Oil pressure problem after oil change


Back in June I ran the Pocono Raceway road course. During one session I checked my gauges and saw 25 lbs. oil pressure. I came in and checked everything and found no problem. There was absolutely no engine noise so we assumed it was a faulty gauge. When I got back home with the car I pulled the oil pressure sender and attached a mechanical gauge and indeed there was only 25 lbs. of pressure. I talked to Rich and he told me about some of the oil pump shafts being machined improperly therefore not providing the proper clamp load on the pulley. Since I have a fully built Accufab engine I talked to John and he had me pull off the cover and belt. When I did I found the pulley just wobbling on the shaft with no connection between the two. The splines on the pump pulley which are cast iron are much softer than the hardened splines on the pump shaft. As a consequence of the improper factory machining there were no splines left in the pulley at all and those on the pump shaft were worn down by 50 thou. The only reason the pump was turning was the friction between the pulley and the shaft caused by the belt tension. I replaced the entire pump and pulley with a new Accufab unit and I'm back in business. It seems that this is not an uncommon occurrence but I was lucky not to burn up a $60 thousand dollar engine. It is an easy check to remove the sending unit and screw in a $20 mechanical gauge then you'll know for sure.
 
dpdive said:
Back in June I ran the Pocono Raceway road course. During one session I checked my gauges and saw 25 lbs. oil pressure. I came in and checked everything and found no problem. There was absolutely no engine noise so we assumed it was a faulty gauge. When I got back home with the car I pulled the oil pressure sender and attached a mechanical gauge and indeed there was only 25 lbs. of pressure. I talked to Rich and he told me about some of the oil pump shafts being machined improperly therefore not providing the proper clamp load on the pulley. Since I have a fully built Accufab engine I talked to John and he had me pull off the cover and belt. When I did I found the pulley just wobbling on the shaft with no connection between the two. The splines on the pump pulley which are cast iron are much softer than the hardened splines on the pump shaft. As a consequence of the improper factory machining there were no splines left in the pulley at all and those on the pump shaft were worn down by 50 thou. The only reason the pump was turning was the friction between the pulley and the shaft caused by the belt tension. I replaced the entire pump and pulley with a new Accufab unit and I'm back in business. It seems that this is not an uncommon occurrence but I was lucky not to burn up a $60 thousand dollar engine. It is an easy check to remove the sending unit and screw in a $20 mechanical gauge then you'll know for sure.
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Here's the whole story form my pulley meltdown including pics....

http://www.fordgtforum.com/forums/s...ed-oil-pump-pulley-the-sad-saga-of?highlight=
 
If you absolutely have to take your GT to a dealer, make sure you can stay with the car. the minute they start the crap about "oh you can't be with your car in the service dept. due to insurance reasons" that's the time to say adios! Ford dealer insurance covers "anyone" in the service dept. That's a line of garbage so you can't watch what's going on. My dealer encourages me to stay with the car.
 
So the sending unit did not arrive today at the dealer (shocking) but they did put a manual gauge on it and saw the proper pressure - 25+/- at idle, 40-60 at throttle. Just waiting for the sending unit now. And while I did try to stay with the car, they turned me away when I showed up with my sleeping bag. Thanks all.
 
Northwood mentioned he has them in stock on the shelf.

Justin said:
So the sending unit did not arrive today at the dealer (shocking) but they did put a manual gauge on it and saw the proper pressure - 25+/- at idle, 40-60 at throttle. Just waiting for the sending unit now. And while I did try to stay with the car, they turned me away when I showed up with my sleeping bag. Thanks all.
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good news that it is just the sender.
 
well not so fast! dealer put in the new sending unit today and.... same issue. Car goes to 25-28 pounds at start, maybe 30-35'at throttle, then zero at idle. it goes to zero when the rpms drop low when at a complete stop and idle. if i press the gas just a bit it pops to 25-28 pounds and stops like something grabble the needle. According to the dealer as I previously stated it checks out fine on a gauge screwed right into the engine. So i'm hoping its the in dash gauge that has failed. It is odd because I just replaced the oil gauge this spring. i just ordered one on ebay, hopefully it is here by Friday so I can swap this weekend.
 
