Whats wrong with my tune?

yellowlt1ta · Post by **yellowlt1ta** » Wed Feb 06, 2013 5:16 pm

see I always thought that I had to change that to a higher level just because its will see higher than atmospheric pressure. I live very close to sea level so thank you for the info on that I did not know.

Is the diagram above correct for adding an external MAP sensor? Id like to add it and see if my problem persist.

yellowlt1ta · Post by **yellowlt1ta** » Sat Feb 09, 2013 5:09 pm

I have not changed the MAP sensor just yet but I got the car to make 15psi but It misfires all the way from 100kpa to 205kpa

yellowlt1ta · Post by **yellowlt1ta** » Sun Feb 10, 2013 11:31 pm

so adding the external map sensor turns out to be used only as a baro correction and I cant seem to get it to do the work of the MAP sensor.

there are no settings in tuner studios that allows me to do this. do I need to rip the old sensor off?

Matt Cramer · Post by **Matt Cramer** » Mon Feb 11, 2013 6:14 am

The way to add an external MAP sensor that is not used as a baro sensor is to remove the internal MAP sensor and wire the external MAP sensor to pin 1 of the internal MAP header.

yellowlt1ta · Post by **yellowlt1ta** » Mon Feb 11, 2013 11:53 am

Thanks Matt I had thought of that but didnt want to do it and mess something up.

yellowlt1ta · Post by **yellowlt1ta** » Wed Feb 13, 2013 5:28 pm

so I got the external MAP sensor installed and I can say that Im seeing much less noise in the datalogs but it seems like the plugs are fouled because its misfiring as soon as it starts up. that is unless there is somthing still wrong with it. the plugs where new about 100 miles ago and I took them out and cleaned them real good but it still misfires badly. Im gonna buy my 4th set of plugs and see what happens.

here is the data log

misfire idle 3bar.msl

kjones6039 · Post by **kjones6039** » Wed Feb 13, 2013 7:13 pm

8.4 AFR during startup, idle and warmup will certainly foul plugs I suspect...............

Ken

yellowlt1ta · Post by **yellowlt1ta** » Fri Feb 15, 2013 11:32 pm

so today I pulled the plugs and put some new ones in. there is no dought that there is an excessive amount of fuel. But here is what I dont understand, the car was running great for more than 1k miles and out of no where the plugs are getting fouled because of fuel. when I changed the plugs I pulled tons of fuel out of the fuel map and the car started to feel great again. I turn it off and turn it back on and check to make sure the fuel map is the same (and it is) then the car runs like crap again. I pull more fuel out and the o2 sensor is reading a lean mix but the car runs great. Is there something adding fuel to the tuen???

could some sort of bad sensor be the problem?

here is whats going on. I pull fuel and it runs good (reads lean) I turn it off and it runs like its got too much fuel. I pull fuel again and it runs good. I turn it off and it runs rich again. what the heck is going on?? I

kjones6039 · Post by **kjones6039** » Sat Feb 16, 2013 3:25 am

could some sort of bad sensor be the problem?

here is whats going on. I pull fuel and it runs good (reads lean) I turn it off and it runs like its got too much fuel. I pull fuel again and it runs good. I turn it off and it runs rich again. what the heck is going on?? I

Good question...........

What kind of wide band setup are u using? Calibrated correctly?

Just a thought based on your description..............

Ken

EDIT: How about exhaust leaks upstream from the sensor? How are you "pulling fuel"?

billr · Post by **billr** » Sat Feb 16, 2013 9:30 am

Post the latest .msq, it sounds like it has changed since the beginning of this thread.

yellowlt1ta · Post by **yellowlt1ta** » Sat Feb 16, 2013 2:27 pm

kjones6039 wrote:
Good question...........

What kind of wide band setup are u using? Calibrated correctly?

Just a thought based on your description..............

Ken

EDIT: How about exhaust leaks upstream from the sensor? How are you "pulling fuel"?

Im using an Innovate LC1 single wideband. I have it wired up just like the instructions say. (no ground to MS) just grounded to where all the factory sensors were. (that is on the front shock tower) I have puched the calibration button before to see if it was miscalibrated but it made no diffrence.

billr here is the latest msq.file

tuning for problems.msq

billr · Post by **billr** » Sat Feb 16, 2013 3:48 pm

Yeah, I'll ask too... where/how are you "pulling fuel"? Just for a sanity check, what is the engine size, injector flow, and fuel being used? Might as well verify your req-fuel is fairly correct, hasn't been "faked".

yellowlt1ta · Post by **yellowlt1ta** » Sat Feb 16, 2013 5:00 pm

billr wrote:Yeah, I'll ask too... where/how are you "pulling fuel"? Just for a sanity check, what is the engine size, injector flow, and fuel being used? Might as well verify your req-fuel is fairly correct, hasn't been "faked".

I am pulling fuel by taking it away from the VE table. (example. if its at 50(VE) on 1,200rpm and 30kpa ill place it at 45 then burn it)

the engine is a 350cid LT1 chevy (GENII)
the injectors are 96lbs/hr (trick flow) low impedance injectors (already have about 3k miles on them)
using 93 octane pump gas. (from my local 7-11)
reqfuel 4.8ms

the msq. file that I placed says reqfuel 7.8 but that is not whats on the megasquirt right now. that was me messing around with the tune at home thinking about other ways to pull fuel but I have not tryed it yet.

billr · Post by **billr** » Sat Feb 16, 2013 7:42 pm

I'm going to wish you the best of luck, but bow out of this. Your AFR, VE, and ignition maps all look strange to me, and I am a firm believer in leaving the req-fuel at "calculated", not using it for a tuning tool. Understand, I am not saying your approach is unworkable, but any suggestions I can make will probably be counter-intuitive to you and will only confuse your efforts, or just annoy you.

yellowlt1ta · Post by **yellowlt1ta** » Sun Feb 17, 2013 12:21 pm

I know that its a desperate approach to my problem but this has been driving me crazy for far too long. I didnt burn it to the ms yet and I guess I wont take that approach.

what do you find weird about my maps?

I just dont know what to do now. and when I dont know what to do I could get very experimental with everything.

yellowlt1ta · Post by **yellowlt1ta** » Wed Aug 27, 2014 9:43 am

This is old but I did find why the car had a bad misfire. And here is the link to why this was happening. http://www.msextra.com/forums/viewtopic ... 01&t=53018

MaxxAction · Post by **MaxxAction** » Wed Aug 27, 2014 12:17 pm

Won't comment on the tune...

but as a general rule, in my 40 years of messing with motors, a bad miss under load is almost ALWAYS a spark related issue. Considering that your car ran great for 1k miles, then started this, I would be looking at something mechanical in the distributor.

yellowlt1ta · Post by **yellowlt1ta** » Thu Aug 28, 2014 7:12 am

That is what I thought. Its a DIS. The truth is the problem was fuel issue caused by the megasquirt adding large amounts of fuel.

MaxxAction · Post by **MaxxAction** » Sun Aug 31, 2014 6:18 pm

yellowlt1ta wrote:That is what I thought. Its a DIS. The truth is the problem was fuel issue caused by the megasquirt adding large amounts of fuel.

So you solved it?

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