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 ?
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.
ECM delete
- Thread starter Timgoheen
- Start date
Hope you have better luck with the sniper crap than i did .
Great, that's a real confidence builder.
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.
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.
Ok, it must be an ESC system then. But the TCC wires do run through it.
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.
I have the diagram Wes, don't worry about 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.
I haven't seen any vacuum lines pertaining to 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 
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
I don't think there was a 700-R4 used that didn't use vacuum lockup, at least pre-TBI. I don't see it on the 87 K5 in my garage however.
It's not vacuum to the trans, it's a vacuum switch on the firewall that the TCC wiring runs through. Just a single hose to a diaphragm as I recall.
Do you have a picture of one ?
The confusing thing is that there were a lot of different configurations over the years - both inside the trans and under the hood. Some of them have a wire from the trans that activates a vacuum solenoid (I've seen it mounted near the valve cover over cylinder #8). IIRC, it has some connection to the EVAP system, so it purges the canister when the TCC is locked (i.e. cruise conditions), but it's possible there is some connection to ESC.
Here's an old picture I posted of an ESC bypass I ran for a little bit, but I wasn't using the module inside the HEI. You can also jumper the green and black wires in the 4-pin weatherpack connector together.
