EGR elimination ?'s

shootshescores

New Member
May 1, 2005
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For all of you who have removed your EGR's and/or went to a blank, could you provide some details on the process as well as some input on your engine's behavior after removal?
Just looking for some details.
Going to be purchasing a 70mm TB soon and was just wondering if I should keep the EGR system or remove it if its worth the trouble.
 
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Leave it on, unless you have a specific reason for removing it.

There are no gains to be had, performance or otherwise by removing the EGR. I have mine removed, but that is only because both the sensor and valve went bad, and I already had a Tweecer...so it was much easier and cheaper to remove it. But I wouldn't go out of my way to remove it for no reason....especially if you don't have the means to bypass it's function in the PCM.
 
Yes, but I want to say that an EGR failure code alters fuel trim at cruising RPMs. So it's not just a matter of the PCM turning off the function when the failure code is tripped, and nothing else is effected.
 
Yes, but I want to say that an EGR failure code alters fuel trim at cruising RPMs. So it's not just a matter of the PCM turning off the function when the failure code is tripped, and nothing else is effected.
No it doesn't, as explained in the GUFB strategy extract below, the FMEM table shown per sensor circuit failure, and many test cases I've worked over the years that had the EGR disabled (EGR failure codes logged), w/out the owner knowing about it.

EGR_FMEM.jpg


FMEM_Strat.jpg
 
I always thought that was true of EEC-V PCMs, because EEC-IV PCMs weren't able to alter fuel trims based on failing components.

You learn something new everyday. :)
 
If I can't fix the problem then its bye-bye EGR.
It seems like a pretty simple task to remove the EGR. I can just take the car to Alternative Auto and have them delete things in the computer. Are there any surprises I may need to know about?
 
If I can't fix the problem then its bye-bye EGR.
It seems like a pretty simple task to remove the EGR. I can just take the car to Alternative Auto and have them delete things in the computer. Are there any surprises I may need to know about?

You were given good information regarding how to check the EVP signal through its range, suggest to verify for 5vdc VREF, the integrity of the SIGRTN ground reference for the sensor, and the mechanical aspect of the valve........ if these check OK, you only need to replace the EVP sensor, which BTW is the most common cause for that type of failure code. LUK
 
I used an egr simulator, don't really know if it ever did anything productive for me, but it was $20 and plugged in, and i had no codes, so....

U can get them on ebay.
 
I plan on checking out the EVP today to see if I should order my throttle body with an EGR blank or with the EGR plate. If the EVP's bad I plan on eliminating the EGR system.

Does anyone have any tech articles that describe the EGR system removal steps in depth?
 
I plan on checking out the EVP today to see if I should order my throttle body with an EGR blank or with the EGR plate. If the EVP's bad I plan on eliminating the EGR system.

Does anyone have any tech articles that describe the EGR system removal steps in depth?

Well, I had zero volts when I tested the EVP sensor before and after depressing the plunger.

I think my best bet is to eliminate the system with a new throttle body with EGR blank vs. replacing the broken parts. I haven't replaced my stock TB yet so why not. What do you guys think?
 
I used an egr simulator, don't really know if it ever did anything productive for me, but it was $20 and plugged in, and i had no codes, so....

U can get them on ebay.


That may be leaning you out at part throttle.

It's telling the computer the EGR is working and dumping inert gas into the chamber so the computer pulls fuel out. However...that inert gas is replaced by combustible gas and now you are running lean.



BTW, the purpose of the EGR is to improve emmissions and fuel economy as well by reducing the amount of fuel used during cruising.
 
That may be leaning you out at part throttle.

It's telling the computer the EGR is working and dumping inert gas into the chamber so the computer pulls fuel out. However...that inert gas is replaced by combustible gas and now you are running lean.



BTW, the purpose of the EGR is to improve emmissions and fuel economy as well by reducing the amount of fuel used during cruising.
Nope.... as soon as a code 33, or any EGR related code is registered, the EGR function is disabled, deleted, bypassed.

BTW.... if the inert gases were replaced by combustible gases, the O2 sensors will detect that condition and cause the EEC to perform a fuel trim correction.... close loop operation is not affected by the EGR being snafu'ed or with failure codes, as explained in the GUFB strategy.....

EGR_FMEM.jpg
 
Nope.... as soon as a code 33, or any EGR related code is registered, the EGR function is disabled, deleted, bypassed.


But i beleive the function of those resistor circuits it to trick the EEC into thinking the EGR works and therefore not trip the code 33 at all?

Not sure if that's true. I've never looked into what those EGR electronic resistor bypasses did
 
But i beleive the function of those resistor circuits it to trick the EEC into thinking the EGR works and therefore not trip the code 33 at all?

Not sure if that's true. I've never looked into what those EGR electronic resistor bypasses did

They cause the EVP signal to be set between .24 vdc and .67 vdc (= closed EGR valve "pass" window, or prevent a code 31 or 34)..... since there is no EGR valve actuation to cause the EVP signal to increase when the EEC cycles the EVR solenoid to open the valve..... the EEC detects the valve as "not opening" when commanded to....... a code 33 is logged, the EGR function is automatically deleted/bypassed and the CEL is not triggered.
 
OK so here is my question (sorry OP)..

I am about to perform a 5.oh swap in my 91 hatch. Should i even bother with all the sensors (as in hooking up all the vac lines, EGR sensor, and the small sensors on the passenger side rear shock tower)??????

I am going to run a high flow X pipe WITH cats, and run the smog pump. I want to get through emissions and with a good catted pipe i should be ok. I'm just worried the car will not run right (i want a nice cruising car).