High idle speed

[CDeeZ]

I picked up two 7427 PCMs yesterday. I have been looking around in TPRT at some 7427 bins, and yes there is quite a few more things in the 7427!!

Speaking of 7427 PCMs, I tried to carefully remove the PROMs from the MEMCALs of these PCMs..... While I did get the original PROMs removed, the "connector bed" on the MEMCAL itself where it was soldered (not sure what it's called??) that the pins of the PROM attach to got pretty mangled... I found this on thing on Moates and it looks as if it just bypasses the stock PROM, and retains the knock circuitry. http://www.moates.net/g1-memory-adapter-tpi-etc.html But can someone confirm that this is indeed what I need to get going with the 7427 PCM??? I tried to remove the PROM very carefully using this as a guide http://www.gearhead-efi.com/Fuel-Inj...r-27SF512-Chip but I ended up making quite a mess like I said. I would try to upload some pics of my MEMCAL with the stock PROM removed but I'm not sure if the pic would show enough detail?

I wish I would have found out about this G1 adapter before I removed the stock PROMs from these MEMCALs, but I guess that it's kind of a moot point since I planned on recalibrating the BIN anyways right???

[CDeeZ]

BTW, if a person was to solder in a PROM or a DIP socket or whatever onto a MEMCAL, how do you solder the pins?? You can only get to it from the side and it doesn't look like there's enough room to solder anything?

And what do you do about the pins still stuck in the MEMCAL from the PROM, I snipped them off, but is there a better way?

[EagleMark]

I snip the legs off, then stuff a 27FS512 chip in, no dip, it's easier to solder the chip legs, flux the legs and pinpoint solder, must be good soldering station or iron, not cheap stuff that can't stay hot fast.

In the end the G1 is cheap easy and foolproof!

[JeepsAndGuns]

I did one memcal where I sodered in a 27sf512. I took a sodering iron tip and filed it down to a very fine tip. I then cut the chip off from the top of the legs closest to the chip as I could get, leaving as much of the legs there. I then used the fint tip iron and some very fine needle nose plires and heated and removed each pin. This left the chip "bed" or whatever its called intact and then I used the same tip and some very fine soder to attach the new chip.
All said and done, just not worth the time and trouble. I have never done another one. I bought the above adapter and never looked back. Its well worth every penny.
Actually the best deal would be to get this:
http://www.moates.net/gp1-package-gm-adapter-with-2-chips.html
That way you get a nice ZIF socket and two chips. You want that real nice zif for chip swapping. I love mine.

[CDeeZ]

Well I went ahead and ordered the G1 and a ZIF to drop in it. I already have 13 of the 27SF512s so I really don't need anymore of those at this time.


Even if I messed up the MEMCAL plug where the PROM goes, it shouldn't matter since that portion is bypassed anyways by the G1 right?? The knock module and the other two little PROMS underneath it I left alone...




I'm thinking of making an adapter like you did, so I can swap back to a 7747 if I should ever want/need to for some reason... I have two extra 747 ECMs that I was thinking about desoldering the plug from to make said adapter... But you said you just ended up repinning the existing harness to work with the newer 427 PCM right?


What needs to be changed in bin when running a 427 PCM so that the PCM doesn't throw a ton of “where-the-hell-is-your-transmission” error codes?

[EagleMark]

I haven't done a lot of them but think it's as simple as taking an auto bin and checking the manual trans, then turning off error codes for tranny. There is also a 700R4 bin/patch/procedure.

[JeepsAndGuns]

“where-the-hell-is-your-transmission” error code

Had to laugh out loud on this comment.

But yes, as mark said, simply take the bin of your choice, and check the manual transmission flags and then turn off all error codes for transmission.

Looking back, if I knew then what I knew now, I would have never even bothered with the adapter. The ammount of time spent making it was just not worth it. Just swap the pins from your harness into the plugs for the 7427. Like I said, from the first time I plugged in the 7427 and ran it, I never looked back. Now I am like 77-what?..lol

[CDeeZ]

lol....

