surreybrad

As I live in Canada where our dollar is worth $.73 and everything costs twice what it does 20 miles away in the US I decided to build my own CAI. I saw a video on youtube about making your own CAI because the cost of a K&N was beyond me after exchange, shipping, tax, and whatever else makes it so expensive up here. Of course I had to test it which is always fun and it really did work. Unfortunately things started to go wrong quickly. My fuel mileage dropped and when I would start the engine warm it would rev up for about 10 seconds. I just began to lose power until today when I put the factory system back on. Just wondering if anyone else tried to build their own and suffered the side effects. If so what did you do and were you able to make it work.

To build it I bought a 12" piece of 4" PCV pipe and used aluminum flex pipe to make the bend. I then added a Edelbrock cone style filter at the end which was mounted Just below the engine bay with direct access to the air underneath the car.

Injuneer

Is the IAT sensor still connected and functioning?

Ditto on the coolant temp sensor in the water pump.

SES light on?

surreybrad

All sensors were connected and no SES lights. I did the ground thing on the OBD plug and it gave no error codes.

Injuneer

Did you get DTC 12 acknowledging the ECM was in diagnostic mode?

Do you still have the stock rubber 90-degree inlet elbow, with the 4" PVC pipe connected to it? Is the aluminum flex tube used to bend down from the horizontal 4" PVC pipe, toward the hole in the front fender structure? Is this like flexible dryer tubing? Is it possible it is collapsing under the intake vacuum?

How big is the Edelbrock cone filter?

surreybrad

Yes the DTC did show the diagnostic mode and then no issues. Yes the factory rubber elbow was used. The dryer flex tubing didn't collapes and we made sure the joints were well sealed. The filter has a 4" inlet expanding to 6" and is 6" long. it's the same size as a K&N filter. I made sure I included the pipe that connects to the egr system (I think) just before it bends around the brake lines in my homemade CAI. Something I should mention is that when I take the rubber elbow off the TB I notice the butterfly valve is closed when it starts. I wondered if that is supposed to be closed. It didn't open when it started right away either.

Injuneer

The connection mid-way up the intake tube it for the AIR pump, not EGR.

The throttle body blades are only actuated by your foot. They stay closed when you turn the key to start, and when the engine starts. The air required to allow the engine to start and idle is supplied by the idle air control valve, in the base of the throttle body. That is positioned by the ECM to control the idle speed.

If the engine runs fine when you use the stock intake, and also without the inlet ducting in place, it has to be a restriction of some sort in your homemade unit. Does the hood crush the dryer tube when it shuts? There is very little room between the radiator and the ABS unit.

Does your filter require oil? Did you possibly overload it with oil?

surreybrad

Air pump, okay, I appreciate the knowledge I get from your replies as my knowledge has been restricted to carbs and pre 90s vehicles. As I intend to keep and build up my Z28 I need to learn all about it. To the clearance issue with the hood it's about a 1/8th of an inch. I am beginning to think I left the filter to exposed to dirt and rain. Being blue it's not as easy to tell. I blast it out with air but I know it doesn't mean it's drawing enougfh air. Would it be better to move the filter up and build an insulated box leaving the air to come up through the hole I cut out to get the filter and tube through. I removed the small piece of plate under that area as well so air flow would be good. Maybe the problem is the filter getting damp and staying blocked when it dries out?

Injuneer

The typical CAI filter is located in the left front fender, with the plastic shielding under/behind the front bumper still in place, and below the filter. But some people add a small scoop to the shielding, and don't experience problems.

Is this a reusable "gauze" type filter, that requires a VERY LIGHT coating of oil? If so, do NOT use compressed air to blow dirt off it. It should be washed with soapy water and rinsed completely, allowed to dry, and VERY LIGHTLY reoiled.

surreybrad

No it's not the reusable type. I can now see that I followed the wrong video. I am going to follow the system you just described and replace the panel. I'll go with the scoop to help bring air in. The Edelbrock filter was only $25 so I'll get a new one to be sure and do as others have done. Once again I appreciate the knowledge, feedback, and advice, and will let you know if this revised system solved the problems. Thanks, Brad

maybe2fast

I sounds like something was connected correctly...but you are a 93 so no MAF

Injuneer

The "scoop" isn't really necessary.