Write up on how I made my not so great A/C a little better.
10-10-2014, 11:11 AM
#311
Senior Member
Gentleman, in another post a ford truck owner was just told by his dealer that the evaporator sensor probe is the issue on these trucks! Ford knows this but has yet to issue a tsb because of the complexity in replacing. The poster stated the dealer will be installing a new ac unit in his truck.
I too can confirm this after discussing in detail with a service manager who has fixed these problem trucks by replace the evaporators sensor temp probe. The problem is, Ford makes them jump through hoops to duplicate and then and only then will they authorize the removal of the dash, in order to replace this simple probe under warranty.
What happens as was seen with mine, the probe returns varying signals from the coil to the PCM, then the trucks compressor goes into the cycling.
Very important here and as was confirmed without my mentioning, are the temperature conditions. Regularly happens when temp hits 91 and above on these trucks. Also came about in later models, 2011 and up!
There you go, Ford knows and the dealers know, but they are made to jump through hoops by Ford for the warranty repair!
There may be light at the end of the tunnel, with a possible tsb coming from Ford!
I too can confirm this after discussing in detail with a service manager who has fixed these problem trucks by replace the evaporators sensor temp probe. The problem is, Ford makes them jump through hoops to duplicate and then and only then will they authorize the removal of the dash, in order to replace this simple probe under warranty.
What happens as was seen with mine, the probe returns varying signals from the coil to the PCM, then the trucks compressor goes into the cycling.
Very important here and as was confirmed without my mentioning, are the temperature conditions. Regularly happens when temp hits 91 and above on these trucks. Also came about in later models, 2011 and up!
There you go, Ford knows and the dealers know, but they are made to jump through hoops by Ford for the warranty repair!
There may be light at the end of the tunnel, with a possible tsb coming from Ford!
Last edited by digitaltrucker; 10-10-2014 at 11:15 AM.
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Engineer Guy (10-10-2014)
10-10-2014, 11:38 AM
#312
Member
Thanks
Ed ~
I read this entire Thread a few months ago, but did not repeat that feat recently. So, if the Post you allude to was here, and not elsewhere, I would have missed/forgotten it.
Based on your helpful info, I'll get my new Truck in for Warranty Work well within the initial time period. I'll leave myself PLENTY of time for all the back & forth posturing and BS that might occur. I was in High Tech Support Int'l for much of my Career, so I know how to write e.mails for the record, and how to put the Hammer down as a potentially-dissatisfied Customer who talks and posts. It's a Game, and I'm good at it.
I read this entire Thread a few months ago, but did not repeat that feat recently. So, if the Post you allude to was here, and not elsewhere, I would have missed/forgotten it.
Based on your helpful info, I'll get my new Truck in for Warranty Work well within the initial time period. I'll leave myself PLENTY of time for all the back & forth posturing and BS that might occur. I was in High Tech Support Int'l for much of my Career, so I know how to write e.mails for the record, and how to put the Hammer down as a potentially-dissatisfied Customer who talks and posts. It's a Game, and I'm good at it.
Last edited by Engineer Guy; 10-10-2014 at 11:40 AM.
10-10-2014, 11:42 AM
#313
Senior Member
Ed ~
I read this entire Thread a few months ago, but did not repeat that feat recently. So, if the Post you allude to was here, and not elsewhere, I would have missed/forgotten it.
Based on your helpful info, I'll get my new Truck in for Warranty Work well within the initial time period.
I read this entire Thread a few months ago, but did not repeat that feat recently. So, if the Post you allude to was here, and not elsewhere, I would have missed/forgotten it.
Based on your helpful info, I'll get my new Truck in for Warranty Work well within the initial time period.
I am not at home and do not gave the link to the other post. Having said that, I am not sure if I can post it here if it is from another website.
When I get home later, I will pm you. It's a real shame that with all of the posts, we find out ford is aware and further knows what the fix is!
10-10-2014, 11:47 AM
#314
Senior Member
10-19-2014, 04:34 PM
#315
Has anyone used dei heat shroud on here. Someone mentioned it but never if they used it. Looks like it would give a clean look.
http://www.designengineering.com/category/catalog/design-engineering-inc/line-hose-protection/heat-shroud
http://www.designengineering.com/category/catalog/design-engineering-inc/line-hose-protection/heat-shroud
10-22-2014, 01:50 AM
#316
Senior Member
Many thanks Gwpfan ~
I was hoping someone with your background would come along and shoot holes in my idea[s] so that we could plot some useful way forward.
