Haven't cranked the car in 9 mos (93Z) but had this problem even before hibernation. Oil pressure would fluctuate at idle but hold steady while driving and dip a little under braking. I figured possibly the oil pressure sending being bad so I purchased a mech guage to verify. Well it's erractic to say the least. At idle it'll start @ 40psi and match the OEM oil pressure but after 5 mins it would drop down to 20psi and bounce up and down from 35 to 55 psi.....all this at idle. Not burning oil I only have a rear main seal leak and that's it. Run 50/50 w/ 15-40 and 10-30 castrol dino oil thinking that would cure it but to no avail. Like I said it holds steady under load and increases as the rpms increase all the way to 6700 rpm's....but the moment it goes back to idle it's all over the place but nothing lower than 20psi. Is that bearing damage I'm looking at?

The volt meter is another problem I had before hibernation as well. Under load it would drop to 7 volts esp reaching 2500 rpms and then it would regain itself and hold a steady charge at 13-14 volts. I was thinking the alternator so I bought a used one off a friend and worked perfectly on his car. Put in mine and I still have this dip underload causing the car to lose pwr and trip off sensors in the dash. Only thing I've done since its storage was put 4 guage engine ground wires on and nothing else. I'm running a total of 6 guages, 1 amp w/ a stealth box, and a speed calibrator and it was fine until recently out of the blue the dip in volt guage. Is this the battery perhaps?

Sorry for the lenght but I'm trying to be accurate as possible w/ no misunderstandings. Thanks for any advice or inputs.

Silas,

 

It sounds like the idle speed is hunting. Are you sure the engine speed is staying steady? It would appear that something other than the alternator and those items having to do with oil pressure is causing the problem and what you see is the result of the problem.

I think Gripenfelter had a problem recently where his power steering pump was on the way out and it would get extremely hard to rotate for a short time and cause the idle to drop off and then would rotate for while and be ok. You may want to go to his profile and have a look.

You may want to try removing the fuses to the accessories you added and then if need be, remove some others and see what that does. You may also want to look at the fuel pressure before and during the problem.

 

FP is a steady 41psi on start and gradually increases under load. As far as the pwr pump it's the original pump but I change the fluid yearly and I don't have a problem w/ it in regards to turning or giving me resistance. All the symptoms I listed are as the car sits on jack stands. When I put it on the road it's ok until 2500 and then it bogs down on pwr big and the guage reads 6-7 volts and after it clears that part it's back to normal for the most part. I have a high miss but I can't tell if that's from the delteq or the something else and the miss just started recently so I've actually have ruled out the delteq because I spun that thing up to 6700 no problem.

Hunting for idle? Possibly. My idle is set/programmed at 850 which may be too low so I'll bump it up to 1K and see if that does anything. I'll try disconnecting the amp as well. May have to disconnect some of the wires connected to the fuse's for all my guages and rewire them and maybe that'll work because it is a mess the way I have it wired up.

Thanks for the response.