problem getting 84 5.0 to correct RPM

[xctasy]

pretty much.

You do have to be cautious though, at around 1.2 volts the ecu will consider the throttle to be partially open and back the iac out in a strategy to bring the engine to idle slowly when the throttle is shut. (less than the threshold voltage).

This could cause a high idle.

As the EECIV increased its memory and tasks, it became more important to control its TPS signal. In its infancy, the CFi 5.0 HO has no idle Air Control, just TFi 6 degree idle tip in. That tip in is based on partly on TPS reading.

It would have to be well out of the 0.8 to 1.0 volt range to cause a problem. TPS is sub-subservient to all the other settings, not a big issue unless its past 1.2 volts.

[fgross2006]

You shouldn't have to be mucking with the tps voltage at all, it should zero itself at startup, tps problems come from jumping voltage and limited range, not initial voltage.

I hate to disagree, but just watch this video from LMR and see how they show to set the TPS voltage. This vid shows on a 2 eyed Stang, but the TPS is the same on my 84 although its mounted vertical on the passenger side of the CFI with 2 screws.

Trust me when I say, if you back probe the green wire. then turn the fast idle screw, you will see the voltage climb or drop. It's a must to loosen the screws and rotate the TPS to get the voltage at .98 or lower.

[emerygt350]

I will let the engineers chime in on this one. From all I have read on here and elsewhere, the computer takes a glance at start up and zeros the tps at that. Perhaps if it is way off it chokes on it but I suspect the zeroing bit is the case, maybe later models didn't do that but it makes zero sense that they wouldn't. The absolute voltage has no meaning here, it is just a measure of change. The only people I ever see mucking with setting voltages on tps are tuners dreaming of pulling another horsepower or people desperate to figure out why their engine isn't running right. I can muck with my fast idle screws till the cows come home, doesn't affect anything else. Xctasy? Any deep knowledge here?

[emerygt350]

If you read the owner's manual, it does state that cold starts require you to turn the key to on, depress the pedal to the floor and let off, and then start the engine. This might be why, but truthfully, I rarely remember to do that.

[emerygt350]

I just saw xctasy's post, so I guess he already chimed in... Are your readings that high while adjusting fast idle? Maybe that is why 2200 might not be a good idea...

[emerygt350]

Yeah, the video seems right, the tuner bs I see is always 'is your tps saying .93 volts? Bring it up to .97 and experience the power'...

[fgross2006]

I just saw xctasy's post, so I guess he already chimed in... Are your readings that high while adjusting fast idle? Maybe that is why 2200 might not be a good idea...

Wheres xctasy's post?

[xctasy]

Wheres xctasy's post?

Area #51 above....

The EEC.Org Forum is simply excellent. The guys are helpfull. SailorBob is the man!

The was one guy who just copied over the 9 volt reference algorithims from the 1982 EECIII to the new for 1983 EECIV development 5.0 CFi. It uses the 5 volt reference voltage, and when it hit town in mid 84, very little changed from an EECIII CFi. The ignition tip in and some of the new for 1982 reworked TPS signals stayed the same, despite the ignition becoming the new TFi, and no longer the external Crank Sensor Duraspark III.

The AOD line pressure, Choke pulldown and proper VOTM plants the TPS in the right range, and its got further adjustments. Our Australian EECIV 2bbĺ 1988 to 1991 CFi had a non adjustable version and adjustment comes in handy.

Base set up should include the sequencd in the shop manual. TPS change is a last step.

[fgross2006]

So I got the choke thermostat and the pull down working perfectly. I got my idle set.

The only thing I'm not sure about is the VOTM/Dashpot. Mine doesn't hold vacuum and I would like to know if it's normal for it to leak down. Until I find one with a matching number to mine I dont wanna chance it with something almost the same.

I know that when AC is on its supposed to bump up the idle a notch, mine doesn't. It drops the idle a notch. That's why I'm thinking the leak down isn't good.

Would appreciate if anyone that has this set up would test with a hand vacuum pump and see if it holds vacuum.

[xctasy]

So I got the choke thermostat and the pull down working perfectly. I got my idle set.

The only thing I'm not sure about is the VOTM/Dashpot. Mine doesn't hold vacuum and I would like to know if it's normal for it to leak down. Until I find one with a matching number to mine I dont wanna chance it with something almost the same.

I know that when AC is on its supposed to bump up the idle a notch, mine doesn't. It drops the idle a notch. That's why I'm thinking the leak down isn't good.

