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Can I run gas on untuned 42lb injectors?

industrialfish

industrialfish

New member
Running E85 now but cold starts are killing me. Been adding 2 gallons of 93 at fill ups to combat it and have my SC belt off. If I run straight gas can the car compensate enough to get by this winter?

2005 GTP
 


First of all. You should be running at the least 60LB injectors. Sorry to say it, but 42LB on E85 aren't gonna cut it, especially since they are not tuned in your PCM. Ok, now I read your post a little clearer. 42LB on gas.....untuned, your asking for trouble right there...----->"untuned". Find somebody with a DHP or ask Reptile to make a PCM for you for those injectors. Wait better ask ZZP or Overkill to do your PCM since you got a 2005 GTP and DHP wont do it. Reptile I believe only does 97-03 maybe 2004 but not sure. So ZZP or Overkill is your best suggestion. :th_thumbsup-wink:

Edit: Find someone willing to use 2 credits of their HP Tuners and let them do it for you. They need to download your bin file and then edit the injector tables and MAF and some other adjustments for the 42LB on gas.
 
I don't see how running straight gas through injectors that haven't been tuned for the car would help. 42.5 lb injectors will flow about 15% more fuel than normal, so your computer's injector flow rate is going to be squirting that much more fuel in your car, and that might be enough to trip a P0172 code for rich fuel condition. I'm not sure how E85 works in relation to the volume of fuel being squirted.
 
15% is a lot of fuel. the factory specs are + or - 5 of 0, so I would bet no. not sure how far or close Daniel smuts is to you, but he could help get your tune adjusted properly.

edit: looks like you are living in toledo, and daniel is in coldwater, which is about 2 hours. might be worth while to make that drive.
 
You could play with it...

If you have a way to monitor the trims, you could creep up on it, right up until you trip a P0172.

Having said that, it's not what I would do, but it's your ride.
 


SgtMarshal said:
15% is a lot of fuel. the factory specs are + or - 5 of 0, so I would bet no. not sure how far or close Daniel smuts is to you, but he could help get your tune adjusted properly.

edit: looks like you are living in toledo, and daniel is in coldwater, which is about 2 hours. might be worth while to make that drive.
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And I have an 04 PCM on hand, which he has whole year unlocked. I thought the PCM could adjust +/- 16.4?
 
industrialfish said:
And I have an 04 PCM on hand, which he has whole year unlocked. I thought the PCM could adjust +/- 16.4?
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The computer can add or take away, but ideally you want your fuel trims at zero, however it is extremely unlikely to always have your trims at zero so the factory tolerance is within 5 percent of zero. Anytime it's not within, it won't run as good as it should and other problems could pop up
 


Sorry, can't do 05's, only 97-04. However, side note here, 42's are good for E85 as long as you're not running a sub 3.2 pulley. Nick's green pile of junk handles them just fine.
 
Reptile said:
Sorry, can't do 05's, only 97-04. However, side note here, 42's are good for E85 as long as you're not running a sub 3.2 pulley. Nick's green pile of junk handles them just fine.
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Yeah I thought 42's were fine for E85 since I'm only on 3.4, runs just fine for me as is but could be better.

ericspecullaas said:
what about running an 04 ecu in an 05+?
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DHP doesn't work on 05+ because the way the data is handled or something. Bricked a pair of 04 PCMs finding that out. Can use an 04 PCM, just not tuned in car.
 
ericspecullaas said:
what about running an 04 ecu in an 05+?
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I ran an 04 PCM in my 05 for months and there are differences in the way the tune is. 04 seems to be richer as when you let off the gas you will get a little backfire with some popping and such. 04 also sets the initial timing at about 15-18* whether it's in gear or not. the 05 will drop the timing to between 5-8* in P or N and will go to 15-18* when in gear.

Jeff
 


I tried it this morning and it goes to 5* when in P or N. I will log it and post it up. Was the car warm when you did it?

Jeff
 
I'll log it and post a graph. It never did it with the 04 PCM it stayed the same whether in or out of gear. This 05 is different. I noticed it before I put the 04 in there and thought it was odd and I was new to the BAFX and Torque app. I know the 04' PCM causes the engine to burble and pop when decelerating, but the 05' doesn't do that to the same degree. If I get on it to change lanes and let of quickly it has done that but anytime that I was decelerating with the 04 it acted like an old truck running rich with glass packs.

Jeff
 
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