Blazer79

About 3 years ago, I started my conversion from 165 to 730. I built this ALDL adapter: this adapter, which worked fine with ECM852 dos application through serial port.

When I finished the adapter, I tested it, but then car went to paint, transmission rebuild, etc. 3 years later here I am trying to start the actual process of datalogging and burning with the same hardware (except new old laptop with a physical serial port and DOS)

Problem is my adapter doesn't work. Went through it, checked all solders, etc. I did find some broken soders, and practically re-soldered everything, even replaced some cables. I'm now able to get echo from the adapter. But still won't connect.

When I was about to toss it to the garbage, I decided to check the codes via the SES light blinkining method. But I can't make it work! Engine off, key in the ON position, I jumpered the cables which would be A & B on the ALDL but SES light just lights still (don't have the connector right now, just the wires comming from ECM). This makes me think that my ALDL adapter is not receiving a signal from ECM.

I know I still have to check the wires, but as I remember this used to work. This is an aftermarket harness I bought new from an old member here. Every cable is labeled, and the labels haven't been removed. Cables are short and come directly from the ECM connector.

I do get voltage from terminal M. As I was going to dig deeper into this, it started pouring, so couldn't finish diagnosing.

Has anyone had this problem? Jumpering A&B terminals on the ALDL connector and not getting the flashes on the SES light? I know newer vehicles can't be scanned if an unrelated fuse is blown. Does the 730 suffer from this too? Will check fuses tomorrow. Is there an order like: jumper first, then turn key? or first turn key then jumper?

Also, I had a problem with timing. I thought it wasn't being controlled by ECM, but checking it carefully I discovered it stays on the 6deg steadly, even if I slowly start reving it. When a certain RPMs are reached, it jumps to about 15deg and stays there. Shouldn't it move progressively instead of a jump?

Any ideas greatly appreciated!

RBob

iTrader: (1)

ECM is in limp mode. IOW, it isn't running from the PROM.

RBob.

Blazer79

You're right. That must be it.

But how can I read or find out what's causing the limp mode?

At one point, I did disconnect the battery for more than a minute to see if that changed anything.

RBob

iTrader: (1)

PROM bad, PROM missing, PROM in backwards, wrong PROM, wrong MEMCAL, or bad ECM.

RBob.

Blazer79

mmm. I thought it wouldn't even start if it were a PROM issue.

I'm using Xtronics ROMulator. Going to wipe it clean and start over tonight.

Thanks for the info guys!

RBob

iTrader: (1)

Limp mode is when the ECM runs the engine via the Redundant Fuel Device (RFD). This is what the two small chips with all the resistors are for. Along with one or two that set the hardware injector firing rate.

The advance that you saw is also part of limp mode. Although this is built into the ICM.

RBob.