LT1-LT4 Modifications 1993-97 Gen II Small Block V8

Converting from "E85" back to 93

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Old Jun 21, 2022 | 11:13 PM
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Exclamation Converting from "E85" back to 93

Hey, team,

It is me again. I just got back again to work on my dream car. '95 Z28 M6. When I bought it came with 42lb E-85 inectors, and a 255 Wabro pump. This was around December. When I bought it, I was informed to put e85 in it because the car was "tuned" for it. However, after purchasing, the seller informed me that his buddy said he actually never "tuned" it. The car ran pretty alright for the 2 weeks I was in Nashville. However, coming back in March, I start her up and she ran great until 6 days in and would not crank over. Flash forward to now, now being home, I replaced the opti and she fired up like nobodies business on 2 gallons of e85 in the tank. After 10 minutes of idling she died. In order to start her over (while warm) I had to press on the gas and keep pressing to make sure she idled. If I did not, she sounded like she would drown in fuel. Anyways, I have purchased 250CC "stock" injectors and am currently changing them out from the 42lb ones - based off the premise that the car is still running on the stock tune and that stock injectors will eliminate what appears to be flooding.

To sum it all up! I have attached the .bin file of my beauty and I just wanna know if anyone can confirm if it actually is stock! Thank you guys! You all rock!
Attached Files
File Type: bin
BaseLine(z28).bin (128.0 KB, 9 views)
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Old Jun 22, 2022 | 12:51 PM
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You can easily leave the 42lb injectors in they aren't going to hurt anything.

Just get a mail order tune to tune it back to 93.
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Old Jun 22, 2022 | 01:37 PM
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Originally Posted by Z28Roxy
You can easily leave the 42lb injectors in they aren't going to hurt anything.

Just get a mail order tune to tune it back to 93.
Yes, true! I just really want to know the guy just decided to wing it and add big injectors and say it was “meant” to run on e85 now (no o2s).

again, haha, I’m just trying to see if someone can take a look at the .bin file and tell me if it’s actually the stock one. I do plan on using the 42lb injectors but that’s going to be in a couple months
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Old Jun 22, 2022 | 04:40 PM
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Correct me if I'm misunderstanding; you're running e85 in it now, and it came with e85 in the tank. It ran fine when you bought it.

If I could read .bin files I would hook you up, but im on team .hpt
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Old Jun 22, 2022 | 04:51 PM
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It ran "fine" enough for me to drive it from Ft. Campbell to Nashville. But holy cow it averaged 6-4 MPG and e85 would come out the exhaust. Dont get me wrong at WOT it was glorious but idling it sounded like a small cam. Here are all of the mods if it helps: 42Ib E-85 Bosch Injectors, 255 Iph Walbro fuel pump, Long tube headers, milled down factory heads, and removed O2 sensors ISO E-85, 4.56 gears.

The guy informed me his friend basically did not mess with the pcm at all but was able to "tune" it by tricking the pcm by removing the O2 sensors and installing the bigger injectors. I just rewired the supply fuel line from the Fuel Pump because the e85 dissolved it last week.

I currently have the fuel rail off and trying to pry off the 42lb injectors. And soaking the stock rated injectors in wd40. I appreciate the help but I have no idea what form .hpt is haha! I just want to make sure its the stock tune!

Also, I just realized my entire EGR hose (from header to manifold) is just sticking up in the air from the manifold. Would this cause stalling? I have LTs - haha

Last edited by maralada; Jun 22, 2022 at 05:03 PM.
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Old Jun 22, 2022 | 05:08 PM
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The way I understand it, if the PCM is not tuned to different injectors the pulse width(?) will not be right and will spray too much fuel into the cylinders which can wash them out. Reads like a real clusterfuck of a setup that was never ran after being thrown together. Unplugging the O2's will make the car run in open loop, but don't see how that would help with fuel injectors running correctly.
Have you checked your oil for gas? Does it smell of fuel?
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Old Jun 22, 2022 | 05:12 PM
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Exactly! That is why I am hoping that someone can look at the file and see if it is still set to the stock pulse rate. I would honestly be impressed if this was hagwired in such a way without a tune - which I was told it was lol. Don't worry, I am 100% going to do an oil change after this!
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Old Jun 22, 2022 | 05:19 PM
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I'm guessing it's still OBDI? There's at least one guy here who does OBDI tuning. I can't remember his screen name. Try searching this forum for OBDI tuning/tuners/etc...
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Old Jun 22, 2022 | 05:23 PM
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YES - still OBDI which is nice but frustrating at the same time haha. Ahh Okay I gotcha!!!
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Old Jun 23, 2022 | 12:51 AM
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I spot checked some scalars and tables in the bin file you posted. Everything matches the stock values I pulled from a 95 Firebird. Looks like your guy just swapped 42lb injectors into the car and unplugged the o2 sensors.

Thanks!

Chad
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Old Jun 23, 2022 | 08:44 AM
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I do not see the need to unplug o2 sensors. They target stoichiometric for whatever the fuel is. Gasoline is 14.70. E85 is 9.73. That puts the 42 lb/hr injectors quite a bit larger than the 33 lb/hr that are needed for 40-41% more fuel. That being said it would be better if the PCM was correctly calibrated for E85 especially given how much more timing E85 wants.
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Old Jun 25, 2022 | 11:43 AM
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@chadtn
You're Amazing! Thank you so much! Finally, I feel confident whipping her around franklin and nashville. I changed the oil to last night.... It smelled and looked straight like E85. I got a little frisky and grabbed some of the "oil" and put it on a plate - it lit on fire like nobodies business. The poor thing was running so rich

I appreciate you so much man! thank you!
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Old Jun 25, 2022 | 11:45 AM
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@Fast355
The dude just through parts at it before and hoped it work - the beaut was not taken care of before I got her. Blows my mind that it even ran okayish on e85 not too long ago on stock tune.
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