newly rebuilt, no oil pressure? help!
03-23-08, 07:02 PM
#1
newly rebuilt, no oil pressure? help!
not sure whats going on. i'm considering a few common culprits and have a few questions:
1. oil gear key installed incorrectly, no oil pressure being produced
- i don't think this is the case, i verified that the gear was locked on a few times before the front cover was installed. is there a way to check if i am actually getting pressure or not? like checking to see if oil is getting pumped up to the oil filter?
2. bad oil pressure sender?
- not sure what to think about this one. it was working perfectly before the teardown. any way to test to see if the sender functional? like applying pressure to it using a mityvac. if possbile what key position would the sender be turned on? or would i have to be cranking
3. bad wiring .. not sure where to start with this one. i cleaned the connectors and i can check for. breaks local to the connector.
1. oil gear key installed incorrectly, no oil pressure being produced
- i don't think this is the case, i verified that the gear was locked on a few times before the front cover was installed. is there a way to check if i am actually getting pressure or not? like checking to see if oil is getting pumped up to the oil filter?
2. bad oil pressure sender?
- not sure what to think about this one. it was working perfectly before the teardown. any way to test to see if the sender functional? like applying pressure to it using a mityvac. if possbile what key position would the sender be turned on? or would i have to be cranking
3. bad wiring .. not sure where to start with this one. i cleaned the connectors and i can check for. breaks local to the connector.
03-23-08, 07:14 PM
#2
Original Gangster/Rotary!
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Are you sure you have the oil regulator installed that's located at the inner bottom of the rear iron? Large hex-shaped bullet looking thing, takes a huge wrench. Only reason to remove it would have been porting, or if you used a different rear iron that didn't have it on there.
03-23-08, 07:18 PM
#3
1. You can check it by getting a cheapy oil pressure gauge to verify what your dash gauge is seeing. However, you'll either have to find a creative place to put it for testing or make sure to have an adapter which can allow you to pull the factory sending and put the cheapy gauge in it's place for testing.
2. First, I would try backing out the sender a few turns. I've seen it not get a reading if it's tightened too much before.
BTW, also make sure you didn't mix up the oil pressure and the coolant temp connectors.
2. First, I would try backing out the sender a few turns. I've seen it not get a reading if it's tightened too much before.
BTW, also make sure you didn't mix up the oil pressure and the coolant temp connectors.
03-23-08, 07:18 PM
#4
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What are the symptoms? Sending units easily fail causing the gauge to read 0 - also after a motor job I've seen a lot of shops / people never hook them up, again causing the gauge to read 0.
03-23-08, 07:25 PM
#5
i just noticed that none of my gauge needles seem to be functioning. no RPM is showing up when i crank. however the odometer readout is working, and the fuel level gauge did drop to 1/2 tank, but is still reading incorrectly.. since i only added 4 gallons after draining the tank of old fuel. is this a gauge issue?
03-23-08, 07:25 PM
#6
Are you sure you have the oil regulator installed that's located at the inner bottom of the rear iron? Large hex-shaped bullet looking thing, takes a huge wrench. Only reason to remove it would have been porting, or if you used a different rear iron that didn't have it on there.
1. You can check it by getting a cheapy oil pressure gauge to verify what your dash gauge is seeing. However, you'll either have to find a creative place to put it for testing or make sure to have an adapter which can allow you to pull the factory sending and put the cheapy gauge in it's place for testing.
2. First, I would try backing out the sender a few turns. I've seen it not get a reading if it's tightened too much before.
BTW, also make sure you didn't mix up the oil pressure and the coolant temp connectors.
2. First, I would try backing out the sender a few turns. I've seen it not get a reading if it's tightened too much before.
BTW, also make sure you didn't mix up the oil pressure and the coolant temp connectors.
i'll try backing out the sender too..
checked the coolant and oil pressure senders, look good. i believe the coolant temp is off the main harness and oil pressure is off the alternator section
Last edited by sevensix; 03-23-08 at 07:47 PM.
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03-23-08, 08:34 PM
#8
just cranking, new build never started. gauges should read rpm and some oil pressure when cranking shouldn't it? its been so long since i've driven the fd, but im pretty sure it should be showing both.
edit: *im getting oil pressure*. after some more cranking i took off the oil filter and it is saturated with oil. i'm going to start troubleshooting the gauge problem
edit: *im getting oil pressure*. after some more cranking i took off the oil filter and it is saturated with oil. i'm going to start troubleshooting the gauge problem
Last edited by sevensix; 03-23-08 at 08:55 PM.
