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ECM delete

Timgoheen

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Feb 18, 2026
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Summerville, SC
I'm cleaning up the wiring on my 85 Blazer. Im installing a sniper 2 fi system with a hyperspark. As far as I can tell the only thing that the ecm would be doing is the tcc, which can be controlled another way. The ecm was never plugged in when I got the vehicle either. Any thoughts on eliminating this ?
 
The sniper 2 fixed the issues the original sniper had.

Delete the ECM. Make sure there are zero vacuum leaks or exhaust leaks. Even after the O2 sensor. Clean wiring will make a lot of difference also.
This and keep the coil away from all sniper wires especially the power and ground.
 
If the truck came with an ECM, then it's a California model with the CCC (electronic control of carb primary needles). If that was unplugged, it's unlikely the thing would run right. More likely, is that your truck came with a 305 and the ESC system. That box above your glove box plugs into the distributor and retards timing if the knock sensors ring. It can be bypassed. TCC lockup was not controlled by a computer until the TBI system came out ~1987. If you keep the factory vacuum switch and brake pedal switch, the transmission should continue to lock normally, but the sniper may give you the option of electronic control, if desired. Without knowing any more, it's hard to predict if that could work any better.
 
The tcc wires to esc are probably just a signal to inform esc of tcc status. I will try to look for that diagram today. Hope I still have it.
 
Got an '85. Stripped it down and added same kinda thing. IF you have a concern about the TCC stuff, look into the BTO (Bowtie Overdrives) kit that simplifies it all.
 
the vacuum switch is not included in the BTO kit. The vacuum switch make the tcc lock up much more drivable.
 
Agree. The factory controls are better than the aftermarket ones. If you want an upgrade, you'll want a PCM controlling the transmission.
 
Yeah, everyone talks vacuum lines but my truck didnt come with one. And when I have the trans rebuilt (89) it had a newer valve body installed that let it unlock in 4th. Before it always locked 4th and unlocked downshifting :dunno:
 

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