ACT + Warm weather (AGAIN)

[Synned]

So do you guys remember my threads last year about the problem I have with my stupid ACT sensor? It's back...right on time with the 70-80* weather

If you don't remember, I have this problem. Whenever my car is in hot weather, it runs like complete ****. Feels like I lose 4 cylinders, hesitation, bog on take off, etc.

Last year I *patched* the problem by replacing my ACT sensor with a resistor, tricking the computer. The weird problem is, simply replacing the ACT didn't do a thing. So as soon as the sluggishness started to come back (today it was really noticable) I drove right over to Radioshack to pick up a 47K OHM resistor. It instantly made a difference in the car, and I didn't even reset the computer.
I'm not even talking a 5hp difference, I'm talking more the difference between having stock gears and throwing 4:10's in

Now from what I've read from the real smart guys, the ACT can barely touch timing, maybe 3-5 degrees at the most. But it CAN affect fuel, injector pulse-width etc.
I also started getting into this: http://www.usnaaaa.com/pingisgone.pdf
But it gets a little over my head.
I'm just wondering if theres anyone out there that can explain this for me. Maybe the ACT wire is open/grounded on the way to the computer.

Thanks guys,
Joe

 

[HISSIN50]

Joe, I cannot get the PDF to open for me. If there's one certain part that's of interest, can you post an excerpt?

If you wanna see what the puter sees, either put your meter on the ACT pin at the puter (it's something like pin 25). Or if you can see PIDs, just see what the scanner shows you.

Good luck bud.

 

[final5-0]

Joe

Yes ... the act can do a + or - thing with fuel and spark

But ... the same thing can happen with ect as well

Of the 4 main pcm's our cars use ........

More of that goes on with GT stick and auto Stangs ... 3 out of 4 pcms btw
and
The least of it happens with the Cobra Stangs

Grady

 

[Synned]

But the thing is, if it was just the PCM at fault, why would my car be such a freak?
This can't be programmed into the stock tune to make it run this ****ty under these conditions, its just toooo bad.
It's gotta be something causing it...but what? I'm going to play with different resistor values to see what happens...I'm just curious. I remember last year when I put a 3.3K in by mistake, it ran almost exactly the same. Thats around 200* or something if I remember correctly.

JT: Would I put one end of the meter on pin 25 on the computer, what about the other lead? Back at the ACT?

Thanks guys
Joe

 

[HISSIN50]

Joe, you'd ground the other meter lead. You're just checking what the voltage reading of the sensor is. Look for ~0.60V at ~195*F or ~3.0 volts at ~70*F.

Joe, I do know what you mean - the AODE's seem to get real funky with high ACT's, though nothing on paper suggests the ACT has that much effect [that I recall].
In addition, didnt Don or Grady say that fuel is actually added when ACT temps get real hot? I thought so (I recall that something was counterintuitive to the issue we saw). Then the risk is that without the compensation (less timing, more fuel with higher ACT temps) while running a resistor, could that cause issues.

I'm considering doing a different inlet (chrome right now) to see if it helps. Joe, is your CAI chrome? Is the air filter in the fenderwell?

Good luck bud.

 

[final5-0]

OK Guys

Now that I look at this stuff, I remember you two talking about doing that
mod to the act plug

I guess this not just a case of only Joe seeing the power fade away as the
temps climb

I guess I could look later when I got more time to see what all the act temp
works with but I do know without looking, it hoses with more stuff on the
non Cobra pcm's

Grady

 

[MLC Stang]

Synned,

I'm another one who has had a hot weather pinging issue on and off for as long as I can remember. Now that it's back in the 80s in Atlanta again, its back!

I too tried to cure it with ACT replacement. It works for a while and then the computer seems to learn its way back to lean mixtures at high ambient temps! I have never been able to get it to go away and stay away. Driving home yesterday at 5:00pm in 85 degrees, she pinged like a bee-atch when I got on it full throttle. Driving to work this morning in nice cool (60 degree) dense air, I couldn't make it ping. Pulls noticeably harder in that type of outside air.

HISSIN50, I'm the guy who posted the info at http://www.usnaaaa.com/pingisgone.pdf It's ten pages out of the Charles Probst book on ACT and ECT operation and testing. I just checked it on my web site and it is loading properly now. Try again and you should get it.

