Well ... this is certainly an interesting little discovery....

After my initial problem getting the check engine light on the SRT6 roadster I just recently bought (preventing me from passing the emissions test, to get my plates transferred over to it!) -- I tried a forum member's suggestion to take out the K&N filters and clean/recharge them.

They were a little dirty, but not horrible ... but I got them cleaned up like new and used a recharger kit on them. Reset the code and drove around for a week or so.

On my trip over to get the emissions test done this morning, guess what? Check engine light comes back on! Argh...

So back to these trusty forums I go for more suggestions... Got the idea this could well be caused by a small vacuum leak, so I started looking all over under the hood for a possible culprit. Didn't spot anything, but I did suddenly notice a little white plastic box with 2 sets of bundled wires coming out of it. Sure didn't look like anything that came with the Crossfire originally, so I got a stubby screwdriver out and was able to unfasten the box to pull it out and see what it was.

Turned out it was this:

Flex-Fuel Conversion

So maybe THIS is my whole issue! Looks like someone did a conversion on my car to run on E85! (I've been putting 93 octane premium gas in it so far. We barely even have any gas stations selling E85 here in St. Louis, MO.)

Anyone know more about this particular conversion? The website talks about the box simply plugging into existing harnesses, but honestly, I can't see anything easy to just disconnect here. All I see is where the guy has the wires off the thing zip-tied as they run down under the engine until I can't see where they go anymore. And the website doesn't even tell you anything about how to install one of these systems. It only refers you to mechanics who install them for you.

 

need to call them. e85 requires huge injectors and tuning to use the corn. its not as simple as a box to run corn

 

I don't know about all that?

I managed to find a technical installation document on the net, now, for this particular unit, and they pretty clearly claim it works with your stock injectors. That's how it seems to hook up... mated directly to the 6 fuel injectors, plus another set of wires for power/ground.

It claims it works in conjunction with your existing engine computer and factory components, but simply increases the injectors' pulse width beyond what's programmed in to the factory computer when it detects E85 fuel is in use.

I'm pretty sure this thing isn't helping advance your timing to make more power from the extra octane, so much as it's just designed as a safe way to run on E85 for "environmentally friendly" reasons and maybe some small potential cost savings on the fill-ups.

I found out, too, the unit has a potentiometer inside you can turn to settings between 1-10, and apparently, a setting of 5 is the factory default and recommended "for 90% of vehicles on the road". But they specifically say if you're getting codes about the fuel mixture being too rich, to turn it down to 4 and try again. In my case, it was already turned all the way down to 2. To experiment, I turned it to 1, and my car started idling weird (occasional surges), so I changed it back to 5. Now it's idling and running normally again -- but guess I'll have to see if the CEL comes back or not with more driving.

 

I would remove that garbage and put everything back to stock. Just my opinion anyway. Ethanol is garbage. Wouldnt run it if it was half the cost of plain gasoline.

 

DING-DING-DING-DING

And the correct answer is: see above

 

For a near stock (bolt-on) car I agree. For high horsepower applications, Ethanol is a lot cheaper to get the higher octane ratings and a cooler charge. E85 is approximately 107 octane, E75 is 103 and E70 is 100 octane. unleaded 100 octane gasoline cost anywhere from $4.50 - $5.50 per gallon. Let alone the lower EGTs from ethanol.

 

Eric did a write up a while back

https://www.crossfireforum.org/forum...d-srt-6-a.html

 

Yeah, I saw Eric's write-up and read through it. But it sounds like he had some sort of custom ECU tune before he installed the E85 conversion equipment, and even had his tune optimizes for the E85 after that.

It's *possible* my car has a custom tune too, but I don't really have any way of knowing, since I bought it used from a dealer. As far as I can determine, it was never owned by any member of this forum before either.

I'm hesitant to just tear this out at the moment, in case other things HAVE been changed for it, and will give me problems without it in place.

 

Well, the Rauscher's own that car now....so, I am sure if Franc sees this post he will let you know how the 6 is doing....

I would spend the money for a tune, and get rid of that device. Eric's was just an ECU tune, plus the device. I ran with him at US41. I have since past his best times, without it...but will be installing the meth soon I hope...

 

Go back to the dealer and tell him he sold you a POS that won't pass smog because it's been modified from factory settings. What state is this dealer in? And why didn't the dealer know the conversion was present? Great used car inspection program.

