Getting the 7427 PCM to work with a Manual Tranny Set Up

[axisT6]

I recently pulled my 4L60E and swapped in a NV4500. I have the truck wired so that when the truck is running, the ECM thinks the truck is in drive or at least I am assuming that based on the fact that "OD" indicator is lit on the dash.

Right now the only problem I am having is that the rev limiter kicks in at 3500 RPM.

I plan to zero out all the tranny tables in hopes that this will solve the problem.

What else should I look into?

[Blue71]

http://www.fullsizechevy.com/forums/3439128-post37.html

[axisT6]

Well, based on that link, I will start by clearing the trans error codes and work my up from there.

Thanks by the way.

[axisT6]

Alright, I burned a chip with only the Trans Error Codes cleared, and I still hit a wall.

My next attempt will include a chip with both the Trans Error Codes and the Trans Parameters Zeroed out.

I have also been searching my $0D Hack for the Auto/Manual flag, but can't seem to find it. I want to say it is here (bit 6 and 7):

L400F: FCB $18 ; MODE WD, DIG I/O 0001 1000
; b7 1 = MAN, (0 = TCC)
; b6 1 = TCC (Non Elect xmish)
; b5 1 = not used
; b4 1 = CONV OVER HEAT
;
; b3 1 = KNK RETARD
; b2 1 = A/C CLUTCH CNT'L, 0 = VAR TUNE
; b1 1 = not used
; b0 1 = 1 DO RPM/MPH LMT

I could be wrong as I am fairly new reading hacks.

[93V8S10]

400F bit 7: Manual Transmission, On = Manual Trans, Off = Auto Trans

400F bit 6: TCC Only (non electronic trans), On = Auto trans with TCC control only, Off = Auto trans with electronic shift and TCC control

Edit: 400F bit 6 and 400E bit 2 must be on if a manual trans is used.

[axisT6]

Originally Posted by 93V8S10

400F bit 7: Manual Transmission, On = Manual Trans, Off = Auto Trans

400F bit 6: TCC Only (non electronic trans), On = Auto trans with TCC control only, Off = Auto trans with electronic shift and TCC control or Manual trans

Awesome! Thanks. I knew I was on the right track. How has life been treating you anyways?

[93V8S10]

Still working on the S10, how about yourself?

[axisT6]

Originally Posted by 93V8S10

Still working on the S10, how about yourself?

Still wrenching on whatever needs it. Anyway, I checked the bit like said, and still hit a wall. The particular chip in the truck has bit 7 at 400F checked, and all the trans. diagnostic codes cleared.

HaulnA$$ was generous enough give me some pointers to get this set-up to work, so I will make another attempt using the info he gave me.

Even though I cleared the codes, is it possible they are still set? What I mean is, do I need to disconnect and reconnect the battery to make sure the codes are cleared?

[951500]

i just did a complete Auto to manual Swap in my 1995 C1500 the other day , My truck is running Great with No Codes showing and No problems. , I put in a 5 speed out of an 88 I never even changed my computer or reflashed it , All i did was took The Park Neutral Switch off the 4l60E and Pluged it in to the wiring harness that it was hooked to in the first place and Put the switch in Park Mode and strapped it to the side of the 5 speed. and all is fine. I am still using my original computer . No troubles yet .

[axisT6]

Originally Posted by 951500

i just did a complete Auto to manual Swap in my 1995 C1500 the other day , My truck is running Great with No Codes showing and No problems. , I put in a 5 speed out of an 88 I never even changed my computer or reflashed it , All i did was took The Park Neutral Switch off the 4l60E and Pluged it in to the wiring harness that it was hooked to in the first place and Put the switch in Park Mode and strapped it to the side of the 5 speed. and all is fine. I am still using my original computer . No troubles yet .

I don't see how you are pulling that off. How far can rev the engine with the truck in gear? Did you wire up the neutral safety switch on the clutch pedal?

