ELVISTAR Posted May 22 Share Posted May 22 Hi Reatta Forum My oil gauge was showing over the Center pressure Then it started showing under the center pressure I happened to luckily pull into a parking lot and the engine quit running It backfired a few times but wouldn't start I talked to some others who said if the oil sending unit goes bad it turns off the fuel pump Well I changed the sending unit but the car still won't start Any help from anyone with a similar story would be appreciated Please advise me Thanks Elvistar Link to comment Share on other sites More sharing options...
Ronnie Posted May 22 Share Posted May 22 1 hour ago, ELVISTAR said: Hi Reatta Forum My oil gauge was showing over the Center pressure Then it started showing under the center pressure I happened to luckily pull into a parking lot and the engine quit running It backfired a few times but wouldn't start I talked to some others who said if the oil sending unit goes bad it turns off the fuel pump Well I changed the sending unit but the car still won't start I think you have two separate problems. Below is what I wrote in a previous post about how the oil pressure sender effects fuel pump operation. If I were you I would test fuel pressure with a gauge to see if fuel pressure is the problem. ------------------------------------------------------ IF the ECM and fuel pump relay are working properly you should be able to unplug the oil pressure sensor/switch and the engine will start and run without problems. I have done it before to prove it. Here is what should happen for the car to start and run normally from a fuel pressure point of view... -When you turn the key to the run position the ECM should pick up the fuel pump relay for a few seconds to prime the system, then it should drop it out. This should happen each time your turn the key off and then to the run position. -Once the engine starts, the ECM gets a signal from the crankshaft position sensor that the engine is turning and it will pick up the fuel pump relay and keep it latched in to power the fuel pump as long as the engine is running. (blue circuit below) Now, here is where the oil pressure sensor/switch comes in... -As long as the engine has oil pressure the contacts in the oil pressure sensor bypass the fuel pump relay and power the fuel pump (yellow circuit) even if the relay is bad. If any of this is suspect, applying 12 volts to the prime connector will run the fuel pump so you can test the pressure. You can even start the car if the pump is capable of building adequate pressure. Link to comment Share on other sites More sharing options...
ELVISTAR Posted May 22 Topic Author Share Posted May 22 Thanks Ronnie Mechanic checked fuel pressure said it was good Said the engine is getting a spark The engine backfired when I tried to start it after it quit running It has 139,000 miles on it My mechanic is gonna pull the balancer off he thinks possibly the Crank sensor might not be right I changed the crank sensor a couple years ago He said something about the balancer getting wore He doesn't think it's the timing chain I'm lost Just following up on his diagnosis No other reset to do after changing a part Thanks Link to comment Share on other sites More sharing options...
Ronnie Posted May 22 Share Posted May 22 8 minutes ago, ELVISTAR said: The engine backfired when I tried to start it after it quit running It has 139,000 miles on it My mechanic is gonna pull the balancer off he thinks possibly the Crank sensor might not be right I changed the crank sensor a couple years ago He said something about the balancer getting wore The last time I had a backfire and the engine quit running I sat on the side of the road for several hours waiting for a tow truck to haul my Reatta home. The problem was a bad crankshaft position sensor. I don't think a "worn" balancer would cause the problem unless the bolt came loose and the sensor was damaged and/or it sheared the key in the crankshaft. Link to comment Share on other sites More sharing options...
ELVISTAR Posted May 23 Topic Author Share Posted May 23 My mechanic bought the oil sending switch from O'Reilly's I'm questioning whether it's any good When my original coil module went bad I bought a module from O'Reilly's Not realizing that the new module was no good The car would run but it missed and you couldn't accelerate quickly Finally after changing everything Another mechanic changed the module again and it ran great Well I guess we'll be working on the crank sensor tomorrow Stay tuned Thanks Ronnie👍👍 1 Link to comment Share on other sites More sharing options...
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