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-   -   Hard starting (http://986forum.com/forums/performance-technical-chat/46610-hard-starting.html)

davedeck 06-24-2013 12:15 PM

Hard starting
 
I'm having some summertime blues. 1998 2.5 is hard to start in hot weather after running about 40 miles or so then shutting it off. Get back in after 15 minutes and the beast won't catch. I have to crank it several times and pump the accelerator to get it to start. By cranking, I mean turn the key and hold for a couple of seconds then turn it off and repeat until it fires. Any ideas what to look for?

JFP in PA 06-24-2013 01:29 PM

Possible fuel pressure issue (pump, pressure regulator). Try running the car with a fuel pressure test gauge attached to the test port on the fuel rail to see if the system is losing pressure. Another perennial favorite is the crank position sensor, which can act up when hot, causing the DME to turn off the fuel pump. You can test the CPS:

1. Connect ohmmeter connector part to rpm/crankshaft position sensor, pins 1 and 2.
Display at 20 °C: 0.8 – 1.0 k Ohms

2. Connect ohmmeter connector part to rpm/crankshaft position sensor, pins 1 and 3.
Display: infinite ohms

davedeck 06-28-2013 01:52 PM

Thanks
I'll give it a try

luckyed7711 06-25-2015 04:24 PM

Quote:

Originally Posted by JFP in PA (Post 348639)
Possible fuel pressure issue (pump, pressure regulator). Try running the car with a fuel pressure test gauge attached to the test port on the fuel rail to see if the system is losing pressure. Another perennial favorite is the crank position sensor, which can act up when hot, causing the DME to turn off the fuel pump. You can test the CPS:

1. Connect ohmmeter connector part to rpm/crankshaft position sensor, pins 1 and 2.
Display at 20 °C: 0.8 – 1.0 k Ohms

2. Connect ohmmeter connector part to rpm/crankshaft position sensor, pins 1 and 3.
Display: infinite ohms

To double check: if the ohmmeter readings confirm the above, then the CPS is not at fault for the issue?

JFP in PA 06-25-2015 05:03 PM

Quote:

Originally Posted by luckyed7711 (Post 455103)
To double check: if the ohmmeter readings confirm the above, then the CPS is not at fault for the issue?

It means that the CPS is functioning correctly under the existing conditions. Problem with a CPS is that you need to check these tests when the car does not want to start, like after a heat soak. If the tests check out then, it is probably not the CPS.

luckyed7711 06-25-2015 05:15 PM

Quote:

Originally Posted by JFP in PA (Post 455107)
It means that the CPS is functioning correctly under the existing conditions. Problem with a CPS is that you need to check these tests when the car does not want to start, like after a heat soak. If the tests check out then, it is probably not the CPS.

I see. Yes. Thank you for the clarification.


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