Justin said:
well not so fast! dealer put in the new sending unit today and.... same issue. Car goes to 25-28 pounds at start, maybe 30-35'at throttle, then zero at idle. it goes to zero when the rpms drop low when at a complete stop and idle. if i press the gas just a bit it pops to 25-28 pounds and stops like something grabble the needle. According to the dealer as I previously stated it checks out fine on a gauge screwed right into the engine. So i'm hoping its the in dash gauge that has failed. It is odd because I just replaced the oil gauge this spring. i just ordered one on ebay, hopefully it is here by Friday so I can swap this weekend.
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If you have an OBDII datalogger you might be able to log the oil pressure to verify the gauge is at fault.
 
i just ordered one on ebay,
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Instead of getting the V2 (stepper motor) gauge through AutoMeter?
 
nota4re said:
Instead of getting the V2 (stepper motor) gauge through AutoMeter?
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Yes, I was going to suggest that the OP look at Autometer gauges. If the gauge failed then a replacement Ford OEM gauge will fail with the same (high) probability. Autometer is the way to go now.
 
I just replaced the oil pressure gauge with an Autometer gauge in April. It took about 2 weeks to get that gauge. Didn't want to wait again. Although I already left a VM for the person at AutoMeter that i bought the gauge from. So I just bought one on Ebay hoping it will be here by Friday so I can test it. As far as an obd scanner, i have an SCT flash device that came with a tune. I'm pretty handy with cars but not with electronics on cars, so im not sure if this sct device can give me oil,pressure readings.
 
Just replace the whole instrument panel with one from Speedhut. I did that, rather than buy a new Autometer temp gauge for $250 (plus shipping). On sale a couple months ago, the whole panel was about $1200. Lifetime guarantee, and no more worries about OEM or Autometer gauges dying. I also ordered the tach with shift lights and the boost gauge to read to 20 PSI instead of 15, since I plan to install a 3.4L Whipple on it.

Do it and don't look back. Don't do it and you'll always be wondering when the next one will fail (and it will).
 
PeteK said:
Just replace the whole instrument panel with one from Speedhut. I did that, rather than buy a new Autometer temp gauge for $250 (plus shipping). On sale a couple months ago, the whole panel was about $1200. Lifetime guarantee, and no more worries about OEM or Autometer gauges dying. I also ordered the tach with shift lights and the boost gauge to read to 20 PSI instead of 15, since I plan to install a 3.4L Whipple on it.

Do it and don't look back. Don't do it and you'll always be wondering when the next one will fail (and it will).
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Is there not a gauge module that could still fail?
 
from what I've experienced, the gauge check module usually takes a large percentage of the them out all at the same time. I've actually seen cars where 4 gauges went out all at the same time and it was the individual gauges, not the gauge check module. to this day I don't get why the module is such stupid money. $5000-8000.00. give me a break
 
Shout out to Northwood who is sending me a new gauge 2nd day air so I can hopefully get resolution to this issue! Thank again.
 
I agree about the cost of the module. Have you considered manufacturing an aftermarket module?

Sent from my SM-N920V using Tapatalk
 
definitely needs to be reversed engineered. not only that, Ford has never stocked it. it comes "vendor ship" direct from the manufacturer which I believe is Pollack in Mexico. they have to be laughing al the way to the bank every time someone orders one. I have to believe that these (may, maybe not) have to start failing as the years progress.
 
Oil pressure gauge reading

Justin,

Here is a plot of some data that I took last year. It gives you an idea of the expected gauge reading once the motor is at a normal operating temperature.

Good luck, Jay
www.analogdesign.com
Ford GT oil pressure sender.gif
 
Interesting graph. My GT still with original (old) gauge reads exactly like the red line. Sample size of 2 of a polynomial, so probability of repeatability is 0.0000001. LOL
 
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Anybody ever teach you guys to label axes?
 
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