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After 300 miles on E85, lean from 2k to 4k rpm

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GSLENK

10+ Year Contributor
1,416
51
May 25, 2011
DC, Maryland
I swapped to E85 5 days ago. That is about 300 miles ago. And something is up. Car was running beautifully for the first tank. Now the performance has degraded. I HIGHLY doubt it is in the tune. It was running perfect.

Between 2k rpm and 4k rpm, the AFR will go stupid lean. Typically jump to 15:1 then crawl through 16:1, then up to 18:1. As soon as ~4k rpm or any real load, then it drops closer to target around 13:1 and high rpm/load to 12:1 as usual. It isn't perfectly on target as before, but it gets close.

Any ideas?

I want to think a fuel system problem (surprised it actually is happening this early though). OR an ECU problem.
Does this sound like anything that has ever happened to anyone? What typically gets clogged badly first?

Here is the rundown on my fuel system (not completely optimized for E85 yet, but pretty close):

Walbro 255hp (regular sock, Basic install kit-jnz or ex-psi IDK)
OEM fuel feed line all the way to Fuel lab 818 fuel filter with 10 micron 3" paper filter
Teflon SS line filter to tank. (installed after E85 swap)
OEM fuel rail, STM 6an fittings both sides
1250 FIC Blue Max injectors, pretty much brand new.
Teflon SS line to Fuel lab AFPR @ 43psi base fuel pressure
GM Flex fuel sensor right off of return side
Teflon return line installed before E85 (for about 500-1000 miles)

I just pulled the filter thinking it was my nightmare. Nope. It was not that dirty. "Cleaned it" with gas and brake cleaner and comp. air. Took another log and the same crap happened.

Could the fuel pump sock be clogged this early? I am really at a loss here.
 
You may need a bigger fuel pump... and bigger than stock feed lines. I was thinking of swapping to E85 and ive been told i would need a 420 pump or dual 255 pumps, and to upgrade all the lines. When you are running E85 you are running alot more fuel than you would be on pump gas.
 
You may need a bigger fuel pump... and bigger than stock feed lines. I was thinking of swapping to E85 and ive been told i would need a 420 pump or dual 255 pumps, and to upgrade all the lines. When you are running E85 you are running alot more fuel than you would be on pump gas.
Not at 3k rpm and 30% throttle and less than 0psi.
 
heres 3 screenshots. Ill describe them by thier labels:
Perfect1: This is from when everything was running smooth and I was taking full pulls etc... Still getting dialed in but very close. You can see the cruise part afterwards is pretty much in line. No stupid lean stuff.

then 2 days later, I get stuff like this: (lean crap)
Lean1: This is one example of it happening.

SpringBack2:This is an example where just keeping throttle constant, once rpm goes up high enough fuel gets sort of back in line, but still not as good as before.

Literally nothing has changed between these two logs.

I had the car parked, woke up hungover one day, moved it from the street to the driveway,engaged the clutch too fast, doesnt like when I do that sometimes, parked the car. Started driving again, walah. Did I jump timing or something?

This is why I suspect an ECU problem, or some phantom fuel problem.
Perfect1:
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Lean1:
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Springback2:
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[DOUBLEPOST=1407946638][/DOUBLEPOST]
Clogged injectors?
Gonna tear down the fuel system to see whats up after class. Pump sock, injectors. (already checked filter). I hope not. I really hope E85 isnt clogging within 300 miles. Ill lose my shit.[DOUBLEPOST=1407981779][/DOUBLEPOST]I really did not want to pull the fuel pump hanger but I did anyway...

Found my sock looked like this:
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Did some research and found a fuel pump strainer that fits... In a pinch, you can go to the parts store and look up 1992 toyota 4runner 2.4L pump strainer. It fits. IKD how long it will last, hope its longer than 250 miles...

Took a cruise log and everything is pretty much back to normal. (except for the fact that may last few logs include compensation for this stupid issue, so backtracking will be necessary.
 
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Well its back again. I assumed it was the fuel sock and I replaced it anyway even though it was clean. That did nothing. Then I checked all fuel lines for leaks, none in the lines and none in the unions (Teflon SS braided lines). Then I checked the 40 micron SS fuel filter, looks new still. Then I did an AFPR test with the air compressor and an autozone fuel gauge. Fuel pressure rises 1:1 with air pressure.

Next I plan another BLT (which I doubt will reveal anything since I have been BLTing on a monthly basis and there have been no leaks.
I also plan on pulling injectors to check for clogs.

I am running out of things to try. I really don't know what is going on here.
Any more ideas?
 
