sputtering problem

[benjimatt]

SO I am running e85 and I wasnt able to spool too quick at all. (yes I have a slow spooling turbo but it was ridiculously slow.)

I changed my fuel map for idle and cruise to 15.8:1 Everything is running much smoother and there wasnt much sputter at low rpms at all.

SO me and friend do a short freeway run maybe about 2-3 miles but we were doing like 130-140 mph. Yeah I know dangerous.

Anyways my car was overheating because I have a low temp thermostat and a half civic radiator. Yeah I need to get a new thermostat and I know it.

So I pulled over and let the car idle for a while to let to turbo cool down then I turned it off. My coolant temp was from 220-225. SO I let that all cool down and started crusing again but now at just crusing temp or when im not in boost I am sputtering.

Right when there is any boost the car feels really nice. But other than that its all sputter and its really annoying. So I logged the car while going home and my cruise reading were so random. Sometimes at -10 vacuum I would be at 12:1 afr. So for some reason I am running rich and lean while under vacuum after the freeway run.

I just changed the spark plugs and wires last week. They are duralast wires but they were working just fine. My spark plugs are ngk's bpr7es.

WHat should I be checking? I didnt see any leaks. I feel it has to be something with fuel. And yes I have an aeromotive fpr and a 255 fuel pump with 750cc injectors running e85 at 15-17 psi with an average duty cycle of 80-85% on a holset he351cw. At wot my target afr is 11.0:1 but I usually see 10.8:1 and I did an oil change last week also.

 

[habitatguy187]

With e-85 your afr needs to be in the 8:1 area if I remember correctly, looks like you're running waaaaay too lean.

 

[benjimatt]

That matters how you have your wideband set. My wideband is set to gasoline. So Stoich is still set at 14.7:1

 

[habitatguy187]

That matters how you have your wideband set. My wideband is set to gasoline. So Stoich is still set at 14.7:1

Even with gasoline people usually aim for 11.1:1 during WOT, for e-85 that would be extremely lean.

Correct me if I'm not understanding you correctly.

 

[benjimatt]

I already wrote on the top that at WOT I am at 11.0:1 so Im reletivily rich at wot. My idle and cruise are 15.8:1. The car was running just fine until after that long run.

 

[habitatguy187]

I already wrote on the top that at WOT I am at 11.0:1 so Im reletivily rich at wot. My idle and cruise are 15.8:1. The car was running just fine until after that long run.

Not if you're running e-85. That's what I'm talking about. If you were running gasoline then your afr's would be fine, but you said that you're running e-85, so you're running dangerously lean.

After that long run you could've easily destroyed your pistons running that lean, although I don't think so since you said it still runs fine under WOT, just not cruise.

Richen up your cruise a little and see what happens.

 

[cheap90gsx]

what he's trying to say is E85 needs more fuel for the same energy released therefore a fuel a ratio or 11:1 is still too lean for E85. Do some research.

 

[habitatguy187]

SO I am running e85 and I wasnt able to spool too quick at all. (yes I have a slow spooling turbo but it was ridiculously slow.)

Anyways my car was overheating because I have a low temp thermostat and a half civic radiator. Yeah I need to get a new thermostat and I know it.

You're probably spooling slow due to the lower power being made due to running lean.

As for the car overheating a low temp thermostat would actually help prevent it from overheating, I'm thinking that you running it so lean got it that hot. I really hope everything's ok man, it looks like you've got a really nice set-up going on.

 

[benjimatt]

Ok Again My wideband is calibrated for a gasoline calibration.

Widebands read oxygen, not fuel. Therefore a wideband set up for gasoline will read 14.7:1 at stoich for any fuel.

Here are some quotes so you know what im talking about

(neons.org) If you're using a wideband sensor that is calibrated for gasoline, you just target the same AFR's you've always targeted with gasoline (14.7:1 at idle and cruise, 11.5:1 under boost, etc..) because the wideband reads lambda, and converts it to AFR's, so just leave it on a gasoline setting and get gasoline numbers.

(e85vehicles.com) On a boosted car, shoot for an AFR reading around 11.5:1 or a little richer, on E85 with a gasoline calibrated wide band at WOT and you will be good. Your idle AFR's on a gasoline calibrated wide band will still be about 14.7:1. Guys running boost like richer mixtures so will run all the way to Lambda .72 or so, which shows as a gasoline calibrated AFR of (0.72 x 14.7 = 10.58).

If you were naturally asperated you could run leaner, very near the 12.5:1 you would shoot for on gasoline.
On light boost you still can run leaner than 11.5 displayed AFR but don't get carried away trying to go too lean, there is a limit even on a fuel as good as E85.

 

[jrohner]

If he's going by gas AFR's he's not too lean; he's still richer than necessary.

By the way, unless you're running open loop all the time, leaning the low end of the fuel maps won't effect anything because the fuel map is totally ignored in closed loop mode. The small radiator would cause your car to overheat, not the low temp thermostat. People often put in a lower temp thermostat to make their car run cooler (basically just makes it take longer to overheat).

The first thing I would do is check the spark plugs over (for damage and that they all look similar) and recheck that the gap is .026-.028. Do a compression test while you have the plugs out.

 

[benjimatt]

looks like number 3 spark plug was really messed up. Looked like possible detonation. Will do some more tests.

 

[dsm_mike21]

Does having the gap .026-.028 really make a difference? im asking due to me having bad sputtering coming from my car.
I just changed the spark plugs like 3 days ago and spark plug wires thinking it would help solve my sputtering problem but it didn't it doing the same thing. I've run out of resources, looked through every forum and i don't seem to find a solution to this little problem.
Actually here is a vid of what im talking about. You can clearly notice the car wanting to die on me...

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[dsm_mike21]

Also, it gets worse after trying to drive it. Sometimes it takes a bit of time for it to turn on.
Could it be the MAP sensor?

 

[habitatguy187]

Almost sounds like it's running rich. How's your gas mileage?

 

[dsm_mike21]

Not bad, i actually tried to drive my car today and all i did was backfire and everytime it would backfire it

would try to die like the engine wants to et out of the car... idk. I thought it was the MAP sensor at first,

went to autozone bought a new MAP sensor, same problem.

Also when i got home i found my negative cable almost coming off so i put it correctly in and tightened

it, it worked fine for a bit then it started doing it again. could it be my negative cable going bad?

 

[lnvisiblejon]

i had almost the same problem

 

[dsm_mike21]

Any ideas? anyone

 

[91AWDGSX1G]

Does it sputter after its warmed up? I am having the same problem. Once my car hits temp it stops sputtering. Sometimes it wont start, sounds like the injectors are not working sometimes. (it idles at 400 - 900 rpm and then just dies, I can hear the fuel in the tank as well) You may try a boost leak test.

 

[dsm_mike21]

Also would crankwalk make something like this happen? i dont have crankwalk but i was just wondering whether this would be a first sign. I have a fully built 7 bolt except for cams and cam gears

 

[dsm_mike21]

yea definatley once it warms up it starts the sputtering and sometimes it doesn't want to start.

 

[dsm_mike21]

no one can help

 

[91AWDGSX1G]

Sorry dont know much about E85 tuning (AFR). Good Luck!