eriksseven

iTrader: (6)

So, I'm working on doing the emissions and rats-nest removal on my '88 TII.

I've had a terrible idle lately due to a major vac. leak from either one source or several... I'm hoping that in simplifying my engine bay, I will be able to either fix my vac. leak in the process, or at least narrow down my trouble-shooting area...

Anyways, I've got all the block-off plates I need (including ACV, BAC, EGR, SAP and OMP).

That being said, I just BROKE something on my UIM... I don't have direct access to a digi-cam, so you're just going to have to picture this 'mentally', lol.

The part is DIRECTLY below the 'holder' for the THROTTLE CABLE on the back of the s4 TII UIM...

The part is ABOVE the larger vac. line going to the brake booster (I believe).

It's connected to the UIM by two 10mm nuts and there's a small diamond shaped gasket seperating 'it' from the UIM.

The 'body' of it is mostly a small cylinder with a WHITE PLUG coming out of the top of the cylinder.

The white plug that comes INTO it (via the wiring harness), is the SHORTER length of the two white plugs that are tied into the wiring harness right at the 'rear' primary injector's plug...

I don't know what this part is, but I broke the base of it, where it bolts into the UIM. Is this something that can be blocked off?

Is it... The OMP something or other? (the OMP block-off plate didn't seem to fit, but I'm going to try again).

Thanks, and sorry for what may be a very n00b question.

buttsjim

I believe you are describing the Air Supply Valve. I just looked at my 87 TII, and that's what's directly below the throttle cable bracket. It's on page 4B-66, if you have the FSM.

iceblue

It is the ISC or ASV I dont remember what it is called right now but it is used to pump meterd air into your system for the power stearing.

Go ahead and remove it feel free to remove your BACV to now and bump your idle up to a grand.

I didnt just seal mine off I removed the studs and filled the holes in for it with JB weld.


When I did my removal I removed the harness and striped all the stuff out of it. Makes evrything look nicer.

eriksseven

iTrader: (6)

Cool, thanks a lot guys.

I was just going to block it off anyways, because I saw it blocked off on Kevin Landers emission removal 'how-to'.

Yeah, my harness looks pretty frikkin' haggard... I'll probably wait until the next rebuild before I go nuts on the "cleanliness" though, lol.

I would've just left the ASV alone, but since I broke it, I'm just going to modify the OMP block-off plate that I got in my 2571 engineering kit, to work for it.

My OMP stuff has already been dealt with, so I don't need it's BOP.

iceblue

Puchi

have a chart like that for the S5?

imdrax

iTrader: (1)

just out of curiousity with everything removed and having the engine looking EXACTLY like that with everything removed as shown correctly will the car idle just fine and have no issues whatso ever? also i keep reading you will need to put in new fuel lines is that just for good measure do to age or because you need to?

NZConvertible

It's basically the same. The only differences are the S5 doesn't have the twin-scroll switching actuator and the secondary air injector line looks different. It runs through the injector bosses. You'll see it clearly when the UIM's off.

I did that sketch. You'll notice the BAC valve is still there. You will have no idle problems or other issues as long as you don't leave any vac leaks.

The set of had vac lines and solenoids that gets removed includes part of the fuel lines. You need to run new hose to reconnect everything.

I don't know why everyone's so keen to rip off the BAC valve. It's for idle speed control. Removing it and "bumping your idle up to a grand" is just a crude hack. You have a reletively modern car that can control it's own idle speed but you'd rather go back to the method used on carbs? There is no advantage to removing it.

iceblue

^ I removed my BACV just so I did not have to plumb it into the IC pipe with FMIC, and to have less stuff under my hood.

NZConvertible

You mean you removed your BAC valve because you couldn't be bothered to plumb it into the IC pipe. It's not like it's difficult to do.

And the advantage of that is...?

imdrax

iTrader: (1)

a couple more questions i have then are:
1.on the MANY threads i have been reading about on this i find conflicted views on whether or not to leave the fuel pressure soleniod in/out for hot starts and what not. and on the same note if i remove the fuel pressure solenoid thereby bypassing the vacuum lines to the damper would i just plug those 2 vacuum nipples on the damper shut?
2.in the corner where it shows the switching actuator and soleniod and check valve, which solenoid is that? the twin scroll? and where the red arrow points away from it where is that line going? to the similar red arrow above the word "caps"? if so is that how it is routed from the factory?
3. im currently running an apexi BOV and it has 2 nipples that have a hose connected to each other. how should this be routed(came like this when i bought it)?
4. when you removed the canister and purge valve what was done with the 2 nipples on the oil filler as well as the hose near the driver side firewall?
5. from my reading i thought that the s4 did not have secondary injector air bleed and that that nipple on the very top of the 4 right there is capped from the factory?
6. and lastly(for now) if i have a boost controller installed is the pressure sensor needed? what is its primary function?