Would appreciate if anyone that has this set up would test with a hand vacuum pump and see if it holds vacuum.

Its a bleed down device, not a permant vacuum holding device. Its a controlled leak for sure. BA or BB suffix, they are both the same. Testing for a VOTM is in M81s pages

Picture is

http://vb.foureyedpride.com/attachme...2&d=1548195684





Post #49 by gr79

http://vb.foureyedpride.com/showthre...um-lines/page2

[fgross2006]

Its a bleed down device, not a permant vacuum holding device. Its a controlled leak for sure. BA or BB suffix, they are both the same. Testing for a VOTM is in M81s pages

Picture is

http://vb.foureyedpride.com/attachme...2&d=1548195684





Post #49 by gr79

http://vb.foureyedpride.com/showthre...um-lines/page2

According to the diagram in the shop manual, the VOTM is supposed to hold vacuum for 10 seconds and slowly bleed down. Mine bleeds down as soon as vac is released.

so you think the E2VE-9E957-AB and E2AE-9E957-BB are the same part? the do look identical. I just dont wanna find out later that the E2AE-9E957-BB is for a van and wont function the same on a Stang.

Since mine is bleeding down in a half second would that explain why its not kicking up the idle when I hit the AC? I'm disappointed that the one I have on there now was a NOS Motorcraft and it barely lasted 4 years.

[emerygt350]

When I had other bad things going on with my sensors the AC kickup wasn't working either (maybe the computer was saying, "dude, not now, we got worse stuff going on"). As all of those were fixed it started working again, I know that isn't of much help but there you go. If you have a new diaphragm in it I can't believe it would be 'bad'. They are stupid simple devices. Wish I could pull the car out and check for you but we just had an ice storm and I don't want to muck with it... or wait, those you can't replace can you? I was thinking of the choke pull down. I bet I still have one in my box. I can look again.

[fgross2006]

Its a bleed down device, not a permant vacuum holding device. Its a controlled leak for sure. BA or BB suffix, they are both the same. Testing for a VOTM is in M81s pages

Picture is

http://vb.foureyedpride.com/attachme...2&d=1548195684





Post #49 by gr79

http://vb.foureyedpride.com/showthre...um-lines/page2

So in your opinion you think the E2AE-9E957-BB is the same part as the E2VE-9E957-AB? the comparability charts on ebay list the E2VE-9E957-AB as being for an 84 Mustang 5.0 but not the other. i know the ebay compatibility is not accurate. So if you think its right for my 84 Ill try it.

According to the testing procedure its supposed to hold vacuum for 10 seconds with a slow leak down. Mine holds vac if there's constant pull, but as soon as the vacuum stop the dashpot loses vac instantly.

I feel this is why my idle isnt bumping up when i turn on the AC. it drops a notch instead.

Also, I'd still like to know if theres any websites out there that can refurbish these dashpots. They are an extinct creature and theres virtually no more of them left. Soon enough it wont be possible to replace them.

[emerygt350]

Look what I found... I will take it down for a quick vacuum test and let you know what it does.

[emerygt350]

Holds and releases in maybe 8 seconds. https://youtu.be/qPBf7KySKh8

[fgross2006]

Holds and releases in maybe 8 seconds. https://youtu.be/qPBf7KySKh8

the instructions on the page that xctasy
posted says to pump it up to 20 and it should leak down to 10 in ten seconds. I assume if it leaks down to 10 in ten seconds that it would be a 20 second leak down from 20 to zero.

I hate to buy a new one to find out they all do the same thing. My original one wont even hold vac no matter how much I pump. The one on my car now holds as long as theres constant vacuum but releases in 1 second when the vacuum stops,

[gr79]

In my post #49, a VDV is also pictured above the VOTM pic.
Maybe there was one and is now gone, inop (VDV to delay the VOTM vac bleed down).
Or add one? No one will tell.
An alternative to replacing or rebuilding VOTMS.
Found sometimes mods have to be done to make things work correctly or help to that are not in the books.
Have gone to the pic-a-part and gotten a few different VDV variations from older Ford vehicles for my experiments.
The book mentions at least 4 basic ones, different colors, sizes, configurations. There are many over the years.
Surely there is database or catalog with the part numbers, picture id, and most important: detailed specs.

Or use the solenoid throttle kicker, which is an all on or off deal.