03-23-08, 10:22 PM
#9
Original Gangster/Rotary!
iTrader: (213)
When you fed the engine wiring harness through the firewall into the cabin, did you plug the mail white connector on the engine harness into the female white connector on the body harness? The female one is often really tucked up in there and hard to see.
03-24-08, 01:57 PM
#12
Full Member
it takes a while to build up oil pressure while cranking, but you will see the needle move off bottom. rpm's should bounce when cranking also. start her up and make sure you have a good amount of pressure. rpm pickup is off the crank angle sensors on the oil pump cover. let us know!
03-24-08, 02:06 PM
#13
it takes a while to build up oil pressure while cranking, but you will see the needle move off bottom. rpm's should bounce when cranking also. start her up and make sure you have a good amount of pressure. rpm pickup is off the crank angle sensors on the oil pump cover. let us know!
03-24-08, 02:09 PM
#14
Full Member
Well, if everything was working before the engine was pulled, and i'm talking about the RPM gauge, start there. I'm sure you have pressure if your filter got oil in it. Double check your connectors on the crank angle sensors, they are difficult to push all the way down sometimes if the insulators get in the way. does the vehicle start at this point?
03-24-08, 02:28 PM
#15
Senior Member
From memory you will not get full oil pressure showing on the guage until the engine is running. On my 2nd gen I had no oil pressure similar to yours, all my guages worked before I rebuilt the engine but no pressure once it was back in. Turns out i was a faulty O ring inside the front cover (mazda apparently do no have faulty parts as it turns out) so oil was no going where it should. I do believe that 3rd gen's eliminated this problem by using a nylon washer and the O ring in the middle of it. I replaced my stock O ring with a Series 6 one but you shouldnt have this problem as you have a series 6.
Have you checked the resistance of your sensors with a multimeter to see if they are operational?
Have you checked the resistance of your sensors with a multimeter to see if they are operational?
03-24-08, 02:30 PM
#16
i'll check the connectors there. i haven't tried to start it due to uncertainty about oil pressure, i didn't want to damage anything running w/o oil.
as far as sensors i think it would be a problem upstream of the crank sensors.. someplace it can effect both oil and rpm readings. but im off 2 check the cas connectors
i haven't, but the sensors were all working perfectly before teardown
edit: its tossing a code, gonna figure out what it is after i grab some lunch
as far as sensors i think it would be a problem upstream of the crank sensors.. someplace it can effect both oil and rpm readings. but im off 2 check the cas connectors
edit: its tossing a code, gonna figure out what it is after i grab some lunch
Last edited by sevensix; 03-24-08 at 02:45 PM.
03-24-08, 02:53 PM
#17
Full Member
the two circuits are completely unrelated. When you start the vehicle, you will have oil pressure, do not worry about it. i'm more concerned that it may not start because of what you are saying about your rpm's not registering.
03-24-08, 03:14 PM
#19
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From memory you will not get full oil pressure showing on the guage until the engine is running. On my 2nd gen I had no oil pressure similar to yours, all my guages worked before I rebuilt the engine but no pressure once it was back in. Turns out i was a faulty O ring inside the front cover (mazda apparently do no have faulty parts as it turns out) so oil was no going where it should. I do believe that 3rd gen's eliminated this problem by using a nylon washer and the O ring in the middle of it. I replaced my stock O ring with a Series 6 one but you shouldnt have this problem as you have a series 6.
Have you checked the resistance of your sensors with a multimeter to see if they are operational?
Have you checked the resistance of your sensors with a multimeter to see if they are operational?
03-24-08, 07:24 PM
#21
Original Gangster/Rotary!
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[edit......not sure on the spec of kilo ohms, but here are the proper voltage specs]
Sounds like you might be out of range actually
As per page F-182 in the FSM:
narrow range---fully closed, 0.75 to 1.25V//closed to open, 1.0 to 5.0V//fully open, 4.8 to 5.0V
full range---fully closed, 0.1 to 0.7V//closed to open, 0.4 to 4.3V//fully open 4.2 to 4.6V
(I think VTA1 is narrow range and VTA2 is full range on the pfc commander, but without having it in front me I can't be sure.)
