Engine simplification

[Prof]

Long live the Prof :god

Cheers man - just happy to help - having lived with my car since late 2002, I\'ve got to know it very well

[infernal]

HOLY THREAD REVIVAL!!!

Hello everyone!

I won\'t lie, I have made this topic originally on RX7club and we are curious to discover what all these you will see are and what they do..
Anyway, here is the post.. Sorry for it being too long. Please help!

I got down to replacing some of the cracked vacuum tubes in my rats nest this evening and I found out that I have 4 solenoids instead of the 3 mentioned in the FSM. The extra one is of green plug colour. My motor is an S5 Turbo2.

I searched and searched again the fora.. At first I thought that it had an S4 turbo nest fitted, but that was not the case, since I traced the green solenoid lines and they were not going to the exhaust mainfold (no flap in mine anyway). This solenoid had 3 lines connected instead of two. One was hardline T-ed to the FPR together with the Orange solenoid, one was coming under the UIM and one was running to something like a vacuum chamber. Yes, I also have that thing. It is located in the right side of the engine bay as we look at it, right behind the headlight and the coils.

I live in Europe, so that\'s a european model.. It originally was fitted with the N380 ECU, which I replaced. No clue if the new JDM ECU can handle this nest.

I was about to believe that I comprehended the nest, but now I\'m back to zero.  

OK so this is the green solenoid..

Please ignore the adjacent one, it is just a replacement I made for my faulty ACV switching solenoid..

This is the other side of it..

It certainly is not turbo port related.
The wastegate duty cycle solenoid is removed since I have an EBC. You can see its hardlines open.

Here you can see the T and the check valve for the vaccum chamber..


And here is the vacuum chamber itself..


Finally an overview:


I also made a drawing of what I think I found out so far, so that I can help you help me.   I may be wrong though..

Here it is:


Thanks for your time!

***UPDATE! If I saw correctly, my stock FPR has 2 vacuum lines, one before and one after the diaphragm, so maybe the green solenoid and the vacuum tank are connected to the extra port on the side of the injectors on the FPR? :Hammer

[infernal]

So based on this update I made a new drawing..


Could it be something like this?

Thanks again..

[Prof]

I\'ve seen fuel rails with the 2 vac lines before as well - I thought the Green solenoid might have had something to do with the more complicated exhaust that the first Turbo FC\'s had - where there was an actuator on the exhaust manifold to operate the twin scroll turbo arrangemet - this got binned in the later T2 models because they used a modified turbine blade profile which starts straight and curves out at the end - it effectively does the same job as all the fancy plumming.
 
If you go with an aftermarket FPR, then pretty much all of that stuff can be removed which helps reduce the chance of vac leaks or erratic behaviour due to electrical issues with our old and crumbling looms.

[Timmyc]

im actually having problems with a standard turbo2 rats nest at the moment as well, my fuel rail has 2 vacuum take offs and i was kinda baffled by them but think i have that covered, not 1005 sure what each solenoid does exactly either lol my problem is it wont idle, will start, will rev but will cut out when down at idle revs

[infernal]

Prof thanks for the response! I\'m afraid in my car the green solenoid is not turbo port related.. :xconfused

I\'m back and hopefully got my hands on a removed hardline assembly for a few mins, so I figured out the pipework lol.

It goes like this:

This is the final, correct layout.

So our green solenoid is for FPR control together with the orange one.. But what does it do?

First of all, does anyone know how a Fuel Pressure Regulator with 2 vac lines work? Should the two lines work as if the diaphragm is placed between them, I may have a clue..

Timmyc you have the dual vac FPR too, how did you deal with it?

Awaiting input..

[Timmyc]

Well when I was doing my engine I changed everthing to aftermarket rails and fpr and new vac lines throughout, I did away with everything, all solenoids, rats nest etc but ive taken the engine out of the car and im now putting it back to standard so im going to try your routing of vac pipes and solenoids and see what happens, did everything work alright for you?

[mick choi]

hi timmy whats happened to ur track fc?

[Timmyc]

Hey, still got it, had to take the engine out and put it in my daily when the daily engine went pop, i had another engine ready to go into the grey one so will update soon