I know there are a lot of posts regarding the installation of downpipes and the removal of the Air Pump and ACV…I just can't seem to find definitive answers or instructions. I apologize for yet another question and thank you all in advance for any help.

The situation is this: '87 Sport (No VDI) on which I am preparing to install the downpipe and presilencer. The down pipe has the pressure tube to allow the auxilliary ports to open. I can see where this connects on the split air pipe. Now, there will be no cats and I don't know what to do with the larger pipe on the split air pipe (The pipe that runs to the stock main cat.) If I remove the air pump, will I have to block anything off? Do I need to be concerned about the ACV? I'll move onto the EGR removal after I complete this project.

Thank you all,
Brian

 

Just remove the big SAP pipe, and cap it off at the back of the intake manifold. If you remove the air pump OR the ACV, you will render all of the emissions stuff useless. it all operates off air pressure from the air pump, and the ACV routes the air pressure. The only thing you should remove is the SAP pipe.

 

The ACV has 2 electrical connectors. When you remove the ACV what happens to the open connectors. Does this screw with the ECU when it's looking for a signal? Also, does the split air pipe that goes to the main cat get removed, does the reamining hole get a plate and gasket like the ACV?
SOrry, about all the questions. I just don't want to introduce any problems.

I noticed in the shop manual that the ACV can affect idle. Anyone wanna explain how?

Brian

 

Those two connectors do not send signals. One , forward is the port air solenoid valve and in inoperative after the first 20,000 miles. The other is the split air solenoid valve that is opened only when in fifth gear. If either or both is off, the car will never know it( should say you'll never know it). The ACV will not affect idle unless one of the diaphrams, like the switching valve diaphram, is torn internally. What happens then is the vac line going to it sucks air, just like having it sticking out in the breeze. I have this condition with one of my spare acv on the turbo. Makes the car idle slightly rough. On my 87N/A I run full dual pipes from front to rear with the acv still attached with the airpump. I have a block off plate for the split air tube but do not use it. I just leave a foot long hose attached and fully open to the elements. I can't hear it so its fine with me. At one point in time I did stick a old spark plug in the hose, but not lately.

 

Thank you Hailers. Why not remove your airpump and ACV?

B

 

I don't remove my air pump and acv because number one I'm lazy, number two is I'm lazy, and number three....one day a year I have to pass emmissions, so I rip off the dual pipes and put the stock exausts on. I used to have to put the acv back on and the air pump, but I got lazy a couple of years ago and just decided I'd leave the two on all the time so I wouln't have to screw with them. There is one other reason... the air pump helps my water pump belt not slip. I know RB sells a pulley to counteract that, but not only am I lazy, I'm cheap.

 

I think you and I would get along.

 

Too funny.

 

Hailers,

Did you also remove your EGR valve and vacuum solenoid mess, a.k.a. spider?

B

 

rxse7..... no, in one of my many not so bright moments, I found out that my egr valve had not been working for a couple of years and threw away over a hundred bucks for a new one from Mazdatrix. The car runs no better. Passes emmissions no better. I don't feel any better. Coulda made a block off plate for 50 cents. Had the vacuum line plugged for two years, coulda left that in place. Oh, the spider. Busted one of the **** and thought I'd do something right for the car just one time, so, Mazdatrix, big bucks, new spider. That is on the 87N/A. On the 87turbo I did not like all that equipment under the throttle body so I put the spider on the firewall with long vac hoses. Thats how I found out a couple of days ago that one of the four oil injectors was bad. I pulled each line off with the engine running, and found that one line did not have a vacuum. I did check each injector before installing them in the engine, but for some reason this one went bad. I'm going to leave it alone. Its just feeding more oil than is required. You know the throttle body on a turbo would be a cinch to remove and replace but for that water line on the bottom of the throttle body. It takes me for never to get the clamp back on that thing. Just complaining.

 

HAILERS,

In regards to the EGR VALVE, I guess it's main function is to burn off residual fuel in the exhaust, but does the ECU require it to maintain idle? In other words, if I remove the valve, block the hole and plug the vacuum hose(?) will the ECU be looking for whatever effect the EGR has on idle? Again, I'm just trying to remove redundant, parasitic or useless systems. Like yourself, I enjoy my car—just don't want spend half of the time playing rotary detective!

Also, if I remove the EGR, ACV, Air Pump AND have completed the TB MOD, do I need the vacuum solenoids at all?

B