No crank, need help.

[Peregrinus]

The yellow goes to the fuse box Crank Relay, and the PCM.
View attachment 16185

Ok, so if I dont get power at the crank relay from clutch pedal then, I'd say it's safe to assume that yellow wire will be my issue, maybe I'll cut some electrical tape back and check the wire right before the fuse box, and worse case I can jump it directly from the clutch pink wire to test it. Thank you, I have some diagrams printed off but the words were blurry lol

 

[Peregrinus]

So all I have at the crank relay is one source of 12v, and a ground, and the other two give me no resistance or Voltage in any order.

The grounded One pin if jump right to the positive post spins the starter. I ran the clutch switch wire right to the yellow wire on the pcm plug, the power from the clutch yellow wasn't getting to the pcm, I checked it multiple times.

 

[Peregrinus]

Okay, so. Going back through all his original wiring, come to find out he never ran the pink/black from the second clutch switch OR the yellow line from the main clutch switch to the back of the car. Lol

 

[Ark :D]

Probably a symptom of doing the wiring for a manual based off the original videos, which were for an automatic, if I had to guess.

 

[Peregrinus]

Probably a symptom of doing the wiring for a manual based off the original videos, which were for an automatic, if I had to guess.

I think he just forgot, he has the two wires into his plugs on both ends he just for some reason forgot to add the last two wires between his plugs lol

 

[Ross]

Woo hoo! You found it. Should be easy to fix now.

 

[Peregrinus]

We gave success boys! I'm so happy now. Lol such an easy fix. Good grief

 

[Desert Sasqwatch]

Most times it is the simplest of things that can cause seemingly major problems. Glad you found this issue and is a lesson learned for the rest of us.

 

[JeffsGoblin]

The yellow doesn't have power when the key is on. The pink does.

I was hoping this thread could help me out. I'm having similar issues on my LSJ with no crank when turning the key.

Here is what I get at the clutch switches:
Key on, clutch NOT pressed:
Yellow gets no voltage
Pink gets 12 volts

Other switch:
Pink/black gets 12 volts
Brown/White gets 12 volts

With Clutch pressed:
Yellow gets 12 volts
Pink gets 12 volts

Other switch:
Pink/black gets 12 volts
Brown/White gets no voltage

From the info above, this looks correct, but I still get no crank.

The only thing I get on the digital display is low coolant and low brake fluid.
Engine will crank by jumping the battery to the starter.
Throttle body works great.
Fuel pump does cycle, but I have no fuel in the tank yet.
Accessories switches work, along with front lights, turn signals and horn. Rear taillights are not hooked up yet.
I have a dedicated ground wire going from the battery to the pedal box to the tunnel ground to the engine which checks out.

Any thoughts?

 

[Peregrinus]

I was hoping this thread could help me out. I'm having similar issues on my LSJ with no crank when turning the key.

Here is what I get at the clutch switches:
Key on, clutch NOT pressed:
Yellow gets no voltage
Pink gets 12 volts

Other switch:
Pink/black gets 12 volts
Brown/White gets 12 volts

With Clutch pressed:
Yellow gets 12 volts
Pink gets 12 volts

Other switch:
Pink/black gets 12 volts
Brown/White gets no voltage

From the info above, this looks correct, but I still get no crank.

The only thing I get on the digital display is low coolant and low brake fluid.
Engine will crank by jumping the battery to the starter.
Throttle body works great.
Fuel pump does cycle, but I have no fuel in the tank yet.
Accessories switches work, along with front lights, turn signals and horn. Rear taillights are not hooked up yet.
I have a dedicated ground wire going from the battery to the pedal box to the tunnel ground to the engine which checks out.

Any thoughts?

Up higher in the post I posted that list of every condition needed to start, check everything on that list.

 

[Peregrinus]

Up higher in the post I posted that list of every condition needed to start, check everything on that list.

Looks like your pedal switches are working, are u sure the yellow from the one and pink with black make a connection with the fuse box? You could pull apart the plug and check continuity at the pcm side that's how I found my issue.


