I am putting a 91 na motor in a 88. I noticed that on the 88 there is an egr valve on the middle housing in between the front and rear rotor housing, but on the 91 there is not. I was wondering where the egr valve is on the 91 motor. Please help i live in ca the worst state ever for cars lol...

 

Is it on the Intake manafold

 

S5s did not have EGR valves. You'll have to ignore the fact that your engine is missing it, and hope smog techs don't go looking. It would be tucked under the intake manifold on an S4 NA anyhow, so it's not really in plain sight. Plus, most people have no clue what they're looking at anyway.

Unfortunately, there is no "legal" way of pulling it off, as getting the engine swap approved by a state referee would not be possible. An engine swapped in must have the same emissions equipment, or more than the original engine. But since the S5 lacks the useless EGR, it'll be a no-go. As far as passing the sniffer portion of the test, not having one will make zero difference in NOx levels.

I ran an S5 manifold on my S4 NA engine for a short while, but did not need to smog it during that time, so I never had to pull it off. But if you find a good smog tech that doesn't obsess over the visual test, you'll be just fine. Oh, and DO NOT say the engine was swapped. That will lead to all sorts of problems, if they want to be a dick.

 

Is there somewhere i can see a picture? I see a valve of some kind but it dosent look like an egr valve. Thanks for the help.

 

Read my post. It doesn't exist on an S5 engine. Emissions laws between '89 and '92 allowed Mazda to omit it.

 

sorry i posted and didn't see yours. Thanks.