I just bought an '87 RX-7 NA and the vacuum lines need some work I think. The previous owner removed the rats nest but did not do the full emissions removal. I have searched all evening for a diagram, or description of the vacuum wiring after rats nest removal, and have come up short.

So my general question is how to connect all the vac lines with the rats nest removed? Do you just bypass the rats nest and follow the start and destination points? Or do you just cap all vac connections that would have gone through the rats nest? Or do you do something different?

 

http://www.rotaryresurrection.com/2n...s_removal.html

 

That is exactly what I was just looking at, but that is removing all of the emissions stuff, which I don't want to do right now. Along with that, it basically says to cap most of the vac connections, but is that necessary if you want to keep the rest of the emissions stuff?

 

Gets mildly complicated. Your sort of right about end point to end point..........but some of the soleoids use the same vaccuum source so you'd need to tee the vacuum feed line to both. Later I might give this a try in some more detail. Like I'll select a given solenoid and tell what to connect to each of the solenoids two nipples and where to find the outputs end point. Maybe.

An example is the Relief solenoid which is blue. On one nipple you'd put the vacuum source and then connect the outlet nipple of the solenoid to one of the two metal nipples that stick up just above the ACV. Same could be said about the Switching solenoid which has a grey elect connector. It's feed nipple gets the vacuum and the outlet nipple gets connected to the OTHER of the two nipples just above the ACV.

If memory serves the FPRs solenoid gets a vacuum from the left side of the dynamic chamber and the outlet nipple of the ORANGE colored solenoid gets connected to the FPR's vacuum nipple.

The vacuum for the Relief and Switching solenoid come from one of the three nipples on the Front of the dynamic chamber.

Then on the back of the dynamic chamber you have two nipples that get connected to the purge valve. That black mushroom/plastic outfit. No solenoid involved there.

Then you've a EGR solenoid that is yellow. The source of vacuum is the same as the Relief and Switching solenoids and the outlet nipple of that EGR solenoid goes to the EGR's only nipple.

That's a general and not so complete way of how things work. But you have to take into consideration that not all the solenoids are configured the same. The small air filter is located differently on a couple of them so you'd have to know just which nipple is the feed nipple and which is the outlet nipple. Actually that is more or less shown in the FUEL AND EMISSIONS seciton of the FSM in a round about way.

Maybe later I'll try to be more clear about what I just wrote. Maybe.

The so called rats nest is actually pretty effiecient. Beats having to run numerous rubber vacuum hose all over the place.

NOTE: Switching, Relief and EGR all use the same source of vacuum from ONE nipple on the front of the dynamic chamber.

FRP soleoid only, uses the vacuum from the left side of the dynamic chamber.

There are but four solenods on series four non turbo so that takes care of those four.

But there are other items to be addressed like the injector air bleeds b/t the two oil injectors on the lower intake manifold and the purge valves two nipples.

See the jpg attached. Port B is the port that gets vacuum. Port A is obviously then the output of the Switching solenoid.

Second jpg shows the relief solenoid. Notice how it is configured differently??? Air filter is put on another nipple vs switching. Air filters pull straight off with some small effort, and can be then put on one of the other nipples. Meaning all solenoids are the same animal but some configured differently. Port A is the vacuum feed on the Relief solenoid............unlike the switching solenoid.

Third jpg shows port B being the vacuum connection on the FPR solenoid.

 

In the jpg shown, the two small black vacuum hose are the end points for the Relief and Switching solenoids. Relief solenoids plug is blue........switchings is grey.

On the front of the dynamic chamber are three metal nipples. The bottom one is the only one that is vacuum. IT feeds the switching, relief and EGR solenoids. You'd have to take vacuum off the bottom nipple and then split it up to go to those threee solenoids.

 

Thank you for the very detailed post. I'm afraid I'm still a bit confused. Are the solenoids you mentioned part of the rats nest? Are those solenoids the only things that need to be rerouted?

It is sounding like putting the rats nest back in might be the easiest fix. Is there a compelling reason to take/leave it out?

 

it looks bad after emissions removal and thats the only reason i would remove it or better yet modify it

 

The maze of pipes that came with the car will work much better than trying to route hoses from point to point.

The solenoids were attached to the piping and are/were easily removed from the piping.

Hopefully you spend most of your time driving from the drivers seat and care not whether the engine has the piping on the engine or does not have it on the engine. Personally I can't see the engine from my drivers seat where I spend most of my time with the car.

 

Yeah I hear you, and I agree, but my car isn't very driveable as it is, and I need to fix a few basic things, the first being the vacuum lines.

If I am understanding it correctly, after removing the rats nest, you must run the vac lines similarly to what the rats nest was. So you are basically replacing the hard lines with soft vac lines. Is that correct?

 

Pretty much , I'm not sure it is an improvement of any kind. imagine all the t's and relocation of solenoids , if your not removing emissions I would buy a used rats nest .

