TBI Questions(MPGuino)
 

I have searched for the past week to find out how to make MPGuino work with a vehicle with TBI [1995 chevy silverado]. I read the post where they were discussing with different resistors.

I was just wondering if there is a official fix. IF so I can go ahead and order a prebuilt or build myself one!


Thanks,
Harrison

Comeon Guys, this is the only thing holding me back.

I am not positive, but it's my understanding that the only things that you need are a Battery (12v Power Source), a Ground, a VSS (Vehicle Speed Sensor), and Fuel Injection. If your truck has Fuel Injection, this **should** work.
Shouldn't your truck have OBD2, and thus work with a Scanguage?
My brother took his car off the road, and it needs a new tire, so we tried to install his MPGuino (prebuilt) into his "new" 1991 Chevy Cavilier wagon. We couldn't locate his VSS no matter what we tried, I may have to buy a manual for his car :( I would recommend finding all the wires you need ahead of time, I bet if I knew which wire to tap for my brother's VSS, it would be a 30 minute install, most of which would be running wires.

Nope my truck has OBDI if it had II i would definitly be all over scangauge. but mpguino will have to work. The VSS should be an easy find. but there is two injectors, does it matter what wire i tap?

I don't know if it matters which injector, I'm hoping not, but don't know why they need separate leads to the ECU.

you want to tap the lead going to the ecu, I believe it will be negative switched. Which means unplug the injectors, turn on the ignition, pick a lead and if it is at 12 volts, tap the other lead.

Thank you very much. I believe I am going to build instead of buy. Just for my customization needs.

Thank you for your help.

ok, have fun. Lemme know if you have success and any specifics you can share with the group.

Well I'm back, and with some Christmas money. So Does anyone know for sure if this will work? I don't wanna blow any of my new found money. If someone can give me a thumbs up for MGGuino working one TBI cars then my parts will be on the way!

From what little I have read I don't think the current form of the MPGuino can give good accuracy with dual injector TBI systems. This thread has some discussion on TBI injector systems. http://ecomodder.com/forum/showthrea...tbi-11899.html

I expect it will be necessary to monitor both injectors which is beyond the current capability but may not be that difficult to add. I have a couple thoughts on how to solve this with some relatively simple logic circuitry.

I think the best approach would be change the injector input conditioning circuitry so that only one interrupt is needed to monitor an injector. This would allow the two interrupts to monitor separate injectors rather then both being used for one injector. As I understand the problem an interrupt can either be set to trigger on rising edge or falling edge but not both and efforts to toggle that in the service routine were not successful at working round this.

I think that by moving the injector state input to another digital input then have a pulse generator circuit that makes a short interrupt pulse for each rising edge and falling edge of the injector pulse. The interrupt service routine just has to read the injectors state input to tell if the interrupt was for the rising or falling edge of the injector pulse.

I could come up with the input circuit for this if the code gods are willing to churn out the software changes.

Mike