87lsttop

iTrader: (2)

trying to get my project up and running. im having a problem with the pcm wiring. harness is from a 01 truck. has been reworked. fusebox is from bp automotive. everything is wired in but am not getting 12 volts from the pcm to the fuel pump relay. im only receiving 2.5 volts max. pcm is receiving 12 volts from fuse block and battery. grounds are good. pcm is from a 99 vette. ohmed the wires and no breaks found. about out of ideas. thanks for any help.

omar2guy

Wire the fuel pump direct to an ignition source

psiconversion

iTrader: (5)

You may want to physically look at the wire coming from the PCM to the fuel pump relay and ensure the crimp is good and it hasnt broken. Remember you will get continuity even if one strand of copper is still attached. Just a thought.

Jon
PSI

87lsttop

iTrader: (2)

Thanks for the replies. I soldered every connection when I did the conversion. I did take the pcm back out all the way and looked the wire over. When I ohmed the wire I took the pin out of the pcm connector and back pinned the fuse block wiring. Is there any other sensors that the pcm sends 12v to so I can measure them to see if it may be a bad pcm?

87lsttop

iTrader: (2)

Better yet I will unpin the pcm connector for the fuel pump relay and measure the voltage directly from the pcm without the wire being installed. That will tell me if its wiring or pcm.

psiconversion

iTrader: (5)

Worth a shot. Send an update when you do it.

Jon
PSI

87lsttop

iTrader: (2)

Well did the test. Took a spare wire and depinned the red connector pin 9 and still only 2.5 volts.so that eliminates the wiring to the fuse block. Only possibility is the pcm being bad. That sucks wish there were a way to definitely make sure. What other vehicles can I take a pcm out of for a 01 harness red blue connectors. Must be able to support cable throttle body

BP Automotive

iTrader: (3)

After you called, I got to thinking. Are you using the vette operating system? From what I gathered you are going drive by cable and the vette is drive by wire. Plus the vette operating system also has the column lock. Feel free to give be a call tomorrow if you want.

psiconversion

iTrader: (5)

Any 411 or 896 red/blue PCM will work. '99-02 f-body, '99-mid '03 GM Truck, Corvette will be DBW.

Jon
PSI

87lsttop

iTrader: (2)

Damn thats what I get for doing half azzed research. The guy I bought it from told me it was a drive by cable pcm. Cant trust no one dammit. I dont suppose the vette pcm will work even if I get my buddy to change the Operating system in the pcm either.

psiconversion

iTrader: (5)

Yes it will work. Just rewrite entire operating system with a 5.3 truck operating system.

Jon
PSI

BP Automotive

iTrader: (3)

If the fuel pump drivers are not burned out, then yes it will work. As we discussed on the phone, get him to pull the file and take a look at it. My email address is below if you want to send me the file to have a look.

87lsttop

iTrader: (2)

I thought that the drive by wire pcms didnt have the drivers to support the cable operation?

BP Automotive

iTrader: (3)

The red/blue pcms can control both. Your friend can flash a new system in there, but since he is using hptuners he will have to license the pcm you have now, and the file you flash. That will cost $200, unless he has a license for a file that you can utilize.

87lsttop

iTrader: (2)

I will see if he can read it first to see exactly what is going on in there. I definitely hope that its a dbw os and not the actual pcm being bad. That way he can just run another file in it.

87lsttop

iTrader: (2)

Well got all of the above figured out. Now I am having a problem with the car actually starting. Seems it turns over fine at first and then very quickly slows to a halt. Seems like the battery may be going dead. But even with the charger on it, it wont stay cranking like normal. I get maybe 5-10 seconds of cranking before it dies out. Replaced the starter as the old one was bad. Only thing I can think of is the battery relocation to the rear of the car. Maybe the cable is not big enough to carry the current from the battery to the front of the car. I believe its 2 gauge not sure have to check again. Any one else have this issue before?

usdmholden

If the wire is too small it will get hot. Crank it for 15 seconds and feel the wire to the starter, if it's too hot to touch, that is part of your problem.

2 AWG is rated 130 amps at 90 deg C temp rise, which is far below the 200-300 amps which the starter will pull during cranking. If you have 10 feet of cable that's not helping you, you could probably get away with 2 AWG if the battery were in the front.

illusions

iTrader: (3)

I have zero (0) ga wire from my battery in the back of my vehicle to a 100amp fuse under the hood. the starter pulls off before the fuse since the starter will use more amps to start it than the 100 amp fuse can handle.

Another thing I noticed since my swap is my alternator was from a 06 silverado and the pcm and harness I used was from a 01 silverado. the alternator was pcm controlled and wasn't charging my battery since no commands were being transmitted to the alternator telling it to charge the battery. I swapped alternators out and everything works.
will this charging system have a battery cut off switch like the ones required for racing with a battery relo kit.

87lsttop

iTrader: (2)

Thats what I was thinking the wire was to small. I will try and look into being able to tell. I modified a fox 130 amp altenator to fit on to the truck accesorry bracket. I have 2 gauge wire from the charge side of the altenator directly to the connection for the battery. Right now I am using the fox solenoid as a post for all my connections for the harnesses. But I just got a firewall grommet with the battery lugs on it so I will be able to get rid of the starter solenoid al together. I have the chebby starter solenoid wired into my bp fuse block already,.

87lsttop

iTrader: (2)

Got some welding cable and rewired it. Now the problem Is Im not getting a pulse from the pcm telling the coils or injectors to fire Sounded like a vats problem so took the pcm back to the tuner to double check he deleted it. He did. So its not that. Checked my pcm pinouts. they are correct. Not sure where else to look. Injectors and coils receiving 12 v when start and run so not that problem. Grounds are are all connected to the frame. Damn thing is making me angry. Any advice. Was thinking maybe a bad crank sensor?