Here is a challange for you tuners!

[Synned]

Okay...so I've fixed a problem that I have been having for over a year...
the problem was that whenever it was hot outside, >70* the car would run like crap.
It would hesitate, no throttle response and straight out lose power.
I don't want to say FIXED the problem, but I did band-aid the problem and get rid of it. I don't want to stay like this long term though.
What I did was replace the ACT sensor with a resistor, one that told the computer it was around 50* outside.
This completely got rid of the problem. BTW I also tried a NEW IAT to fix the problem as well- that DIDNT work.
So now I am really confused...I don't know what the computer is thinking...but with this new resistor its also harder to start the car ( which makes sense)
So I don't want to keep it like this FOREVER.
The only thing I can think of is that the wires going back to the computer maybe are shorted or have an open which changes resistance?
Any input would be great.

Joe

 

[final5-0]

IIRC, the temp that is used during start up is ECT not ACT.

It is one of those kinda deals where the mixture is a bit fat and gets leaner as time & ECT increases.

Grady

 

[Synned]

Okay, well do the ECT and ACT share ANYTHING in common, like wiring?
Its just weird now that its a hard start in the morning after this resistor.

 

[final5-0]

Okay, well do the ECT and ACT share ANYTHING in common, like wiring?
Its just weird now that its a hard start in the morning after this resistor.

I don't know for sure Joe

Seems like they should not

They are supposed to give seperate, independent outputs to the pcm and you would think they would not share the same wiring.

If you take the resistor out, does it fire up normal?

Grady

 

[Synned]

I don't know for sure Joe

Seems like they should not

They are supposed to give seperate, independent outputs to the pcm and you would think they would not share the same wiring.

If you take the resistor out, does it fire up normal?

Grady

It makes a noticable difference starting in cold conditions if I remove the resistor.

 

[blksn955.o]

If its "fixing" the seen volts so it thinks its at 50*'s you might be getting the opposite of your hot issues you had with the stock one.


Like you posted I would look at the wires with a meter to see if they are damaged. maybe hook up a kill switch to the resister to see if its repetable.

Those ACT are kinda known to go bad easy and quick compared to other sensors. At least from what I have heard. Maybe try another new one.

 

[HISSIN50]

I think I recall Don saying something about the IAT having an affect on cold starts, but it had to be about frozen-out for it to matter. Sound familiar to anyone?

I can also vouch for the extended cranking with an IAT resistor (Joe and I ran almost the same exact resistor). I removed mine a month or two ago and it was back to normal - quick fire-ups.

I also get confused with the IAT stuff. As I recall, the puter starts dumping more fuel when the IAT sees fairly low temps (around 210*F or so, IIRC), and it gets fatter as IAT temps go up. This should be good. Yet, with Joe and my high IAT readings (my IAT readings were higher than my ECT readings. . I chalk it up to the chrome CAI and heat soak), the car ran like arsh. The resistor seemed to remove some of the bog when I had driven for some time and underhood temps were high. Seems kinda counterintuitive, no?

Anyhoo, I cant help but just wanted to toss out my observations.

Good luck Joe.