 

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Most those people who remove the tubing, do to remove all the emissions control parts and never go back and add vacuum lines to undo what they just did. They don't have to nor want to pass emissions in their state.

I'm saying, that if you want those solenoids to work, the EASIEST way to do it is to reinstall the piping and solenoids then add the small amount of vacuum lines that will still be needed.

RELIEF, SWITCHING and EGR are all three emissions related and the first two work in conjunction with the ACV. The EGR is emissions...........but let me tell you it is NOT needed to pass emissions in any way. The series five eliminated it. I pass emissions each year with three RX none with a working EGR. My NOX figures are miniscule when compared to what is Required by the State.

The FPR solenoid in my very humble opinion does little in life with MY cars and if I eliminated it and just connected the FPR itself to a steady and reliable source of vacuum, that would work just fine. The FPR gets involved in HOT starting. It vents the FPR's vacuum diaphram to ambient air pressure to drive the fuel pressure in the rails higher than normal (always seemed assbackwards to me....but they done did go to skool and learnt that is the way to do things).

Assbackwards is one word. Much like idiotinamotorboat is one word when I'm sailing. Dictionary is wrong, I'm right.

Still unsure of what is needed?

 

I think I know whats needed, and I can follow the colored vac diagram well enough to create my own lines. I attempted to do this tonight, and I ended up breaking 2 out of the 4 solenoids. My car does not have an EGR valve apparently, so I ignored that solenoid and vacuum wiring completely. The only solenoid that is hooked up right now is the grey one, the switching solenoid.

It seemed to start and run a little better, but it's still stalling on idle. I tested the TPS and I think it's shot.

 

In general the Relief, Switching, EGR will not effect idle since they effect how the airpump air is distributed and as we know airpump air is not ever mixed with intake air.........therefore starting and idle etc will not be effected by making the soleoid system whole again.

TPS can be checked out pretty easily on a series four non turbo with a HOT engine. Just take a digital meter and put its neg lead on a known gnd like the alt housing. Backprobe the GREEN/RED wire of the TPS connector with both halves of that connector coupled together. Reading should be 1vdc. Car can be idling or just with key ON but engine must be fully warmed up (hot).

To see if the TPS is good after that initial setting.......slowly open the throttle while watching the digital meter. Reading should go up to approx 4.5vdc to 5vdc.

The TPS should be fully extended just about the time the secondary plates Start to open. Normal.

TPS do not not add fuel as its reading goes up. TPS determine what are called ZONES of OPERATION for the ECU. That said, a really out of its rigging will cause idle problems......'cause it's so far out of its rigging that it thinks it's in another operating zone.

A TPS is in rig when the output of the TPS is 1vdc at idle............with a HOT engine. With a cold engine the reading will be higher because the water thermowax will MOVE the throttle linkage as the engine cools off. Normal as can be. On a real cold day the reading can be something like b/t 2-3vdc on a cold start. Normal as can be. The reading will come down to 1vdc once the water gets up to temp and the water thermowax's piston extends to fully move the throttle linkage to full close.

BAC valve should be trying to maintain an approx 750rpm ................although if the TRUE idle of the engine is set too low the BAC may struggle to do it's job. A bad BAC valve usually can be ID'd if the car will idle any at all. Say it idles at 500 rpm. Then pull the elect plug off the BAC. If the BAC was working any at all........the car should die or at least the idle should make a noticable drop in idle speed. IF no drop in idle speed is detected then usually it means the transistor inside the ECU that drives the BAC is ........toast and needs to be replaced with a radio shack part ...a TIP 120 NPN.

But a non turbo series four should be made to idle without a BAC by adjusting the screw in the top of the dynamic chamber along with the variable resistor and stopping all vacuum leaks and making sure the vacuum lines on the front of the dynamic chamber are not swapped around wrongly and......general stuff like that. Idles can't be fixed online imho. Spraying starter fluid around helps find air leaks. Fuel injector grommets on the bottom of the injectors can cause air leaks if installed hard as rocks. They should be soft and plyable when installed.

FPR itself should be seeing a vacuum all the time. Idle the engine and pull it's vac line off and feel for vacuum on that hose. Should be there.

Variable resistors can be messed with. Make note of the position of the screw and write it dowm on paper. Then turn the screw clockwise and then anti clockwise while listening to the engine. The screw has STOPS in each direction. Do not try to overcome the stops. Full range is appox 3/4 of a full turn. Clockwise is rich........the other way is.......yes.

Idles can't be fixed online imho. Especially with a engine that someone ripped the tubing off and gosh knows what they did after that.

ACV blockoff plates can leak if installed wrong or any other blockoff plate.

Timing and TPS should be set prior to messing with the idle .....usually.

This car have a working airpump and ACV?

 

HAILERS, I don't know how you do it.
Those were very entertaining posts about a subject I don't give a rat's ***- or nest (see what I did there?)- about.
Bravo.