94 Miata egr delete questions

So turns out the egr needs to be deleted on my 94 miata due to my cheap header. Does anybody have pics of what the intake is supposed to look like with it deleted?

Random thought: could I just put a pipe plug on the egr tube and call it a day?

I was in the same boat last fall with a Raceland header on my 94. I don't know why they include a EGR connector if it doesn't remotely line up. Here is what I did.

1. Welded a rounded peice to a nut that I put on a raceland header EGR fitting. The rounded peice allowed the thin nut I found to screw in with enough threads. Used locate.
2. Blocked off the EGR valve.

If only there was a company that specialized in Miata performance...

Intake manifold side: https://www.flyinmiata.com/egr-block-off-plate.html
Exhaust manifold side: https://www.flyinmiata.com/1994-97-2001-05-egr-cap.html

If you're running a stock ECU, expect a permanent check engine light and possibly some odd running behavior.

If your cheap header is fitted with the EGR fitting for a different Miata, we may have the EGR parts needed to keep the system functioning.

In reply to Keith Tanner: What kind of odd behavior should I expect?

I'm not 100% sure on how the stock ECU handles an EGR failure. It may fail gracefully, or you might have bad fueling under certain conditions. Keep in mind that the permanent CEL will mask any other CELs the car might throw - you'll expect the light to be on, so you won't know when something else triggers it.

As you can probably tell, I'd rather see you keep it working than remove it.

Fitzauto wrote: In reply to Keith Tanner: What kind of odd behavior should I expect?

Keith likely knows more... but typically you may get some surging while on the highway...(lean condition because there is no exhaust flow mixing with the intake) anywhere the EGR system is usually active, is where you may get odd ball running.

I was under the impression the OEM exhaust manifold in '94 was pretty good.

There's not much to be found in a header for those cars, 'tis true. Unless you're chasing everything.

Pretty much chasing everything and the manifold was leaking pretty bad. Planning on switching over to megasquirt asap.

That'll give you a bigger power boost than a header, and will sidestep the no-EGR problem. Done!

In reply to Keith Tanner:

Which megasquirt do you recommend? Im leaning towards 2.

I recommend the Hydra

The MS3 Pro is a modern ECU. The MS2 is roughly equivalent to the old Link we used to sell in the late 90s.

In reply to Keith Tanner:

Better question: is the MS2 good enough for a csp car?

Will it run, especially like a race car (ie, a little rough in the tough spots but happy at full throttle)? Yes.

Will you be at an advantage to someone with a stock ECU? Yes.

Will you be at a disadvantage to someone with a modern ECU? Yes.

For the record, my car with OEM ecu threw a code with the EGR removed. When reinstalled in the car, but blocked off, it does not. (Granted it might only have 1.5 hours of run time)

While the MS2 is lower-spec than the MS3 (or Hydra), it's a ton better than a 90s-era Link.

We've not had the same experiences, then.

I have a block-off plate on the intake side and a plug (read: hammered-over EGR tube) on the header. I left the valve plugged in and dangling. It trips a CEL but it doesn't run any differently. I pass emissions every time because the ECU goes full-ready before it notices the EGR isn't working exactly right. I've had it this way since I put the engine in 6 years ago.

Got it all buttoned up. Ended up just putting a cap on the egr tube to hold it over until I get MS. The car is throwing no codes and run well.

Keith Tanner wrote: I'm not 100% sure on how the stock ECU handles an EGR failure. It may fail gracefully, or you might have bad fueling under certain conditions. Keep in mind that the permanent CEL will mask any other CELs the car might throw - you'll expect the light to be on, so you won't know when something else triggers it. As you can probably tell, I'd rather see you keep it working than remove it.

I can tell you in a '99 it ends up acting down on power/hesitating/surging a little at steady rpm light load. Romp on the throttle and it is happy.

So I've bought a cheap CA-emissions car with some manner of EGR delete done. Racing Beat header with EGR visibly capped. Haven't dug around to see what else is left of the system yet but based on the info in this thread it seems the only way to get rid of the CEL/code is to revert the EGR system to full functionality? I have seen people post elsewhere that there is a way to loop a certain vacuum line to eliminate the CEL but no further details, and it sounds like the questionable running condition will remain. Note that the car in question is emissions exempt, but I don't want the constant CEL or the weird running at cruising rpm.

There's really no advantage to an EGR delete, so I'd just fix it.

RedGT - Here's the best pics I've seen of the reroute.

Here's the original vacuum routing to the EGR:

Swap the cap from #2 to #1 to do this:

Although most people will use a longer tube and go under the throttlebody is my understanding.

Thanks, would be nice to shut up the CEL until I fix it, and yes Keith the long term plan is to fix it properly. I have access to a '99 federal log manfiold and '99 EGR tube...or i could buy a '01 EGR tube to fit this 01 header...depends how borked the threads on the header are and if I want to run it in ES autocross for E36 M3s and giggles.

I've got a 99 on the lift with the same CEL, although it's on a stock header and plumbed up properly.
I pulled the EGR off, it didn't seem too choked up (the plunger moved freely), so I'm going to pop the top of the intake manifold off and try to clean the port next. My understanding is that they'll pop that code even if everything is working perfectly because the stock vacuum port doesn't deliver a good, clean vacuum source so the ECU throws the CEL. So even if/when you get it all fixed up, you may still need the reroute to fix the problem.