Sorry for the double post, I posted this in the "Maintenance" section but didn't get any responses, and I need an answer to this pretty quickly.
So I have a '93 Cavalier 2.2L that I race on dirt tracks, and I have been chasing a couple of problems. One, an oil leak somewhere, and two, the last couple of races it has been cutting out, only in the corners when I get back hard on the gas.
Last night, I was looking for the oil leak. When I was underneath the car, I noticed that the fuel pump/oil pressure indicator switch had oil droplets on the bottom of the plastic electrical connector. I unplugged the electrical connector and oil started dripping out, fairly steadily. Note--I did not unscrew the metal screw that the electrical connector plugs into from the block, obviously I would expect oil to drip out of that. I just unplugged the male electrical connector from the female plastic hookup, which I was surprised that oil would drip from there when I unplugged the electrical connector.
I am relatively new to this, so please forgive what may be a couple of dumb questions. But first, should oil drip out when I unplug the electrical connector? If not, then that is my oil leak and I am guessing I need to replace the switch assembly.
Second, perhaps more significantly, I read the service manual and got a general understanding of the dual function of this fuel pump/oil pressure switch, but I am not exactly clear on it. What role does this switch play with regard to the fuel pump? Is there any way that if this switch is damaged and/or oil-soaked improperly, that it might be the source of my problem with the engine cutting out?
I'm not a secong gen expert by any means but it sounds like the sender is shot. the little diaphram inside it is broke so its leaking oil. I'd replace it and see if that fixes your problem. As far as your second question i have no idea. I know on the 3rd gen cars (95+) there's no interlock between oil pressure and fuel pump but that may not be the case with yours car. hope this helps
Please pardon my ignorance, but is the sender the copper-looking part that actually screws into the block? And I take if it is working correctly, oil should not come out of it at all?
Unfortunately, even the factory service manual didn't have a lot of info on this.
And as far as the second question, I know there is some interplay between the two, as the manual even calls it the "fuel pump and engine oil pressure indicator switch." I can tell by the wiring schematics that the oil pressure switch is part of the fuel pump circuit, but I don't know enough to tell what role it plays.
Yes, the sender is the part that screws into the block. No, oil should not come out of it.
The oil pressure sender is definitely bad, so replace that first and see if it fixes the cutting out problem. On GM trucks of similar age, the oil pressure switch cuts power to the fuel pump if there is not enough oil pressure. Designed to save the engine in the event that the oil pump gives out or you run out of oil. If you can post the wiring diagram I can tell you what exactly the oil pressure sender does with the fuel pump, it may be different on cars.
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'04 Cavalier
2.2 Ecotec Supercharged w/ 2.9" pulley
Charge air cooler
Poly bushings - lower control arm and engine/trans
Trey Lawrence wrote:Hopefully this will work, this should be the link to the 93 engine wiring diagram, from Auto Zone's website, I think you should be able to cut and paste into your browser:
http://www.autozone.com/autozone/repairinfo/repairguide/repairGuideContent.jspchapterTitle=Wiring+Diagrams&partName=Chassis+Electrical&pageId=0900c1528003bdaa&partId=0900c1528003bcbe
I do see that the oil pressure switch is shown in the top right, as part of the fuel pump circuit.
You may be on to something, though. I have noticed in the last couple of races, concurrently with the cutting out, that my oil pressure light will flicker on and off during the course of the race. Now that I discovered that the sender is messed up, I would definitely attribute the light to that. And I really hope that you are right and that it is causing the cutting out too.
Oops, that attempt to post the link sure got messed up. And no edit function to go delete it.
As I said, though, you may be on to something, because in the last couple of races the oil pressure light will flicker on and off at various times during the race. Now that I have discovered the sender is bad, I would attribute the light to that. But if the system is designed as you said, then with the bad sender it would think there is low oil pressure and cause the fuel pump to cut out. I sure hope that is it, it is an easy fix and I have been chasing this gremlin for a while.
Sorry for the mess of the last two posts. An attempt to post a LOOOONG web link gone bad, and no edit/delete function.