You want to check all of this with the motor warmed up, but shut off. Have the key in the 'accessory' position, and rotate the linkage by hand. Also, you'll want to reset the ecu by disconnecting the ground on the battery for at least 20 seconds and depressing the brake pedal.
Sounds like you might be out of range actually
As per page F-182 in the FSM:
narrow range---fully closed, 0.75 to 1.25V//closed to open, 1.0 to 5.0V//fully open, 4.8 to 5.0V
full range---fully closed, 0.1 to 0.7V//closed to open, 0.4 to 4.3V//fully open 4.2 to 4.6V
(I think VTA1 is narrow range and VTA2 is full range on the pfc commander, but without having it in front me I can't be sure.)
You want to check all of this with the motor warmed up, but shut off. Have the key in the 'accessory' position, and rotate the linkage by hand. Also, you'll want to reset the ecu by disconnecting the ground on the battery for at least 20 seconds and depressing the brake pedal.
03-24-08, 07:43 PM
#22
hi rich the kOhms figure i looked up from the forums, someone posted the normal range. not sure why it would have a voltage reading since there is no current through it at the time . referenced this thread for the resistance range: https://www.rx7club.com/showpost.php...8&postcount=12
. referenced this thread for the resistance range: https://www.rx7club.com/showpost.php...8&postcount=12
03-24-08, 08:07 PM
#23
Racing Rotary Since 1983
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in a normal situation w a new motor....
pull the fuel pump fuse.
pull the plugs
crank it for 30 seconds. you will probably not see oil pressure.
let the starter cool for a minute.
crank it again and you should see oil pressure on your gauge. generally around 30-50 cranking.
i do not see RPMs until i replace the plugs/wires, fuse and it starts.
hc
pull the fuel pump fuse.
pull the plugs
crank it for 30 seconds. you will probably not see oil pressure.
let the starter cool for a minute.
crank it again and you should see oil pressure on your gauge. generally around 30-50 cranking.
i do not see RPMs until i replace the plugs/wires, fuse and it starts.
hc
03-25-08, 05:56 PM
#24
in a normal situation w a new motor....
pull the fuel pump fuse.
pull the plugs
crank it for 30 seconds. you will probably not see oil pressure.
let the starter cool for a minute.
crank it again and you should see oil pressure on your gauge. generally around 30-50 cranking.
i do not see RPMs until i replace the plugs/wires, fuse and it starts.
hc
pull the fuel pump fuse.
pull the plugs
crank it for 30 seconds. you will probably not see oil pressure.
let the starter cool for a minute.
crank it again and you should see oil pressure on your gauge. generally around 30-50 cranking.
i do not see RPMs until i replace the plugs/wires, fuse and it starts.
hc
interesting.. thanks howard. any idea why rpms don't show though?
04-07-08, 05:32 PM
#25
so now the problem is i can't get the 1st start i think i may have bled my clutch unsucessfully(leak somewhere?) or i need a new slave.. how obvious would be be if the plate is dragging on the flywheel/still partially engaged. would i be able to crank at all? i seem to be draining the battery VERY quickly from a full charge, 3x 10second crank and it is barely moving the starter anymore. (just a theory im playing with, not sure how valid this is)
im not tossing any codes, rpm shows with fuse plugged in, oil pressure did move a bit. im also getting fuel. spark plugs are new. fuel filter changed. i've been doing deflood procedure and charging battery to full before replacing plugs. small amount of 2 stroke oil injected to lower spark holes when needed. any ideas?
i think i may have bled my clutch unsucessfully(leak somewhere?) or i need a new slave.. how obvious would be be if the plate is dragging on the flywheel/still partially engaged. would i be able to crank at all? i seem to be draining the battery VERY quickly from a full charge, 3x 10second crank and it is barely moving the starter anymore. (just a theory im playing with, not sure how valid this is)im not tossing any codes, rpm shows with fuse plugged in, oil pressure did move a bit. im also getting fuel. spark plugs are new. fuel filter changed. i've been doing deflood procedure and charging battery to full before replacing plugs. small amount of 2 stroke oil injected to lower spark holes when needed. any ideas?