1. Would changing the Thermistor under discussion to falsely measure 'higher' than actual Temps achieve anything re: cooler Cabin temps, in your opinion? I.e., fool the System into thinking the Return Air is warmer than it actually is, and thus keep the Compressor on longer?
I was hoping someone with your background would come along and shoot holes in my idea[s] so that we could plot some useful way forward.
1. Would changing the Thermistor under discussion to falsely measure 'higher' than actual Temps achieve anything re: cooler Cabin temps, in your opinion? I.e., fool the System into thinking the Return Air is warmer than it actually is, and thus keep the Compressor on longer?
2. I don't have Digital Temp Control in my 2014 STX. So, the A/C Temp **** is already as low as it can go. Hows exactly does one achieve what you're suggesting here?
'What your saying about offsetting that sensor one can do with the temperature control by setting it lower than 'normal.' '
'What your saying about offsetting that sensor one can do with the temperature control by setting it lower than 'normal.' '
3. Is the Freeze Stat you mention here something I/we could mod, or is it the the real bottom line in all this? That is, does the Freeze Stat really limit what we can achieve, and we're 'stuck' with this fact of Temp Control Life? Or, do you think we could safely muck with the Freeze Stat - reduce the lower limit Setpoint - and not void Warranty?
'the compressor cycles more so on the freeze stat in the coil from all the reading and testing I've done.'
'the compressor cycles more so on the freeze stat in the coil from all the reading and testing I've done.'
https://www.f150forum.com/f38/compre...ng-fix-271852/
with insulating your suction line as the best fix. Putting your AC on max/check the blend door 2nd best.
The cycling fix though if found out would likely void your warranty as you could allow temps back the compressor that would cause liquid slugging which equal a failed compressor. If it wasn't for the accumulator I would say never even try this, but reading about the settings as well as knowing there's an accumulator tells me there is room for tighter superheat, along with experiencing longer than normal cool down times.
Again the freeze stat and temperature stat both are limits, either one below setpoint compressor cycles off. I really think though the limiting factor here is the freeze stat as if you can make the setpoint 60 or even 65 and the compressor is cycling and there's no way it's less than 65 in the cabin at the return air sensor then the compressor is cycling on pressure/freeze stat. Since from the post we know freeze stat off setting is 36-38 we have ~4 degrees of play. See https://www.f150forum.com/f38/compre...3/#post3703236
02-08-2015, 08:54 AM
#319
Senior Member
Mine is going back this week as weather warms. After replacing the "the Box" under the dash which is a complete new evaporator coil assembly and coil temperature probe, nothing is better.
The key from what I can tell in watching the tech with the computer connected to my truck is:
The operation of the coil temperature probe. My old one would cycle at 44-48, they acknowledged that this is far from the 36-38 which is what it should constantly maintain. So what is causing the operational temperature variance and swing, is the question! Whoever figures this out is the genius!
Either I have yet another defective coil temperature probe or there is still something that is tell this probe NOT to operate within specs, by cycling out of specification.
Looking at the hack and seeing that it causes the system to override its own coil temperature probe readings, which causes the temp (evaporator coil) to get very cold as it should, leads me to believe that either the probe is still bad or the PCM which controls it or some other sensor talking to it, is bad.
While insulation of the line is a great idea, its not the problem here with these units and certainly wont hurt.
No expert here, just trying to narrow it down.
The key from what I can tell in watching the tech with the computer connected to my truck is:
The operation of the coil temperature probe. My old one would cycle at 44-48, they acknowledged that this is far from the 36-38 which is what it should constantly maintain. So what is causing the operational temperature variance and swing, is the question! Whoever figures this out is the genius!
Either I have yet another defective coil temperature probe or there is still something that is tell this probe NOT to operate within specs, by cycling out of specification.
Looking at the hack and seeing that it causes the system to override its own coil temperature probe readings, which causes the temp (evaporator coil) to get very cold as it should, leads me to believe that either the probe is still bad or the PCM which controls it or some other sensor talking to it, is bad.
While insulation of the line is a great idea, its not the problem here with these units and certainly wont hurt.
No expert here, just trying to narrow it down.
