Hi all, I'm hoping someone could explain to me the exact circumstances under which the CEL will come on with the EGR code (16). I've had it come on lately every now and then, and then just go back out. Since yesterday the CEL comes on within seconds of starting the engine. I pulled the codes to check and it sure enough it's the EGR. Cleared the codes(unplugged battery for thirty minutes, and stand on the brake for some time). Unplugged and tested the EGR function sensor for a short. The wires from the plug to the sensor seem rather brittle though.

I'm wondering if the EGR is valve is busted, or the sensor is broken. Or basically wether it's stuck open...

Any thoughts?

 

Some more info...
I cleared the codes again, or so I thought...
So I went ahead and bridged the TEN and GND again but the EGR code is stil there, or maybe again. I didn't fire up the car, just switched the ignition to on.

So, the sensor is supposed to be continueous when the EGR valve is open, right? So, it should be closed when the car is turned off, but then again if it was stuck open I should have been able to measure it when I checked for a short...

Me == Stumped

Guess I'll have to do more testing.

 

EGR will fail around 75k mi. I have a receipt at home (not cheap). Do you have a CA car? ...thought only CA cars had EGR.

 

Not CA, but a '94. Only at 45k though.
I suppose I could remove the hose from the EGR to the intake and cap it of for the time being, until I figure it out. At least I would know that it's not open then. But I also have emissions coming up in a couple months...

Hmm, if it's stuck open, and I take the hose of the intake, then I should be able to notice exhaust coming out of there when the car is running....

 

I think I narrowed it down to the wire going from the EGR function sensor to the plug. Using an Ohm-meter I was getting inconsistent readings, sometime there was resistence other times there didn't seem to be any readings at all. It varies with the way I hold the wire and if I apply pressure to it. Measurements were taken from the the connectors on the plug.
I assume that the wire is damaged.

So, what would the normal state be for this with the car turned off? Should there be any resistence, should the circuit be closed or open?

And how would I fix that wire short of replacing the entire EGR valve... *shudder*

Thanks

 

I was also under the impression that the code 16 was only for california vehicles. Your car might be California-spec. I think the ECU will be slightly different.

There are two different things that could be the problem, the EGR valve itself (test this with vacuum tester), or just the electrical switch that verifies that the EGR valve is opening when it's supposed to be opening.

There's a fix for the electrical switch, I haven't tried it myself, but here's a link:

https://www.rx7club.com/showthread.p...threadid=21848

-s-

 

I am the original owner of '94 FD, purchased 9/94, currently stock except for a Bonez downpipe. The EGR history of the car runs something like this:

5/3/95......8838 mi...EGR replaced under warranty.
11/15/95...13287 miles...EGR replaced under warranty.
4/19/96...16989 miles...EGR replaced under warranty.
5/15/96...17551 miles...Intake manifold gaskets P/N N3A1-13-112 and N3A1-13-111A installed in place of original gaskets due to previous EGR problems; supposed to eliminate future problems.

The car now has about 80 K miles on it, and Code 16 has once again come up. I would like to fix the problem, whether just the sensor contacts or the actual EGR valve, and I would like the operation restored, not bypassed. Contrary to a statement in the above-referenced link, EGR does NOT reduce HC emissions, it reduces NOx emissions. This is a CA car, and I live in CA and also have an emissions test coming up soon. In 2002 I had a disaster caused by failure on CO, followed by buying a new aftermarket cat and failing again, this time on HC, followed by several retest failures with new plugs, wires, O2 sensor, etc, followed by buying a new Mazda cat for $1200, followed by passing emissions. I want EVERYTHING associated with emissions controls working properly this time.

A new EGR valve will cost me $237, but I will diagnose what I have to see if I really need one. One thing that worries me is the solenoid EGR valve, which is buried on the driver's side of the engine. Does anyone have any experience with an EGR problem that had to be fixed by attacking the solenoid EGR valve?

 

You can retard the timing to lower the NOx. The testing places don't know how to test for timing on a rotary. Why didn't you use the denatured alcohol instead of buying a $1200 cat'? You could get two Knightsports cat's for that much cabbage.

 

GoRacer,

I don't want to retard the timing in order to "pass" emissions. I don't want to add denatured alcohol to "pass" emissions. I want the car to meet its specs. I don't think two Knightsports cats would fit under my car, and as I wrote above, I had already tried an aftermarket cat (a Bonez, from Rotary Performance) which did not work properly. IMHO it had to do with the internal design of the cat. Several different techs told me that cat was not large enough to work, and replacing it with the stock unit (although $1200, ouch) did fix the emissions.

To recap, I want the car to PASS, not "pass" emissions testing. Stock timing, working EGR, and hopefully no need for another new cat.

Anyway, has anyone had EGR-related problems with the solenoid EGR valve (control valve) as opposed to the EGR valve itself?