I've got a 2003 Malibu that will start up hard sometimes in the morning and all of the time after about 3-4 hours of sitting. The fastest way to get it started is to crank the engine for a few seconds, shut the key off, and crank for a few more seconds, and it seems to fire up. I've swapped the fuel pressure regulator out twice, fuel injectors (re-man) twice, and also have changed the fuel filter. The car runs fine, but it seems to be lacking torque, but I may be just expecting too much out of it. The engine runs smooth however. Fuel pressure is at about 65 running and 70 with no vacuum on the regulator. I however have not checked the pressure after it has been sitting. Once the car shuts off, the fuel pressure drops from 65 to about 42 and seems to stay there, although I've only watched it for about 15 minutes. If anyone could help me, it'd be appreciated since I've already stumped one local garage...
Also, the check engine light is not on..
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I have the same issue. I haven't looked into it yet. I doesn't happen that often. Sometimes it just takes longer to crank over. You can test the CPS by using an oscilloscope and watching the frequency wave.
I was thinking it was either the CPS or ECT. Again, I haven't really looked into it yet.
It sounds like a simliar issue to what I had (see the post Lee linked, page 3). Sometimes I would have to crank for quite a few seconds to start.. sometimes it would fire right up.. It got worse until it scared me and barely started.. then eventually wouldnt start at all. Did the CPS behind the crank shaft pulley last weekend and so far so good.
94 Z28 - not stock
02 Malibu - very stock
Sounds like this could be a common problem. Sometimes mine turns over and then just drops off again. It doesn't do it all the time. Mainly after I drive it for a short distance and then try to start it up again. I need to do a couple things to my car.
The car only has one Crank Position Sensor. You can test the CPS by checking for a spark. If there is no spark, it would be because the CPS is not putting out a signal.
Sometimes you can get a CPS to through a code, other times it thinks the car is not cranking. In that case, it would not throw a code because it would assume the CPS is working properly and no one is trying to start the car.
I'd have to pay attention to my car to see what the RPMs are when trying to start. I don't know off the top of my head.