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Thread: Increase fuel in mptune

  1. #1
    Supporting Member II Turbo Mopar Contributor jeff1234's Avatar
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    Increase fuel in mptune

    Hey all, I am working on my tuning and I have maxed out on PE and full throttle fuel. I have no detonation but am missing at high rpm and boost. I changed my plugs with the idea of reducing the gap to see if the missing is a case of the spark being blown out but havent been able to test yet because of weather here in Wi. I pulled my plugs (63 Autolite gapped at .035) and put in a set of Autolite 65's gapped at .025. When I examined the 63's I felt that the mixture may be a little lean. In sunlight they look a little lighter than in the image. I would like your views on what you see. As I said, im not detonating but I think the plugs should look a shade more tan which I think means I need more fuel. Can I increase fuel at full throttle fuel by changing the fuel air tables in settings or is there another procedure? The 65"s are a hotter plug so they may burn even whiter. Bear in mind these plugs are colored from testing and tuning instead of a fresh install, followed by a full throttle run and then shutting down and pulling the plugs for inspection.

    Thank you for any input!

    Attachment 63211
    The only substitute for cubic inches is cubic dollars, how fast can you afford to go?

  2. #2
    Moderator Turbo Mopar Staff Force Fed Mopar's Avatar
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    Re: Increase fuel in mptune

    Those look fine. As long as you are at around 11.0-11.5 at WOT and in boost at part-throttle above 5psi, and in the 14.7-15.7 range cruising, your fueling should be good. I'd be looking at the coil if you are having break up in boost. And maybe try some NGK GR4 or GR5 instead of the Autolites. I've not had issues with them but some have. Or you can go to the Autolite AR51 plug, some guys swear by those.

    FYI, you want to go colder on the plugs when you raise the boost, not hotter.
    Rob M.
    '89 Turbo GTC
    2.5 TIII swap is here!

    Project LookOwt
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    Back to basics, then the mods go back on....

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    Supporting Member II Turbo Mopar Contributor jeff1234's Avatar
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    Re: Increase fuel in mptune

    Thanks for your response, I installed a new coil this summer. I did notice on the Autolite's at the point where the porcelain emerges from the metal shell, discoloration on three of the four plugs. I have to assume this is leakage from compression. Relative to colder or hotter I will take your recommendation. I would still like to know whether changing the numbers in the F/A tables in settings will change anything. My understanding is that those tables create the line in part and full throttle as a guide for tuning but do they change anything else? I want to be able to increase fuel at high rpm and boost to richer than 11.5 to 1 to verify that I do have fuel tuning above 6000 rpm and 14 psi. I believe that you cant be certain of sufficient fuel under those conditions unless you can exceed what is needed. Presently, I cannot make it richer at 6000/14.
    jeff1234
    Last edited by jeff1234; 10-06-2018 at 08:26 AM.
    The only substitute for cubic inches is cubic dollars, how fast can you afford to go?

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    Rhymes with tortoise. Turbo Mopar Staff cordes's Avatar
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    Re: Increase fuel in mptune

    What head do you have on the car? I find it very odd that you've maxed out all the fuel you have. What injectors?

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    Moderator Turbo Mopar Staff Force Fed Mopar's Avatar
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    Re: Increase fuel in mptune

    Yeah something odd going on there. I don't really go by the yellow line too much, more or less use it as a guideline to get in the ballpark, then tune according to AFR from there. It is fairly accurate if you have the right numbers to put into it though. If you leave the plugs in for any amount of time (IE a month or so), they should be tan/dark tan looking. Tuning by plug look is really only possible on fresh plugs and after a WOT pull and immediate shut-off and check plugs.

    It is possible to get a rich misfire. Could be your wideband sensor is messed up and not reading right, or needs recalibrating.
    Rob M.
    '89 Turbo GTC
    2.5 TIII swap is here!

    Project LookOwt
    '91 Daytona ES, 61k original miles, Rick Lozier's old 3.0 nitrous car
    Back to basics, then the mods go back on....

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    Supporting Member II Turbo Mopar Contributor jeff1234's Avatar
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    Re: Increase fuel in mptune

    My head is 89 2.5 turbo head ported by Green county machine in monroe wi. Flow numbers look similar to small block chev 186 int. 165 exh. I got new 53 lb inj. from Chris very recently.
    Last edited by jeff1234; 10-07-2018 at 07:42 AM.
    The only substitute for cubic inches is cubic dollars, how fast can you afford to go?

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    Rhymes with tortoise. Turbo Mopar Staff cordes's Avatar
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    Re: Increase fuel in mptune

    What injectors do you have in the car?

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    Supporting Member II Turbo Mopar Contributor jeff1234's Avatar
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    Re: Increase fuel in mptune

    Rob, I will try pulling some fuel at the high end to see if that changes anything. Plugs first, then remove fuel will be my method.
    The only substitute for cubic inches is cubic dollars, how fast can you afford to go?

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    Supporting Member II Turbo Mopar Contributor jeff1234's Avatar
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    Re: Increase fuel in mptune

    Cordes, I can get my F/A as low as10:5 in other gears. To me that says two things, 1. It can be adjusted to that level. 2. That under a heavy load in 5th gear if it can't be adjusted it would be reasonable to suggest it needs more fuel than the tune can provide on those settings.
    The only substitute for cubic inches is cubic dollars, how fast can you afford to go?