[emerygt350]

I couldn't get a good seal on the base of that (wrong hose size, standing in autozone, etc) so it may have held at 10 if were not leaking. Fgross, if you want I can mail it to you but I am not sure it will be better than what you have...

[fgross2006]

I couldn't get a good seal on the base of that (wrong hose size, standing in autozone, etc) so it may have held at 10 if were not leaking. Fgross, if you want I can mail it to you but I am not sure it will be better than what you have...

The fact that yours took 10 seconds to bleed down its better than mine.

I'm just not sure about grabbing a NOS part that has a similar number to mine and it may behave the same way more or less.

[emerygt350]

Yeah, let me know if you want it. I also suspect the votm on the car has a different part number too. When I got the car somebody had put a nonHO cfi NOS on it. They didn't realize the venturies were way smaller. I think it was off a 351 truck or something. When I get a chance I will see if I can get the number off it, obviously it works just fine. When I put the original back on ithe car, I took all the 'new' bits off the smaller cfi and mounted them on the old cfi.

[emerygt350]

I found some pics. The one on my car looks not different from that one I showed above. Hopefully you can see the complete part number in these two views.
. At first I thought it was different, but now I see it just looks new...

However, it does mean that the HO cfi wasn't the only one with the right votm. Check out the different venturies.

[fgross2006]

I did a quick check/set of my cold idle this morning and took a minute to test my VOTM with hand vacuum.

You can see that it wont hold vacuum no matter how much I pump, but you can see the bump stop wiggle with each hand pump. If theres constant draw coming from the blue vacuum line it kind of affects the dashpot, but it's not doing what it's supposed to do.

I should be able to pump up to 20 and it should hold and slowly leak down to 10 in ten seconds. So this NOS Motorcraft part I put in 4 years back is 90% shot. I tried checking the original one I still have but that one is unaffected by any vacuum applied to it.

I'm gonna take a chance with the ebay part even though the numbers don't match 100%. Hopefully it will work out right.

I still would like to find a place that can rebuild these dashpots. They are extinct and in a few years, it may be unavoidable to have to replace the CFI with a 4 barrel if no alternative to the 5.0 CFI dashpot doesnt become available.

.

[emerygt350]

I am already planning for the inevitable. I pretty much expect to be installing a Holley sniper unit in a few years as the sensors become impossible to find.

[xctasy]

I did a quick check/set of my cold idle this morning and took a minute to test my VOTM with hand vacuum.

You can see that it wont hold vacuum no matter how much I pump, but you can see the bump stop wiggle with each hand pump. If theres constant draw coming from the blue vacuum line it kind of affects the dashpot, but it's not doing what it's supposed to do.

I should be able to pump up to 20 and it should hold and slowly leak down to 10 in ten seconds. So this NOS Motorcraft part I put in 4 years back is 90% shot. I tried checking the original one I still have but that one is unaffected by any vacuum applied to it.

I'm gonna take a chance with the ebay part even though the numbers don't match 100%. Hopefully it will work out right.

I still would like to find a place that can rebuild these dashpots. They are extinct and in a few years, it may be unavoidable to have to replace the CFI with a 4 barrel if no alternative to the 5.0 CFI dashpot doesnt become available.

.

The VV2700 and VV7200 is designed to work with an Idle control stepper motor, so the bleed down rate isn't as critical on the BA and BB sub-code parts.

There is plenty of scope for making another one from that more common base, so don't worry.

In the meantime, just keep the parts, and have a go with the other one, and know that your way ahead of where you were before. Ford had a standard part spec, but it'll work out side of that range, I'm quite sure.

Adding the IAC from the 3.8 CFi will allow a 5 speed transmission conversion if a dual sych TFi is used.

There are only good things coming around the corner for the 5.0 HO CFi.

[fgross2006]

The VV2700 and VV7200 is designed to work with an Idle control stepper motor, so the bleed down rate isn't as critical on the BA and BB sub-code parts.

There is plenty of scope for making another one from that more common base, so don't worry.

In the meantime, just keep the parts, and have a go with the other one, and know that your way ahead of where you were before. Ford had a standard part spec, but it'll work out side of that range, I'm quite sure.

Adding the IAC from the 3.8 CFi will allow a 5 speed transmission conversion if a dual sych TFi is used.

There are only good things coming around the corner for the 5.0 HO CFi.

So you think the E2AE-9E957-BB will work OK with an 84 Mustang 5.0 CFI?

Since I have an old one, i'm gonna open it up and wee what makes it work. maybe I can learn how to repair it.