Carabajal87108

Ok gentlemen, I am back at it and now have the car started that is by putting a direct wire from battery to orange wire on fuel pump relay. so now the green wire shows 12vs and the 2 reds show 12vs. I tried a simple test that works on other chevy's but got different results. I disconnected the ground from battery and every wire including grounds are hot, meaning they have .002-.004 volts going through them. even the ground on intake has voltage of some sort. Reconnecting ground to battery everything is showing up as a ground, using a ground/positive finder. Has a point with two alligator clips you connect to battery that flashes green for ground or red for positive.

On another note what colored wires is the fan relay suppose to have? Also which is constant and whichat are the functions of the other wires. when I jump a green wire with the battery fan comes on with key being on.

when inspecting wiring harness on Driver's side that goes towards frond end there are 4 brown wires connected to one is that the way it was done in factory, for CFI's?

Carabajal87108

This is after replacing oil sender, fuelrelay, fanrelay, ecm, ground and ground connectors on backside of dside head, evrthing else is getting power, as in lights, distributer, and interior lights and gages. Just no readings from map sensor, either relay or, oil sender for power. Oil unit is showing reading on gage, around 30-50psi. The wire colors from fan relay are green/white stripe, Black/orange stipe, fat red, and blue that is from harness the wires in the clip are different, two for sure are brown/w stripe connected to blue, green white connected to orange. When I put 12vs to blue wire on fan relay the relay under blower motor kicks, blower doesn't turn on. Also I found out of the 5 grounds on back of head, one wire was orange? NEED HELP PLEASE,about to have a toggle switch board for mean time.

74 LS4-454

Glad you are running, at least you know it still works.....
I'm sure one of the electrical experts will offer some answers and (or) suggestions to your questions. I can look in the 82 shop Manual this weekend, but don't know if that will help you out, as again there may be wiring differences between the 2 years. Keep at it........Tom

1977L48

all i know is on my stepfathers 84 we got fed up with the factory switch and just put an aftermarket thermal switch wired to fan and have it grounding when it gets hot to turn on the fan.

Easy Mike

I'm lost. If you have an 84, you should post in C4. Are you saying you have an 84 CFI system installed in a C3? Could 84 in the title line be a typo for 82?

Carabajal87108

What thermal switch are you refering to and how or what do I need to put one on, what did you use on your step fathers? 84 CFI is correct in 84 they still made a crossfire, 85 is when they came out with TPI-tune port injection. The body style is C4, but wiring and operation is still C3.

Carabajal87108

Yes, made my morning this morning. On plus side, now the ECM is being seen on gage console. Meaning the check engine light will appear when key is on run but not started and will disappear when car is started. Also Injectors are pulsing like they should, no more steady flow. I'm thinking maybe to put hot wire to temp. control(location front of intake near therm stat.) only becuase when looking at wire diagram that is one of the switches that control it. What color wire is knock sensor?

74 LS4-454

Don't be lost.....The OP has posted in the C4 section, I suggested to the OP to post here from previous threads for additional info on our forum, especially the CFI info we have got together over the previous year....Us CFI owners like to "stick" together. Every little bit of info helps!!! Tom

74 LS4-454

Sounds like you are making good progress, wish I had more time to help you check out answers for your questions, but off to work soon.....
Maybe this weekend can look into items further when I have time and if you don't figure it out sooner..... I'll add this thread to the "sticky" also, it will be another good reference in the future for us CFI owners...
Good luck and keep us posted as usual........ Tom

Easy Mike

Thank you for the clarification.

1977L48

it was just one off the shelf at advance auto parts, then cut the 2 wires that ran to the fan, sent one directly to the battery and ran the ground through the switch, it is adjustable so you can make the fan come on whenever you want.

Carabajal87108

I was looking into that, the set up I looked at has you place a temp probe in the upper radiator hose and tap into ignition, ground, and hot.
Something about a wire in the cooling system has me unsettled, incase it breaks and falls into water pump or gets stuck in motors, or intakes water jackets.

I also looked at a set of 2 after market 10inch fans, but wasn't sure if I could use them. hey come with there own shroud and mounting is right up against radiator with zip ties. I did some pondering and just a thought. If I used this dual fan set up , maybe just to be on safe side. Use a fan shroud off a 91 vette, becuase it has on off set mounting for what looks like a 10inch fan units. When comparing 3core alluminium radiators, the size for both 84 an 91 are the same. Any suggestions on this from anyone? I hear cooler is better, in New Mexico it gets pretty hot in summer.

One more thing has anyone out there ever used a switch panel in their car, I mean hooking up main feeds to panel for theft and control purposes. Fan, Fuel pump Relay, ECM, and other ma to panel.