  10. #10
    Supporting Member II Turbo Mopar Contributor jeff1234's Avatar
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    Re: Increase fuel in mptune

    NEW INFORMATION!!! I was working with my tune and discovered that the arrow at the end of the graph wouldn't move higher. and I clicked on it more and got the arrow in the green circle. I did not know I could do this! I was then able to raise the fueling as high as I wanted so this is likely the solution. It remains to be seen as the stupid rain keeps falling here in south central Wi. Its unfortunate that better user instructions could have prevented much of this conversation, however the conversation was valuable in that it covered a number of angles to the problem and led me to the answer to my initial question of how to raise full throttle fuel.
    Thanks to all who responded! I will update.
    Jeff1234
    Last edited by jeff1234; 10-07-2018 at 10:37 AM.
    The only substitute for cubic inches is cubic dollars, how fast can you afford to go?

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    Re: Increase fuel in mptune

    you can also enter the values directly in the grid on the right side.
    89 Voyager LE, 2.5T2 - rest in peace
    87 Charger Shelby T2 (2.4 conversion in process)

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    Supporting Member II Turbo Mopar Contributor jeff1234's Avatar
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    Re: Increase fuel in mptune

    I looked at this just this morning. After 10 PSI up through 6000 RPM all boxes have the positive number 3. Is that number added to some other number? It seems unlikely that there is only three degree's of advance. What does that number represent?
    The only substitute for cubic inches is cubic dollars, how fast can you afford to go?

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    Supporting Member II Turbo Mopar Contributor
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    Re: Increase fuel in mptune

    which cal, which table?
    89 Voyager LE, 2.5T2 - rest in peace
    87 Charger Shelby T2 (2.4 conversion in process)

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    Supporting Member II Turbo Mopar Contributor jeff1234's Avatar
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    Re: Increase fuel in mptune

    My error, I see what you are referring to. I haven't made any changes in the boxes and at this point wouldn't. I really only barely understand the X-Y presentation. I can see what is displayed but don't know how to interpret it. My main disadvantage in this turning is that I cannot as of yet graph out my F/A over time so that I can see variations where they occur and with reference to rpm and psi. I'm hoping when I get my tuning device from you guys I will be able to do that for my LM scans and make precise changes at the points they are needed.
    The only substitute for cubic inches is cubic dollars, how fast can you afford to go?

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    Rhymes with tortoise. Turbo Mopar Staff cordes's Avatar
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    Re: Increase fuel in mptune

    Have you tried dragging the brakes while at WOT and taking your readings after it has been steady at an RPM and boost level for some time? I drag the brakes for 30-45 seconds and take my readings while at WOT for tuning purposes.

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    Supporting Member II Turbo Mopar Contributor jeff1234's Avatar
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    Re: Increase fuel in mptune

    That has been suggested before but I had just completely changed over to Kelsey Hayes front calipers pads and disc's and all new rear drums/linings and spring kits and I wasn't excited about abusing that investment before it was broken in. What I have been doing is WOT from about 2000 rpm in 5th gear which I think is about the same. Please let me know if you disagree.
    The only substitute for cubic inches is cubic dollars, how fast can you afford to go?

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    Boost, it's what's for dinner... Turbo Mopar Staff Aries_Turbo's Avatar
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    Re: Increase fuel in mptune

    Quote Originally Posted by jeff1234 View Post
    That has been suggested before but I had just completely changed over to Kelsey Hayes front calipers pads and disc's and all new rear drums/linings and spring kits and I wasn't excited about abusing that investment before it was broken in. What I have been doing is WOT from about 2000 rpm in 5th gear which I think is about the same. Please let me know if you disagree.
    how fast are you going at redline? 150+? lol

    it doesnt kill your brakes if you do a quick pull in 2nd gear and then let it cool down.

    besides you have to let it cool down or you wont be able to stop lol.

    Brian

    Quote Originally Posted by turbovanman
    This one is easy, I have myself to blame, I rush things, don't pay attention to gauges when I should, change to much stuff at once then expect miracles, the list is endless.

  18. #18
    Supporting Member II Turbo Mopar Contributor jeff1234's Avatar
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    Re: Increase fuel in mptune

    Ha ha, very funny Brian! I let off at 87 mph, just before the bright flashes of light happen. Bwahahahaha
    The only substitute for cubic inches is cubic dollars, how fast can you afford to go?

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    Boost, it's what's for dinner... Turbo Mopar Staff Aries_Turbo's Avatar
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    Re: Increase fuel in mptune

    hehe 

    Quote Originally Posted by turbovanman
    This one is easy, I have myself to blame, I rush things, don't pay attention to gauges when I should, change to much stuff at once then expect miracles, the list is endless.

  20. #20
    Rhymes with tortoise. Turbo Mopar Staff cordes's Avatar
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    Re: Increase fuel in mptune

    Quote Originally Posted by jeff1234 View Post
    That has been suggested before but I had just completely changed over to Kelsey Hayes front calipers pads and disc's and all new rear drums/linings and spring kits and I wasn't excited about abusing that investment before it was broken in. What I have been doing is WOT from about 2000 rpm in 5th gear which I think is about the same. Please let me know if you disagree.
    I like to have take my readings after at least 30 seconds of steady state WOT, as even that can be too little time. From everything I've read Both 5digits and Dave Z. go through about 3 sets of pads on average when tuning a car. Is that extreme? Maybe. Is that what guys from Chrysler did when tuning the MP cals? Absolutely.

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