Ramdom Oil Pressure Warning on Cold Start

RocketcarX

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I've seen this a few times in my 08 GT, and now in a customer's 07 GT.
Is this a common thing with these cars, or maybe an indicator of something larger?
Side note, I had a buddy with a turbo 08 GT who had to rebuild his lower end over oil pressure issues caused by the crank thrust clearences if I remember correctly he and I both have manual trans cars, where my customer with this issue owns an automatic.

So, is the instrument cluster right, am I actually seeing no/low oil pressure on random cold starts or am I likely looking at a faulty sensor? Testing for this is troublesome because it is not a constant with either car, so the testing would have to be random and often to verify a sensor or pressure issue with a mechanical gauge.
 

JeremyH

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I always thought this was just common for the oem dummy sensor. My car has sporadically done this since I got it in 07. Light will randomly stay on for a few seconds on a cold start. I would say it does maybe once every month or two.
 
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Wild White Pony

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I had this problem and used contact cleaner on the connector. A lot of oil gets on that connector as it's right next to the oil filter and can get wet from oil changes. I did change the sensor later on for peace of mind and it's pretty inexpensive.

Scares the hell out of you as that buzzer is loud when the sensor doesn't see a signal.
 

drive_55_not

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If it's random, the first thing I would check is the connector to the sensor.


^^ Check the wire doing into the connector, when it breaks you''ll start seeing sporadic low oil pressure lights.

Ford makes a replacement cut-n-splice connector 3U2Z-14S411-MHA.

After I replaced it I took the old connector apart and saw where it could've been fixed without spending $20 for a new connector.

If that is the issue, or isn't, you wanna wrap some tape around the connector and wire to eliminate the same thing happening again.


.
 

Totheboards

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Agree with above, random makes me think electrical connector/wire. Couple more thoughts:

Could it be a bad check valve in the oil filter allowing full drain back? ...would expect it to react similar to the first time you start up after an oil & filter change.

Other thought is maybe a restricted pressure sensor oil passage... lets just say sludge? Sludge isn't a big concern with full synthetic oil, but maybe someone ran dinosaur oil...
 

RocketcarX

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Thanks guys!
Ill look over the wiring on the cars, I may just go ahead and do the a new sensor and plug pig tails just to to fully rule these things out.
 

Marble

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I would check oil to make sure there isn't metal in the oil. And then manually check the oil pressure.

Mine was similar symptoms and when I pulled the oil filter, lots of fine metal...
 

RocketcarX

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I would check oil to make sure there isn't metal in the oil. And then manually check the oil pressure.

Mine was similar symptoms and when I pulled the oil filter, lots of fine metal...

What turned out to be the main issue for you?
What was the metal from and what did you find when you did the tear down?
 

Marble

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What turned out to be the main issue for you?
What was the metal from and what did you find when you did the tear down?

I haven't done the tear down yet. It starts and runs ok (idles) after it starts now with just a filter change. Prior to this the pressure was pretty low and you could hear the valves pretty good. I guess because there wasn't enough oil pressure to make them function properly. You could also see the motor acting like it was missing. But after the oil filter...if you rev the motor and then shut off to listen to the engine stop, you can hear what sounds like a spin rod bearing.

I hope to pull the motor in the next month, rebuild it, sell it and do another from L&M. The block is fine, I think the internals will be ok, possibly I could have a bad rod, but you never know until you tear it down.
 

RocketcarX

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I haven't done the tear down yet. It starts and runs ok (idles) after it starts now with just a filter change. Prior to this the pressure was pretty low and you could hear the valves pretty good. I guess because there wasn't enough oil pressure to make them function properly. You could also see the motor acting like it was missing. But after the oil filter...if you rev the motor and then shut off to listen to the engine stop, you can hear what sounds like a spin rod bearing.

I hope to pull the motor in the next month, rebuild it, sell it and do another from L&M. The block is fine, I think the internals will be ok, possibly I could have a bad rod, but you never know until you tear it down.

I would look for used engine before I did all of that, they are a dime a dozen as far as junkyard motors go.
 

Marble

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True, but I am looking for 4 digit power in the high 8s. So I want tip get rid of the iron block and get the aluminum one with better stuff in it.

It's a lot of money, but I am not sure I could get there with the block I have. Internals, maybe.

Plus I just got this yesterday...
 

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RocketcarX

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True, but I am looking for 4 digit power in the high 8s. So I want tip get rid of the iron block and get the aluminum one with better stuff in it.

It's a lot of money, but I am not sure I could get there with the block I have. Internals, maybe.

Plus I just got this yesterday...

It sounded like you were saying you were going to rebuild your current engine only to sell it and then get your built L&M deal...I must have misunderstood you.
If you have an iron block engine, pick up a used 05-09 GT engine and rebuild that one since it's aluminum block, then its one and done, swap it in and do your thing.
 

BruceH

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It could be a bad connection. It could also be a combination of motor clearances, oil pump relief spring, and oil viscosity along with brand.

What I'm saying is the oil sensor could be telling you that the pressure isn't right. If it changes after the motor is warmed up this would point to oil viscosity and bearing clearances imo.
 

RocketcarX

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It could be a bad connection. It could also be a combination of motor clearances, oil pump relief spring, and oil viscosity along with brand.

What I'm saying is the oil sensor could be telling you that the pressure isn't right. If it changes after the motor is warmed up this would point to oil viscosity and bearing clearances imo.

This was my concern, there more I think about it the more I want to send out an oil sample and install a manual gauge in the mean time with a tee.
This is probably the only way I'll get the answers I want.
Being a stick car I worry about thrust clearances a lot, there is a certain amount if fore and aft play in the crank I don't like when pulling/pushing on the balancer.
 

Badd GT

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electrical means of measuring oil pressure are unreliable, one of the first things I learned as a boy watching my father put a manual gauge on our 1970 Oldsmobile because the "oil light" kept coming on. The manual gauge showed there was no problem with the oil pressure.
 

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