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Old 08-31-2010, 01:31 PM   #1
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Default MS, EGR and emmisions

I have a 95 (OBD I with EGR) and emissions are done with a sniffer.
I just ordered a MS, I'm planning to go standalone. What should I do with the EGR? The MS threads don't mention EGR and it seem like the ECU would have to control the valve so I take it people just disable the EGR?

The EGR pipe is in the way of the coolant reroute so I like the idea of getting rid of it. I'm buying a used FM manifold/turbo/downpipe setup from a 99, the manifold fits the head but the EGR bung is in the wrong location.If I get rid of the EGR, that shouldn't be an issue.

Has anyone had issues passing emissions with an OBD I 1.8 with standalone MS without EGR?
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Old 09-08-2010, 08:40 PM   #2
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Default I'm curious too

I'm curious too if anyone is using a MS setup to control EGR, evap purge solenoid, or the PRC solenoid too. The silence seems to indicate not, and I'm having a hard time finding good information on the algorithms in case I wanted to take a shot at implementing it myself.
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Old 09-08-2010, 11:04 PM   #3
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Quote:
Originally Posted by guzerone View Post
The MS threads don't mention EGR and it seem like the ECU would have to control the valve so I take it people just disable the EGR?
Typically, EGR is simply discarded when installing any standalone ECU, along with the canister purge valve and so on.

Actually, canister purge would be extremely easy to implement. Just a simple relay driver set to active whenever TPS (or MAP) > a midrangeish threshold.

EGR would be a little harder. I know that it's a PWM control scheme, however it has four coils and I've never seen any sort of documentation on how they are configured and driven. Possible? Probably. I just don't think that anyone has ever put much effort into it, since it's not really a power adder.

It should be entirely possible to tune the engine to pass without it. There are still vehicles being made today which don't have EGR. The EJ255-equipped Subarus, for instance, don't have it. They do have three cats and a very low CR, but still...
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Old 09-09-2010, 12:59 AM   #4
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Sorry for my ignorance - does that mean that the purge solenoid could just be continuously open at part throttle (assuming the solenoid is normally open to atmosphere)? Does it need any sort of a timer-based cycling scheme?
I do notice that there is an EGR position sensor, so I figure there's some sort of feedback loop going along with a PWM drive. I guess if I want to know more I should go figure it out, but as you point out, the reward isn't there. Maybe I can pass CA emissions anyway - I didn't realize that there were production cars without EGR.

Quote:
Originally Posted by Joe Perez View Post
Typically, EGR is simply discarded when installing any standalone ECU, along with the canister purge valve and so on.

Actually, canister purge would be extremely easy to implement. Just a simple relay driver set to active whenever TPS (or MAP) > a midrangeish threshold.

EGR would be a little harder. I know that it's a PWM control scheme, however it has four coils and I've never seen any sort of documentation on how they are configured and driven. Possible? Probably. I just don't think that anyone has ever put much effort into it, since it's not really a power adder.

It should be entirely possible to tune the engine to pass without it. There are still vehicles being made today which don't have EGR. The EJ255-equipped Subarus, for instance, don't have it. They do have three cats and a very low CR, but still...
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Old 09-09-2010, 01:16 AM   #5
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is the EGR valve basically stuck "shut" when you install a standalone such as MS.. or stuck open?
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Old 09-09-2010, 03:06 PM   #6
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It better be closed.

Here's a thought, could the EGR or Purge solenoid be used for boost control?
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Old 09-09-2010, 03:31 PM   #7
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its shut. I have mine capped, but IF I knew how to operate it with the megasquirt, I'd simply vent it to atmosphere and use it to help idle with A/C.
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