subject line says it all..

I have been wondering why that is ...please teach me

 

GM has used both.
Currently with the way the EPA has written the OBDII mandates, and implimented by GM, they've desided to run both. One as a sanity check for the other. Just a matter of OBDII diagnostics.
Just flipping a switch in the code allows a LT1 to run MAF or MAP as the primary sensor. All other things being equal, from the driver's seat you can't tell the difference, in stock form.

Aftermarkets have to be as universal and as user frinedly as possible. Which means as few of sensors, and programming intuitive as possible. Also economics come into play and a MAP sensor is alot cheaper then a MAF.
And in boosted applications, MAP reigns supreme, again means being more universal in nature.

 

HI Grumpy

Thanks for the answer..would you say the injection system on an ls1 is better than the aftermarked stuff ?

Im considering getting the FIRST TPI manifold www.firstinjections.com it looks like the best ltr style setup, do you know it ?

what DFI system is the best in your opinion ? im leaning towards the TEC3 but not much is said about it on the boards...

thanks

thomas

 

It depends on what your doing. There are few blanket statements about EFI that are Universally true.

Never dealt with them.

The aftermarkets are finding out that it takes a certain amount of sophistication to get EFI right, and now they are getting alot more complex. Easy to tune, often means doesn't run as well as it could. And they have to try and make the systems as versitile as possible so they don't have to manufacturer any more different ecms then possible. The better systems all get into some serious money, and older stuff is lacking in some areas.

It's only under rare circumstances that I consider any of the aftermarkets a real improvement over the stock ecms. But, I have alot of time in on working with stock systems.

I haven't worked with an LS1, so I can't really comment on that, but I have sone some serious tuning with a LT1, and it's flash pcm and I found that really enjoyable. While it wasn't on the fly, I don't see that as being a real big deal, since I note what I doing, and that takes some time anyway. Thou, I have been playing with some R_T oem tuning stuff lately and for minor drivibility stuff, it is a great thing.

For the price of any of the latest aftermarkets, you can do alot with the oem stuff. Thou the OBDII stuff is still expensive.

 

GM used MAF & MAP in my Chevrolet Celebrity ' 88. When I reprog. the PROM... How can I know if this V6 is using the MAF or the MAP as a primary sensor?. When switch from MAF to SD and viceversa?. Which sensor table (MAF or VE) I need modif in the PROM?.

----1227730 ECM - OBD I - $6d bin - MPFI------

Thanks in advance for any reply.


Denis V.