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A while ago I purchased all the pieces needed to build a Jeep. Among those pieces was a Chevy 5.7L engine from a 1991 Camaro and a TPI intake and a bunch of wires. I am a novice with vehicle mechanics so I need to figure out how to put everything together. I already put the engine back together and bolted on the intake manifold and upper plenum. Now I am staring at a bunch of non-labeled wires wondering where to start. Any help you guys can offer is greatly appreciated. Here is my engine-
Here is the wiring harness I am trying to figure out (some things I have already figured out)-
(A) is a check engine light that goes in the dash<br/>(B) is 3 plugs that go into the ECM<br/>(C) is a wire deep inside of a sheath - I think I can ignore this for the jeep<br/>(D) is the diagnostic link
(A) is already plugged in. Don't know what this.
(B) 2 different things (relays?) with associated plugs. I think one is the fuel pump relay, how to distinguish?
Here is a run to the fuel injectors (I think it is for the driver side injectors)
(A) is probably a plug for the oxygen sensor (the oxygen sensor is on the driver side exhaust manifold)
(B) injector plugs in order from left to right (probably) 7,5,3,1
(A) & (B) ?
(C) is actually coming from the main branch by the fuel injectors, it just fell into this picture too. It is a green wire cut end no plug/connector
Here is the engine (passenger side) there are a few plugs on this side that could mate with the wiring, but it seems like more wiring plugs than engine plugs.
DonW, If worse comes to worse, I could convert to a carb. My preference is to get this working. From what I hear, the TPI is a lot better than a carburetor, so I would like to leverage what I have. Also, I would really like to understand what I have. This whole build is a learning process for me so if I can figure out how to get the TPI working it will be a huge learning for me. I'm sure there are members on this forum that know this stuff in and out. So I think with help, I could get it working. But if I need to, I could go with a carburetor
Here is a run to the fuel injectors (I think it is for the driver side injectors)
(A) is probably a plug for the oxygen sensor (the oxygen sensor is on the driver side exhaust manifold)
(B) injector plugs in order from left to right (probably) 7,5,3,1
I don't know what these things are. That black line under (D) is a hose, not a wire
A) Can;t see very well, looks to be the 4wire plug for ignition module (distributor) though
B)Air inlet temp sensor. Under middle of the plenum (bottomside of top of intake)
C) May be EGR solenoid
D)MAP sensor, manifold vacuum port
This is another fuel injector run (probably passenger side)
(A) is for the injectors (this run does not have anything that would plug into the oxygen sensor)
I don't know what B,C,and D are for.
B) Idle air control valve (throttle body)
C) Can't see the wire but, may be Coolant temp sensor (yellow and black wire, front of intake base under thermostat housing). Unlabeled plug it's touching is throttle position sensor.
D) Not sure, may be emissions or A/C ?
(A) & (B) ?
(C) is actually coming from the main branch by the fuel injectors, it just fell into this picture too. It is a green wire cut end no plug/connector
A) Transmission converter lockup. Front drivers corner on top of trans pan iirrc.
B) Most likely Vehicle Speed Sensor, tailshaft of trans.
C) Might be A/C signal input (bumps idle up when A/C turned on)
That's all I know. Might get you started at least.
(A) is already plugged in. Don't know what this.
(B) 2 different things (relays?) with associated plugs. I think one is the fuel pump relay, how to distinguish?
Missed this one...
A) Most likely fuel pump relay
B) fuses inside
Yes, this is the fuel pump relay and two fuses with plugs. The relay at the top plugs into the fuel pump power line. I'm not sure about the second fuse. I found a plug on another harness that might mate with this. I traced the wire and it looks like it might have gone to the starter or close by. Any ideas what this could be?
The plug without blue tape on it was under the EGR solenoid plug in my last picture. This wire would probably plug in somewhere close to the EGR solenoid and the air temp sensor. I don't see a plug for it. Could it be under the plenum? This connector could mate with the EGR solenoid wire just above it in the picture (just so you know the connector type). It has a green wire and a pink wire. Any ideas on this one?
Here is my $.02... Once you find out where 1 or 2 of the plugs connect, see what other plugs are in the same area and they should start falling into place.
#2 - you figured them out:
A - Check engine light
B - ECM (3)
C - figure out what they for, start with identifying the wire colors
D - ALDL
#3
A - Relay for fuel pump
B - 2x fuses
#4
A - O2 sensor (purple wire?)
B - injectors
#5
A - EGR solenoid? At least if two wire
B - MAT - manifold air temp. Plugs in under plenum
C - ? distributor?
D - MAP - bolts to rear pass. side on plenum… except you have an earlier (85-88) plenum as seen in post #9. Not a big deal, just T the vacuum hose.
E - knock sensor
#6
A - injectors
B - IAC - @ throttle body (4 wire, square)
C - TPS = throttle position sensor @ throttle body (3 wire, green seal). Coolant Temp sensor (2 wire, blue seal)
D - green & white plus, two wires each. AIR diverters - emissions controls. Post #9 shows you do not have these.
#7
A - auto trans, TCC
B - ?
C - temp sender in drivers head? That is my guess based on the green wire color.
Thank you guys for helping me figure this out. I have almost everything labeled.
In reply #19 there is an unknown plug connected to that fuse block. Would it make sense for this to go to the starter +12V for a constant power source? Thats my guess.
For reply #20, I don't see another connection near the MAT/EGR area where this would go. Is there another one under the upper plenum? I'm going to take that off to route the wires and plug in the MAT sensor once I get everything figured out.
07-31-2015, 08:13 PM
