Crankshaft position sensor code thrown

[Rakesh_mp]

I have searched everywhere for a solution for my problem and in the process have learned a great deal about my car. I am not a mechanic by any means, but just by searching through this forum I have learned a lot about my 93 Q45 which I purchased a few months ago. Car has 110k miles on it, there was a leak in the radiator, so with the help of nicoclub, I replaced the radiator, changed oil and filter, changed fuel filter, replaced a cracked vacuum hose(90 degree hose next to the throttle body), cleaned the MAF sensor, replaced the air filter and cleaned inside of the throttle body with b12 choke/TB cleaner. I learned how to get to the ECM and read the codes and code 11 and code 54 are being thrown.

I have checked both of the connectors on the CPS, sprayed electric cleaner and they seem fine, no corrosion. I still get the error code. When I drive the car, it lacks power during take-off and at standstill there is vibration while it's in drive. Vibration is a lot less when its in park or neutral. It sometimes starts jumping then shuts off when reaching red lights. Also, on the highway around speed of 70mph, I can press the accelerator and it will accelerate fine but when i let off the gas, the car starts jumping. It's almost as if the car is shutting off and on, like it does when I am approaching a red light.

Could bad injectors or bad spark plugs cause code 11 to be thrown and cause the car to behave the way it does or do I need to replace the CPS(almost a cost of a quarter of what I paid for the car, lol)? Does code 54 relate to the car bucking and vibration problem or is that something that needs to looked at differently?

[Q451990]

The FSM (factory service manual) goes in to a good bit of detail on what the various codes mean and the logic behind them. Unfortunately the '93 FSM isn't available in a .pdf, but the '94 should be close enough. You can download it at www.nicoclub.com/FSM/

I would seriously consider trying another camshaft position sensor off of a salvage vehicle. They're not particularly common failure items, and you wouldn't be out of much $$$ if it turned out to be another problem.

Code 54 is a weird one... A/T Control - which would indicate a bad connection between the transmission control unit and the ECU.

The bouncing you describe sounds more like an injector failure. You might want to ohm test the injectors with a multi-meter. http://www.q45.org/ohminjectors.html

Heath

[Rakesh_mp]

Thanks for the reply Q451990! I have the 93 FSM and it does suggest that code 11 most likely means a connectivity problem. I cleaned the connectors, but I need to check it with a meter to make sure it isn't dead. But the FSM suggests(if I understood it clearly) that I have to remove the cap to turn the shaft in the center of the CPS while the ignition is in ON position. Then check the voltage on the appropriate pins, and here is where I'm confused, it says to check the voltage while the connectors are in. Is this possible or am I just understanding the FSM incorrectly?
Also, I just wanted to see if anyone has had an experience with one of these dying and what the symptoms are. Like the bouncing and the shutting off of the car, I wasn't sure if the CFS is causing that or the injectors. I do not have a meter at home and finals week is here in college, so I won't be able to do anything to the car until next weekend. I will post results when I do this.
As for the A/T Control unit, its a whole different ball game. The FSM suggests checking continuity between pin 10 on ATC unit and 34 on ECM and pin 11 on ATC and 35 on ECM. There's a way to run diagnostics which I will do after checking the pins. Again, after finals and I will post results.

[Q451990]

Good luck with your finals, and let us know.

Heath

[Rakesh_mp]

Did an Ohm check on the fuel injector harness and well, Heath, you guessed right. Seems #4 is out. The reading was around 1 ohms. On some of the other injectors I got a read around 15ohms and the link you posted says it should be between 10-14. Is this something I should be concerned with?

I think I will deal with this before going on to messing with CPS, although, at the cost of sounding stupid, I am going to ask, "should I be checking the voltage of connector on the CPS side or on the cable side". The cable side slots 1 and 2 give me a reading but on the CPS side there is hardly any reading. Around .1 or was it .01.

[Q451990]

Injectors typically fail with a high ohm reading that gets higher and higher until it fails open... I've never seen one go down. Always a first time for everything I guess.

Heath

[Rakesh_mp]

The craziest thing happened! I was sitting in the driveway, with car in gear, and all of the sudden, the rpm's jump up to around 900 or so and the vibration is completely gone. I checked the codes and the ecm is only left with tcu code(54). Code 13 is gone. Checked the resistance and now #4 injector is reading 28 ohms. I drove the car around town to make sure it wasnt just a fluke, but no more vibrations. I can still feel a very, very slight deprivation in power when accelarating, but im sure that will change once i change the injector. I had the car up to 105 and it was smooth, not to mention, exhilarating. Thanks for your inputs Heath. They really did help me think in terms of what the car is doing. I knew nothing about engines until started reading nico forums a couple of months ago. Maybe now i will get brave enough to get under the hood of my 348.