Re: '97 Grand fuel pump relay killed fuel pump?
Those volt readings are within any tolerances, when you start to see
tenths, you have issues. Could have just been a bad pump, it happens. I believe the code will reset with a key start count like it counts to give you codes. Mike Joe_M wrote: > Grand back with new fuel pump and running. > > I checked voltages with digital meter while engine idling with lights on, > wipers on, and heater fan on. The reading was just over 13.5 volts across > the battery terminals. About 2 to 4 hundredths of a volt higher with > negative taken from bolt attaching coolant overflow reservoir to body. About > 3 to 5 hundredths higher with negative taken where the coil attaches to the > engine. I expect that a bad ground would create a much higher difference, > but I don't know how big a difference it would be. I don't think most > mechanics are going to be checking for differences measured in hundredths of > volts. > > I still get code 12. The battery had been disconnected in the shop. My OBD > reader can reset OBD codes, but not the 12 code. Does it reset after 50 > start cycles? Does start cycle mean starting the engine and then stopping it > without any requirement to let if run for a while or get to closed loop? > > Thanks, > > Joe M > > "Mike Romain" <romainm@sympatico.ca> wrote in message > news:4695486b$0$6292$9a6e19ea@unlimited.newshostin g.com... >> Sometimes the cables can rot inside the clamps which is why the meter test >> is a good one just to make sure. >> >> It wouldn't hurt to meter the engine block with the volt test also. >> >> Code 55 should be the only one. >> >> Mike > > |
Re: '97 Grand fuel pump relay killed fuel pump?
Those volt readings are within any tolerances, when you start to see
tenths, you have issues. Could have just been a bad pump, it happens. I believe the code will reset with a key start count like it counts to give you codes. Mike Joe_M wrote: > Grand back with new fuel pump and running. > > I checked voltages with digital meter while engine idling with lights on, > wipers on, and heater fan on. The reading was just over 13.5 volts across > the battery terminals. About 2 to 4 hundredths of a volt higher with > negative taken from bolt attaching coolant overflow reservoir to body. About > 3 to 5 hundredths higher with negative taken where the coil attaches to the > engine. I expect that a bad ground would create a much higher difference, > but I don't know how big a difference it would be. I don't think most > mechanics are going to be checking for differences measured in hundredths of > volts. > > I still get code 12. The battery had been disconnected in the shop. My OBD > reader can reset OBD codes, but not the 12 code. Does it reset after 50 > start cycles? Does start cycle mean starting the engine and then stopping it > without any requirement to let if run for a while or get to closed loop? > > Thanks, > > Joe M > > "Mike Romain" <romainm@sympatico.ca> wrote in message > news:4695486b$0$6292$9a6e19ea@unlimited.newshostin g.com... >> Sometimes the cables can rot inside the clamps which is why the meter test >> is a good one just to make sure. >> >> It wouldn't hurt to meter the engine block with the volt test also. >> >> Code 55 should be the only one. >> >> Mike > > |
Re: '97 Grand fuel pump relay killed fuel pump?
Those volt readings are within any tolerances, when you start to see
tenths, you have issues. Could have just been a bad pump, it happens. I believe the code will reset with a key start count like it counts to give you codes. Mike Joe_M wrote: > Grand back with new fuel pump and running. > > I checked voltages with digital meter while engine idling with lights on, > wipers on, and heater fan on. The reading was just over 13.5 volts across > the battery terminals. About 2 to 4 hundredths of a volt higher with > negative taken from bolt attaching coolant overflow reservoir to body. About > 3 to 5 hundredths higher with negative taken where the coil attaches to the > engine. I expect that a bad ground would create a much higher difference, > but I don't know how big a difference it would be. I don't think most > mechanics are going to be checking for differences measured in hundredths of > volts. > > I still get code 12. The battery had been disconnected in the shop. My OBD > reader can reset OBD codes, but not the 12 code. Does it reset after 50 > start cycles? Does start cycle mean starting the engine and then stopping it > without any requirement to let if run for a while or get to closed loop? > > Thanks, > > Joe M > > "Mike Romain" <romainm@sympatico.ca> wrote in message > news:4695486b$0$6292$9a6e19ea@unlimited.newshostin g.com... >> Sometimes the cables can rot inside the clamps which is why the meter test >> is a good one just to make sure. >> >> It wouldn't hurt to meter the engine block with the volt test also. >> >> Code 55 should be the only one. >> >> Mike > > |
Re: '97 Grand fuel pump relay killed fuel pump?
Joe_M proclaimed:
> I have a '97 Grand Cherokee 4x4 that has had a myriad of ignition problems > (well ... maybe one problem with a myriad of 'solutions'). I finally > replaced the computer and the problems stopped for a couple of months. This > week the engine died a couple of times while driving in hot weather and then > would start again after a few minutes. It then began not starting when > driven and then parked for about a half hour. It finally would not start > again. No codes, no engine light. Towed to mechanic. > > He says the fuel pump and the fuel pump relay are bad. It was replaced last > year. The mechanic says the relay may have burnt out the fuel pump over time > by creating spikes and low voltage. I don't know much about the system, but > that sounds very strange for relays. Is this a likely diagnosis? OK, it *could* happen, but I'd try a different mechanic. |
Re: '97 Grand fuel pump relay killed fuel pump?
Joe_M proclaimed:
> I have a '97 Grand Cherokee 4x4 that has had a myriad of ignition problems > (well ... maybe one problem with a myriad of 'solutions'). I finally > replaced the computer and the problems stopped for a couple of months. This > week the engine died a couple of times while driving in hot weather and then > would start again after a few minutes. It then began not starting when > driven and then parked for about a half hour. It finally would not start > again. No codes, no engine light. Towed to mechanic. > > He says the fuel pump and the fuel pump relay are bad. It was replaced last > year. The mechanic says the relay may have burnt out the fuel pump over time > by creating spikes and low voltage. I don't know much about the system, but > that sounds very strange for relays. Is this a likely diagnosis? OK, it *could* happen, but I'd try a different mechanic. |
Re: '97 Grand fuel pump relay killed fuel pump?
Joe_M proclaimed:
> I have a '97 Grand Cherokee 4x4 that has had a myriad of ignition problems > (well ... maybe one problem with a myriad of 'solutions'). I finally > replaced the computer and the problems stopped for a couple of months. This > week the engine died a couple of times while driving in hot weather and then > would start again after a few minutes. It then began not starting when > driven and then parked for about a half hour. It finally would not start > again. No codes, no engine light. Towed to mechanic. > > He says the fuel pump and the fuel pump relay are bad. It was replaced last > year. The mechanic says the relay may have burnt out the fuel pump over time > by creating spikes and low voltage. I don't know much about the system, but > that sounds very strange for relays. Is this a likely diagnosis? OK, it *could* happen, but I'd try a different mechanic. |
Re: '97 Grand fuel pump relay killed fuel pump?
Joe_M proclaimed:
> I have a '97 Grand Cherokee 4x4 that has had a myriad of ignition problems > (well ... maybe one problem with a myriad of 'solutions'). I finally > replaced the computer and the problems stopped for a couple of months. This > week the engine died a couple of times while driving in hot weather and then > would start again after a few minutes. It then began not starting when > driven and then parked for about a half hour. It finally would not start > again. No codes, no engine light. Towed to mechanic. > > He says the fuel pump and the fuel pump relay are bad. It was replaced last > year. The mechanic says the relay may have burnt out the fuel pump over time > by creating spikes and low voltage. I don't know much about the system, but > that sounds very strange for relays. Is this a likely diagnosis? OK, it *could* happen, but I'd try a different mechanic. |
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