Wiring+Non Starting = Headache

[RocketKing]

Okay, my head hurts from trying to figure this out so it is time to call in the Pros! (that'd be you guys!)

Truck will crank but will not start.

First a little background.

I have an AAW harness that allowed 6 extra fuses so i did not have to buy an extra fuseblock.

2- Battery Hot
3- Key Hot
1-Acessory only (powered when key is on but off when in crank)

All the battery hots have power and all the key hots retain power through crank. Accessory only is powering OBDII, lighter bulb, TCC, relays for AC and Fans.

Fuel pump will power for 2 sec cycle when turned to on, but will not repower at crank. No power at the relay when the key is turned to crank. It seems that the crankshaft sensor is not sending back the pulse to tell the fuel pump to open back up at crank, which I believe would not allow any spark at the injectors either. I have power to the crankshaft sensor.

So I am guessing that either

1-I am not getting a signal from the crankshaft sensor (I have already tried a new sensor)

2-Somehow the Accessory fused wires are cutting power at crank although I am not sure how that would affect if with what I have wired to it.

I am out of ideas and wondered if maybe some of you have run into a similar problem.

[Clyde65]

If it are me, I would hook another power source to your PCM, meaning I used a always power from a direct fuse block source and the power windows cucuit for the ignition power.
Good luck!
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[skoffice]

I think if you are using a pre-65 ignition key switch, that it cuts power when cranking. I think I read that somewhere on here. I swapped mine for a 71 switch and it worked with no issues.

[skoffice]

I see that your truck is a 67 though. I would jump all necessary engine wires to a temporary 12v hot, or I guess you could just leave them in the ign. on position.., and hook up a starter bumper button. If you turn it over with just the button and it fires up then you know you've got a bad switch. It sounds like that's your problem, because if you are getting signal to the crank sensor and this doesn't work then you may have a computer issue. Also check for spark, and make sure the cam position sensor is getting signal. And that you have the coil packs properly wired. 1-3-5-7 Bank 1 and 2-4-6-8 Bank 2. I don't have the schematic in front of me but check to make sure you don't have the coils hooked up backwards, like 7-5-3-1 too. Had that problem the other day haha. But it sounds like the switch!

[usmcchevy]

Has VATS been removed from the PCM? Are you getting any fuel smell after cranking? Have you checked for spark?

[RocketKing]

Originally Posted by skoffice

I see that your truck is a 67 though. I would jump all necessary engine wires to a temporary 12v hot, or I guess you could just leave them in the ign. on position.., and hook up a starter bumper button. If you turn it over with just the button and it fires up then you know you've got a bad switch. It sounds like that's your problem, because if you are getting signal to the crank sensor and this doesn't work then you may have a computer issue. Also check for spark, and make sure the cam position sensor is getting signal. And that you have the coil packs properly wired. 1-3-5-7 Bank 1 and 2-4-6-8 Bank 2. I don't have the schematic in front of me but check to make sure you don't have the coils hooked up backwards, like 7-5-3-1 too. Had that problem the other day haha. But it sounds like the switch!

Oh man, like I don't have enough to worry about, now you say maybe my coil packs could be on backward!!
Looks like I need to find a schematic to see if this has happened

Originally Posted by usmcchevy

Has VATS been removed from the PCM? Are you getting any fuel smell after cranking? Have you checked for spark?

Vats removed, Yes on fuel smell, No spark.

[Super73]

Did you confirm power at the coil packs?
Did you confirm power at the fuel injectors?

[BR3W CITY]

i agree on running the pcm on its own power source for sure.
Why does your crank sensor need to tell the fuel pump to run? I'm just running a relay'd hot to the fuel pump and haven't had a problem keeping fuel up.

[usmcchevy]

I would start checking power at the coil packs, cam sensor and crank sensor while cranking. If you have the least bit of doubt, run temporary jumpers straight to the battery just to be sure.

EDIT: Just looked though your build pictures. Is it possible you swapped your cam and crank sensor wiring? Did you keep the temp sensor?

[RocketKing]

Originally Posted by Super73

Did you confirm power at the coil packs?
Did you confirm power at the fuel injectors?

I read that without the CKP (crankshaft position sensor)signal that I will not get power to the coils or fuel injectors. I may be totally mistaken about that even though I read it on the internets so it must be true.lol

Originally Posted by BR3W CITY

i agree on running the pcm on its own power source for sure.
Why does your crank sensor need to tell the fuel pump to run? I'm just running a relay'd hot to the fuel pump and haven't had a problem keeping fuel up.

Here is the way it was explained to me. Battery 12v to the relay like yours but when the ignition turns to crank, the CKP sends a pulse to the PCM that it needs gas to start the motor. This signal is carried from the PCM back to the relay with the grn/wht fuel sending wire, which in turn sends the signal from the relay to the fuel pump. The PCM itself powers the the grn/wht fuel sending wire with Key 12v. So if I am not getting a signal back to the relay, either from incorrect or faulty wiring from Key12 or bad CKP it will not pump gas to fire off.

Originally Posted by usmcchevy

I would start checking power at the coil packs, cam sensor and crank sensor while cranking. If you have the least bit of doubt, run temporary jumpers straight to the battery just to be sure.

EDIT: Just looked though your build pictures. Is it possible you swapped your cam and crank sensor wiring? Did you keep the temp sensor?

Will check these out, right now I am recharging the battery, for some reason repeated cranking seems to make them tired. ha

Thanks Guys!

[mcbassin]

Man Rex, sorry to hear you're having some bugs getting your fired up. I'm sure it's something simple.
Did you say you double checked all your connections at your add on fuse terminals. for continuity?
Does it ever try to fire?

I'm interested in seeing what you find.

[RocketKing]

Originally Posted by mcbassin

Man Rex, sorry to hear you're having some bugs getting your fired up. I'm sure it's something simple.
Did you say you double checked all your connections at your add on fuse terminals. for continuity?
Does it ever try to fire?

I'm interested in seeing what you find.

Thanks Mike.

Well I finally found where I had some Key 12 wires in the Acessory plug. I got them switched out and now I am getting power from the PCM to the relay and I now have gas and spark.

But, it would not start, all I had were some pops so I figure I got me some clogged injectors. Gonna check my firing order and injectors and go from there.

Thanks

[Super73]

When I first did my swap, I did plug the cam/crank sensors in wrong. Figured it out quick enough with HP tuners.

Yes, with out the crank sensor, you will get no power to the coils, I am not sure about the injectors though. You however do not ned a cam sensor for it to start, sure makes it easier though.

[BR3W CITY]

Originally Posted by RocketKing

Here is the way it was explained to me. Battery 12v to the relay like yours but when the ignition turns to crank, the CKP sends a pulse to the PCM that it needs gas to start the motor. This signal is carried from the PCM back to the relay with the grn/wht fuel sending wire, which in turn sends the signal from the relay to the fuel pump. The PCM itself powers the the grn/wht fuel sending wire with Key 12v. So if I am not getting a signal back to the relay, either from incorrect or faulty wiring from Key12 or bad CKP it will not pump gas to fire off.
Thanks Guys!

That sounds complicated for no reason

[RocketKing]

Its Alive!

She is up and going. Although the plug in the power steering fell out and blew fluid everywhere

Thanks for all the help guys!

[usmcchevy]

Congrats