ESC & check light problem

[steve ravet]

Have you looked at the schematics, either in a service manual or on the
WWW page?  You'd be way ahead to pay $70 or whatever to get the factory
service manual from helm, www.helminc.com.

1)  CEL is supplied +12 when the key is on.  When the ECM wants to light
it it supplies a ground to the other side of the light. See
ftp://ftp.diy-efi.org/pub/gmecm/manuals/1227747/747ecm4.jpg

2)  Sort of.  There is a voltage level from ESC to ECM that means "no
knock".  You could force it to that level with some resistors, or you
could just get a junkyard ESC and connect it to the ECM without a knock
sensor connected to the ESC, but you'll still get periodic code 43s. 
Once in a while the ECM will run a test where it causes knock by
advancing the ingition while under load.  If it doesn't see knock under
these conditions it'll set the code.

You could either disable the code 43 check, or try to put together a
knock sensor that works.  I've "read" (for what that's worth) that the
frequency that the ESC looks for is related to cylinder bore, so maybe
look for a GM engine/app with a similar bore and use the knock sensor
and ESC module from that.  The knock sensor uses a 1/4" pipe thread.

--steve

TomQ wrote:
> 
> Hello all. I am new to the list and I have a question I hope someone can
> help me with. I am currently installing the FI system from a Chevy S-10
> on to my Inline 6 Toyota motor. The FI is from a '88 Chevy S-10 w/ 4.3 L
> TBI. The ECM I am using is #1227747. The Toyota motor is 4.2L so I think
> I should be OK. Anyway I have everything hooked up and it starts and
> runs, although not very well. Here are two of my current problems. First
> the engine light does not come on at all, not anytime. I pulled the
> light and using a VM checked the voltage at terminal A5, it never goes
> to 12v. Bad ECM or Prom? My second problem is the motor seems to be
> retarding the timing all the time. I purchased one of the handheld
> diagnostic meters (EZLink) and hooked it up to the ALDL. It gave me an
> error code of 43 ESC failure. checked it out and sure enough I had not
> hooked it up at all. I guess that would be the reason for the timing
> retard. Can I just pull the line (terminal B7) high or low to fix the
> error without getting and installing the ESC module and knock sensor?
> Thanks
> 
> -TomQ
> SF,CA

-- 
Steve Ravet
steve.ravet at arm.com
ARM,Inc.
www.arm.com
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