Ok... so is a IAC temp sensor really needed?

[Esasky's85GN]

Gents,

Here is my dilemma. My car does not have a IAC temp sensor installed. I have heard some people say that you need it and some people say that you dont. I have been having some issues that are making me wonder if I should install one. Here is goes...

Car runs good but seems to dump a lot of fuel. If I get on it, it puffs black smoke (not oil related) and when I start it once its shut down, it smells real rich. I also have a very bad throttle tip in stumble. MAF is reading good, BLMs seems to be off a bit when car is in closed loop. around 105 to 115. Fuel regulator set to 43 static, TPS .46 VDC. IAC @ 30 @ operating temp. Thinking that maybe not having that IAT may be throwing off my MAF readings...? Any thoughts to this.

Help is always appreciated!

For anyone who need to know mods they are listed in my signature.

Chris

 

[TurboDave]

Which are you referring to? IAC or temp sensor. IAC is Idle Air Controller, the device that controls idle rpm. Temp sensor is self explanitory.

 

[Esasky's85GN]

Sorry, meant IAT not IAC. My bad. Car just seems to be stuck @ 105 no matter what I do. Was wondering in my MAF may be shot...?

 

[turbofabricator]

You do not NEED the IAC (Idle Air Control) motor. All it does is adjust the idle RPM when the engine is cold it opens a port a little and adds more air, when the A/C is turned on it prevents the engine from stalling. YOu can leave the IAC off of the throttle body and use a cover plate that seals both sides of the ports. You just need to turn the idle adjustment screw to obtain the desired RPM. IT has no effect on tip in stumble or black smoke.
Look for a hose/vacuum leak between the MAF and intake ports. Also check the TPS sensor for proper readings at all points in the swing. You might have a flat spot in the TPS.
You DO need the IAT (intake air temp sensor) though. Some guys locate it in the intake manifold to get a more accurate reading. But I don't think it makes a whole lot of difference.

 

[turbofabricator]

Might be a bad IAT sensor. Have you tried replacing it?

 

[INEEDAGN]

Who's chip do you run? MOST modern chip burners don't use the IAT sensor. It's used only for cold fueling and I know the extender/commander chips use that chip space for other things. I don't run an IAT with my extender setup. LS1 style mafs have temp correction built into the MAF itself and don't need an external IAT sensor. Or so I've read. I'd imagine turbotweak doesn't use the IAT programming either.

 

[Esasky's85GN]

Ok. Will install IAT sensor. I didn't think IAT would effect car this bad. Thinking I could have a TB leak too. Here are other ways car is acting up:

- when car gets to operating temp, it will one of 2 things: TB blade acts like its sticking. Throttle return upon revving returns to 1500. Have to spike throttle to get to idiling RPMs. Or... rev it to like 4000, and car will stall out.

Chip is a PTE 100 octane chip. Plan on ordering a TT chip after I get these issues worked out. I can give scanmaster readings if u like...?

Car also has a slow crank restart once car is @ operating temp.

 

[Esasky's85GN]

Ok. Here are scanmaster readings. Closed loop, after about 10 mins:

O2 - 250-750
KR- 0
AF - 4
L8 - 32
BAT - 13.8
INT - 129
BL - 126
MPH - 0
CLT - 196
ATS - 71 (note, no IAT installed)
R - 775
TPS - .46
IAC - 31
cc - 236
MAL - 23 ( air temp sensor low)

I know these numbers are somewhat decent but it runs real rich. House is filled with fumes right now...

 

[Esasky's85GN]

Forgot to mention, I turned battery switch on right before I started car. Car has battery disconnect...

 

[Esasky's85GN]

Ok,

Update. Apparently, in my stupidity, I didnt realize that hot air cars never came with a IAT sensor. Johnny over at Caspers has a kit for like $40.00. I know that Eric disables the IAT readings in his chips but I am runnint a PTE 100 octane chip in my car. Not sure if they disable it or not.

Would it be worth my while to just install one or just wait until I order my chip from Eric?

your thoughts peeps?

Chris

 

[Esasky's85GN]

Update.

So I found some issues. TB shaft seal is leaking vacuum. Lots of carbon buildup on exterior of shaft behind TPS. Also found out that the person I bought the car off of pulled BOTH MAF screens. I am sure that this may have something to do with the off idle stumble as well as running a little rich @ idle.

any thoughts kids?

Chris

 

[Boost231]

get atleast one maf screen in the MAF and fix your other problems. As for the IAT sensor, install one. Its easy and its nice to have. later on down the road install the IAT in the intake and see how hot your hotair car really is

 

[Esasky's85GN]

My plan is to install both screen and IAT sensor. With my car being intercooled, would it matter where the IAT is installed?

 

[Boost231]

I think the best place is in the Intake myself. better data in the intake.

 

[Esasky's85GN]

is there an open port on our intakes that I could put it in? Seems that all the intake ports are used...

Dont really want to drill and tap...

 

[Boost231]

drill and tap is the only way. if your intake is off its easy. if not just put it at the filter.

 

[TurboDave]

You dont' really need to put it in the intake since you're using the stock computer, and chips. They don't really use the info to any degree. Put it in the intake piping somewhere between the air filter and maf as it was stock.
Another thing you need to look at (assuming you have at least a Scanmaster or some other scan tool) is to see what your IAC and TPS numbers are. If they're out of whack that can cause an off idle stumble.

 

[John Larkin]

Your car is running pretty hot. 196 is up there unless you had the a/c on. With a 160 stat mine stays about 150 - 160 a/c off with distilled water and RMI-25. EDIT - **Duh, you have a front mount, probably normal**

 

[Boost231]

You dont' really need to put it in the intake since you're using the stock computer, and chips. They don't really use the info to any degree. Put it in the intake piping somewhere between the air filter and maf as it was stock.
Another thing you need to look at (assuming you have at least a Scanmaster or some other scan tool) is to see what your IAC and TPS numbers are. If they're out of whack that can cause an off idle stumble.

i agree, but if the intake is off i would rather see intake temps more then inlet temps. yes the chip/stock computer doesn't use it in the same fashion as a XFI or BS3 but why not if the intake is off

 

[Esasky's85GN]

Guys. I have a stock computer but not a stock chip. I thought the temp was high too. Got a 160 stat...