So I recently switched over to E85, this is my 3rd tank actually. Last night I was down to about 2 gallons of E85 left and decide to fill up at the only place in town. So far, the car is loving the E85. I haven't had any troubles with the tune while everything was normal... well until last night. After I filled up and went for about 25 miles, my car started to act up. I was no longer able to get into boost like usual and the AFR was super lean like 16-19afr on the XD-1 gauge so I immediately left off. Nothing changed between before fill up or after, I didn't touch anything so all things point the the E85 I just got. Is it possible that the E85 is causing this? I've changed the map back to pump gas just to see if anything would happen and actually it runs like normal when not in boost but when under boost, the AFR is still very lean (14's) so now I'm just putting around town and going back to 91 my next tank.

 

Sounds like fuel shortage under boost.

1. Dirty fuel filter?

2. Fuel pump failure or partial failure?

3. Plugged up / dirty injector(s)?

4. FPR failure or partial failure?

You might want to get a small mechanical pressure gage on a length of hose and tee into fuel rail. Tape gage on windshield in plain view. Test drive car and ease into boost keeping an eye on the FP gage.

 

My Defi Fuel pressure gauge read 70psi @ WOT which was what its been running prior to the fill up. It is reading at the FPR. I have it on record and my second walbro kicks in at 4 psi of boost which jumps my FP up a few psi which is noticeable. The pumps seems to work fine, I'm thinking about changing the fuel filter and is there any way to check if the injectors are dirty or plugged?

 

Check the filter, same thing happened to my personal car.

 

I have heard of stories of bad E-85. Supossedly batchs of E-85 can vary and are more like E-70. Good luck with your situation and hopefully it was just a bad tank.

 

Just my luck. I try to pull the intank pump out to have a peak to see if its the filter. Looks like one of the 8mm nut is strip from the previous owner installing a walbro so now I can't even get the nut off. WTF!

I don't what to do about it, I've try everything short of cutting the bolt off but since its the fuel tank, I have a spark and fuel issue and if I was to cut it off, I may run into pressurization issues after wards?

 

have you tried those small vice grips?

 

That wouldn't make it lean out though, if anything it would richen up

 

I'm gonna run to the store in a bit to pick up a pair, the ones I have are too big. Thanks for the suggestion!

 

You might try back flushing the injectors.... you will be surprised how much junk you will get out of them....

 

so I finally able to check the in tank filter, it had a little bit of particles but nothing enough that would have clogged the pump or filter. The tank and pump looks good, I also verified that the second pump is working, I do have an external filter but I don't think that it is my problem either since the in tank hardware is good.

How do you back flush the injector?

 

Supra injector flush.

Porsche 911 injector flush.

 

I did some more monitoring while I was driving around. What I noticed on the LC-1 was it idles around 14.7-15.5 afr gasoline. When I cruise it stays anywhere from 15.5-16.5, then this is where it gets interesting... when i blimp the throttle, the AFR goes to anywhere from 17.0-18.5. This happens like I said when I blimp the throttle or just ease into the throttle, then as I stay on light throttle, the AFR drops back down to 15-16.5 AFR then when I let off, the AFR drops all the way down to 10.0 and slowly works its way back to a 14.7-15.5 idle.

Prior to this ordeal, it would cruise at a steady 14.5-15.5 range while it drops to the low 12's under WOT. AT lift off, it still went down to 10.0 and back to 14.7ish. It never cruise higher than that nor did it ever go lean when I blimp or tap the throttle.

So far I have done the following:

-Verify in tank fuel filter is not clogged
-In tank fp is working properly
-No residue or excessive dirt in the gas tank
-Second fp is working properly


I'm wondering if something is wrong with my tune or something. I'm running race tuner/accessport and like I said, the map ran fine for the first two tanks of gas and then this. Nothing has change to the hardware and nothing to the software after the initial adjustments to the tune to run E85.

In the meantime, I think what I'm going to do at this point to run this tank of e85 out and put in 91 to verify if this is a map/tuning issue or hardware related. At that time I might run a can of injector cleaner or seafoam to hopefully clean out the injectors and any junk in the system. Worse case is, I'll pull the injector out and get them cleaned individually too.
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double post*

 

Have you checked your FPR?

Are your fuel trims different now then before?