Car bucking hard all of a sudden after mixing in few gallons of e85

[bsbllfit7]

As the title says my car was running fine and i mixed a few gallons of e85 in to try and diagnose if i had phantom knock or real knock. The car ran fine and found out it was real knock and was just driving around when all of a sudden whenever i get over like 15% throttle it bucks like crazy. Now last time this happened i changed out the coil packs and transistor and that fixed my issue. With those being new and the car running fine i was wondering if perhaps a bad fuel filter could do this. Also i had been getting a faulty throttle position circuit code but the tps seems to be registering through link still. Anyway just wanting some ideas on what to check for!

 

[90gsxjuice]

How many gallons did u mix in?

 

[bsbllfit7]

only about 3-3.5 gallons on a full fill up. The car ran on just that until i drove another 10 miles to the other station with no issues. Then i filled up with another 9-10 gallons of 92 and drove fine. Knock went down car drove great and pulled hard. Last night i went out in the car and drove it and was doing some hard pulls. Then i tried to do a 1-2 pull and broke up HARD in first and went to second and same thing happened. Every since i cant even build boost or get WOT without it bucking hard!

 

[mebetter]

Having same problem. I think the problem is fuel filter but I haven't changed mine yet.

 

[PieEyedPiper]

I'd be impressed if 3gal. of e85 clogged up your (insert fuel component). Worth investigating though.

 

[JusMX141]

Do you have a wideband in the car? Just curious what your air/fuel ratios are like after dropping in three gallons of Ethanol.

 

[genegoesfast]

Do you have a wideband in the car? Just curious what your air/fuel ratios are like after dropping in three gallons of Ethanol.

I would assume he's seeing leaner afr's due to the less efficient e85.

 

[jtmcinder]

Stoich for E85 is only 9.7:1. Should be careful about throwing E85 into a car not set up for it. A much better way to boost octane is a gallon of toluene for each 5-6 gallons of gas.

 

[talonDSMerr]

I would look more into that TPS code you're throwing. That's a common symptom for a faulty TPS.

 

[pats16valve]

How many gallons are in it total now? E85 vs. Gas. I was having similar issues when my 4 bar map sensor went out, replaced it with a 3.3. Turned out it was very lean. Pull the plugs to see what they look like.

 

[bsbllfit7]

logs look good up until when the bucking happens then everything starts going very high then very low in extreme succesion, afrs included in that. When i was tuning with the wideband i was getting 10.1-10,5 afrs. My car doesnt like any leaner then that and my guess is because of the 92 octane and 9.0:1 compression with the 2.4l. Is this normal of a tps going bad to cause major bucking of the car?? What else could cause this to happen. I know ignition components such as transistor and coil packs but they are new so i feel they are less likely to be the cuplrit

anyone else have any thoughts on what could cause this bucking. Im about to go take a drive (attempt to take a drive) and get a log of everything. Anything i should be looking for when im out?

 

[B00st3d_Eg0]

we the map sensor can cause this, also a bad or dirty MAF can cause bucking and its usually pretty bad. When i tried mixing in a few gallons of e85 i got a fuel trim MIL "system too lean" and i thought my fuel filter was bad so i changed it and it turned out it was just running lean from the e85 and needing to run 30% more fuel

 

[bsbllfit7]

I'm running speed density with no maf

Sent from my PG86100 using Tapatalk

I would look more into that TPS code you're throwing. That's a common symptom for a faulty TPS.

whats a common symptom the code or the car bucking like crazy??

 

[bsbllfit7]

here is a log idk what the hell its telling me. No CEL either

here is another one, the rpms are jumping around big time in the log, it will go from 3300 to 6500 and then back. What can cause this, possibly the transistor again or can the tps cause that problem? I also can see the tach moving when it does happen

also the car seems to idle just fine and rev fine, its when i start getting into it while driving that the car starts having the issues. The logs should show everything though

 

[bsbllfit7]

problem fixed, i installed the new tps today and car pulls like a bat out of hell again! Am i able to mark this thread as resolved or does a mod need to do that

nvm figured that last portion out as well

 

[mebetter]

Thx for the update glad you got it fixed.