Using TBI knock "board" on '727/'730?

I'm sure it's out there, if anyone has a link, I would appreciate it.

Hadn't actually looked at one of the later ECM setups until tonight. Pulled the V6 memcal out, and took the cover off.

Prom portion is easy. Netres I think I've got figured out based on this post http://www.thirdgen.org/techboard/po...66-post39.html (jumper pin 10 to 13).

The knock "board" I haven't quite figured out. Conventional wisdom says the V6 knock setup won't work correctly on a V8. Got it. Not a whole lot of the V8 knock boards I can get my hands on, at least out of cars.

Trucks of the proper vintage on the other hand, are still fairly common. From say, a 1993 350 TBI truck, will the knock board interchange with the '727/730?

Thanks as usual! :)

I've been wondering if a TBI V8 Memcal from 93 ~ 95 pickup would work in a '7730 / '7727 if pins 10 to 13 were jumped together? What I've done, was install a TBI V8 Memcal from a 93 ~ 95 pickup into a '7727 in an attempt to make the '7727 a V8 TBI configuration. I ended up getting a cylinder select error.

dave w

Yes, I read a fair amount over on thirdgen (and others) about the memcals, and I saw the same thing that others got, cylinder select error.

But the knock board is completly separate. Is there any reason that a 350 knock board for a truck app would be different than a 350 for a car? I *assume* if the knock sensors are the same, the knock board should be the same, right? I assume that it may very well depend on mask, but from a $ standpoint, it would make far more sense for GM to use the same sensor and board if they could.

Are there part numbers out there for just the knock boards?

Adding info, part number for a 1994 5.7L Blazer knock *sensor* (213-92) is the same as a 1990 5.7L Camaro.

unless the layout of the knock filter changed between the two designs, feel free to desolder and resolder, they should be interchangeable in that sense.

Excellent!

I agree with RobertISarr, the knock filter from the 93 ~ 95 TBI (4L60E Auto Trans) should work when soldered / installed into the pin 10 / 13 modified V6 memcal. I was thinking the why not try connecting pins 10 / 13 on the 93 ~ 95 TBI Memcal, which I think will fix the cylinder select fault, and correctly function like a TPI V8 Memcal.

dave w

SHOULD work.......

i mean, it's simpler to test a bridged connection that it is to transplant the knock filters.

Looked at some I had. Not sure if there is any difference in how it works, or if the difference is simply the year difference and changes in manufacturing, but they definately look different.
Bottom is a 7730/7727 AUJP 350/auto TPI V8 memcal (90-92 camaro), top is 7427 BJYL 350/auto TBI V8 memcal (94-95 truck).

it may look different, but i bet it functions the same... legs go out to the same place on the MEMCAL, a couple of components changed size, some are missing, some are added, but i can almost guarantee it will work.

The AUJP is a very valuable Memcal! Typically, a TBI Memcal is about 1/4 the price of an all numbers matching AUJP (if you can find one)! I agree with RobertISaar, a jumper modified TBI Memcal will work just as nice as the AUJP, but for a fraction of the price.

I work in a R&D department of a major consumer electronics company, it's common practice to reuse proven components to reduce cost. Why would GM completely redesign the knock filter for the low cost 8192 Baud TBI system? Answer is "They Wouldn't".

dave w

Yeah don't modify that AUJP!!!

Woah..lol, calm down. Not gonna do anything to that memcal. Just pulled the cover off the take a pic.
What do you mean by a numbers matching AUJP?
Knew they were a little less common than others, but judgeing from yalls reaction, didnt know it was that valuable. It came in the 7730 ecm that I bought with the harness I am now using as my test bench, and the tpi intake I sold.

just curious what is the resistance between these two points on the bjyl ? http://i43.photobucket.com/albums/e3...memcaltest.jpg

If I have my meter set right, or reading it right. 865 ohms.
Ohms are still a mystery to me...lol, and still not sure what the setting on my meter mean. It has 5 different settings for ohms. 200, 2000, 20K, 200K, 2000K. I get nothing when its on 200. I get 865 on 2000, I get 0.86 on 20K. 00.8 on 200K, and nothing on 2000K.
Hope this helps.

Edit, tested some more.
BDYT, 94 TBI 4.3 V6 reads 675 on the 2000 setting.
AUJP, nothing on 200 or 2000, on 20K I get 17.95, 200k I get 17.9

ok, Id be curious if the knock filter will work on a v8. The P knock filter for a tpi sd 305 LB9 measures 14K, the aujp and corvette sd R measure 18k on for the knock filter.