NZConvertible

The Hot-Start Assist system is there to make the engine idle smoother when a hot engine is restarted after sitting for a while. Heat soak causes fuel to boil in the rails, so the engine runs badly when you start it. By increasing fuel pressure and idle speed idle quality is improved. This lasts for 50 seconds, by which time the fuel rail has cooled sufficiently. Many EFI engines have this system, because idle quality is something manufacturers try to maintain under all conditions.

The results from bypassing this are pretty obvious. When the engine's heat-soaked, idle quality will be poor for the first few minutes after restart. If you can live with that then remove it. All you have to do is run a vac line from the angled nipple on the inside of the LIM to the FPR, just like in my drawing. You don't need to cap anything.

Yes to all.

I'm pretty sure one of those is supposed to be open. Get the instructions off the Apexi website.

I ran two 1/4" hoses from the nipples on the engine down underneath the car and zip-tied them to the fuel lines. This leaves the sump vented like it has to be and keeps oil vapour out of the engine bay. I did the same thing with the fuel tank vent line (the one on the firewall) using vac line.

That seems to be the case. I think it's just an error on the FSM vac diagram. I left it on my drawing becayse I wasn't sure at the time. I s'pose I should change it.

The MAP sensor is definitely needed. The ECU uses it as a secondary load sensor controlling (amongst other things) ignition timing. Do not disconnect it.

imdrax

iTrader: (1)

ok nz got the nest out and all injectors and rails removed. had a question. when removing the manifold i couldnt reach the fat coolant line so i just yanked until it ripped. coolant ofcourse went everywhere. i cant imagine how hard hooking it back up will be. are these coolant lines needed? can i just cap the coolant passage on top of the motor and bottom of the TB? i thinki have read something about a TB mod and getting rid of the double throtlle and what not but i really am to lazy to do all that stuff. and also about the long coolant line that bolts to the BAC can that be eliminated?

NZConvertible

If you've never removed that hose before, cutting it and replacing it is the best option as it'll be baked on (it's very cheap from Mazda). You should've drained the coolant first though...

Hooking it up is nowhere near as hard as some of the crybabies around here will tell you. Attached is a photo of my UIM sitting in place so I could reconnect that hose. As you can see there's plenty of room. You have to remove the rubber elbow from the TB to do this. Spray a little lube inside the hose and it'll slide right onto the TB. Change the stock squeeze clamps for screw clamps. It's much easier to get a screwdriver or small socket in there than a pair of pliers.

The coolant lines are for the thermowax that increases idle speed when the engine's cold so it doesn't die. If you want the thermowax to stay working you have to keep the hoses. This is totally seperate from the double throttle system. That can be removed and the thermowax left in place and functional.

imdrax

iTrader: (1)

thanks nz i went ahead and just did the TB mod last night while i watched TV it only took maybe a half hour. couple questions though first off if i have access to a welder can i weld the two hole on the outside instead of JB? will the spot where the hole is on the inside affect velocity or air flow if not smooth? understand what i mean? and also now that i ditched the thermo what is the best way to route the coolant? should i go from the block opening just under the manifold and route a hose to the line that bolts to the BAC?

NZConvertible

I don't see why not.

Any effect would be tiny.

Run a hose from the nipple on the rear iron stright to the nipple on the back of the water pump, bypassing the BAC valve entirely.

imdrax

iTrader: (1)

ok after 3 weeks i finished my rats nest and emission removal. after tracking down a short just now that was causing the egi to constantly blow i got the car started. BUT itwil start run for approximatly 5 sec. and then die. i removed EVERYTHING including the cold start valve, charcoal canister, and did the throttle body mod. would a vacuum leak be causing this issue of the car immediatly dying? not even gas helps if i first start it and give it gas the idle goes to ~2k and then it will straight plummet to dead not even a sputter and then die out but just straight dead. im going to go back outside and look over everything but i hope you(NZ) could give me a little advice hear.