I am now trying to track down a high resistance problem in the wiring from the ACT to the PCM. All I've done so far is to test the resistance in the short wiring harness from the ACT to the round connector that connects at the fenderwell. I suspected that portion of the wiring since it gets pulled on and off a lot with just routine maintenance/changing air filter, etc. It would make sense to me that this piece of wiring harness would get a lot of bending and flexing and maybe have some damaged wires inside the harness somewhere. But, mine seems to read OK.

What I need to check is the resistance all the way to the PCM. I'm not quite sure how to do that.

Sure would like to solve this permanently! It's the only complaint that I have ever had about my car.

 

[Synned]

Joe, you'd ground the other meter lead. You're just checking what the voltage reading of the sensor is. Look for ~0.60V at ~195*F or ~3.0 volts at ~70*F.
In addition, didnt Don or Grady say that fuel is actually added when ACT temps get real hot? I thought so (I recall that something was counterintuitive to the issue we saw). Then the risk is that without the compensation (less timing, more fuel with higher ACT temps) while running a resistor, could that cause issues.

I'm considering doing a different inlet (chrome right now) to see if it helps. Joe, is your CAI chrome? Is the air filter in the fenderwell?

Okay, got it. And if I wanted to check resistance, could I do it straight from that pin back to the other pin on the ACT?

And I do remember reading waaaay back...that fuel is affected more than spark.
What if theres an open on the wire on the way to the computer...does that greatly affect resistance? Or would just a ground?
As for my inlet, it used to be the stock rubber box, now its a powdercoated aluminum cai that I'm sure gets way hotter. I'm replacing it with the stock piece

I am now trying to track down a high resistance problem in the wiring from the ACT to the PCM. All I've done so far is to test the resistance in the short wiring harness from the ACT to the round connector that connects at the fenderwell. I suspected that portion of the wiring since it gets pulled on and off a lot with just routine maintenance/changing air filter, etc. It would make sense to me that this piece of wiring harness would get a lot of bending and flexing and maybe have some damaged wires inside the harness somewhere. But, mine seems to read OK.

What I need to check is the resistance all the way to the PCM. I'm not quite sure how to do that.

Thats exactly what I think my problem is. I don't have worse pinging issues though, just horrible performace and driveability. Like if I went to pull onto the street and put the throttle like half way down it would practically go nowhere, then I guess clears up a little.

 

[Synned]

uuup!

 

[HISSIN50]

MLC, I'll try the link again (if it's 10 pages of PDF, it probably bogged with dial-up. In general I only give PDF's about 5 minutes to load before closing them). I have the Probst manual for MAF-equipped fox III's.

Joe, I was kinda mulling things over and had a question for you: Does it feel like your converter is not locking or slipping when the car runs like chit? That's the feeling I have - if I nail it and stay on it, it sings above 3K and as long as I keep the shifts well above 3K, it zings. It's only when I'm cruising in 3rd or OD [and at low RPM] and nail it, where it's a dog (till about 2800 RPM).
For Grady, it feels a bit like you're going 25 mph in 5th and trying to accelerate while slipping the clutch continuously.

I've been wondering if the U4/W4 putes have some tuning in them where the ACT affects trans operation. That would explain a bit to me (and why the timing and spark values alone don't explain what we see, and why the stick guys don't see it either).

For comparison purposes, my coolant temps are always the same during this stuff (190*F). I have seen my ACT temps be above my ECT temps. I don't ping when it runs doggish either.

I figure if we toss enough personal notes out there and think-tank a little, we might figure something out or find some commonalities for Joe. He's been fighting this crap for atleast a couple summers. And We have a great group posting on the thread for doing this.

 

[Synned]

MLC, I'll try the link again (if it's 10 pages of PDF, it probably bogged with dial-up. In general I only give PDF's about 5 minutes to load before closing them). I have the Probst manual for MAF-equipped fox III's.

Joe, I was kinda mulling things over and had a question for you: Does it feel like your converter is not locking or slipping when the car runs like chit? That's the feeling I have - if I nail it and stay on it, it sings above 3K and as long as I keep the shifts well above 3K, it zings. It's only when I'm cruising in 3rd or OD [and at low RPM] and nail it, where it's a dog (till about 2800 RPM).
For Grady, it feels a bit like you're going 25 mph in 5th and trying to accelerate while slipping the clutch continuously.

I've been wondering if the U4/W4 putes have some tuning in them where the ACT affects trans operation. That would explain a bit to me (and why the timing and spark values alone don't explain what we see, and why the stick guys don't see it either).

