UH-60ZX Posted March 25, 2012 Share Posted March 25, 2012 I'd like to see a picture of the A11-652 805 ECU's pin output from someones federal emissions 1983 naturally aspired manual transmission 280ZX that runs. I'd also like to see the pin output of the same car with any other ECU's that people are running. I'm asking for pictures of the pin output because I've never seen what it should look like (I can only assume based on the factory service manuals wiring diagram and the pins being used on the wiring harness) and I can't find any pictures online that guarantee they're for the same model car as mine. When I got the car it was running horribly and I found out it had an ECU for a 1981 with an automatic transmission. I ordered an A1-Cardone remanufactured ECU and sent the other to them as the core. When I got the ECU from A1-Cardone I hooked it up and tried to start my engine. The engine seized up and I could smell something electrical burning. The ECU fried itself. I got to looking into the problem further and discovered that the pin output was inconsistant with the FSM for my model. Pin four was missing, which is used for the cold start valve and thermotime. I did some testing and found that this ECU was providing all of my injectors with a constant 12.5V even with the key out of the ignition. My engine seized up because the cylinders were filled with gas. I returned the ECU to A1-Cardone with an image of the pin output from the FSM and told them it fried in my car because it was the incorrect ECU. They ended up fixing that ECU and sent it right back to me disregarding the fact it's not the one I ordered. I returned it and have been without an ECU for a while. I just recently found an ECU on EBay with the factory tag A11-652 805, so I ordered it and when I got it I got to looking at it and pin four is missing. I opened the case and it looks brand new on the inside, so I figure it must be a remanufactured ECU. I got it from a used parts warehouse, so they were probably just posting it as it was labeled. Quote Link to comment Share on other sites More sharing options...
UH-60ZX Posted March 26, 2012 Author Share Posted March 26, 2012 Here's a picture of the ECU I just got and another picture of the EFI wiring diagram from the FSM. The pins not on this ECU are the #1 and 4 pins. The FSM shows that pins #1, 9, 11, 12 and 23 aren't used. I've actually taken the time to trace every wire on my harness to confirm what the FSM is telling me, so knowing that the #4 pin that's missing from the ECU should connect to the Cold Start Valve and Thermotime Switch has me concerned. Although, another thing that has me confused is that I've looked at every 280ZX FSM from 1979 to 1983 and they all indicate the #4 pin is used, yet I haven't seen the #4 pin on any images of 280ZX ECU's that I can see the pins. Is there a sure fire way of telling what ECU you have other than the sticker on the top such as a mark on the circuit board? I just don't want to plug this thing in and fry it like the last one. Thanks for any help in advance. Quote Link to comment Share on other sites More sharing options...
HowlerMonkey Posted April 6, 2012 Share Posted April 6, 2012 (edited) Battery connected backwards fusing the injector driver/s. Only takes a second. Edited April 6, 2012 by HowlerMonkey Quote Link to comment Share on other sites More sharing options...
NewZed Posted April 6, 2012 Share Posted April 6, 2012 I've noticed the same thing about the CSV circuit from 76 to78 ECUs. They changed along the way, but have the same part number. I didn't go as far as you did but assume that they just branched off of another circuit outside the ECU that's on at the same time instead for simplicity, since the current flow is so low and it's only on for a few seconds. How do you know you fried an ECU? What were the signs? Quote Link to comment Share on other sites More sharing options...
UH-60ZX Posted April 9, 2012 Author Share Posted April 9, 2012 Battery connected backwards fusing the injector driver/s. Only takes a second. The battery was never connected backwards while I've owned the car, so that wouldn't be the cause unless the previous owner has some aspect of the positive and negative wiring screwed up which isn't an impossibility since they basically had it wired so they could bypass the ignition switch. Quote Link to comment Share on other sites More sharing options...
UH-60ZX Posted April 9, 2012 Author Share Posted April 9, 2012 I've noticed the same thing about the CSV circuit from 76 to78 ECUs. They changed along the way, but have the same part number. I didn't go as far as you did but assume that they just branched off of another circuit outside the ECU that's on at the same time instead for simplicity, since the current flow is so low and it's only on for a few seconds. How do you know you fried an ECU? What were the signs? I'm not sure what the first part of your comment is about, what is the CSV circuit and what does it have to do with my situation? I know the ECU fried because I could smell it and when I touched it after figuring out where the electrical burn smell was coming from the ECU was too hot to hold. Quote Link to comment Share on other sites More sharing options...
HowlerMonkey Posted October 10, 2012 Share Posted October 10, 2012 (edited) I remember that none of the many ecus I had on the shelf at the blue streak warehouse for a 280zx had a pin 4 and that checking a customer's car showed that the ecu had nothing to do with cold start functionality. It was controlled by the thermo time switch on the thermostat housing. The main differences in the various non-turbo S130 ecus was the fuel pump scheme. Some had 1 relay, some 2, and some had 3 relays. Edited October 10, 2012 by HowlerMonkey Quote Link to comment Share on other sites More sharing options...
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