imdrax

iTrader: (1)

ok well after a little more diagnosing i found that one of my nipple plugs had fallen off, the coolant temp sensor was not plugged in and my knock sensor wire has been ripped from the connector. after everything was fixed (minus the KS) the car ran and didnt kill itself. but for at least about a minute i had to keep the throttle up for it not to die but after that it held a rock solid 750 idle which it NEVER has before. so i was happy about that. took it for a drive and everything seems kosher. now comes a few comments/questions:
1. driving with the knock sensor signal not being sent to the ecu, will that effect high rpm/heavy load conditions adversly?
2.is it normal to have to use the throttle to keep the car running when first warming up for that long?(i did the TB mod)
3. i was going to use the green solenoid and check valve for my twin scroll system but upon removal of the vac rack one of the solenoid nipples broke off. so i plugged that port on the intak manifold where that would plug into and just left the actuator nipple(by the EGR right?) vented open. im still not to sure how this actuator works so i dont know if its just sucking in atmospheric pressure with the nipple open or if its blowing??? could you explain this to me and whether or not i should cap the nipple or leave it vented.

NZConvertible

That's because you removed the thermowax, which increases idle speed to stop the engine stalling when it's cold. Remember I suggested you leave that on...

No. The FC's knock-sensing is pretty crude compared to modern cars and really only works at low-mid rpm. The engine's too noisy at higher revs. It's mainly to protect against lugging the engine at low revs.

Yep. Reinstall the thermowax or get used to it.

If it's not connected to the manifold (complete with correctly oriented check valve), the twin-scroll system won't work. Manifold vacuum is used to close the flap, so without it the flap will remain open. You can use one of the other solenoids but you'll need to swap the little filter to the correct nipple. Unfortunately this may result is more broken nipples...

imdrax

iTrader: (1)

***If it's not connected to the manifold (complete with correctly oriented check valve), the twin-scroll system won't work. Manifold vacuum is used to close the flap, so without it the flap will remain open. You can use one of the other solenoids but you'll need to swap the little filter to the correct nipple. Unfortunately this may result is more broken nipples...***

ok so this is my take on this.. when vacuum is applied to the actuator it keeps a secondary wastegate flapper type door shut in order to help spin the turbine faster and as the car builds boost the signal being sent to the solenoid will now be a positive pressure thus resulting in the vacuum signal that has been suplied to the actuator to be cut off causing the flapper to now go open? is this right or am i way off? also, the way the car sits right now (with the line running to the actuator seeing atmospheric pressure at all times i.e. not connected to anything) ,besides increase lag persay, will it affect any other aspect of the engines running condition? if only i knew exactly what this "actuator" physically did i would be able to understand things alot better. this is my first rx7 but not my first turbo car. ive had MANY DSM's and they dont use a system like this and furthermore ive never even heard of it before i started to research the rx7. thank you for any input.

imdrax

iTrader: (1)

one more thing, just out of curiousity what would be the difference between the way i currently have the actuator, and if i were to run the source line straight to a vacuum nipple on the intake manifold? for example the same one you would run the solenoid line to, but instead bypass the solenoid and check valve completely.

NZConvertible

AFAIK this sytem is unique to the S4 RX-7. Many other cars used and still use twin-scroll turbos, but none had the S4's control system.

The flap covers one of the turbine's scrolls when closed, forcing all the exhaust gas down the other scroll. This increases it's velocity so it hits the turbine harder, accelerating it faster.

The flap is held open by a spring in the actuator, and applying vacuum to the actuator pulls the flap closed. When the solenoid is turned on by the ECU, the actuator sees manifold vac. When the solenoid is turned off, the actuator sees atmospheric pressure.

When the engine is started, the ECU turns on the solenoid and the flap is pulled closed. The check valve holds the vac in the actuator even if manifold vac changes, holding the flap closed. When the engine exceeds 2700rpm the solenoid is turned off, the vac is released to atmosphere and the flap springs open. When the engine speed drops below 2700rpm the solenoid is turned back on, the flap is pulled closed and the cycle repeats.

Without the solenoid and check valve the flap would open the instant you put your foot down no matter what the revs were. This would make the system completely ineffective and useless. With nothing connected and the flap held open by the actuator's spring, there are no negative effects other than increased turbo lag at low revs.

imdrax

iTrader: (1)

ok so what would happen if i were to hook up the line straight to a vacuum source with no solenoid?

NZConvertible

Did you miss this bit?

imdrax

iTrader: (1)

i saw that but didnt know if your were reffering to if the line was hooked up to a vacuum source without using the solenoid and c.v. or if you left the line not hooked to ANYTHING. thats what im after. i want to know what, if any, the difference would be between running the line unhooked to ANYTHING or hooked straight to a vacuum source without the solenoid and c.v.