EGR with EFI

[CityHick]

As some of you know, I have started gathering EFI parts (finally). I've been searching around for information as much as I can and I'm aware of the EGR delete device that RJM sells, which fools the EEC with respect to EGR data.

My question is this - my engine (351w Ford crate motor) has non-EGR heads. The Lightning lower manifold and Explorer upper that I have both have EGR passages. Am I correct to assume that with non-EGR heads, when the lower intake manifold bolts on it'll just form a sealed no-man's land in the upper and lower intakes? Do I need to block these passages for reasons that are not obvious to me? Or do I just ignore the fact that they exist and run the RJM EGR delete electronic thing-a-ma-gig and go on about my merry way?

I'm sure I'll have more questions but I'm doing a lot of reading on my own to try and eliminate the really dumb questions...

[Lars]

Re: EGR with EFI

Ignore the passages. Unless you are running E7 heads (and you aren't) they are passages to nowhere.

The RJM device is just a resistor network. You can make your own and install it on the harness; I have the resistor values somewhere. What it does is to make the computer see the EGR vacuum operated valve as being stuck closed. It will throw a code (33, if memory serves) but it won't set the check engine light.

No one that I'm aware of seems to know exactly how the ECU handles the "failure" but it doesn't appear to affect performance. Note that in a perfect world, a functioning EGR system actually improves fuel economy. It does so by displacing air, which contains combustible oxygen, with exhaust gas, which is inert. Basically it's a lean-burn system. Just how much of an improvement, I can't say. I've never had a functioning system either, and I disabled all EGR functionality on my Bronco by flipping the appropriate bits with the chip on my ECU.

[Lars]

Re: EGR with EFI

More info...

I don't know if RJM is still selling anything, but American Bronco Company is. One thing they sell that is useful is the "EGR eliminator plate":

http://americanbronco.com/products/electrical.html

The plate sits between the upper intake and the throttle body; its most useful function for you is that it provides mounting tabs for using a Mustang 5.0 throttle cable, which is an easy (and cheap, if you get one from a yard) way to connect the gas pedal to the throttle body.

I see that they are now selling a combo with the EGR resistor network. Price looks attractive enough that I'd probably just go that route instead of sourcing the resistors.

[CityHick]

Re: EGR with EFI

Excellent, thanks Lars. I realize that EGR was intended to be an efficiency booster and I'd run it if my heads supported it but they don't. I don't think my budget will support a head swap at this time... but it doesn't sound like it really matters to me at this point. Baby steps.

I went through three yards just to find an upper intake from an Explorer. The one that I ended up with was conveniently already removed from the donor vehicle.

There do not seem to be many fox body mustangs in the yards anymore for donor computers and harnesses, throttle cables, etc. Thinking Craigslist and Ebay will be the more convenient options for the remaining parts that I still need.

[Lars]

Re: EGR with EFI

I manage to get a repeatable 16-17 mpg at 65 mph on my travels, Tony. Which frankly astonished me the first time I measured. The extra hassle (and limitations on compatible parts) to get EGR wasn't, and isn't worth it to me. I'm interested in a 351W myself, so I'm going to follow along with your build and see how it turns out, efficiency-wise. Pippin Mader in Woodland has a sweet running EFI 351W now (having driven it) but I haven't seen fuel burn numbers yet.

Depending on how cheap you are and how much you want to do yourself, my advice on the harness would be to consider buying one from a vendor. Big time saver. And the aftermarket harnesses I've seen have improvements on the OEM fox body harnesses while still using OEM Ford connectors and terminations. Nothing wrong with used, but you'll want to break into the harness and check insulation in a few spots. Those harnesses are coming up on 20 years old, and some I've seen were pretty nicely cooked.

[CityHick]

Re: EGR with EFI

I have given some thought to the aftermarket harnesses for the same concerns that you noted. That may be what I end up doing for ease and reliability. Investigating all options at this point and all input is welcome. I don't even give myself a timeline for this... when it happens it happens.

As for fuel economy - as a baseline right now my rig gets around 12mpg loaded down with gear. That is with 37" tires, no overdrive, and 4.11 axle gears and a 4-barrel carb that I'm sure could use some attention. I cruise 65mph at 2500 RPM, and the mpg calculation is not exact given that my speedo isn't accurate. I do calibrate with the GPS on my phone from time to time though. I should pay more attention but I don't.

My 351 was rated at 250hp/350 ft-lbs, peaks on both metrics being generated between 2500-3000 RPMs as I recall. I have never had it dyno'd to confirm where it's actually at but I suspect its a bit lower. Hard to say.

So... we'll see how this transpires.

[Delta 4 Wheel]

Re: EGR with EFI

I used the plate from http://www.ronmorrisperformance.com/05spec/index.html He also provided a sensor simuator to plug in avoiding a check engine light...but not like I even have one hooked up!

[GREMLIN]

Re: EGR with EFI

i used a throttle cable from cougar. stock pedal to mustang injection

[CityHick]

Re: EGR with EFI

Well... it turns out that I do have heads with EGR ports. I guess my original question is moot at this point. The good news is that all of the old carburetor junk is gone and my EFI manifold is sitting in its place today.

Time to order more parts


EDIT. Wasn't thinking when I originally posted this... After studying several 5.0/5.8L engine bays in the junkyard on Saturday I realized that I won't run EGR afterall. In my mind previously I was thinking that the passages in the upper and lower intakes were all that was needed. Then I realized there's an external EGR tube that goes up to the plate that sits behind the TB that "feeds" the passages in the upper and lower manifolds. So anyway... EGR eliminator kit ordered (thanks for the links above). Throttle cable ordered. I am getting very close on this.