Are you still in closed loop when this happens? A lot of times a dead time issue with the injector settings can cause this in transition from closed loop, to open loop.

I would disable the flex fuel for now, tune for straight e85, and lock it in open loop to nail the part throttle tuning. This is also a great time to have a calibrated maf on the car instead of guessing at airflow with a map, iat, and ve tables.
 
Pull the injectors and check the end tips for black goo. The injectors, from my experience and many others on tuners, develop this thick tar substance on the end of the injector and can almost block the flow of fuel and cause a shitty spray pattern. I half to clean my injectors about every 3 months or they will get clogged up and cause my car to run lean, on e85.
 
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Quick question...
1-who is this stacy tuning guy and what does he say?

2-whats the "e85 " content or tested ethanol %

3- is this the same tank of fuel or 2-3 diff tanks of fuel since the tune and have they all been tested for ethanol content % ?

4- how many miles are on your fuel tank and chassis ?

5- do you realize the superior cleaning and "stripping" capabilities of "e85"

6- what are your dead times and global for the inj. ?

7- are you trying to explain a lean tip in issue and or a open loop to closed loop transition issue.

8- is this a SD car or MAF car?
 
Part throttle was "nailed". Stacy does it pretty well.
With no changes to the tune this BS started happening out of nowhere. Injectors pulled is next... (probably should have done it sooner but now I have time/patience)

Anyway, My latest test suggests the AFPR and Pump are "good" I hope.

I used an Air compressor regulated output to provide some positive pressure to the AFPR. I used a tool similar to a hand pump vacuum bleeder thing to apply vacuum to the AFPR. I used the MAP in link in an attempt to calubrate the sutup and make sure everything is in line. I also used a parts store ACTRON brand fuel pressure tester and a 3 way Tee, 6an M/F and 1/8 npt to schrader valve in the middle.

First to represent the ACTRON parts store FP tester reliability:

Comp. MAP ACTRON This was to compare the actron, the comp regulator gauge, against each other and the MAP
40-----40.8----39
90-------------85
30-----29.6----28
20-----20.6----20

The next tests are fuel pressure. Tovic gauge on the AFPR.

ACTRON Tovic MAP
47-------45-----.2 ***base FP (was supposed to be 43psi but whatever...)
76-------85---40.4
74.5-----74---29.6
66-------65---20.6
32-------30---N/A ****I just watched vac drop down slowly
20-------17---N/A **** and recorded these as best I could
42-------40...-10.6 in/hg
37-------35...-20.2 in/hg

All results are in PSI except for vacuum.

Seems like the FPR is inline... remember 2in/hg ~1 "negative psi"
 
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Quick question...
1-who is this stacy tuning guy and what does he say?

2-whats the "e85 " content or tested ethanol %

3- is this the same tank of fuel or 2-3 diff tanks of fuel since the tune and have they all been tested for ethanol content % ?

4- how many miles are on your fuel tank and chassis ?

5- do you realize the superior cleaning and "stripping" capabilities of "e85"

6- what are your dead times and global for the inj. ?

7- are you trying to explain a lean tip in issue and or a open loop to closed loop transition issue.

8- is this a SD car or MAF car?

1) Stacy is a well known tuner on here and has MANY positive reviews across many platforms. MY1gDSM...
2) content according to the ECMtuning sensor bundle is around 75% and has not fluctuated significantly. (stays around 75% to 78%) Bought from the same exact station. Ft Meade service center in laurel MD.
3) This was the fuel used to start the tune, which started out great. Then all of a sudden the mid- part throttle, low vacuum, high gear parts started to feel power loss (smooth power loss), and I noticed AFRS out of wack and jumping around. I drained the tank with the drain plug and jacked up the passenger side to get damn near all of it out at the pump just before putting in E85.
4)Chassis ~35k (hint, I bought it from a recently widowed woman in 2011 with 23k miles and all service records to back that up. This is not a lie.) had about 300 miles when the problem first arose.
5)yes I realize alcohol cleans hydrocarbons really well.
6)Ill have to ask Stacy before posting his work, but they are in line with what one would expect them to be for 1250cc BM fic injectors.
7) neither I think. What I am doing is accelerating under vacuum. And the poser is lost when the AFRS diverge, and comes back to normal when they converge. Again, the tune/calibration was spot on before this is not a tuning issue.
8) This is SD. ECMlink full version, latest firmware etc...[DOUBLEPOST=1408919038][/DOUBLEPOST]
SO DO YOU NOT HAVE AFPR INSTALLED ON TOP OF ALL OF THIS?
MY MODS LIST IS IN MY PROFILE! THERE IS EVEN A PIC OF MY ENGINE BAY. AND I THINK I HAVE STATED ALREADY THAT I HAVE A FUEL LAB AFPR

I don't mean to be mean, but the types of questions you are asking imply that I am a Neanderthal. I don't mind answering them but really... All that info was in my profile and those simple questions are easily answered there.
 
neither I think. What I am doing is accelerating under vacuum. And the poser is lost when the AFRS diverge, and comes back to normal when they converge.