It's the far left blue micro 64 plug on the pcm, yellow wire is pin 46 I think, I forget which is the pink with black. I'd start there if you know relays and switches are good

 

[JeffsGoblin]

Still get no crank when I turn the key. All the dash warning lights go out when I turn the key to crank. Not sure if that is normal. I just hear a click in the BCM when I turn the key for start/crank.

The only thing I get on the digital display is low coolant and low brake fluid.
Engine will crank by jumping the battery to the starter or by removing the crank fuse and jumping it that way.
Throttle body works great.
Fuel pump does cycle, but I have no fuel in the tank yet.
Accessories switches work, along with front lights, turn signals and horn. Rear taillights are not hooked up yet.
I have a dedicated ground wire going from the battery to the pedal box, to the tunnel ground, to the engine which checks out and seems to be grounded correctly.

Any thoughts? Need some help to get this thing to crank! please.

 

[Ross]

I'm in the same boat. My engine sometimes doesn't start with the key. I jump the starter, and away I go, but I never know when or why it does this. I'm trying to find an electrical gremlin too.

 

[SACTX]

A quick Cargurus search for this issue pulled up some typical 10+ year old car wiring shorts and problems with the ignition switch/relay. That's where I'd start.

Check the ignition and relay and the fuses in the box. Probably not the switch since you do get some activity when you turn the key but might as well check it. Does the fuel pump start to cycle when you turn the key or only when you jump to the starter? Hearing the click makes me think it's the relay. Not the same thing but we get the same situations all the time with some of our equipment.

Make sure your pedal switches all make connection correctly in the BCM. The clicking might be something shorting or not being connected correctly.

Also, make sure your power supply to the starter is connected all the way back to actually receive power. The relay might be clicking like it's supposed to and you may not have power from the box to the starter.

Remember that the videos are all for an automatic and I remember having to look up some wiring from the forum for the manual trans. You're experiencing my biggest fear.

Good luck and hopefully I can help once I get mine in.

 

[Ark :D]

For me, the problem was a bent pin inside the engine harness fuse box connector, the big black rectangular one. You could have a similar issue, Jeff.

 

[JeffsGoblin]

For me, the problem was a bent pin inside the engine harness fuse box connector, the big black rectangular one. You could have a similar issue, Jeff.

Yeah, I checked the pins when I saw your posts and just went back and double checked them at lunch today. No bent pins. Still no crank.

SACTX, ignition switch key assembly is brand new. It was installed before I started the donor disassembly and worked great on the donor. The fuel pump does cycle when I turn the key on.

Also, make sure your power supply to the starter is connected all the way back to actually receive power. The relay might be clicking like it's supposed to and you may not have power from the box to the starter.

This is where I'm heading next and double checking all the power that comes into the starter.

 

[ctuinstra]

This is where I'm heading next and double checking all the power that comes into the starter.

There are only two wires to the starter. One is the heavy positive from the batter and alt. The other is the purple wire that actuates the solenoid to power the starter. Then, of course, you have the body grounded to the engine and the engine grounded to the frame. The starter relay should power the purple wire on the starters.

 

[SACTX]

There are only two wires to the starter. One is the heavy positive from the batter and alt. The other is the purple wire that actuates the solenoid to power the starter. Then, of course, you have the body grounded to the engine and the engine grounded to the frame. The starter relay should power the purple wire on the starters.

Check that you're getting power from the big power cable and check that the purple wire does or does not get power when you turn the key. It should power up to tell the solenoid to go. If not, trace it back.

 

[Peregrinus]

Definitely check both clutch sensor wires, mine did everything but crank because my wires wernt correct. I wasn't getting power to the purple wire at the starter. Jumping it worked for me, soon as I fixed my clutch lines all was well.

All this just makes me very glad I disabled vats and went to a keyless button start.

 

[Ross]

I disabled VATS in HP Tuners, and my car sometimes won't crank when requested... Wierd that it will let the engine run, but not let it start.
I took the electrical ignition switch apart, but it was in good shape. I hear the BCM relay click, so I know that it noticed the key in the start position.
I'm still thinking my issue is a GM Lan communication issue, as I have the guages sometimes die in my car. Not sure if Peregrinus has the exact same issue, but there is a lot of similarities.