No EGR/DPFE system?

[Rockledge]

Hi all,

I looked at a '94 ATX motor today and noticed it had an EGR valve and a DPFE sensor. My '94 MTX does not have any sort of EGR/DPFE setup, just a cover plate where the valve would normally be ....I hadn't really given it much thought until now.

I am wondering why there is a difference b/t my MTX and the ATX regarding emmisions control?

Any feedback on this would be appreciated.

 

[Mr Anonymous]

Generally, only CA MTX's had EGR, whereas all ATX's have EGR.

 

[Groo]

Every ATX SHO came with an EGR system. Only California MTX SHOs came with EGR, the rest were EGR free.

The reason your MTX has a spot for it is because, at the time, Ford used the same manifolds for both the MTX and ATX, they just drilled out paths on the ATX manifolds.

 

[Rockledge]

So without the EGR valve, I'm probably blowing more NOx out, but getting more air and fuel into the combustion chamber which probably helps performance, right?

It makes me wonder too if the MTX and ATX are held to the same standards when testing for emissions...?

 

[Mr Anonymous]

You're thinking too hard. Just be glad you don't have all that extra carbon entering your intake tract and gumming up the works. Emission standards are the same regardless.

 

[Rockledge]

SHOooo:
You're thinking too hard. Just be glad you don't have all that extra carbon entering your intake tract and gumming up the works. Emission standards are the same regardless.

I guess maybe you're right ... I have a feeling I'm thinking about it because of my experience with the 3.0L vulcan ...as you probably know, the vulcan is prone to pinging and the EGR system is one of the ways in which that is kept under control (cooler combustion chamber temps)...sort of a nice by-product of the original purpose of the EGR system (emissions control). So I'm trying to get feel for the differences in the motors.

Also, I did a carfax on my SHO before I bought it and it failed emmissions a few times before finally passing (you guessed it...NOx levels too high). Even when it did pass it did so by the slimmest of margins. So I have to keep that in mind, even though I know the car is running much better now since i've acquired it.

And I agree wholeheartedly with you regarding the benefit of no EGR system blowing crud into the intake...

Here's another related question...the computers for California MTXs would have to be different than the other 49 state MTX computers because of the EGR system difference, is that correct?

 

[NotSoSlowSHO]

Somehow my CA SHO managed to sneek past the EGR getup.

According to the paperwork I have (I have it all, original documentation, order, fees, window sticker...) My '89 was special ordered. It came from New Jersey, but has always been registered in CA. and no EGR shrug

 

[SHOZ123]

My '97 doesn't have any EGR components either. thumb

 

[sdpatt]

The abscence of the EGR system on the 49-state MTX SHOs may come back to haunt us as the emission regulations are only getting more restrictive. The regulations were not nearly as limiting when the SHO was originally produced in the late 1980s and I recently had difficulty getting my 1991 SHO to pass the NOx limits in Dallas County on the annual inspection dyno tests.

It is the function of the recirculated exhaust gasses to lower the combustion temperatures to minimize the production of the NOx combustion byproducts. Only by correcting all vacuum leaks was the engine able to get clsoe to the rather restrictive NOx limits in the smog zone of Dallas. Removing the SPOUT plug dropped the NOx output to values far below the limits and the engine was then able to pass.

This points out a problem that these older engines may have in this country's current environmental climate. They were not designed to restrict their emissions output to comply with the present and possibly future emissions regulations. This is not just the SHO's problem, but that of many older automobiles that were designed and produced before the environmentalists and air quality required that they breathe more cleanly.