JeepsAndGuns, you're running a manual trans right?? Which bin did you use?? I'm taking your advice, I will forgo making an adapter and just swap pins...

And Mark, for your sons IH 7427 conversion.... Which bin did you use??

The reason I ask is because Mark you were kind enough to educate me several months back on the fact that IAC logic is drastically different on a AT bin versus a MT bin

So far all I've seen for manual bins using the 7427 were 4.3L V6s......

What do you all think?

[EagleMark]

We've had some deep discussion and search on that and found there never was a 5.7L manual for these PCM. So we took a 7.4L manual trans bin and modified it. I think I ended up with BHDC or BMHK which are $0E just because everyone else is running $0D, not sure what the differences are? The mask/XDF and ADX are just as well documented, not sure if all the hacks for $0D would work, but I had no intensions of doing more then TBI.

[JeepsAndGuns]

I am running BMHK, I think I might have suggested mark try it to. 454 manual trans bins were the only V8 7427 manual bins we could find. I have changed a few things on it over the time I have had it, but still has been a pretty decent one to start with.

But on that note, I did a couple weeks ago try a 350 auto bin, I copied in all my tables, and other misc changes, and selected the man trans flags and was surprised to not have any idle/iac problems. I tried a few diffrent tests. I would be driving push in the clutchand let off the gas ecpecting it to stall, it wouldnt. Would never stall coming to a stop, after downshifting, or anyhting. About the only real diffrence I did notice was when not giving it any gas while pulling out. My current bin (bmhk) will pull and go, mabey even rev a bit. The 350 bin, didnt pul as well, probably stall saver settings were just not as agressiave. I later swapped back to my old bin for a few reasons, nothing major.
So my best reccomendation, would be to simply try a couple diffrent bins and see witch one works best for you. Just remember to unhook the battery and let the pcm reset before swapping bins/code masks

[CDeeZ]

We've had some deep discussion and search on that and found there never was a 5.7L manual for these PCM. So we took a 7.4L manual trans bin and modified it. I think I ended up with BHDC or BMHK which are $0E just because everyone else is running $0D, not sure what the differences are? The mask/XDF and ADX are just as well documented, not sure if all the hacks for $0D would work, but I had no intensions of doing more then TBI.

Yeah I didn't think there was a 5.7L/stick BIN.... Looks like I'll be trying that 454-manual bin on for size.

I am running BMHK, I think I might have suggested mark try it to. 454 manual trans bins were the only V8 7427 manual bins we could find. I have changed a few things on it over the time I have had it, but still has been a pretty decent one to start with.

But on that note, I did a couple weeks ago try a 350 auto bin, I copied in all my tables, and other misc changes, and selected the man trans flags and was surprised to not have any idle/iac problems. I tried a few diffrent tests. I would be driving push in the clutchand let off the gas ecpecting it to stall, it wouldnt. Would never stall coming to a stop, after downshifting, or anyhting. About the only real diffrence I did notice was when not giving it any gas while pulling out. My current bin (bmhk) will pull and go, mabey even rev a bit. The 350 bin, didnt pul as well, probably stall saver settings were just not as agressiave. I later swapped back to my old bin for a few reasons, nothing major.
So my best reccomendation, would be to simply try a couple diffrent bins and see witch one works best for you. Just remember to unhook the battery and let the pcm reset before swapping bins/code masks

Ok, I'm going to play around with several bins, but probably end up running the 454-manual bin, if nothing else I can hassle you and Mark if I have questions with the bin and mask

[EagleMark]

I'm sure you can!

Now JeepsandGuns has also just recently tried a 5.7L Auto bin with manual flag set and said it ran well with no ill effects there is still a lot of differences in IAC logic with shifting, most of which are for emmissions but side effect is slower to idle inbetween shifts making shifts easier.

[JeepsAndGuns]

Yea I figured IAC would be all kinds of screwy, but it wasn't. AE was way off, and for some reason that bin made my engine have a very light surge during accel. Went back to my old bin and it went away. Couldn't figure that one out.