For comparison purposes, my coolant temps are always the same during this stuff (190*F). I have seen my ACT temps be above my ECT temps. I don't ping when it runs doggish either.

I figure if we toss enough personal notes out there and think-tank a little, we might figure something out or find some commonalities for Joe. He's been fighting this crap for atleast a couple summers. And We have a great group posting on the thread for doing this.

I don't know about the torque converter...my problems are definitally low end...but more so like no throttle response, bogging out on launch. When symptoms are really bad, the car actually feels like it is going to die when I step on it. But it will still have low power untill like 3k, and then it accelerates without a hiccup (but still less power)

I just ohmed out my ACT, and it was 10K OHMS, not too bad considering the engine bay was hot. I guess thats around 120*, not enough to be causing this problem.
I really have to trace the wire all the way back...measure actual voltage at that lead. I think I'll do that tomorrow.

BTW: We do have a great team on this thread, excluding me haha. I WILL figure this problem out though, I don't care what it takes

 

[MLC Stang]

I've been wondering if the U4/W4 putes have some tuning in them where the ACT affects trans operation. That would explain a bit to me (and why the timing and spark values alone don't explain what we see, and why the stick guys don't see it either).

Exactly what I was beginning to think! You never hear the 5-speed tranny guys complaining about this stuff.

I not only have my hot weather pinging issue above 3,500 RPM at WOT, but I also get some when going up long slow hills in too high a gear, i.e. not getting on the gas hard enough to cause the AODE to downshift a gear or two. If I do force a downshift, the pinging stops immediately. What the heck is the computer doing with these darn fuel/spark tables in these situations?!?!?

In the case of my AODE, it was completely rebuilt about 15,000 miles ago. And, I mean completely. I did several upgrades to it that were subjects of TSBs over the years. Everything new and upgrdaded. Cost me nearly 2 grand total. (I can't blame this tranny for any of my woes!)

Isn't it interesting that my symptoms and Synned symptoms are both aggravated by high outside ambient temperatures. There's got to be a common thread here somewhere.

 

[Synned]

Isn't it interesting that my symptoms and Synned symptoms are both aggravated by high outside ambient temperatures. There's got to be a common thread here somewhere.

My problem IS something with the ACT sensor. It gets fixed with a resistor. I just don't know how or why.

 

[final5-0]

Joe

As I understand it, the two pcms you find in auto trans Stangs and the pcm you find in the GT Stangs have basically the same programming

I have only the GT or t4m0 to look at but I did see this about the act and spark on that file

I should have remembered this but I moved away from that file so long ago, specifics slipped my mind until this thread came up and I found this tonight.

temp.....-256...0...50...130...150...210...254
spark.....20....20.....0......0....-10....-20....-20

As you can see ... you loose some spark as the temps rise

Grady

 

[HISSIN50]

......... but I also get some when going up long slow hills in too high a gear, i.e. not getting on the gas hard enough to cause the AODE to downshift a gear or two. If I do force a downshift, the pinging stops immediately.

I hate to take a tangent from trying to get Joe all fixed up, but I did want to comment real quick here. You are NOT alone. This is something I have been posting about as an issue for quite some time. For me and my consistent reference point, it's a decent sized hill near the house. 45 mph so I'm in OD and not doing much for RPM's (3.55 gears). It will lug and ping a hair sometimes (I think it's from the lugging. If I took the same hill in 5th in my fox, I'd ping too).

As counterintuitive as it is, if I give the loud pedal a solid jab (it seems like I really gotta stand on it to get it to kick outta OD and into 3rd), it's fine. I just hate making it shift into 3rd. Even if I activate the BOO and unlock the converter (no one behind me to wonder WTF is he doing ), getting those couple hundred extra RPM help (if I let it stay in OD). In cooler weather, this is not an issue, EVERYTHING else (including coolant temps) being equal.

I just wanted to post that up so you know you're not alone bud.



Joe, this would be a lot easier if we could all meet up and drive eachothers' cars to compare notes.

WHen you talk about bogging, I'm trying to find an analogy so we know we're all on the same page. There are times for me (especially when taking off from a roll) where I press the gas pretty good and am not really goin anywhere (like there's a tennis ball stuck under the gas pedal which keeps me from getting full throttle travel). This isnt bad in first gear but gets worse in all the higher gears. Then for me, I hit 2800 RPM (in any gear) or so and it takes off. It will keep on the boil as long as I keep my RPM's above 2800 in any gear.

