is beyond me.  I guess because they do repair work, pumping gas is secondary to them yet people do pull into have their cars filled up by an attendant.  Go figure. 

My truck has a blackened pipe too when compared to the Honda. So maybe the Honda is normal. I don't know.

When I get home from the business trip I hope to have some time to get under the hood.  My brother has a scan tool that can record outpooted data.  I'm not sure if we'll be able to discern anything by doing this but who knows.

Guys,
        here is one more thought to ponder. Sometimes things are not as they seem. I was thinking about this the other night and came up with another scenario.

Many of these cars have an intake air preheat stove to warm the incoming air to the engine. (Sucks hot air off of the exhaust manifold.) If the thermostatic actuator for that is stuck on, you could easily have too high intake air temp on a warm day. Thus causing the compooter to compensate for what it thinks is an extreme operating condition.

I dont know whether or not your buggy has one, but if it does it may be worth looking into. If it does, the simple pulling and plugging of 1 vacuum hose should tell the difference.
                                                The Slab Bacon