So far I have removed the Park Neutral Switch from the truck and spliced the necessary wires to put it in "D". The neutral safety switch on the clutch pedal is wired in as well. Tonight I am hoping I found the problem. We will see.

[93V8S10]

With the older ECM's used in the 1991 S10 trucks with a manual trans, the park/ neutral switch isn't wired at all (no wire from the ECM), this will result in a open circuit.

Have you checked the wiring for the speed sensor and DRAC?

Originally Posted by axisT6

Even though I cleared the codes, is it possible they are still set? What I mean is, do I need to disconnect and reconnect the battery to make sure the codes are cleared?

Don't know if there still set or not, but I would reset the PCM if I was you. I usually reset mine frequently when tunning, so I know that I'm starting from the same point.

I've got a BHFM bin (I4 engine, manual trans), if you need it for comparison?

[951500]

Originally Posted by axisT6

I don't see how you are pulling that off. How far can rev the engine with the truck in gear? Did you wire up the neutral safety switch on the clutch pedal?

So far I have removed the Park Neutral Switch from the truck and spliced the necessary wires to put it in "D". The neutral safety switch on the clutch pedal is wired in as well. Tonight I am hoping I found the problem. We will see.

I never got a chance to do my neutral start switch or reverse yet . I am starting that today. but so far it drives perfect , i had it reved up to 4000 in gear and not problems yet . The reason i did this was because I was talking to a mechanic at the dealer and he told me he done the swaps quite often , I will be double checking it today

[axisT6]

Alright, got it to work.

You need to check bit 6 and 7 at L400F as mentioned above, and also check bit 2 at L400E which is the shift light.

In also zeroed out the kickdown constants with respect to RPM.

As for wiring, I disconnected the above mentioned wires so that nothing is lit on the gear indicator in the dash.

I am lovin' it!

[93V8S10]

Glad to here you got it going!

I'm surprised that bit 7 at L400F had to be checked, didn't think it would mater. O well, that's what we get when engineers design things.

I'm not surprised that the shift light had to be turned on. I had assumed that you had already tried it, I should have mentioned it earlier.

I thought that all of the trans tables would need to be zeroed out. Is it just the kick down vs. RPM ones that need to be zeroed?

[axisT6]

Originally Posted by 93V8S10

Glad to here you got it going!

I'm surprised that bit 7 at L400F had to be checked, didn't think it would mater. O well, that's what we get when engineers design things.

I'm not surprised that the shift light had to be turned on. I had assumed that you had already tried it, I should have mentioned it earlier.

I thought that all of the trans tables would need to be zeroed out. Is it just the kick down vs. RPM ones that need to be zeroed?

I just zeroed out kick down vs. RPM stuff, and cleared the codes. Also, did you mean bit 6 at L400F?

[HaulnA$$]

Originally Posted by axisT6

Alright, got it to work.

You need to check bit 6 and 7 at L400F as mentioned above, and also check bit 2 at L400E which is the shift light.

In also zeroed out the kickdown constants with respect to RPM.

As for wiring, I disconnected the above mentioned wires so that nothing is lit on the gear indicator in the dash.

I am lovin' it!

[axisT6]

Originally Posted by HaulnA$$

Thanks again for your help!

[HaulnA$$]

Originally Posted by axisT6

Thanks again for your help!

How hard did Ike hit ya?

[93V8S10]

Originally Posted by axisT6

I just zeroed out kick down vs. RPM stuff, and cleared the codes. Also, did you mean bit 6 at L400F?

Oops, just saw this. Yes, it was bit 6, not bit 7.

Originally Posted by HaulnA$$

How hard did Ike hit ya?

X2

[axisT6]

Originally Posted by HaulnA$$

How hard did Ike hit ya?

My area got slammed. On my street we had damaged roofs, chimneys blown off, downed trees etc. A guy that lives just outside the neighborhood had his house cut in half by a falling tree. Lost power for 5 days as well.

I had minor roof damage, a downed fence, and torn gutters. Not the best weekend I have had.

All is well now that I patched the roof, and the power is back on. I am waiting on the insurance adjuster now.