When I’m driving, my oil pressure is perfect. At idle, it sits at around 20-22 psi and when cruising, it sits at round 50-55 psi. But when I slam on the gas and go WOT, it'll jump to around 55-58 and then drop to 20-30 and then climb back up to 40-50 psi... the fluctuation always varies, it's never the same... I don't know what to take of this. I don't know if it's the sensor or if something's seriously wrong. Once it even showed it dip down to 15 psi for not even a second before climbing up to around 45 or so. It's always sparattic when it dips, it usually goes down between 20 and 30. The car hasn't been tuned yet since I put the dart heads, comp cams 503 cam and the HSR w/ 58mm TB, but I don't think this would have anything to do with the oil pressure acting retarded. What would cause such a thing to happen? Thanks for all your help in advance

 

sounds like to me the oil pump pickup (piece with the screen in it) has fallen off the oil pump.

i wouldnt worry about it until the motor needs to come out,but when that happends pull the pan off and see if its on there or laying in the pan.

 

robvas, it hit around 15-18 not at idle but when i let it loose on WOT, and then went back up to around 40-50 psi. u think it won't cause a problem if i continue to race the car with this problem?

 

I definately don't like what it is doing. If the pickup fell off, I would definately fix that asap. If you can't, keep the oil level up(maybe a 1/2 quart high or so).

 

how would i go around at fixing that?

 

T-money,
Mine did the same thing. I took the stock one off and put in an autometer. The stock unit is ridiculously wrong. I would try the new gauge (maybe a reason to get a triple A pillar pod) and if it still acts up then you can point your finger at the pickup/oil system.

 

When you replaced the stock unit, what did the autometer read? I think the majority of oil pressure problems are caused by the sending unit on third gens.

 

lol t-money... your too funny chris

yeah man... i was thinking about getting a new guage, but i dunno... how would the stock one go up to good oil pressure, then drop, and go back up... wouldnt that have to do with the sending unit itself and not the guage? where is the sending unit located btw?

 

right above the oil filter

 

hmm... well let me throw this one at ya so you can tell me what you think. i've been noticing that there was some oil coated over the oil filter... and it looks like the top of where the oil filter connects to is shiny, like if it itself is covered/coated in oil. would this have anything to do with the problems im having?

 

Well, if the sending unit is somehow leaking, I would definately start there and see if your problems went away. If after that and a gage you are still having problems, you might want to check your pickup. In response to your earlier question, you will need to take the pan off and reinsert the pickup and tack weld it to the pump body. Even if it is not the problem, a small weld would be good insurance for the future.

 

If your engine has a one-wire sensor behind the driver side cylinder head to the right of the distributor, and a two-wire sensor above the oil filter, then:

1. The one-wire sensor is the oil pressure gauge sending unit. Don't put anything on the threads that will prevent it from grounding properly through the block.
   
2. The two-wire sensor is the fuel pump switch, you can safely use teflon tape, or liquid sealer, it doesn't need a ground because it switches power. The tan/wht wire goes through a junction to the fuel pump & fuel pump relay, the orange wire goes through a junction to Inline Fuse #2 (hot at all times.)

The fuel pump switch, and the fuel pump relay switch are in a parallel circuit, as long as one is closed the fuel pump will work.

 

I'd go ahead and replace the oil perssure sender. It's cheap, not too difficult (especially if you're changing the oil anyway,) and it's the most failure-prone part of the system. If it doesn't make a difference, buy/borrow/rent/steal a mechanical gauge and see if it matches the readings.

You might try overfilling it a bit for a couple days too. The sudden acceleration may just be slinging the oil to the back of the pan and allowing air to enter the pickup.

edit: It's a '90 model, so unless it's a swap or something it should have the single 3-wire unit above the oil filter.

 

My autometer reads about 40 on start up and will hit about 50 or 60 at WOT and completely burried on a juiced run. TPI motors have the fuel pressure safety switch which is located on the base plenum by the Dist. Tommy your probably seeing oil around the lip of the filter because they didnt oil it when they put it on. The stock sending unit sucks bad like every other sensor on 3rd gens-go figure. Change your filter and dip your finger in oil and spread it on the the o ring on the top of the filter. That will stop your leak. There is a plug in the block right above the oil filter where you have to run the line for the gauge. I ran mine there, covered it in loom till it hits the trans tunnel then zip tied it to the gas lines and ran it through the shifter hole and into the console. Thow out the ****ty plastic and use the copper lines. I used copper lines for a couple reasons. IHRA rules require it. No plastic lines in the car, and if that **** sprouts a leak say good bye to your nice interior and leather seats. So go get your auto meter and be done with it. Let me know how it works out bro bro. BTW me and my buddie joe are trailoring our cars down there for fun ford weekend, i know boo ford but hes paying for it, see ya then.

 

Third gens don't have a fuel pressure safety switch, but they do have an oil pressure safety switch, which is probably what you are thinking of. He has a 90, which will have the sender/OPSS combo part right above the oil filter, unlike earlier model third gens that have the sender near the distributor.