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I've started having a stall plus no restart when hot issue. The dealership did some diagnostics and said the fuel pump was going, but not bad. It was about 10 psi low on a restart. Otherwise, everything else checked out with the engine. Picked it up from the dealership and stopped for an errand, but it would not stop. Once I got it home, I changed the fuel pump with a new VDO pump and changed the fuel pump relay. Took it for a test drive and it started fine and accelerated sharply. On the 3rd or 4th stoplight it stalled (not sure when but I noticed it when I tried to accelerate for the green light) and would not restart. Pushed it into a parking lot and tried to restart but no success. This was about 6 or 7 pm. Went back the next morning and it started fine. Got it home and checked the codes. The only code thrown throughout this ordeal was a SAI bank 2 code. I have taken apart the SAI and cleaned it, taken out the MAF and cleaned it, cleaned and recalibrated the throttle body valve. I did some research and noticed a lot of stall when hot and no restart until it cools tend to point to the CPS. I took out the CPS and cleaned it and have before and after pictures. The sensor and cable looks fine so I'm not sure if I should change the sensor or look some where else. After the cleaning the car started just fine, just like before, but I haven't had a chance to do a test drive yet. I would prefer not to kill my back having to push it through another intersection. Any help would be appreciated.
These are the dirty pictures.
Here are the cleaned pictures. I noticed what appeared to be corrosion at the base.
Some CPS sensors have some minor circuitry in them that can die,
I've replaced them at 80 to 150 K on several cars... Every one of mine
started with longer cranking times then at some point they just quit.
Now-days I just buy the set, at about 80 K and swap them all..
CPS,TPS,IAT,MAF and 02. Then all the working ones go in a
box for emergencies.
Hot start issues can be caused by many things - i'd check:
- Starter to alternator cable - thats my bet - if its original just change it - it's a wear item
- Starter itself - can do it while you're doing the cable
- Battery - can be tested at an auto shop or with a multimeter
2000 911 C2 Cab. It's arctic silver with grey top and interior. The boxster was totaled when a truck on I-95 ran it over.
But, none of those would explain it stalling while the engine is hot and then restarting after several hours would they? If the battery wasn't charging and died would it have enough power to restart the car hours later? I need to look into the y-cable and see how that is doing. I've inspected the grounds and they were all clean. I also want to swap out the fuel filter just to verify that isn't the problem.
2000 911 C2 Cab. It's arctic silver with grey top and interior. The boxster was totaled when a truck on I-95 ran it over.
But, none of those would explain it stalling while the engine is hot and then restarting after several hours would they? If the battery wasn't charging and died would it have enough power to restart the car hours later? I need to look into the y-cable and see how that is doing. I've inspected the grounds and they were all clean. I also want to swap out the fuel filter just to verify that isn't the problem.
Just about every CrankPS/TPS/Cam Position sensor failure I've seen, heat was a factor/initiator of the problem.
Fuel is tested with pressure,, I just tap in a pressure gage and see if it holds pressure well, Electric fuel pumps again are
usually triggered by heat. A regulator that's stuck shut will overheat the pump due to excess head pressure,
bad filter also will cause the pump to get hot. When they get hot they often can cavitate so bad they quit moving fuel.
Good Luck!
Last edited by pdxmotorhead; 07-22-2019 at 03:56 AM.
You will have to hook up a proper scanner and monitor it when the stalling and no restart happens or else you will be chasing you tail for a long time.
That's what I thought too. Based off the responses so far I'm ordering a new one. The tach doesn't appear to bounce while cranking either. It's sits on the bottom until the engine catches and the jumps up to about 1500rpm.
The CPS is swapped out, but haven't had a chance to take it for a test drive. My daughter decided to help and "installed" the CPS mounting bolt into the rotor. Yeah, she put it into one of the wheel mounting bolt holes and inside the drum portion of the rotor. When it's time to change the pads and rotors in5 already a leg up. Process seems to be the same as my old 944. I was not planning on taking apart the brakes today, though.
I took it for a 10 Mike drive over the weekend and all was good. Decided to chance it and drive it to work today. No stalls and drove like a dream. It's about 30 miles one way highway on the way in and in town on the way back. No issues. Appears the CPS was the problem.
I finally just started doing it as a maintenance item on my cars at about 80K,
New CPS/TPS/IAT/Cam Position Sensor.
The drive-ability improvement is almost always worth it and the engine always seems to run smoother,
I put the old ones up on a shelf for emergency failures.
07-09-2019, 10:04 PM
Is this CPS bad?
