PCM delivering wrong fuel mixture?

[Fless]

Solenoid I cannot get it to switch opened or closed on the bench w/ 12v command signal. It's froze open. Perhaps from being held open for too long (command side)? I assume it's normally closed (when not powered).

True. The purge solenoid should be closed without voltage applied. The vent valve, on the other hand, should be open with no voltage applied.

 

[Marky Dissod]

Usually ATF is routed through the radiator sidetank(s?), then through the external ATF cooler.

 

[strutaeng]

GREAT Help...

TRANSMISSION COOLER: Ambient temp 45F trans temp < 100F. Ambient temp 75F trans temp around 120F.



Interesting, I had kind of thought that liquid to liquid / radiator cooler whatever you want to call it, would help heat the transmission up. The oil cooler / cooler gets feedback from the radiator & engine coolant if it's plumbed through there. Makes since.

From what you are telling me, the trans cooler must be after the radiator in the plumbing?

Trans output -> Radiator -> cooler -> trans input?

Or is it

Trans output -> cooler -> radiator -> trans input?

My thought was to install oil thermostat as follows...

Trans output -> radiator -> thermostat (too hot) -> trans cooler - Trans input
bypass (too cold) -> trans input

Oh, I was just asking if you still had the radiator internal cooler; a lot of folks will bypass it altogether, which I don't think is a good idea because it won't heat the ATF in cold temperatures (at least in the climates where that's necessary.)

You are correct on that warming up the ATF. Also, from a thermodynamics standpoint, liquid-to-liquid is superior heat transfer than air-to-liquid, so even in the real hot operating conditions, it's a good idea to run the internal radiator cooler.

I looked at my suburban and it's your first scenario...

Did you just install the ATF cooler? You've run it an entire winter season? Maybe the external cooler is simply too big? I'll pay attention to my ATF temperature gauge in the next few days, but I think around this time, it barely makes the first tick mark.

So, ATF temperature I don't think you should focus rekated to your main concern. At least not until your other concerns are investigated.

 

[Matthew Jeschke]

True. The purge solenoid should be closed without voltage applied. The vent valve, on the other hand, should be open with no voltage applied.

Awesome just what I needed to know!

Usually ATF is routed through the radiator sidetank(s?), then through the external ATF cooler.

Awesome, that would make most sense to me. Thanks!

Oh, I was just asking if you still had the radiator internal cooler; a lot of folks will bypass it altogether, which I don't think is a good idea because it won't heat the ATF in cold temperatures (at least in the climates where that's necessary.)

You are correct on that warming up the ATF. Also, from a thermodynamics standpoint, liquid-to-liquid is superior heat transfer than air-to-liquid, so even in the real hot operating conditions, it's a good idea to run the internal radiator cooler.

I looked at my suburban and it's your first scenario...

Did you just install the ATF cooler? You've run it an entire winter season? Maybe the external cooler is simply too big? I'll pay attention to my ATF temperature gauge in the next few days, but I think around this time, it barely makes the first tick mark.

So, ATF temperature I don't think you should focus rekated to your main concern. At least not until your other concerns are investigated.

You hit the nail on the head. The external cooler is WAY to big. Factory I found was actually really good for what I do, despite it's really small size. It worked for 95% of what I did. The 5% I have a trans temp gauge. I'd just stop and let it cool off. Everybody buys the largest cooler from TruCool (Dana). In hindsight, I'd never do that again. The transmission builder I was working with suggested it, but he also suggested a bunch of stuff I didn't agree with and completely switched my build from what he had suggested. I had bought the cooler though and figured why not install it... famous last words. Might be worth buying some Derale cooler stuff. Something slightly bigger than the factory one and with a thermal bypass but not this 40k trucool unless your doing some serious towing or something really heavy duty.

 

[Marky Dissod]

I'd keep the cooler you have, and just modify it somehow.
I always block off my external coolers in the winter.

 

[strutaeng]

So this what my transmission gauge showed today on my 99 Silverado after about 30 minutes of highway driving. Ambient temperatures was about 70F.

This truck actually didn't come with the external transmission cooler, so probably not a good comparison. I was supposed to add one after I swapped the transmission, but low on priority list of action items.

My suburban is currently down for repairs, but I want to say that one runs a bit cooler (it does have the factory external cooler.

 

[Fless]

So this what my transmission gauge showed today on my 99 Silverado after about 30 minutes of highway driving. Ambient temperatures was about 70F.

This truck actually didn't come with the external transmission cooler, so probably not a good comparison. I was supposed to add one after I swapped the transmission, but low on priority list of action items.

My suburban is currently down for repairs, but I want to say that one runs a bit cooler (it does have the factory external cooler.

I'd probably recommend comparing the gauge with the PID on a scan tool, just to know if it's displaying fairly accurately. My '04 (4L60e with OE external cooler, not towing) runs right around 150° F after it warms up.