 

All E85 conversions I have seen use a male and female fuel injectors connector on what is termed a spider harness. Your factory injector is unplugged, and one connector of the spider harness plugs into the OEM harness. Then, the mating connector of the spider harness plugs into your stock injector. Here is how it works. The stock computer sends out a calculated fuel pulse. This pulse is diverted to the E85 box which adds a pre calculated percentage to the factory fuel pulse. That increased pulse goes to the stock injector. To go back to stock, follow the wiring until you find the dual injector connectors. Disconnect the E85 box and connect OEM connector back to your injector.

 

Yeah, I'd like to - but that's a lot of trouble because I drove all the way up to a northern suburb of Chicago, IL to get this car in the first place. It was sold at Rockenbach Chevrolet in Grayslake, IL.

I'm sure their "used car inspection" program pretty much consists of slapping new tires on the car, changing the oil, and verifying all the lights work properly. They pretty clearly knew next to nothing about the Crossfire. Initially, when I saw them advertising it, they were asking something ridiculously high for it like $23,900. I only jumped at the chance to buy it when they discounted it a second time, down to around $16K.

Regardless .... it's clear that these conversion kits have at least some value to them. The one they have on here still seems to sell for about $425 on the manufacturer's web page. So I imagine I'm just as well off to disconnect it and put it up for sale someplace, vs. complaining to a dealer who would just remove the thing and keep it.

Right now, I'm really just trying to determine if this thing is the cause of my CELs or not. According to the instructions for it, at least, it's not supposed to be, as long as it's set properly. The claim seems to be that I can still run normal gasoline whenever i want to with it attached. It simply increases my options so E85 becomes another choice.

I emailed the company to verify this, though.

 

How does it sense the amount of E85 in the fuel? Increasing the injector pulse width would just cause higher fuel trims. I would love to see how this thing changes closed loop AFRs.

 

When e85 is used, the afr on the stock fuel pulse will show lean so stock computer starts adding fuel pulse. The conversion box sees this and adds its fuel pulse offset, so then the stock computer will back off the fuel trims closer to normal. You have to remember in closed loop it is all about the 14.7 afr from the O2 sensors. What I would be curious is how the open loop afrs look. Most cars can run up to 64% total fuel trim before injector is maxxed out. But, you would get a lean bank code long before that. The box just increases the pulse so the factory computer does not have to. There is plenty of injector size to run e85.

 

Ok that makes total sense, thanks. I thought stoich for E85 was a different ratio, that's why I couldn't see how it would work. You can't get away from 14.7 on these cars, I've been trying to enrich closed loop for a while now (signal modifiers).

 

Yeah... all of that makes sense to me too. I'm pretty sure signal modifiers aren't viable anymore for modern ECUs and all of their sensors, if you're trying to do anything having to do with enriching closed loop settings or even fooling an ECU into advancing timing based on an alternate map or maps.

I went through some of that when I had my Hyundai Genesis Coupe V6. I foolishly paid over $450 for a "fuel controller" module from a place called Road Race Motorsports. It had plug and play harness connections to place itself in front of the MAF sensor and supposedly had a custom AFR map programmed into it, so it could lean out the overly rich defaults used in the factory maps -- gaining some power and saving gas at the same time.

Sounded good on paper, except in reality? The ECU was smart enough to learn around its changes over time. Basically, it had enough other sources of data input so it could see something had changed, and after 40-50 miles of driving, the improvements the box gave you initially were always negated (until you pulled the battery terminal and forced a reset, anyway).

I've become a big believer that with today's cars, you have to re-flash the ECU (and probably also the TCU) to make any worthwhile changes. This E85 box *may* also be this way, except I think it may actually work in this scenario because they're not attempting to trick anything to improve performance. They're basically keeping the ECU "content" that it's making its own adjustments within its usual tolerances, and getting back results that tell it the adjustments had the expected results.

 

I think you are right.
I tried doing that with a Split Second enricher. The ECU is hard to fool.

 

I will be glad to sell you a super mileage platinum gizmo optimizer for your carburetor that will get 150 mpg. Only $19.95 plus S+H. It's left over from my 66 Buick. Detroit kept these secret.

 

That thing won't work unless you also put on the fuel line magnets so those pesky ions in the fuel are in alignment before contact with the platinum gizmo ........

 

GIFSoup
You talkin' to me?