[320IN54]

I recently purchased an used JB4 and when i got into the ECU, I found out that the previous owner had an older version of the JB4 installed. I still attempted to go through with the installation only to run into a huge roadblock. After installation I tried to start my car but it would only crank and crank. I triple-checked everything and event tried to revert my to the stock ecu but the problem still persists. Any help would be great because i'm at my wit's end.

[Mezzy113]

I had a similar issue when I first installed my JB4 in that everything seemed to be hooked up correctly but the car wouldn't start.

It turned out to be that the pin for the orange power wire in the vehicle harness had become dislodged and was not making contact properly. Basically there was no power being fed to the DME and the JB4, so the car would crank but nothing would happen.

I'd double check pins within the stock harnesses, especially as it relates to power, if you've already triple-confirmed that the right connections have been made. Good luck man.

Originally Posted by GotPwned

I recently purchased an used JB4 and when i got into the ECU, I found out that the previous owner had an older version of the JB4 installed. I still attempted to go through with the installation only to run into a huge roadblock. After installation I tried to start my car but it would only crank and crank. I triple-checked everything and event tried to revert my to the stock ecu but the problem still persists. Any help would be great because i'm at my wit's end.

[320IN54]

I've managed to fix the problems and get the car running but after turning it off and leaving for a little bit then tried to turn it back on it seemed like the battery was dead. Could this have been from cranking it too much because not even the idrive or lights would turn on.

[JM98]

Originally Posted by GotPwned

I've managed to fix the problems and get the car running but after turning it off and leaving for a little bit then tried to turn it back on it seemed like the battery was dead. Could this have been from cranking it too much because not even the idrive or lights would turn on.

Likely. I'd throw a charger on it

[FIFTW]

Having a similar problem, but with an uninstall.

I recently uninstalled a JB4 with 2-step relay from a friend's car. The entire process was done correctly (to my knowledge) as I followed the video and instructions to make sure the connectors were in the right place.

The problem is that when I go to start the car, the car cranks, but it doesn't turn over. I've seen this before when I had a bad tune install with Cobb. Car wouldn't start because there is no tune on it. I know that I made sure that the JB4 was on Map 0 before taking it out and the battery was disconnected. The 2-step relay was also disconnected, and it still won't crank.

Here's the process that I did:
Jb4 to Map 0
Disconnected battery
Disconnected both hubs from the DME
removed all 4 connectors from the DME hubs
replaced the original connectors back into the hubs
plugged hub back into DME
removed red power wire from the green connector, replaced with original orange connector
removed all wires from the 2-step relay

everything is back to stock, but the car still won't crank. It worked just fine before and I even uninstalled a JB4 from another 335i right before I uninstalled his (although the previous car didn't have the 2-step relay).

Also, I can't hear the fuel pump prime. I have a 335i with MHD and it doesn't sound the same.

All the interior lights and stuff turn on. The only thing I haven't tried is running jumper cables from my car to the other to see if it will crank, but I don't think it's a battery problem.

Thanks!
0 New

[Jeff@TopGearSolutions]

Originally Posted by FIFTW

Having a similar problem, but with an uninstall.

I recently uninstalled a JB4 with 2-step relay from a friend's car. The entire process was done correctly (to my knowledge) as I followed the video and instructions to make sure the connectors were in the right place.

The problem is that when I go to start the car, the car cranks, but it doesn't turn over. I've seen this before when I had a bad tune install with Cobb. Car wouldn't start because there is no tune on it. I know that I made sure that the JB4 was on Map 0 before taking it out and the battery was disconnected. The 2-step relay was also disconnected, and it still won't crank.

Here's the process that I did:
Jb4 to Map 0
Disconnected battery
Disconnected both hubs from the DME
removed all 4 connectors from the DME hubs
replaced the original connectors back into the hubs
plugged hub back into DME
removed red power wire from the green connector, replaced with original orange connector
removed all wires from the 2-step relay

everything is back to stock, but the car still won't crank. It worked just fine before and I even uninstalled a JB4 from another 335i right before I uninstalled his (although the previous car didn't have the 2-step relay).

Also, I can't hear the fuel pump prime. I have a 335i with MHD and it doesn't sound the same.

All the interior lights and stuff turn on. The only thing I haven't tried is running jumper cables from my car to the other to see if it will crank, but I don't think it's a battery problem.

Thanks!
0 New

The JB4 and map aspect is not important.

It sounds like one of those plugs is simply backwards when you reconnected the stock harnesses.

Double check each plug as they can go in backwards, the orientation is critical and this is the most common mistake.

See page 16/31: http://burgertuning.com/instructions/JB4PnP.pdf

Any one of those sub connectors can go in backwards. There are little arrows that can help you reference the correct orientation. It's been so long I can't remember how exactly but they need to be examined closely.

[FIFTW]

Originally Posted by Jeff@TopGearSolutions

The JB4 and map aspect is not important.

It sounds like one of those plugs is simply backwards when you reconnected the stock harnesses.

Double check each plug as they can go in backwards, the orientation is critical and this is the most common mistake.

See page 16/31: http://burgertuning.com/instructions/JB4PnP.pdf

Any one of those sub connectors can go in backwards. There are little arrows that can help you reference the correct orientation. It's been so long I can't remember how exactly but they need to be examined closely.

I checked for bent pins and all the connectors slide in just fine, but I think I'm going to kick myself if one of the arrows aren't in the right place. I spent about 2 hours uninstalling, installing, uninstalling again. I'm sure its a common mistake from what I've seen, but just in case...what if that doesn't work?