I own a 2000 Ford Taurs SE V-6 3.0 L OHV, 197,000 miles on it. Back in March I had the Coolant Temp sensor replaced allong with the EGR pressure Sensor. Since these 2 sensors were replaced whenever I turn on my heat or A/C the rpms conisistently jump up and down on the engine. I don't mean the occasional jump when the condensor or fan are pulling more from the engine, it's a constant non stop jumping and it jumps almost 1k. The car did not do this prior to these two sensors being replaced. I'm in Denver, and this week it got hotter then normal, up to 102. I was driving in the heat of the day, did NOT have the a/c on, just the car running and the radio running. My car temp gauge went up to the hot mark, and starting running rough, like it was trying to stall. I parked the car checked under the hood there was no steam, no hissing, no broken hoses, no leaks, etc. The coolant system was just flushed 9 months ago. Any idea what this may be? When I called the shop who did the work the first time I was told I was crazy and cars rpms jump like that normally (I know they don't). And now I'm told a coolant temp sensor has nothing to do with this problem, all it does is tell the computer to tell the engine when to run the fan, open the thermostat etc. Well then it seems to me that that would be the problem. Thank you for any help or advice you can provide me. I feel like this shop is trying to rip me because I'm a woman.
Thanks for getting back with me. The fan operates normally. I did go ahead and have the thermostat changed because they refused to check the previous work they did on my car any further if I didn't. They stated that it was all the thermostat causing the problems. I found it funny that if my thermostat was bad why was the car not either staying cold all the time or overheating all the time and there were absolutely no leaks. The RPMs jump constantly with the heat on, the A/C on, or the defrost on. It's not just a jumping from the compressor drawing power when it kicks on, it is constant it jumps up and down every half a second. The shop states now that my A/C compressor is " short cycling". In speaking with another shop they state that does not sound right to them with how I'm explaining the jumping. But they don't want to charge me and touch it because if it is something the other shop did they don't want to void any warranty I may have.
When the guys at the shop who did the work and stated it's was the A/C compressor short cycling that is causing the jumping I told them that didn't make sense to me because when I run the heat or defrost it does the same exact thing. They said it was because the heat and defrost in cars runs off the A/C compressor. Really? What about cars with no A/C in them?
In answer to your specific questions the fan is operating normally with A/C/defrost/heat on and off. The only time the car does the RPM jumping is when those things are on and it is constant up and down up and down every half second or less. When these things are off the car operates normally at approxitmately 700-800 RPMs.
July, 30, 2007 AT 12:32 AM
Sorry for the length of time on my last response, I was out of town. I REALLY appreciate all the help you are willing to provide me! : D
My check engine light was on for a month or two and I took it into them to fix whatever was causing that and they came up with those two sensors as being the issue. After they supposedly replaced these 2 sensors the light went off but the issue with the RPMs jumping began as soon as I ran the heat/defrost/AC.
They CLAIM they did a pressure check and they found no problems. They were also trying to force me to do a coolant flush, at 90.00, although one was done approximately 8 months ago. They did not run a diagnostic on it, they immediately went after the thermostat and stated it was bad. When I got the old one back you could push it open with your fingers and it would close again. : : They also wanted me to spend 100.00 for them to do an A/C inspection. I'm thinking they just want me to keep spending money.
The car ran fine before they did this work (only issue I had was the a/c started blowing warm last summer I assumed this was a freon/condensor issue and I was going to take care of it this summer, but these other issues occurred). I had no issues with RPMs jumping nothing, nada, zip until these sensors were replaced. I explained this to the guys at the shop and all they said in a real nasty tone was " I can't speak to how your car was running before.&Quot; : shock: All my vehicle maintenance and repairs are in their records!
The statement about my heat and defrost running off the a/c compressor still makes no sense to me.
This is funny, when I took the car in I put in writing the problems I was having, I espcially made reference to the fact that I was NOT running the A/C when it would overheat, that the A/c stayed warm so there was no point in running it. When I picked the car up and looked over the paperwork they had it typed in there that the car was overheating while using the A/C! Idiots!
July, 30, 2007 AT 12:11 PM
Is this something I would be able to do at home? I really hate the thought of spending even more money at a shop. Since replacing the sensors and the thermostat I've already spent over 500.00. I read the link you sent and I'm not quite understanding this tool that needs to be made. I know recharging the freon is something I can't do at home anymore because of law, but I'd like to save as much money as I can, and really having the A/C blowing cold is not a big deal for me right now, I can live without that. I just want the car to run right when I'm running the heat or defrost, that I can't live without, not here in the winter in Colorado, and don't want to have to worry about it overheating.