Alright, well i have a 91 blazer with a tbi 350 in it. I was tired of outdated 7747 ecm so i swapped in a 427 pcm. The truck runs absolutely perfect, except for a few things. Seems like after 2 hours or so of driving it will go into limp mode. I can unplug pcm and it will run fine again usually. I also am having problems with a rev limit set at 4300 rpm. I am tuning with an ostrich and i have the limiter set at 6300 rpm. Here are a few things i dont have hooked up yet, but am going to in the near future. I am still using my old knock senser from the older ecm, i also dont have a park neutral switch wired into pcm. I dont know if this is the reason i have the low rpm limiter. I am also having problems getting the TCC lockup function working. I think that is all i have. I appreciate any ideas you guys might have. Thanks
Joel

 

Old knock sensor definately will not work. You need to bypass the ESC module under the hood and put in a 1993-1995 TBI 350 knock sensor.

Park/Neutral switch is pretty easy, just plug it into E5. E5 will read either Drive/Neutral duplicating what is there on your old system.

The TCC output gets wired to pin E10. You need to flip the non-computerized transmission bit in the code for it to work. You also need to supply +12VDC to pin E13 for the TCC to lock (this is usually routed to the brake pedal switch) and pin E13 MUST recieve +12VDC for the TCC to lock.

As far as the low-rev limit, it sounds like the PCM is not setup for the Non-Computerized transmission but rather the 4L60E. There is a seperate rev-limit value for transmission errors logged. That happens to be set at 4,300 rpm.

 

Hey, thanx a lot fast. I am using your bin file for a stock tbi 350 with 700r4 lockup tables added. I will check into what you have stated. I was wondering if the pcm had a lower rev limit for park/neutral vs in gear. I will check into my wiring to see what is up. Thanx for those ideas. Joel

Also, i have already bypassed the esc module on firewall.

 

Alright i just did this swap and am having trouble too. I am also using a 1st gen blazer. 7747 to 7427

I fire it up and its stupid rich because its in limp home mode i guess idk, but i fire it up and the ses light comes on after a few seconds, i put a wire in the aldl to pull codes and i get the codes 43 and 59. 59 im not worried about because thats just a trans cold code. but 43 is the knock sensor circuit code.

Will that code cause it to run like this? i wouldnt think it would. I cant get datamaster to run either, (never used it before so either)

Tried stock prom, and ostrich tune. Using the exact same bin as joel and i called him to veryify my ecm wiring so i have no errors there. I also made sure the two wires were jumped at the esc module and that it was unplugged. I dont know what the hell is the matter with it.

ANY IDEAS??

 

well, the esc wires were blue and ****ing black, not brown, on these trucks anyways... so i got that fixed. Its running truely in limp home mode now. Its got a **** ton of codes 14-15-16-21-22-24-28-32-33-34-35 just to name a few. Is this ecm ****ed or somthing?

The cal pack was on my ostrich g1 adapter backward for i dont know how long, ive unplugged and repluged everyconnection so many times. It was right before. anyways. i went to reset the ecm too but after a minuit or so id didnt reset because it still had all the codes in it. Im just unplugging the son of a bitch for tonight and see if it has any codes tomarrow.

Before i switched the prom cartrich around it only had that one tranny code. Its in the right way now im sure, the pins line up with the two little chips not the prom chip. STock prom no ostrich it runs the same, come to think of it, it runs now like the stock prom always has when i have the ostrich in, so before it must not have had the limp home data since it was in backwards. but anyways. **** ton of problems.



Edit- i went back out later and the codes WERE clear this time, fire it up ses light comes on after a second or two and pulls that stuipid 43 code, then a bunch of tranny codes, like 67 81 82 and 59 or somthing.

 

got another computer, ran the same, had a handfull of trans codes.

so its not the puter.

 

Alright, everything is working. The problem the whole time is i put .xdf on the end on my xdf's file name My check engine light still comes on but its stricktly trany codes. 59, 67,81,82

Any ideas around those.

And 2 THE REV LIMITER IS IN GEAR on mine too. I have factory colum shift and all the wiring is origional, nothing wrong there.

 

i have my 283 tbi s10 almost ready to go

when i get to 4k on my tach (not re calibrated so it is really 3k) it acts like it is redline limiting the engine (like a damn honda on a drag strip)

the computer is the 7427 pcm, 94 s10 4.3 harness


Eld 2703 intake (same as 2701 but with oil fill)
jeggs tbi adapter
new cap and rotor
new plugs
5.7 dist
94 4.3tbi computer (7427 PCM)
700r4
not sure what the cam is, but it is nothing extreme, idles fine

NEW HO2S
knock sensor is mounted on fuelpump blockoff (this may be the issue not sure) knock is from 91 noma 4.3

the harness is setup for 2 knock sensors and i only have one, read somewhere that i only needed one since the 5.7 has 1 on same computer

codes are as follows

24 Vehicle speed sensor (VSS) - open or short circuit
problems or park/neutral switch circuit problem

--leaning for p/n sw, truck has not moved , still on stands)

43 Electronic spark timing (EST) circuit - low voltage
detected
Electronic spark control (ESC) - circuit problems



--VOID NO AC--
66 Electronic Control Module (ECM) computer circuit fault
or air conditioning pressure sensor circuit fault or low
air conditioning refrigerant charge
(Transmission) 3-2 shift control solenoid - circuit
problems

67 Cruise control - switch circuit problems
Air Conditioner (A/C) pressure sensor - circuit problems
Torque Converter Clutch (TCC) solenoid - circuit
problems
Cruise control switches - circuit problems
Retrieving ECM Codes




--VOID CODES DUE TO 700R4 installed, pcm for 4l60e--
59 Transmission Temp Sensor (TTS) - open
Transmission fluid temp low

73 Air conditioning evaporator temperature sensor circuit
fault (high temp.)
(Transmission) Pressure control solenoid - circuit
problems-

83 Torque Converter Clutch (TCC) solenoid - circuit
problems
Reverse Inhibit - open or short circuit in reverse inhibit
solenoid

 

so are you asking for help on your truck or just posting what yours did?

if so we got ours all figured out so we can help you.

 

yeah i have no clue why its busted, im stuck at the stated issue, i just need help fixing it

 

hit me up on aim or msn if you can.