I don't know if anyone can help me but i am replacing my 305 for a 350. i have tranny, exhaust and some other things hooked up but what my problem is, is that i can't seem to find the plug that hooks to the air temp sensor on the bottom of the TPI plenum. I was hopeing someone could point me in the right direction to find it, for example does it come from a big coil of wires or a small. Or else just describe it as best as posssible. My car is 87 iroc-z with tune port injection.

Others may jump in, but I'll try. There is a short "Jumper" wire that plugs into the MAT sensor. The Connector on the end is the same style as the Water Temp Connector on the front of the mainfold. This short jumper wire ( about 12-15" long) then plugs into the harness back by the distributor. IIRC, it is a 2 Prong weatherpak connector.

HTH

If your already dealing with the IAT, I'd suggest doing yourself a favor and.......

Relocating the IAT properly

When I tore my engine down, the connector from the mat sensor was connected to the egr solenoid. I'm not sure if that is correct but that is the way mine was hooked up. From my understanding, the sensor tells the egr valve to open and close based on the temp from the manifold.

so in short just get a IAT from a TBI and relocate it to the intake track? I always wondered about that, think I now have a project for this weekend!

Yep. That sums it up.

My TPI IAT is still under the plenum in place. I just had the wires to it cut & extensions spliced in, to put the IAT where I wanted to.

The clip stub on the TBI one is different, but a razor blade will trim it down to fit in the TPI plug.

thanks for the info...

well I got my TBI or birdcage air sensor and hopefully plan to install it this weekend when I remove the plenum to clean out and maintenance the egr... I also got the pigtail for it, so I just plan to remove the clip from the old and splice in the "new" and seal up with shrink wrap...

hey i have a 87 iroc 350 tpi and have done alot of work on it...it runs really good and has no misfires or nothing...however after i drive my car for a litttle while or while im driving and come to a stop sign or redlight or stop...my car wants to idle down and cut off...if i dont give it gas it will bog down and shut off. i have replaced plugs, wires, cap, radiator, water pump, thermostat, fuel filter, fuel pump, fuel pump sending unit.... I have been wondering alot....i know its not getting enough air intake currently because when i rev it up it sucks in that hose a little bit in fron of the throttle body which means not enough air is flowing in i believe...but i am bout to take care of that....do u think that could be a problem...or my cadiallac converter could be causing it..... or throttle body a little clogged up..... it also seems the idle air control kicks on and it idles at about 1000 rmps it runs good idleing and isnt missing a lick but sometimes it will bog down and idle at about 600 rmps and wants to kind of cut off.....any advice please help me.....

If the hose is collapsing, either it is really weak from age/abuse, or your filter really sucks (no pun intended) and not flowing enough air, causing a suction in the intake tubing, collapsing the tubing.

If you want a better IAT setup...... IAT Relocation

other than reading accurately. what does relocation the IAT sensor do in terms of performance?

You answered your own question. Reads accurately. The TPI sensor is actually a WATER sensor, being used for the air reading.

No only is the other sensor more accurate, but it doesn't sit in a heat soaked (plenum) location. You can relocate it to a much cooler area, allowing it to read the actual AIR, not the metal plenum.

i know . but i mean whats the big advantage to it. i mean obviously it makes sense to put the sensor somewhere where its actually useful. but by my question i meant, whats the advantage other than accuracy, yes the temperature will be for the actual air but why should a person do this to their car as opposed to putting a new sensor in the stock place and call it a day? im not saying this to attack your idea, im just asking this because im really not to sure what an intake manifold air temp sensor does, other than sense the temp. in the plenum

I don't know what answer your looking for. I think I pretty much said it all. About the only other things I can think of, us ease of sensor replacement and slight mpg increase?

I had mine fail & changed it out, in the Autozone parking lot, on a hot engine. Try that with the IAT in the stock location.

I was tracking my mpg back in & noticed a 2 mpg average increase. 2mpg seems more like a variance, I know. But my average of 13-15, became 14-16. Tracking it over long term, all I can say is yes. The average mpg increased.

The mat sensor is what it is really called. Its primary function that i know is to tell the ecm when to cycle the egr valve. I'm guessing relocating it will ensure better egr operation

yeah. thats what i was interested in. that seems like a good mod then. but my other question was , what does that sensor really do in terms of what it tells the computer. does it trim fuel?

The computer uses the sensors (like the IAT) to determine how much fuel to add, how much advance/retard of the timing to apply, etc.

Kinda like being told you need a spacer to fit a 4th gen wheel, vs being told you need a 2 INCH spacer (which isn't 100% accurate, but what most people go with). Which tells you more? Make sense?

thanks for the info. i might decide on doing this mod in the future, whenever i have my plenum off.

No need to take the plenum off.

We reached under, unplugged mine, snipped the wires, spliced in longer sections of wires, then put the new IAT where I wanted it.

You'll want to leave the old IAT in place to plug the hole, or go find a pipe plug that fits those threads.

your right. probably some long needle nose will be able to reach under there