Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum - View Single Post

fredbblakemore · 09-11-2005, 09:42 PM

Thanks for the info folks. caall99, are you still able to pull the codes by looking at the CEL in the cluster? I can't seem to do that even. My lenghty follow-up post is below:

That FSM is my Bible. Honestly, it's not the easiest document to navigate in digital format, especially when sitting in the car, trying to browse around on the laptop. I'm going to print it out (at least the "EC" section) and use it to check voltages and operation of my sensors at the ECU as soon as possible.

It's very strange that the car wants to run well (better) when set above ~30 or 40 BTDC. I started messing around with the location of the CAS gears and got it to run decent in that range but I decided to set it back to the FSM directed location and focus on my sensors/ecu. It's a real bitch living in Michigan where 62's and E5's are mostly non-existant. I think I got a bum ECU. It has no LED inside and it won't flash the CEL. The only time I see the CEL on is when I'm cranking to start the engine. That leads me to think I should check with a known working one but really the only way for me to do that is buy another one. It's also possible that the wiring for the CEL is incorrect I suppose.

Also, I realized that when the TPS is connected and the throttle is opened, the ECU will retard the timing for some reason. I know that BASE timing should be set and observed with the TPS disconnected, following the FSM instructions (I've done it a million times already.) However, when the TPS is plugged in, I'd expect the ECU to advance the timing as the throttle is opened and the RPMs rise. I'm seeing the timing retarted to as much as 0 degrees. When this occurs, my wideband is reading rich as hell (9.5-11 ish).

Logically, I just can't put these clues together to make a diagnosis. I can tell the TPS is reading becaues the wideband datalogger (which also connects to the TPS) reads valid values ranging from 8% to 90%. The MAFS has been changed between two "known good" units with no effect. The stock O2 sensor was used and then I tried changing to the simulated narrowband output of the wideband O2 sensor. No effect.

Throttle body and IACV were cleaned using carb cleaner, IACV screw was adjusted and tinkered with, all had really no effect. I relocated the battery to the trunk. To make sure I had good grounds, I added 2 more ground wires (in addition to the original one) from block/intake manifold to chassis ground. Battery is grounded well to the chassis in the trunk.

So, the other things I need to confirm are CAS, coil packs, ignitor, wiring (done professionally so I doubt it's the issue), ECU. If I'm missing anything or you can think of a possible solution, please let me know.

Also, I'm continuosly searching for past similar problems. I'm finding that once people fix their issue, they don't post a follow up and discuss what actually fixed the problem...

I like to type. Type type TYPE. Typie Typie Type. Tpyie Type Type.

09-11-2005, 09:42 PM	#8
fredbblakemore Leaky Injector Join Date: Aug 2004 Location: Michigan Posts: 80 Trader Rating: (0)	Thanks for the info folks. caall99, are you still able to pull the codes by looking at the CEL in the cluster? I can't seem to do that even. My lenghty follow-up post is below: That FSM is my Bible. Honestly, it's not the easiest document to navigate in digital format, especially when sitting in the car, trying to browse around on the laptop. I'm going to print it out (at least the "EC" section) and use it to check voltages and operation of my sensors at the ECU as soon as possible. It's very strange that the car wants to run well (better) when set above ~30 or 40 BTDC. I started messing around with the location of the CAS gears and got it to run decent in that range but I decided to set it back to the FSM directed location and focus on my sensors/ecu. It's a real bitch living in Michigan where 62's and E5's are mostly non-existant. I think I got a bum ECU. It has no LED inside and it won't flash the CEL. The only time I see the CEL on is when I'm cranking to start the engine. That leads me to think I should check with a known working one but really the only way for me to do that is buy another one. It's also possible that the wiring for the CEL is incorrect I suppose. Also, I realized that when the TPS is connected and the throttle is opened, the ECU will retard the timing for some reason. I know that BASE timing should be set and observed with the TPS disconnected, following the FSM instructions (I've done it a million times already.) However, when the TPS is plugged in, I'd expect the ECU to advance the timing as the throttle is opened and the RPMs rise. I'm seeing the timing retarted to as much as 0 degrees. When this occurs, my wideband is reading rich as hell (9.5-11 ish). Logically, I just can't put these clues together to make a diagnosis. I can tell the TPS is reading becaues the wideband datalogger (which also connects to the TPS) reads valid values ranging from 8% to 90%. The MAFS has been changed between two "known good" units with no effect. The stock O2 sensor was used and then I tried changing to the simulated narrowband output of the wideband O2 sensor. No effect. Throttle body and IACV were cleaned using carb cleaner, IACV screw was adjusted and tinkered with, all had really no effect. I relocated the battery to the trunk. To make sure I had good grounds, I added 2 more ground wires (in addition to the original one) from block/intake manifold to chassis ground. Battery is grounded well to the chassis in the trunk. So, the other things I need to confirm are CAS, coil packs, ignitor, wiring (done professionally so I doubt it's the issue), ECU. If I'm missing anything or you can think of a possible solution, please let me know. Also, I'm continuosly searching for past similar problems. I'm finding that once people fix their issue, they don't post a follow up and discuss what actually fixed the problem... I like to type. Type type TYPE. Typie Typie Type. Tpyie Type Type.