Car is breaking up and surging at wide open throttle. Need help please

[z06mustang]

We have a 03 4.6 gt that we recently switched to a E 85 tune. Mods are P.P intake manifold plenum and throttle body. BBK cold air intake, Pypes cat back,4:10 gears, UDP's, 3200 stall UCA's and LCA's Jeg's wheels and Mickey Thompson fat skinny set up.

The night we put the tune in we took the car out and it ran great, dead on. The next day when we took it out started acting up and not running right. Emailed the place where we got the tune and asked him if he might know what's up and told him I didn't think it was tune related. No reply.

I thought the problem might be fuel related because I read E 85 brings the crap up on the bottom of the tank and runs it through the system. So I changed the fuel filter and still the same. I then ordered a Focus upgrade fuel pump and still the same.

We then proceeded to email the tuner again and ask for help. He replied that he previously sent us a message. I emailed him back and said we didn't get it. He replied do you have any other email addresses? Emailed our other address never got a reply. So much for that.

I thought it might then be spark related so we installed a set of Accel coil on's yesterday and still the same. Also no CEL and no codes coming up. I'm so bummed because we worked so hard to get this thing to the track and we're about out of time in Indiana here. I'm in no way bashing the tuner. If he doesn't have time to mess with me so be it. Any help in the right direction would be greatly appreciated. Sorry for the long rant.

[z06mustang]

Anybody help?

[Stin42]

I dont know much about e85, but I do know you need ALOT more of it to run the same you do on gas. Have you upgrade your injectors and fuel pump? Try a different tuner, maybe ask the big dogs from here, Doug, Justin, Mike, PMP

I think it was justin who wrote on here about his ethanol experiences.

[z06mustang]

When I got the tune from one of the tuners you mentioned I was told I wouldn't need to upgrade the pump or the injectors but I did the pump. Like I said when we took it out for the first time the car was right on and really strong. So it messing up like this is strange. It might be the tune or a injector I have no idea.

I'm gonna try to find another tuner or ask on Modfords. There is some guys over there running E 85 making big numbers. E 85 is really neat to run though with the octane rating about $2.49 a gallon and there is a abundance of it here. Thanks for help though.

[MustangDon4.0]

excuse me if i sound like a noob but whats E 85 and if its giving you that much of a problem contact VMP and have him make you a normal 93 octane tune or whatever is around you area..

[z06mustang]

E 85 is 85% ethonal and 15% gas made from like corn and such. It is suppose to have a 105 octane rating. VMP is where we got the tune:102:. As for a regular 93 tune we would have to drain the tank.

We were gonna dyno tune at Logans Motorsports yesterday but decided to wait till spring since we are doing major stuff over winter. It's a shame we never made it to the track this year. Thanks for the reply though.

[RedfirePony]

Like the poster above said, E85 doesn't have the same amount of energy per unit of fuel as gasoline does thus you have to use more to get the same level of power. I'd be willing to bet that your stock fuel system may not be able to keep up with the demand. May need to go to larger injectors and / or higher volume fuel pump. Your tuner said that you didn't need to upgrade either, but I question that.

[z06mustang]

Hey thanks for the reply. The car will soon be tore down for a complete winter build up. We have upgraded the fuel pump. I'm sure we will be needing bigger injectors as we will being going forced induction or spraying next year. I'm just going to tow the car to Logans next year for dyno tuning.

[jcalvin1126]

hey im no expert on the e-85 stuff but i heard for a couple peeps that that ethonal loves to eat up your seals and gaskets in your engine. maybe you could check into that during your tear down. i just know some people that warn me of that stuff on normal engines.

[z06mustang]

We're in the middle of the build right now so we're checking everything. Can't wait to get it done. It's been a long A$$ winter. Plus I got two foxbody builds going on. Thanks for the reply.

[temugen]

Man, you don't deserve to have this crap going on -_-
I have absolutely no idea what could possibly be going wrong, and since it pulled just fine during the first run, I doubt the injectors are the problem at this point. I hope you get it figured out soon because it sounds like a sweet setup.

[z06mustang]

Hey what's up Brad? Are you back home or still out west?

We're taking our time now and enjoying putting this together. Hope to have it up to Logans Motorsports for the dyno tune in about three weeks and then I can do more with my foxbodys. Woo Hoo!

[temugen]

Hey what's up Brad? Are you back home or still out west?

We're taking our time now and enjoying putting this together. Hope to have it up to Logans Motorsports for the dyno tune in about three weeks and then I can do more with my foxbodys. Woo Hoo!
Taking your time is the best way. I'm back home and in a couple months will be looking to get down and dirty with the car again :fixtit:. Transfered to University of Illinois; the school is much better but I wish I still had the west coast environment. If you need any serious help this summer I might be able to swing by and lend a hand. But I'll probably be loaded down with my own things (hint: KITT).

[z06mustang]

Glad your home Brad. Thanks for the offer of help. Lets just make sure we go to the track or get together with some other stangs or something. Hmm wonder what you got planned for your car?