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ony
08-05-2015, 05:23 PM
does the 7427 have a built in esc? I put one in my truck to replace a 44288 now after I start it I almost imedelty get cel that says esc open or shorted? it has a 1994 4.3 memcal in it.it was my fault the module smoked.I had the pcm hooked up with the key off and connected a wire in the right place but it sparked the it wouldn't start

whatif3387
08-05-2015, 06:00 PM
My truck is a 1995 with the 7427 and yes the ESC is built in.

PJG1173
08-05-2015, 06:09 PM
yep. some of the 39/94 4.3's also had two knock sensors on the same wire too.

ony
08-05-2015, 08:43 PM
does anyone know how to bypass the esc module on the engine so the pcm see's the knock sensor

PJG1173
08-05-2015, 08:58 PM
the knock sensor on the 7427 is connected directly to the computer. Just remove the module under the hood and wire the sensor direct. that is how I did it on my Toyota v8 conversion

Six_Shooter
08-05-2015, 09:52 PM
You will also need to change the knock sensor to one that matches the ECM and engine combination. The knock sensors are different between the internal and external ESC set-ups.

Alternatively, you can modify the MEMCAL and use the external ESC. I know this works on the '7730, I'm pretty sure the '7427 would be the same type of modification, just the actual pin to use for teh input from the ESC module may need to be figured out.

ony
08-06-2015, 01:42 AM
I will try diconeting the esc sensor and connecting c and e with a jumper, the engine had 2 knock sensors on it that was 8000 ohms each, I have one on it now that has 4000 ohms if this don't work may try the memcal mod if it is easy for me to understand. thanks for everones reply. :jfj:

ony
08-06-2015, 02:38 AM
well that didn't work,i may have to put this off till I can put my pcm in a vehicle that came with one. I bought this off ebay and it may not be in working order. it runs richer than my 288 going by my nose I have tuned on the 288 for 5 years playing iam going to rebuild my engine and put a litter better cam in it is why I was going to upgrade to the 7427. tuner cat sure shows a lot more things you can adjust compared to the ecm that came in the truck. I got some more knock sensors at work iwill try tomorrow if I get time, one of the 8000 ohms might fix it. the light didn't come on as fast jumping the wires with the esc disconnected.old engine is so noisey it was running 4 degrezz retard at idle, got up to about 1200 rpms went down to 3 degrezz retard. this is a std trans vehicele and the throw out bearing cross shaft even rattles.:laugh: thanks again for all your replys

whatif3387
08-06-2015, 05:09 PM
You will also need to change the knock sensor to one that matches the ECM and engine combination. The knock sensors are different between the internal and external ESC set-ups.

Alternatively, you can modify the MEMCAL and use the external ESC. I know this works on the '7730, I'm pretty sure the '7427 would be the same type of modification, just the actual pin to use for teh input from the ESC module may need to be figured out.

I'm glad I posted on this thread because I just learned the solution to a problem i've been chasing for over 2 years. My truck is a 95 that I swapped added a 96-00 L31 to which I'm controlling with an EBL flash. I retained my stock 7427 to control my trans. Since the 7427 handles the ESC stuff internally I had to buy an external ESC off of ebay and connect it to the EBL. I've been chasing knock counts since day one and couldn't do anything to get rid of them pulling tons of timeing did nothing. I've readjusted my valves and went over my entire engine bay looking for false knock. Well when I did the swap I bought a brand new knock sensor for a 1995 gmc sierra 5.7 TBI. If it's true I've been using the wrong sensor this whole time that would explain alot. Now to figure out what year sensor I need. Thank YOU!

ony
08-07-2015, 04:18 AM
I started typing and our electricity went out. I got the wires in the horness adapter all connected I think the right way all I am getting now is a 42 or 43 code it runs good setting still at idle or revining it up. that is with the xternall spark module by passed.not remembering what code it was sucks I have to wait till tomorrow an hook everthing back up before I can ask a ? but that is why I was making a horness adapter I have to drive the truck to work every day. wish I was a wiring and trouble shooter guru :laugh::popcorn:

ony
08-07-2015, 03:51 PM
it was a42 code, my scanner says [electronic spark timming monitor error] got any thought on this?

PJG1173
08-07-2015, 04:52 PM
I ran into a similar issue on by buddies CJ5. it kept getting a knock sensor code less than a minute after cranking it up. I could find nothing wrong with the wiring and we replaced the sensor twice. I ended up disabling the code. the funny thing it still registered knock counts and would retard the timing if we gave it too much so we said the hell with it and left it disabled.

ony
08-08-2015, 03:43 AM
hy, smoked the dist module so going to put this adventure a side till I get a vehicale at work I can test my pcm and memcal in. thanks for every ones reply.:thumbsup:it was my fault the moduale failed , I had the key off but ecm still pluged in and I connected a wire that I had disconnected to check ic low reference, I know better dumby me.http://www.gearhead-efi.com/Fuel-Injection/images/smilies/rock on.gif