Is that anything like what you feel?

BTW, your comment about yourself earlier was some lame BS. Not true at all!

Anyhow, it's cool that we're commiserating together. Maybe we can find a commonality or reinforce the ideosyncracies we're seeing in hopes of figuring something out.

 

[MLC Stang]

.... Whenever my car is in hot weather, it runs like complete ****. Feels like I lose 4 cylinders, hesitation, bog on take off, etc.

I drove right over to Radioshack to pick up a 47K OHM resistor. It instantly made a difference in the car, and I didn't even reset the computer.

Joe,

OK, let’s go back to the basics here and try to eliminate some of the clutter.

You say above that your symptoms immediately clear up if you replace the ACT sensor with a 47 K Ohm resistor across the ACT connector pins.

If you look at the chart on page 275 of www.usnaaaa.com/pingisgone.pdf you will see that 47 K Ohms translates into an ambient temperature reading of about 60 degrees. That’s pretty cool air. Not cold, but far from hot too.

Both the ACT and ECT sensors affect air\fuel ratios more than they do spark, at least according to the Probst book.

All that considered, I’m saying that your symptoms are all due to fuel starvation. Why? When it's reall hot outside, the ACT makes the PCM take out some fuel. When you stick a 47 K Ohm resistor in place of the ACT the resultant signal ends up telling the PCM that the car is running in cool weather and the PCM ADDS some FUEL as a result.

It’s the added fuel that fixes your problem. That’s why I’m betting on fuel starvation as the root of your problems.

PS) I think that lean A/F mixtures at high ambient temperatures is the exact same reason for my hot weather pinging problem. I think I'll try the 47 K Ohm resistor ACT replacement trick in my car and see if the pinging stops.

Then again, maybe I’m completely off base, and my logic here just plain sucks!

What do the rest of you think about too lean an air/fuel mixture as the possible cause for Joe’s ills?

 

[final5-0]

I found some more info today

First of all ... I found an auto trans pcm binary I did not know I had
Its a U4P0 and after comparing it to the T4M0 ......
the info I offer in this thread is the same between them

Here is a function called Open Loop Fuel Multiplier vs ACT

temp ......... -256***116***126***176***210***254
multiplier ... 1*****1*****.781***.719**.703**.703

I'll try and see if this is multiplied against the base table
or what as I really don't have a clear cut undrstanding
at this time as to how this really works.

Grady

 

[millhouse]

I would think too that on a MAF equipped vehicle the ACT sensor would have less effect on timing/fueling than on a MAP equipped vehicle. Just food for thought.

 

[Synned]

I think we're all getting on to something!!!

WHen you talk about bogging, I'm trying to find an analogy so we know we're all on the same page. There are times for me (especially when taking off from a roll) where I press the gas pretty good and am not really goin anywhere (like there's a tennis ball stuck under the gas pedal which keeps me from getting full throttle travel). This isnt bad in first gear but gets worse in all the higher gears. Then for me, I hit 2800 RPM (in any gear) or so and it takes off. It will keep on the boil as long as I keep my RPM's above 2800 in any gear.

Is that anything like what you feel?

Yeah, it actually feels like I'm going nowhere. Like I'll go to pull out onto the road, and if I try to do it quickly I wont go anywhere and it scares the crap out of me. Kind of like the car isn't getting into WOT state but I know it is. And yes, the effect is very small up there around 3k.

MLC Stang: It makes sense man...makes perfect sense. If theres 47K OHM at the ACT right now, and I'm positive of it, if I go to the PCM and measure voltage it should match up. But if it did...it doesn't make sense. I'm guessing if I did go and measure voltage, it wouldn't be what it should at 47K Ohms, and if it DID match up I'd be stumped. Cause then the car should operate normal, being that my ACT sensor ohms out fine.

Grady- MORE INFO! Haha...you have me very curious man! Continue to fill that sponge of a head that you have with all of this information...


Thanks everybody
Joe

 

[WhiteDevil]

My experience has been that the during WOT the ACT does not affect the timing. I have data logs driving during the winter in 50 degree weather and at WOT im seeing 34 degrees total. I also have Data logs in the summer at 85 degrees and i still see 34 degrees total advance. Wouldnt it adjust it somewhere in there?