Well I just replaced my 7mgte in my cressida and ever since getting it running it has been flashing the oil light. The motor i replaced it with was out of a 88 but all electronics were swapped over, oil pan and 7mge pump was swapped over from the other motor. This problem never occured with the other motor and I didnt even think the light worked. Now it flashes when the car is started.
Oil Light
- Thread starter BKCressida1718
- Start date
It flashes?? I dont think its suppose to flash, at least mine never has. I would start with the connections first.
the only connection i know for that light is the oil pressure sender on the block. it wasnt plugged in at first and after we plugged it in it was still doing it.
Well, it's normal in this case. Not very useful though.
A stock GTE sender outputs a pulsing ground with a frequency based on pressure. It's designed like that to communicate with the ECU. It's not a pressure switch in the typical sense. If you want a warning light for low oil pressure you'll need to put a normal switch in there...
A stock GTE sender outputs a pulsing ground with a frequency based on pressure. It's designed like that to communicate with the ECU. It's not a pressure switch in the typical sense. If you want a warning light for low oil pressure you'll need to put a normal switch in there...
hvyman;1480234 said:
That was my concern too. I hope the GE pump is up to that flow demand.
So jetjock why would it blink? That doesn't make sense to me.
The stock oil pressure gage is a bimetallic servo type. Picture a circuit where 12 volts comes from the ignition switch then goes through a little heater coil that's wrapped around a bimetal strip in the gage. As you may know bimetal is a sandwich of two metals with differing coefficients of expansion. This difference causes bimetal, when heated, to physically deform.
The strip is mechanically connected to the gage's pointer. If the other end of the gage coil is grounded current will flow through it, heating the bimetal strip which in turn warps and causes the gage pointer to move. Course, if the current is left flowing not only will the pointer go to max but the coil may burn out. What is needed is a ground only long enough to move the pointer to a position representative of oil pressure.
The sending unit does that through a contact on another heater-wrapped bimetal strip in the sender that is mechanically biased by a metal diaphragm sensing oil pressure. At a given pressure the diaphragm pushes up on the strip causing the contact to close and connecting the gage's coil to ground. This causes the gage's pointer to begin deflecting upward.
This same contact causes current to flow in the sender's own heater coil which warps the strip in the sender. The warping continues until the the bias of the diaphragm is exceeded. At that point the strip will open the contact, breaking the circuit and causing not only the gage to begin falling back towards zero but also causing the sender strip to cool and quickly close the contact again. The process repeats itself at a fix rate as long as the diaphragm bias on the sender strip (how much it's pushing up on the strip) remains constant.
The result is an output signal from the sender to the gage that's an on/off pulse whose duty cycle varies with oil pressure. In simple terms the warping of the strip in the gage (and hence pointer deflection) closely follows the warping of the strip in the sender. That's why it's called a servo.
You can see this behavior on a cold start by closely watching a stock gage. It should rise to some value and then fall slightly before rising again. This slight up and down pointer deflection will continue until the heating in each strip reaches equilibrium. The relatively slow response time (about one second) of the design is what prevents the gage from having noticeable oscillations once this happens but the bottom line is the stock gage is always turning off and on and, as the TRSM points out, so will a bulb connected in place of it.
It was done this way because the oil pressure input on the ECU (used to trim idle speed) requires this type of "digital" signal. Toyota chose to do it this way rather than use an analog equivalent. Why I don't know.
The strip is mechanically connected to the gage's pointer. If the other end of the gage coil is grounded current will flow through it, heating the bimetal strip which in turn warps and causes the gage pointer to move. Course, if the current is left flowing not only will the pointer go to max but the coil may burn out. What is needed is a ground only long enough to move the pointer to a position representative of oil pressure.
The sending unit does that through a contact on another heater-wrapped bimetal strip in the sender that is mechanically biased by a metal diaphragm sensing oil pressure. At a given pressure the diaphragm pushes up on the strip causing the contact to close and connecting the gage's coil to ground. This causes the gage's pointer to begin deflecting upward.
This same contact causes current to flow in the sender's own heater coil which warps the strip in the sender. The warping continues until the the bias of the diaphragm is exceeded. At that point the strip will open the contact, breaking the circuit and causing not only the gage to begin falling back towards zero but also causing the sender strip to cool and quickly close the contact again. The process repeats itself at a fix rate as long as the diaphragm bias on the sender strip (how much it's pushing up on the strip) remains constant.
The result is an output signal from the sender to the gage that's an on/off pulse whose duty cycle varies with oil pressure. In simple terms the warping of the strip in the gage (and hence pointer deflection) closely follows the warping of the strip in the sender. That's why it's called a servo.
You can see this behavior on a cold start by closely watching a stock gage. It should rise to some value and then fall slightly before rising again. This slight up and down pointer deflection will continue until the heating in each strip reaches equilibrium. The relatively slow response time (about one second) of the design is what prevents the gage from having noticeable oscillations once this happens but the bottom line is the stock gage is always turning off and on and, as the TRSM points out, so will a bulb connected in place of it.
It was done this way because the oil pressure input on the ECU (used to trim idle speed) requires this type of "digital" signal. Toyota chose to do it this way rather than use an analog equivalent. Why I don't know.
Ok, well explained. That is a strange way of doing things. So OP does your gauge show any pressure?
You're confused. He transplanted a GTE into a Cressida which may only have an oil light that ended up connected to the GTE sending unit. Or maybe I'm the one confused...
I thought he said he swapped over the senders?
Do the Cressida's run both a gauge and an idiot light?
If so maybe the idiot light wire wasn't connected ever and now is shorting against something?
BKCressida1718;1480138 said:
Do the Cressida's run both a gauge and an idiot light?
If so maybe the idiot light wire wasn't connected ever and now is shorting against something?
Well, there's this:
Who knows. That's the problem with trying figure shit out on the internet, especially when all the facts aren't given...
BKCressida1718;1480138 said:
BKCressida1718;1480145 said:
Who knows. That's the problem with trying figure shit out on the internet, especially when all the facts aren't given...
Ok well that makes sense if the Cressida didn't have a gauge and only a light. Atleast if I understood your posts jetjock. Unless of course the sender was swapped over, then I'm totally confused.
the cressida doesnt have a oil pressure gauge. I was going to install one when doing the swap. The light i felt was a pressure light seeing that it cant measure fluid levels. This is why im asking if the constant blinking/flickering was because of low pressure. The sender wasnt swapped over. I figured I'd use the gte sender cuz of the gte harness.
Well you thought wrong.
For reasons posted above a pressure sender is not the same as a switch.
Easy way to make it stop is to unplug it because there is no way in hell to swap senders. Well maybe with a crows foot.
For reasons posted above a pressure sender is not the same as a switch.
Easy way to make it stop is to unplug it because there is no way in hell to swap senders. Well maybe with a crows foot.
