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My GM 3 bar MAP sensor took a dump. Can I use my stock MAP sensor without having to retune the car until my new 3 bar arrives? Running 9 psi on aem series 2 ems. Could I just go into aem tuner and descale the MAP sensor to the stock sensor and start driving with no issues?
Thanks.
A quick search would tell you the stock map sensor is good up to 11-12psi. So yes if you get your calibration updated to account for the different map sensor you should be fine without retuning.
The scaling for the map sensor is rarely spot on. Yes you can run your stock map, but it will take some tweaking. Try the stock sensor settings, and watch afr. If it doesn't match what it was before, start tweaking the map scaling up or down until afr does match what it was. And when you install the new sensor, you'll probably need to do the same to compensate for variances in sensor signal
The scaling for the map sensor is rarely spot on. Yes you can run your stock map, but it will take some tweaking. Try the stock sensor settings, and watch afr. If it doesn't match what it was before, start tweaking the map scaling up or down until afr does match what it was. And when you install the new sensor, you'll probably need to do the same to compensate for variances in sensor signal
Thanks for the info Anyone know a "normal" pulse width for the injectors would be while trying to start the car? Because when I go to start it im getting a pulse width of around 7.37ms-19.25ms and then the car stalls.? I know when the car is running properly at idle im around +-1.1ms. I have AUS 750cc injectors already tuned to the car and never adjusted by me. Im wondering if my injectors are done?
depending on coolant temp and ambient air temp, 750cc injectors would crank at anything from 13ms down to 4ms. it sounds to me like your cranking pw is too high and is flooding the motor out if it is over 13 at colder temps, and over 7 at operating temp.
it's also possible that the post start enrichment is too rich.
a good way to find out for sure is to have a wideband active in the car. start it, and LET it stall out. then look at the wideband after it stalls. anything 10's or lower is too rich. ideally you want to see high 11's to high 12's during and immediately after cranking when below operating temp. at operating temp it's normal to see mid 12's, 13's, or even into low 14's sometimes during and immediately after cranking.
and when I say immediately after cranking, I mean only for 1-2 seconds at most. after 2 seconds the afr will be reading post start enrichment, and actual fuel tables.
depending on coolant temp and ambient air temp, 750cc injectors would crank at anything from 13ms down to 4ms. it sounds to me like your cranking pw is too high and is flooding the motor out if it is over 13 at colder temps, and over 7 at operating temp.
it's also possible that the post start enrichment is too rich.
a good way to find out for sure is to have a wideband active in the car. start it, and LET it stall out. then look at the wideband after it stalls. anything 10's or lower is too rich. ideally you want to see high 11's to high 12's during and immediately after cranking when below operating temp. at operating temp it's normal to see mid 12's, 13's, or even into low 14's sometimes during and immediately after cranking.
and when I say immediately after cranking, I mean only for 1-2 seconds at most. after 2 seconds the afr will be reading post start enrichment, and actual fuel tables.
Im pretty sure youre right about flooding the engine with gas, cause my wideband durring crank is high 10's. When I went back to stock due to state ref inspection i left the injectors sitting on my shelf for about 6+ months, never cleaned them or anything so im thinking they may be stuck open, rusted open?
08-16-2017, 04:43 PM
Retune needed for switching MAP sensors?
Anyone know a "normal" pulse width for the injectors would be while trying to start the car? Because when I go to start it im getting a pulse width of around 7.37ms-19.25ms and then the car stalls.? I know when the car is running properly at idle im around +-1.1ms. I have AUS 750cc injectors already tuned to the car and never adjusted by me. Im wondering if my injectors are done?
