[Gmecm] Vortec swap info needed

[Steve Ravet]

passlock came along in '98, so if it runs at all it must be a '96 or
'97.  '99 half ton pickups got the new style LS1 derived motors, while
Suburbans, Tahoes, and heavier pickups carried on with the SBC vortec
until 2000.  If the passlock system isn't satisfied the computer will
cut off fuel shortly after startup.
 
The ECM is going to be unhappy about not having an electronic
transmission connected.  It will expect signals from the trans.  There
are plenty of smog sensors also -- in the evap cannister system, and
feedback O2 sensors to keep an eye on the catalytic converters.
Probably others, and who knows if what's left of the harness is correct.
 
You may spend a lot of time debugging this system.  Is the smog
equipment still available?  It would be faster, probably, to put
everything back together the way the factory made it, get a replacement
harness, and get it running that way.  Then, if you want, start
disconnecting smog equipment.  Then you'll at least know what things
affect what.
 
It is a flash ECM, I haven't used the tunercat tuner so I'm not sure how
it works.  There is a scheme on the gmecm page for dumping the flash
image, although it involves some simple soldering inside the case.  You
can get replacement computers for $30 or so on car-part.com, so it's
easy to experiment on them.  A harness will run around $150.
 
--steve


________________________________

	From: Ne14RoxCJ [mailto:ne14roxcj at comcast.net] 
	Sent: Tuesday, September 13, 2005 6:27 PM
	To: Steve Ravet
	Subject: RE: [Gmecm] Vortec swap info needed
	
	

	Forgot to mention this is the 5.7L vortec from 97-99 (the guy
doesn't know). I was under the impression that these were Flash ECM's
(or VCM). It has the CPI system under the intake. I guess I just need to
know what the ECM is looking for as far as inputs from the smog
equipment or is it strictly outputs. The ECM got a plate-aluminum
interior built completely around it, so I'm going to have to cut an
access hole to even see what it is (it needed one anyway). I've seen
mention of VATS or PassLock that started in 99? This wouldn't just limit
the engine would it? Shouldn't it just kill it after a few seconds and
did these trucks have any such system? Well, I'll try to get these wires
capped properly and get the Snappy hooked up and talking to it. I'll let
you know what I find.

	 

	Beau

	 

	
________________________________


	From: Steve Ravet [mailto:Steve.Ravet at arm.com] 
	Sent: Tuesday, September 13, 2005 5:11 PM
	To: Ne14RoxCJ
	Subject: RE: [Gmecm] Vortec swap info needed

	 

	Beau, had to answer the question until you've got the scan tool
hooked up.  I'll be interested in the answer as I've put a vortec in a
Monte Carlo.  I'm keeping as much of the smog stuff intact as I can but
still expect to have some problems.

	 

	Tunercat has a tuner for these computers, are you using it or
something else?

	 

	--steve

		 

		
________________________________


		From: gmecm-bounces at diy-efi.org
[mailto:gmecm-bounces at diy-efi.org] On Behalf Of Ne14RoxCJ
		Sent: Tuesday, September 13, 2005 3:41 PM
		To: For discussion of GM EFI hardware and software
		Subject: [Gmecm] Vortec swap info needed

		A friend of mine is having problems with his rock
crawler. He built the buggy and put a Vortec 5.7l in it without any smog
equipment, no AC, and a TH400 trans. Whoever he bought the engine and
wiring from just hacked off the wires that weren't needed. I tried to
hook up the Snap-on scanner only to find out that the data wires were
also cut out of the DLC connector. The problems he is having is a lack
of power. It idles great and in low range it crawl's fine (a geo engine
would crawl great with the 4:1 t-case and 5.13 gears). But when it gets
revved a little, it starts cutting out. I know that we need to properly
cap these un-used wires and I expect we will need to have the ECM
flashed to get rid of the smog stuff and whatever else is not used. I
haven't dealt with these later model systems yet, so can anyone tell me
what else I'll need to do to make this a V-8 again instead of the 4-cyl
that it's acting like. I know that getting the DLC put back together and
looking at the data is the first thing, but what else needs done if
anything?

		 

		Thanks a lot in advance,

		Beau

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