On Friday, half way to work, my car starting acting real funny. The Service engine light came on, and it started "putting" and acting real sluggish. We have and OBD machine at work, so we checked the codes:

P0172 - System too rich

P0300 - Random/Multiple Cylinder Misfire Detected

P0341 - Camshaft Position Sensor A Bank 1 CKT Range/Perf

P0711 - Trans Fluid Temp Sensor A CKT Range/Perf

P0507 - Idle Control System RPM High

P0300 - Random/Multiple Cylinder Misfire Detected

This really threw me off. Could make sense of all of it. I checked fluids, and the coolant was low, so I added some coolant and that seemed to take care of P0711. After looking in the book, the cause of some of the other codes seemed to be electrical, so I replaced the plugs and wires. Still no change. What I think threw me off the most was the P0341, since there is no Camshaft sensor on the car. I took the car up to AutoZone, and one of the guys that I know there suggested that the combination of codes might be from the Crankshaft Position Sensor. So we replaced that. Still nothing. He looked again, and said it looked like the coil packs were not arcing properly, and that could have been the problem. So I took the coils from my wifes 00 SL2 (which is not running due to an unrelated problem). Still nothing. We're now up to Sunday with no clues. We pulled the plugs out (that I had just put in Friday night) and they were too black for just being two days old. We figured that it might be something with the injectors or the fuel system. So we put a fuel pressure tester on it. When running, it stayed constant at about 38 psi. If we check it when it is not running, but the key in the On position, it spikes at about 44 psi, and then steadily drops. It was down to about 25 psi when we finally gave up and took the tested off. We couldn't find the specs on exactly what the pressure should be at.
This is becoming a major issue for me, since currently neither one of my cars run. Can anyone make some sense of this for me?
After all the work that we have done, the codes are only the P0300 and P0341. Hopefully someone will have some better ideas. I can't afford to keep throwing money at the car to replace things that are not the actual problem.
Thanks
Jim

 

It would help to post the year, mileage, and recent maintenance done for reference purposes otherwise incorrect information may be suggested.


A rich running condition and black spark plugs suggests a failed engine coolant temperature sensor(ECTS). Depending on the year (hint) most S-series came with a faulty designed coolant sensor that cracks leading to excessive rich running and high idling. Its the two-wire one that's replaced with a brass sensor and the connector may need to replaced also if its corroded from leaking anti-freeze. Replace the two-wire connector from a pc,junk yardair temperature sensor connector or the dealer's $30 part.


The misfiring along with the cam error code suggests removing the coils, wirebrushing the exposedbare metal that grounds the coil, Scotch-briting the towers shiny, coating them with dielectric grease, cleaning the ignition module contacts as clean as possible for good electrical connection, checking for worn/failed plug wires by spraying a water mist on the plug wires at night with the engine idling to see if sparks jump across the wires indicating replacement time.


The fuel pressure testing was very good of you topostas it indicates that pressures are OK and within range - pressure available to the injectors when either in pre-start or running mode. Edited by: ducky

 

Thanks Ducky.
I appreciate the info. I thought I had put the information in the post, but I see I only had it in the title. It is a 97 SC2 w/ 83000 miles.
I can't say that the regular maintenance is done on the dot, but it is usually close. It is about due for an oil change now, but that is going to have to wait, at least til the rest of this gets straightened out.

If the ECTS went bad, shouldn't the computer give a code for it? I have seen alot of recommendations that it be replaced here, and I figured it was something that I would need to do eventually, but I also thought the computer would let me know if it went bad.

The plug wires are good (I just replaced them on Friday). We did put a different coil pack on, but I guess it would be a good idea to pull it off and scotch brite everything up good to see if that solves the problem.

As I looked back over my previous post, I realized that what I left out is that it idles rough in P or N, but as soon as I put it into gear, the idle drops and it wants to stall out. I can keep it going by giving it some gas, but as soon as I let off the throttle with it in gear, it wants to die.

I can't believe that I forget to mention that, as I am sure it is very important and may change the diagnosis.

Thanks again for all the help

Jim

 

the resistance from the corrosion on the etc/connector is giving a false reading to the pcm. the pcm thinks the engine is cold so it is delivering more fuel.

the code P0341 is a camshaft code. yes your motor doesn't have a actual cam sensor. they call it compression ignition. if basically knows what stroke the cylinder is on comp. or exhaust by monitoring the necessary voltage required to jump the gap of the spark plug. it takes 4 times as much voltage to jump on the compression stroke then the exhaust stroke.
replace spark plugs with factory plugs not autozone junk. some plugs aren't really compatible.
my guess would be a coolant sensor. go to dealer and replace sensor and connector.

 

Again, thanks for the information.
I wouldn't think all this hassle just from the ECTS.
When I replaced the plugs I already knew better than to use the cheap AutoZone junk, so I got the AC/Delco plugs, which I was told were originally used (not sure the info was correct, but hopefully).
Thanks again.
I will replace the sensor, and hopefully that will solve the problem. I just didn't want to throw more money at the car to fix something that I didn't need to.

Jim