I assume you mean POWER? and air fuel ratios "separate from another route and go in a different direction" and then you say your Power comes back to normal when the air fuel ratios "come together from different directions so as eventually to meet."

Its hard to help out with a situation when the problem isnt correctly defined,

also since when are dead times / global a secret?

Plus what does "pretty much brand new mean" did you buy them used and just new to you?

Just trying to analyse the problem to help out..
 
Hmmmmm might just be whet I "wanted" to see.... This doesn't seem too bad though?

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well,it looks like the "hesitation" or stumbling as stated above. is the shity throttle response caused by air getting into the chamber faster than the fuel needed to burn with it.

In simple terms......the injectors can't keep up with how fast the throttle body allows air into the engine when first stepping on the gas. causing erratic af/r and lose of power.[DOUBLEPOST=1408920618][/DOUBLEPOST]boom.. get those cleaned and flow tested and tell your tuner to double check the lower end of the map to make sure its in speck with the new inj.
 
neither I think. What I am doing is accelerating under vacuum. And the poser is lost when the AFRS diverge, and comes back to normal when they converge.

1) I assume you mean POWER? and air fuel ratios "separate from another route and go in a different direction" and then you say your Power comes back to normal when the air fuel ratios "come together from different directions so as eventually to meet."

2) Its hard to help out with a situation when the problem isnt correctly defined,

3) also since when are dead times / global a secret?

4) Plus what does "pretty much brand new mean" did you buy them used and just new to you?

5) Just trying to analyse the problem to help out..

1) Yes, typo, poser=power. and you are describing the problem exactly. Typically everything is very much in line. Idle is spot on. Cruise is damn close and Pulls are spot on (there is an unnoticeable lean when going to WOT too fast, but it is expected/acceptable.)

2) Problem definition: When I press the gas pedal, I expect a certain (albiet low) amount of part throttle power. It starts ok, then AFR goes dumb lean, and feels weak (no feeling of a real misfire, I know what those feel like) then if I hold the pedal and let load slowly increase, the AFR comes back, and the normal amount of power I expect returns. Anything above 0psi seems to be gernerally normal, but not as precise as it used to be initially.

3) IDK, my tuner and I agreed to certain conditions. One is that I do not post his work publicly, I am happy with what he does so I do not post. You can consider him very competent, more so than most "tooners".

4) Definition from the seller: Mounted on fuel rail never, had fuel ran through them. The orings and smell (lack thereof) seem to support this. I have bought actually used injectors and know the smell.

5) Anything you need to know, just ask.[DOUBLEPOST=1408921324][/DOUBLEPOST]
well,it looks like the "hesitation" or stumbling as stated above. is the sh**y throttle response caused by air getting into the chamber faster than the fuel needed to burn with it.

In simple terms......the injectors can't keep up with how fast the throttle body allows air into the engine when first stepping on the gas. causing erratic af/r and lose of power.

Nope it is certainly not. How many times do I have to say this is not a tuning/tip-in issue?

The posted screen shots clearly indicate this. See the spring back 2 picture. that is over a 5+ second interval. Goes dumb lean, comes back for a moment (half second) then goes dumb lean again. all under constant throttle.

I appreciate the help but the problem (with the tune) you suggest is not it. This is a "car-side" problem.[DOUBLEPOST=1408929604][/DOUBLEPOST]Got the injectors nice and clean. Idle improved slightly (more consistent) just not where it should be all the time. And the low throttle still does that weird crap. I want to say its the pump, but the AFPR tests seem to state otherwise, unless a pump can pass that and still be bad?

Could this be ignition related?
 
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So whats my next purchase gonna be? So far I'm thinking:

Power Transistor or Fuel pump (AEM 320 E85 version) or any other ideas (or am I jumping the gun here)?

Here's my fuel setup start to finish:
76-78% E85 from the sunoco pump
walbro 255hp pump
new sock from autozone
Teflon feed line from hanger to fuel filter (-6an)
Fuel lab filter with 40 micron SS element
Oem fuel rail (STM adapters -6an) All teflon lines around here)
FIC BM 1250 injectors
Fuel lab AFPR set to 43 psi
Teflon return line almost all the way to tank
4"rubber to go from -6an adapter to barb end to tank barb for return
 
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