Wacked Out Gauge

[01_redfire_GT]

I did a search and found a few threads with similar problems but I couldn't get a definate answer.

My 01 GT has 66,000 miles and about a week or two ago I noticed that the oil pressure guage would dip way down at idle only and that when I revved a little that it popped right back up. The car was completely 100% stock at that time. It did it just a hand full of times. Well, this weekend I put a MAC CAI on and a BBK 75mm throttle body. Just yesterday the oil pressure guage dipped into the the red everytime I stopped and was at idle. I don't know if this is just coincidence that it went nuts yesterday after I put the parts on or if maybe it had something to do with it.

I got home and let it idle and it the guage started to read low then pop up and it did it several times without me doing anything. The car also seemed to studder a very little bit when the guage read low but it could also just have been me being paranoid.

After the searches, I ran to the auto parts store and replaced the oil pressure sending unit. I haven't noticed it move at all but the temp also went down 30 degrees outside by the time I replaced it. I guess my newb question is, based on what the guage was doing, does it sound like it was the oil pressure sending unit? I would think with 66,000 miles that an oil pump would be a little premature althought anything can happen I guess...

Thanks for looking! Sorry for the newb question, please don't shoot me.

 

[fobnicat]

Sounds like the sending unit. Ambient temperatures would have little to no effect on operating temps of the oil.

Make sure to check your oil levels though. Such a check never hurts.

 

[01_redfire_GT]

Ok, so it is not the sending unit as the guage still did it today when the new one in. It seems to do it a lot more often when it's warm outside and the engine fan is running...

 

[trinity_gt]

Time to get a proper pressure gauge on it (in place of the OE sending unit) to test the actual oil pressure.

Low oil pressure generally comes from:

• insufficient oil in the sump
• blocked oil pickup
• damaged pump and/or stuck oil pressure relief valve
• one or more bearing clearances is opening up

 

[01_redfire_GT]

Time to get a proper pressure gauge on it (in place of the OE sending unit) to test the actual oil pressure.

Low oil pressure generally comes from:

• insufficient oil in the sump
• blocked oil pickup
• damaged pump and/or stuck oil pressure relief valve
• one or more bearing clearances is opening up

My buddy is testing it after work with the proper guage. Now I was thinking that maybe the oil screen could be really dirty as this actually happened in my oil Explorer and the cause for the fluctuating guage was a very clogged oil screen. So if it is the oil pump/screen/relief valve, how hard are those to replace in these cars?

 

[01_redfire_GT]

Could a bad or going bad PCV valve be causing this possibley? When I took off the stock intake this past weekend, there was a crap load of oil in the intake and I was told this was caused by a weak PCV valve.

 

[trinity_gt]

Could a bad or going bad PCV valve be causing this possibley? When I took off the stock intake this past weekend, there was a crap load of oil in the intake and I was told this was caused by a weak PCV valve.

No. The crankcase is ventilated by a tube connecting the driver's side valve cover to the air inlet. The PCV valve on the passenger-side VC simply regulates the running conditions under which the resulting fresh air/oil vapor mix is pulled into the intake for combustion.

A ton of oil being blown out the PCV system can point to an internal engine problem (blow by) where combustion pressures are making it into the crankcase and pressurizing it. More likely though is that the leak is simply where the PCV valve plugs into the valve cover and not the valve itself.