Inconsistent mapping

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angus99
MS/Extra Newbie
Posts: 31
Joined: Sun Mar 13, 2011 4:44 am

Inconsistent mapping

Post by angus99 »

I'm been having an issue for a while where I seem to get the mapping spot on one day and then next time I take out the car it runs differently. The car is a 5.0l TVR chimera running ms2extra with wasted spark.

For example I had the car out for a good run yesterday with the intention of sorting out the mapping. The car was initially running rich, especially at low speeds and cruise, but was running well higher up the rev range. After a few stops to check the megasquirt logs and autotune results, I leaned out the map across the problem areas and it ran perfectly for the rest of the day.

Today I took the car to work and had the opposite; running lean at low speeds, cruise and a pig to drive in traffic. I didn't have time to make any changes to the fuelling, but did have autotune running which indicated the fuelling needed to be richer the same areas that I'd leaned it out yesterday.

No sure sure what could be causing this, thoughts so far are:

Stepper motor
Dodgy fuel injector
Fuel pump
Fuel pressure regulator
TPS sensor
Wide band sensor or controller.

Any other ideas before I waste to0 much time and cash pon the trial and error approach.
LT401Vette
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Re: Inconsistent mapping

Post by LT401Vette »

:msq:
Phil Tobin
EFI Analytics, helping to simplify EFI
Next Generation tuning software.
Supporting all MegaSquirt versions and firmwares.
http://www.TunerStudio.com
http://www.efiAnalytics.com/MegaLogViewer/
Support the firmware running your engine:
http://www.msextra.com/doc/donations.html
thieledj
MS/Extra Newbie
Posts: 28
Joined: Wed Jan 02, 2013 1:32 am

Re: Inconsistent mapping

Post by thieledj »

Check your fuel filter. Restricted flow will cause leaning of the mixtures.
Check your fuel pressure. Make sure it is steady and consistant. Different battery voltage will also cause different fuel mixtures.

Hooroo

David Thiele
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