I've had a lot of problems over the years on my R53, but this current one is probably the most irritating. After replacing a the water-pump-to-water pipe hose in my MCS last week, I can't get the car to start. Several days of troubleshooting later, I'm at the end of my rope. I really hope the community can help before I throw in the towel and have it towed to a shop (where I suspect they won't have much more luck that I've had, but will want to charge me a lot for the privilege.)

Back in May, I removed the S/C off for a service. While bolting the S/C and waterpump back on, I got a little rough with the water-pump-to-water-pipe hose and it later started to leak. This leak didn't manifest immediately, and it required some weeks before I even noticed a loss of coolant (this hose only leaked once the thermostat had opened, and didn't leave puddles on the ground). I eventually found this leak while poking a borescope around in the engine compartment while idling the engine. I replaced this ~4" hose last week and bolted everything back together. To my surprise, the starter would engage, but wouldn't start the car. I subsequently spent a few days troubleshooting with no joy and I have no idea whether this non-start issue is related to the leak and/or the repair, or is a completely unrelated phenomenon.

Today, I was flipping through my copy of Bently's Diagnosis without Guesswork, and decided that I probably need to ask for assistance before I have an aneurysm.


Here are a few nuggets of information:

1) I do not get any spark (I pulled a few plugs and also tried a new one grounded with a jumper cable).

2) While the starter engages I have RPMs displayed on the tachometer (if there is a short or a bad crank position sensor, I wouldn't get spark or fuel, but also I wouldn't read RPMs on the gauge I think).

3) My immobilizer does cause a chime when placed next to the ignition (I was exploring this as a possible cause since there have been a few occurrences over the past months when the starter wouldn't engage and I would just get a chirp).

4) The starter sounds normal, and it doesn't seem like something is binding.

5) I checked most of the fuses and found them good.

6) I saw this post a few days ago, and will check the bottom of the engine fuse panel area tomorrow for signs of liquid or corrosion since it seems like a good idea to check.
https://www.northamericanmotoring.co...t-problem.html

7) I cleared the trouble codes and then tried starting the car to see if any new ones would pop up, and there were several -- This seems like an effect of the problem and not a cause, but might indicate an electrical issue if something got wet/shorted/etc. These codes showed up: p0500 road speed sensor, p0130 O2 sensor malfunction, p0222 throttle position sensor low, p0123 throttle position sensor high, and p0420 cat. converter efficiency below threshold (this is the only code present BEFORE the problem started).

8) I checked the ECU headers for damage to pins, and tried re-seating them to no avail.



Does anyone have any advice or next steps?


Chris

 

Having replaced that hose I'm trying recall anything in that area...what comes to mind with all those engine sensor codes is to check all of your ground connections. If you missed connecting a ground or fully seating a connector somewhere it could be causing these issues. Found this thread while searching NAM for some help diagnosing my own no start situation!