Converting Cruise Control from NA to GTE 7M

[suprasick]

After swapping a 7mgte into my NA chassis about two years ago, I have noticed that cruise control has a major issue. Whenever cruise is set and accelerating or going up a hill the CC system shuts off. After some research, it turns out that whenever in that scenario (accelerating/uphill) there is no vacuum to the CC actuator! Imagine that! So, after studying the TSRM and the EWD for a little while, I noticed that the 7MGTE requires a vacuum switch and a vacuum pump.

According to the 1987 EWD, on the Cruise Control Computer(CCC) there is VP (pump) and VAC (switch). It seems pretty straightforward. VAC is open when above 6.69inhg and then enables the VP circuit?

My questions:

1.Is there anything else I need to be able to operate the CC flawlessly?

2.Am I going to need the CCC out of a turbo model?

3.Similar to the super computer wiring, will there already be wiring there for VAC and VP? PIN 6 & 18 on A1?

4.Is there simply a better way to get CC working in my situation?

Cars date code is FEB 1987
CC works perfect when the engine is under a vacuum scenario.

Thanks in advanced for entertaining all of my mundane issues I have had lately:icon_bigg

 

[jetjock]

Yeah, the CC doesn't work too well as you get near ambient. Boost is even worse


>Is there anything else I need to be able to operate the CC flawlessly?<

Nope.

>Am I going to need the CCC out of a turbo model?<

P/Ns appear different.

>Similar to the super computer wiring, will there already be wiring there for VAC and VP? PIN 6 & 18 on A1?<

Unsure but I'm gonna guess since it's part of the engine harness it won't be there. Check though.

>Is there simply a better way to get CC working in my situation?<

Reservoir might be adequate depending on terrain. Finding a place for it though.

According to the factory CC training manual I have the switch set point for the pump is 170 millitorr (170 mmhg) which jives with your 6.7 inhg.

 

[supraguy@aol]

I have the same issue, but was wondering if it would be possible to simply retain the na actuator, and use a vacuum resevoir with a one-way check valve, so as to maintain vacuum during ambient/positive manifold pressures?

 

[jetjock]

Yes. Why I mentioned it above. Apparently great minds think alike...

 

[suprasick]

Reservoir might be adequate depending on terrain. Finding a place for it though.

I have the same issue, but was wondering if it would be possible to simply retain the na actuator, and use a vacuum resevoir with a one-way check valve, so as to maintain vacuum during ambient/positive manifold pressures?

After digging through my parts bin, I found what I believe to be a ACIS vacuum canister. I found a tidy place for it under the intake manifold, hooked up the hoses, and installed a one way check valve.

I noticed with my hand pump that pulling a vacuum of 20inhg took 30 to 40 pumps which seemed promising.

After finding a highway with a steep enough grade for about a half mile, I tested the system and it performed flawlessly! The whole time up the hill was hovering about ambient pressure and CC was consistant!

Here are some pics:





Hopefully this will help other members. And no my engine doesn't have a fungal infection, its just some spun off polishing compound :naughty:

As always thanks for the help.

 

[jetjock]

Well that was an easy fix. Apparently the CC actuator's size and valve design (low loss 20 hz duty driven proportioning) doesn't require a large tank volume. In hindsight the turbo system's tiny pump kind of implies that. On the other hand many Toyotas employ an all-electric motorized actuator that would have made the problem nonexistent.

 

[supraguy@aol]

Well, I had been intending to utilize the acis can for this purpose, as it simply looked to be a vac cannister with a vsv mounted to it.
And suprasick- why didn't you mount it in the original location- do you have other things mounted below the intake manifold?

 

[suprasick]

And suprasick- why didn't you mount it in the original location- do you have other things mounted below the intake manifold?

Wow... I didn't see you reply, sorry about that. The reasoning behind my mounting location was that the longer the hose the more of a chance it has to collapse under vacuum. I have already had one line collapse so I had to upgrade to thicker walled hose. Plus it's easier to get to :icon_bigg

 

[SeeUSmile]

Wow that looks alot different to what I have here in Australia. It's much more smaller than the actuator you have in the picture.

 

[yhatzee89]

Wow that looks alot different to what I have here in Australia. It's much more smaller than the actuator you have in the picture.

Pics? Anything that saves space in the bay is worth stealing

 

[1986.5supra_kid]

This thread was useful on my 2j swap! thanks!