tuneable ecm for 4t60e?

[95cutlassproject]

Hello 95cutlassproject here with a few questions. I went to the local junkyard a few days (i was with my brother get parts for his Honda, we do that a lot) i believe (not 100% sure on this) that the 93 cutlass supreme got the 3100 SFI and also had a 4t60e. would it be possible for me to use that if i wished to get a tuneable computer, and keep SFI (i like to keep SFI if possible) and would this be an easy plug and play sort of deal. Any help and feed back to my idea would be nice. (reason being to keep SFI is they charge $20 less for a SFI computer than a MPFI one)
Thank you

[jman093]

3100 started in 1994. 93 will be the (batchfire) 3.1mpfi. And the only way to tune pre 96 is by burning a new ROM chip for the PCM.

[95cutlassproject]

thank you, if i grab that ecm from the cutlass since it controls the 4t60e will i need to do re pinning or will it be a plug and play deal?

[mickaz]

3100 started in 1994. 93 will be the (batchfire) 3.1mpfi. And the only way to tune pre 96 is by burning a new ROM chip for the PCM.

you mean flashing the computer with a tuner?

[3400beretta]

The 3100 debuted in 1993 in a few cars - one being the cutlass. If it is a 3100, then it will be a flash based OBD1.5 PCM, which is not currently tuneable.

[robertisaar]

in 1993, the ONLY vehicles to get the 3100 were LATE cutlass supremes. in 1994, it replaced all 3.1s with the exception of the lumina, u-bodies, and j-bodies, and in 1995, the 3.1 was only in the u-vans.

ALL 3100 PCMs used FLASH memory and were designed to be flashed through the ALDL port, with the exception of the 94-95 A-bodies, those used good old-fashioned MEMCALs which can have custom chips burnt into them, or using an adapter to just bypass the factory tune.

ALL 3100s were hooked up to 4T60E transaxles until the 65E replaced it in 2000(the n-bodies dropped it earlier for the 40E IIRC).

that being said, if you want to use the PCM for fuel and spark control as well, instead of just as a trans controller, you have a few options:

tuneable MAF:
all 91-up 3800 PCMs(except 91-92 regal and 91 u-van) through 1996(for supercharged applications) and through 1997(N/A) are meant to control a 4T60E
94-95 3100 a-body
94-95 LQ1 w-body

tuneable speed-density:
91-93 LQ1 w-body
93-94 LH0 w-body

i may have a missed few, especially cadillac and 4 cylinder applications, but that's due to not knowing a whole lot about them.

of the listed PCMs, the MAF setups are all SFI, while the speed-density are all MPFI.

[95cutlassproject]

ok, that helps me a lot. i am looking to have the ecm control the trans and fuel and spark, i am very new and what is really the difference between the MAF and speed density is one of them better than the other?.

Edit: also my guess is using any of these MPFI ecms requires me to repin the harness.

[robertisaar]

MAF setups: the PCM reads a sensor stuck in the airstream to directly measure the amount of air flowing into the engine, so it knows exactly how much fuel to inject. this sensor is in all senses a restriction to airflow, which is why is i disliked them for so long. but if the one you use is of sufficient size for the motor, there is no difference in the amount it will flow compared to an open tube

MAP: used in speed-density systems, which use a combination of RPM, air temp, manifold vacuum and a few other variables along with an estimation of volumetric efficiency at multiple RPM and vacuum points.

it is MUCH simpler to setup a MAF system perfectly compared to speed-density, and takes to boost much easier as well, since you won't have to worry about pressure ratios and instead just worry about calculated airflow.

i assume this is going into a 95 3100 cutlass? going with a MAF system, i believe the best choice would be to grab the PCM from a 94-95 3.4DOHC w-body, since they are weatherproofed and were at least availible in the same vehicle, though the connectors the stock PCM uses are FAR different(the 94-95(possibly 93 as well) 3800 regals use the same connectors, but i know VERY little about that PCM other than it using a second generation MEMCAL and is indeed tuneable). i got around this by building a conversion harness, though it would be cheaper to just cut the existing connectors off and solder on the ones for the 94-95 LQ1 PCM(which BTW, the p/n is 16196401).

IIRC, the only sensor that is not present on your vehicle now, is the the MAF, but i would need to look again to make sure. you can use quite a few different ones actually, you'll just need to rescale the MAF tables in the PCM to match them and it will more or less interchange with no other issues, but i believe in order of lowest flow to highest, it goes 94-95 L82 a-car, 94-95(possibly earlier as well) L27 3800, 94-95 LQ1, 94-95 L67 3800SC. there are likely more, but i haven't needed to look into it since the 94-95 LQ1 MAF should suit any 3100 up to ~350HP.

did i miss anything?

[95cutlassproject]

i dont know if my car has maf as there is no sensor in the actual intake tubing, i just has a temperature sensor and a lil vacum line on the intake, I will have a picture up soon of the engine bay.

[robertisaar]

if you have a 93-95 w-body with a 3100, you would NOT have one from the factory. you would have the air temp sensor right after the filter box, and then on the top near the TB, a line for the fresh air return for the PCV system.

trust me, i know the view well.

[95cutlassproject]

I trust that you know its just, when i pulled off my air box to put a warm air intake on, i saw no senor.

Edit: had a brain malfunction you were saying that i do have map.