The Not A Build Thread, Build Thread - no carb yet but other stuff happening - Page 6
- Thread starter Vettn71
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Sorry man, I know zero about electrical, hence why I just posted "I like turtles" boy in Mike's thread when all that MS talk was going down. Hopefully some will chime in with ideas, I just like to chime in that Im here for moral support, lol. Glad to see you still at it.
It's simple really, distributor coil was fired by the ecu. You have that part covered.
-fans were triggered by the ecu, this is done by pulling the relay to ground that controls the fans. So if your looking at a Bosch 5 pin relay (very common)
Pin30 gets fused battery 12v
Pin87 goes to the fan
Pin 85 gets 12v
Pin86 gets ground from ecu
To make the fan work get a temp switch and have it pull the relay to ground in place of the ecu.
The ac wot relay gets a ground signal from the ecu to turn the ac off at high engine load. You can trigger this with a micro switch in place of the ecu signal, set it to trigger at wot.
The tach likely triggered by coil should be good there, the dash has a separate sender from the ecu for the temp gauge. Remove the ect sensor and use it's location for the temp switch for the fans.
that should cover it
-fans were triggered by the ecu, this is done by pulling the relay to ground that controls the fans. So if your looking at a Bosch 5 pin relay (very common)
Pin30 gets fused battery 12v
Pin87 goes to the fan
Pin 85 gets 12v
Pin86 gets ground from ecu
To make the fan work get a temp switch and have it pull the relay to ground in place of the ecu.
The ac wot relay gets a ground signal from the ecu to turn the ac off at high engine load. You can trigger this with a micro switch in place of the ecu signal, set it to trigger at wot.
The tach likely triggered by coil should be good there, the dash has a separate sender from the ecu for the temp gauge. Remove the ect sensor and use it's location for the temp switch for the fans.
that should cover it
I found the tach wire, but not the ignition circuit, yet. I need to go through the wiring and get rid of the taped or Styacon connections. This is pathetic. Someone actually molded the stereo in with fiberglass. It makes my head hurt to see this type of crap work. At least the wife is gone for a week. I might get it running again before she gets here and at least not have to listen to that.
@a91what, I don’t have an ecu, as this is a pre-fuel injection car. That’s one reason I was set to go back to a carb. If I had any problem with the FITech, I was sewed, blued and tattooed. At least with a carb it should be more reliable, if I can find the fuel pump circuit. This car has a sn95 dash that has been married to the 85 body harness. They also did a partial tuck of the wiring in the engine compartment I’ll look over what you have posted tomorrow. I’m pooped tonight, but thank you very much.
I’m wondering if the FITech was spliced into the various circuits and just closed a set of dry contacts. Don’t know
Jim
@a91what, I don’t have an ecu, as this is a pre-fuel injection car. That’s one reason I was set to go back to a carb. If I had any problem with the FITech, I was sewed, blued and tattooed. At least with a carb it should be more reliable, if I can find the fuel pump circuit. This car has a sn95 dash that has been married to the 85 body harness. They also did a partial tuck of the wiring in the engine compartment I’ll look over what you have posted tomorrow. I’m pooped tonight, but thank you very much.
I’m wondering if the FITech was spliced into the various circuits and just closed a set of dry contacts. Don’t know
Jim
All I have to do is track them down - and sepythose from the Viper alarm wiring.
Not all bad news today. They built a new Summit Supercenter not too far from me. I bought anHEI distributor, coil, fittings and braided hose for $208. I sold the MSD billet distributor and Blaster coil for $150, so the day only cost me $50. Woot! Woot!
Jim
Not all bad news today. They built a new Summit Supercenter not too far from me. I bought anHEI distributor, coil, fittings and braided hose for $208. I sold the MSD billet distributor and Blaster coil for $150, so the day only cost me $50. Woot! Woot!
Jim
Man, autocorrect is killing me. I spent the day chasing down wiring. I really hate this. Gearheads told me that whoever wired the car wired it so that there was no ignition during the star5 cycle. It would start right up as soon as the key went to the run position. I fixed that by finding a wire off the ignition switch that is hot during star5 and run, but not when it’s off.
I got the fuel pump to run by bypassing the circuit and running a temporary wire to the same lead. The car has an in-tank pump (about 35-40 psi). I have an Aeromotive fuel pressure regulator that Summit told me would drop the pressure to 4psi. Well, maybe not. I turned the adjustment screw all the way out, turned the key on and fuel poured out of the carb. I ordered a Holley 4-9 regulator today.
I guess I’ll tame the beast one wire at a time. I sure wish I knew why the circuits just quit when I removed the FITech. PIA
Jim
I got the fuel pump to run by bypassing the circuit and running a temporary wire to the same lead. The car has an in-tank pump (about 35-40 psi). I have an Aeromotive fuel pressure regulator that Summit told me would drop the pressure to 4psi. Well, maybe not. I turned the adjustment screw all the way out, turned the key on and fuel poured out of the carb. I ordered a Holley 4-9 regulator today.
I guess I’ll tame the beast one wire at a time. I sure wish I knew why the circuits just quit when I removed the FITech. PIA
Jim
- Mar 2, 2015
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If it was the aeromotive return style FPR...I had the same issue. The regulator only cut pressure to 15psi. I had to use a Mr.Gasket FPR to cut it down to 6psi. I never found out if there was a restriction in my return line causing the 15psi limit. Using 2 FPRs worked for me for years. Was a pain but I couldn't return the aeromotive.
Not sure what my pressure was; I never had a chance to look at the gauge with all the fuel pouring out of the carb. I need to find the relays for the fuel pump and ignition. I can bypass all this, but they should be going through the Viper system. Actually, I know where there’s relays. There’s a bunch stuck where my air bag would normally go.
Jim
Jim
Well, I learned something today. Apparently my 85 does have an ecu. I thought the carbed cars were non-computer. Why would a carbed car need a computer? Sheet, this complicates things. If I bypass the fuel pump if hit thee u is liable to shut down the car bacause there’s no fuel. I can’t believe this crap
Jim
Jim
Lol. 85 was using a 4180c Holley carb. In 86 it switched to speed density setup multiplier efi I bet if you check the door date code or vin it's in the grey area for model year.
I found a set of prints for an 85 over at 4-eyed pride. It doesn't look like the ecu did a whole lot on the 85 model year. Mostly ac or pcm stuff. There's no fuel pump relay that I can see. The ignition ran through an electronic ignition modulator, which I bet is not in service, so this might not be as bad as I first thought
Jim
Jim
@a91what , I actually have a Holley 4180c carb. I'd be willing to let it go to a collector, LOL. I was considering using it, but it has a lot of negatives, such as not being able to adjust idle unless you grind the caps off, the rebuild kits are crazy expensive compared to other carbs, and it's difficult to tune for power unless you spend a bunch of money on metering blocks and the like. Just didn't seem like a good plan, even though the carb was off a running car.
I did manage to run a new power source for the fuel pump and ignition. It helped having a schematic, although I took the extra measure of verifying the circuits were hot in run and start. As noted above, the previous owner had connected the ignition to run only, so when starting the car you had to pump the gas pedal, start, then release the key to run to get it to start. If you kept it in start it would never fire. I got a couple of nice backfires with the old set up
Jim
I did manage to run a new power source for the fuel pump and ignition. It helped having a schematic, although I took the extra measure of verifying the circuits were hot in run and start. As noted above, the previous owner had connected the ignition to run only, so when starting the car you had to pump the gas pedal, start, then release the key to run to get it to start. If you kept it in start it would never fire. I got a couple of nice backfires with the old set up
Jim
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