Help with engine harness mating

[penguin nx]

Hey guys,

Not new to the forum, I've been browsing under my brothers sn for a while. I own a Manual Trans 1987 Nissan Pulsar NX CA16DE. Body is immaculate and interior as well. Unfortunately, this past year, I've been getting nothing but headaches from the motor and transmission. I completely rebuilt the CA16DE manual trans and soon after (not even 3 months), the motor started to crap out on me. It would die when shifting to neutral and eventually stopped starting.

Initially the mechanic had told me that the engine was no good since it would not idle. It would start, then die right after. He said it was a bad head. So I got a imported JDM CA16DE for him to swap over. After installing it, he still had issues with the car not holding idle. After ruling out pretty much everything from timing, fuel, ignition system, etc, he finally told me the engine harness was just bad.

I asked him if he could send the harness to get repaired. He said "it's not worth it." So he's asking me to find another CA16DE MT harness. Unfortunately, Nissan no longer makes them and OEM-surplus sold the last one a few months ago. So I'm s*** out of luck unless someone knows where I can get a CA16DE harness ASAP.

So here's my question (sorry for the long history). I have a CA18DET long block sitting here for me to rebuild and I have a complete and mangled CA18DET S13 harness and ECU. If my CA16DE harness is "wacked," can I still mate it with the CA18DET harness and use the CA18DET harness to connect to the engine and ECU while the mated CA16DE harness connects to the gauges and other pieces?? Or will I be able to use the CA18DET harness with CA16DE connectors?

Sorry if it sounds stupid or my thinking is incorrect. I'm just trying to see if there are other options for me in order to save my classic car from the scrapper. Thanks for any responses!

-Penguin

[float_6969]

IDK what your relation to your mechanic is, but I think he's full of poo. Did you overheat the motor? Why would the motor just, "be bad". That doesn't make any sense.

Have you pulled the codes from the ECU? It's most likely a sensor, or idle control valve issue.

[penguin nx]

IDK what your relation to your mechanic is, but I think he's full of poo. Did you overheat the motor? Why would the motor just, "be bad". That doesn't make any sense.

My car was already showing some signs of engine problems. When I was driving the car, it was losing horsepower. Putting the pedal to the floor didn't give me much pull at all. My brother has the same car and engine. We were running side by side on the highway one time and we both put the pedal to the floor... his car pulled away while mine couldn't even keep up.

Also, the car would stall on idle while driving. Say i would be traveling 60mph on the highway, I'd shift to neutral to coast and then my car would stall out.

Have you pulled the codes from the ECU? It's most likely a sensor, or idle control valve issue.

When I did actually have the car, I did run the ECU codes. No errors at the time. I'm not familiar with troubleshooting engines so I let my mechanic figure it out. When he checked the codes, there were no errors either. So even he hasn't figured out why the car wouldn't stay idle. He was able to get the car to start several times, but it would die soon after it started. He even got the car to run for 2 hours w/o an issue but all of a sudden it stalled out and didn't want to start up again.

He checked the timing several times. Thought it was the fuel system, so he provided his own fuel to the engine and it wouldn't idle. Then he tried the ignition system, replaced the ignitor module with a spare one i had. No go. Swapped with another CA16DE MT ECU. Still didn't idle. According to him, he's tried everything he could to rule out what's the problem whether it was motor, fuel, ignition, timing, ecu, etc.

My only guess is the engine harness has gone bad somewhere? And he thinks so as well.

So I'm thinking to just do a CA18DET swap for the car instead of wasting more money on my mechanic "diagnosing" instead of fixing or dishing a ridiculous amount of money for a CA16DE harness somewhere like Japan. I already dished out $500 to rebuild the CA16DE transmission, $700 for a JDM imported CA16DE, $60 for a CA16DE ECU and another boat load for labor for troubleshooting what's going on.

So any other clues as to what it could be? If not, then would it be smarter just to do the CA18DET swap and utilize the "messed up" harness to pair with an intact CA18DET harness? Thanks!