[froop]

Hi all,

I purchased a JB4 G5 ISO used from a forum member and I'm having issues with installing it.

I've triple/quadruple checked all the connections and everything is in place. All of the subconnectors are plugged in the right way, power cables are in, everything is connected.

I checked all of the pin outs on the harness which are correct and have even made sure that every single pin on the ECU harness has a corresponding jumper cable for the JB4 harness.

When I start up the car the it cranks and and starts up but with really low revs and then just stalls almost immediately after. When I return the car to stock it is fine.

Does anyone know what could be the possible cause? I've ruled out the JB4 unit itself being a problem as I've also plugged in a JB4 G4 and the exact same problem occurred (unless both have the same fault). I've uninstalled and re-installed the harness and JB4 at least 6 times over the past week.

Any helpful input would be greatly appreciated.

[M3_Dylan]

Plug it all in again but don't start the car until after you update the firmware? Might be useless but worth a shot

[WedgePerformance]

Check your small inside connector on the DME. Make sure the arrow points in and they slide in easy without force. You might have them flipped around. I helped another member with this same issue just a week back. If not, then email BMS Support.

[froop]

Originally Posted by Dylan335i

Plug it all in again but don't start the car until after you update the firmware? Might be useless but worth a shot

Thanks, I might try this.

Originally Posted by WedgePerformance

Check your small inside connector on the DME. Make sure the arrow points in and they slide in easy without force. You might have them flipped around. I helped another member with this same issue just a week back. If not, then email BMS Support.

Thanks for the reply Ken. I'd be 99.9% sure that they're all pointing the correct way as I've uninstalled/reinstalled it so many times so and was extra careful in making sure they were all the right way.

Unfortunately, as I purchased used, BMS do not offer email support. I did post a thread on N54tech but so far nothing has worked.

Also, on the JB4 install instructions, in the troubleshooting section they only mention long cranks or throwing CELs as the possible issues.

[LMB335IS]

I had a similar problem. It ended up being a bad board but since I bought it new from BMS it was promptly replaced.

[WedgePerformance]

Originally Posted by froop

Thanks, I might try this.



Thanks for the reply Ken. I'd be 99.9% sure that they're all pointing the correct way as I've uninstalled/reinstalled it so many times so and was extra careful in making sure they were all the right way.

Unfortunately, as I purchased used, BMS do not offer email support. I did post a thread on N54tech but so far nothing has worked.

Also, on the JB4 install instructions, in the troubleshooting section they only mention long cranks or throwing CELs as the possible issues.

You know the biggest expense is the harness, so if you think it's a bad board, email Terry and see if he'll make you a deal on a replacement. Otherwise I would go back to the seller and ask for a refund. Hopefully you paid through PayPal or a service that will stand behind your purchase.

[froop]

Originally Posted by LMB335IS

I had a similar problem. It ended up being a bad board but since I bought it new from BMS it was promptly replaced.

Originally Posted by WedgePerformance

You know the biggest expense is the harness, so if you think it's a bad board, email Terry and see if he'll make you a deal on a replacement. Otherwise I would go back to the seller and ask for a refund. Hopefully you paid through PayPal or a service that will stand behind your purchase.

Thanks guys. The seller has been perfect throughout this, trying to troubleshoot me through the problem. He's offered a full refund and/or to pay for shipping to return it to him to try and fix but I wanted to try and get it working myself, rather than go through the hassle and expense of shipping. If nothing else works then I guess I will have to return it.

[Miller335]

Sorry for your luck man. See it through though, it will be worth it.

[CHECKERED]

Like said earlier plug in your JB4 to a laptop and update firmware, make sure that all settings are reset to default

Make sure the settings are correct, G5, G4, non ISO, non BMS flash whatever you are running.

Make sure fuse is not blown and ground is good, test a different grounding location if possible,

[robc1976]

Make sure user before you didn't have a 3.5 map sensor. If under "user adjustment" page look at AFR's....if they have a 3.5 map sensor it will say AFR 1500 = 1.

[froop]

Thanks so much for the tips guys. I'll plug it into a computer and update to the latest firmware and check all the settings.