87 bronco it has the fuel injected 5.0. What happens is ill let the truck run for a few minutes to warm up. then what she does is the oil pressure gauge just drops and the truck stalls. but if i hold the gas down right before she dies, she'll stay running a little bit longer.
what would cause this?
- Thread starter Ilduce
- Start date
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yes, when i throttle it up i can keep it running. But as soon as i let off the oil pressure drops and stalls.
gatorbronco
New member
So if I understand correctly, one of two things could be happening:
1. Your truck is running perfectly fine, the oil pressure gauge drops and THEN your truck stalls.
OR
2. Your truck is running perfectly fine, then starts stalling and sputtering and your oil pressure drops because of this.
Either way, search the forum on how to pull codes for your Bronco and start from there.
1. Your truck is running perfectly fine, the oil pressure gauge drops and THEN your truck stalls.
OR
2. Your truck is running perfectly fine, then starts stalling and sputtering and your oil pressure drops because of this.
Either way, search the forum on how to pull codes for your Bronco and start from there.
first one sounds like whats going on. I was thinking the oil pumps shot. but cool ill try searching the forum and check on the code thing.
Broncobill78
New member
Sounds like the main bearings are worn. You get good oil pressure when you first start it because it's cold and everything is *relatively* tight. When it warms up after running for a few minutes everything expands a bit, the clearances open up and the oil pressure drops.
Try changing the oil to a 20/50 or straight weight 50 and see what that does. I suspect the pressure will improve.
I hope this isn't the truck you're racing
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The suggestion to ck your codes is a good one. See what the KOEO test tells you.
Try changing the oil to a 20/50 or straight weight 50 and see what that does. I suspect the pressure will improve.
I hope this isn't the truck you're racing
/emoticons/[email protected] 2x" width="20" height="20" />The suggestion to ck your codes is a good one. See what the KOEO test tells you.
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nope, different truckSounds to me like the main bearings are worn. You get good oil pressure when you first start it because it's cold and everything is *relatively* tight. When it warms up after running for a few minutes everything expands a bit, the clearances open up and the oil pressure drops.
Try changing the oil to a 20/50 or straight weight 50 and see what that does. I suspect the pressure will improve.
I hope this isn't the truck you're racing
/emoticons/[email protected] 2x" width="20" height="20" /> this one i was fixing for my brother. but thanks, ill give that a shotIf I had to guess I would have to say it was you Idle air motor not that costly to replace and I bet you that does the trick let me know what happens please
Electrical issue maybe? Where does the Oil PSI sit when warming up? When it drops does its bottom the gauge out instantly? The gauge will drop once power is removed, but i doubt your oil psi could bottom out instantly unless you had a big hole in your motor. I agree that parts warm up/expand but i would find it hard to believe its enough to make your oil pressure act up instantly. If the mains were worn id think the oil passages would be partially clogged if anything.
Whats the engine temp during all this? can you get it up to normal operating temp?
Anything else we should know about this truck? whats the high idle go to? does it take long to fire when cranking? miles?
Whats the engine temp during all this? can you get it up to normal operating temp?
Anything else we should know about this truck? whats the high idle go to? does it take long to fire when cranking? miles?
Broncobill78
New member
Do you have an actual gauge or is it the stock doohickey in the dash ? A real gauge with numbers probably wouldn't be a waste of $$$. I don't know if the 302's are the same but with my 460's I found it useful to use the stock sender location at the top rear of the block plumbed to a pressure gauge in the cab with a second gauge installed under the hood & plumbed into the oil port just above the fuel pump. It was diagnostically helpful to be able to see the pressure at the front of the block right above the oil pump as well as pressure at the top rear after it had run thru the valvetrain.
Shift may be right, I only mentioned it because I saw this just a couple yrs back in a friends 5.0 explorer. He had 35-40 lbs at startup and within 4 minutes or so it was down to 2 or 3 lbs. It had been rebuilt "professionally" less than 3yrs earlier & when we took it apart all the mains were worn down to the copper but the rest of the engine looked great and mic'd to spec. A new set of bearings brought the pressure back up and that was the end of it. I figured it would be worth a few qts of 50wt to see what happens.
Shift may be right, I only mentioned it because I saw this just a couple yrs back in a friends 5.0 explorer. He had 35-40 lbs at startup and within 4 minutes or so it was down to 2 or 3 lbs. It had been rebuilt "professionally" less than 3yrs earlier & when we took it apart all the mains were worn down to the copper but the rest of the engine looked great and mic'd to spec. A new set of bearings brought the pressure back up and that was the end of it. I figured it would be worth a few qts of 50wt to see what happens.
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wow bill, i guess you dont get what you paid for anymore Anything is certainly possible. Only bottom end trouble ive had out of bearings has produced knocks but never any oil pressure issues for me so i guess it really could go either way.
A mech gauge can be had for cheap. The local parts stores usually sell them for $20. I would do as bill said and mount it under the hood or somewhere you can see it easily with the hood open(just for testing).
Anything is certainly possible. Only bottom end trouble ive had out of bearings has produced knocks but never any oil pressure issues for me so i guess it really could go either way.A mech gauge can be had for cheap. The local parts stores usually sell them for $20. I would do as bill said and mount it under the hood or somewhere you can see it easily with the hood open(just for testing).
BroncoJoe19
Active member
Pull Diagnostic Trouble Codes (DTCs) From your onboard computer.
Your engine and transmission are computer controlled.
The computer uses sensors to tell it a number of different things and it controls actuators that push or pull mechanical levers (kinda). If one or more sensors aren't working properly, the computer goes "blind" and doesn't know what to do. If the computer can "see" but one of the actuators is broken and therefore can't follow the commands of the computer; the engine won't run correctly. The computer is preprogrammed with set values for each of its sensors, and each of its actuators. It will run a self check of all systems, like the space shuttle; it will compare its set value(s) to the value(s) it recieves from its sensors, and actuators. If any sensor or acutator is out of the "normal" range the computer will generate a "code." It will generate some codes on the fly, and others will be stored while you are driving. There is a simple method to "pull codes" out of the computer for one to use for diagnostic purposes.
Earlier versions of On Board Diagnostics OBD 1983-1995 can flash the error code to the dash board and can be pulled in one's driveway without any special tools.
Later versions of On Board Diagnostics OBDII some 1995, and pretty much all 1996 and newer, require one to use a code reader or scanner tool.
Some auto parts stores will scan your engine codes for FREE, you may want to call around. Some will scan OBDII but not the older (prior to 1996) OBD systems.
SO here you go...
How to scan FORD on board Diagnostic Trouble Codes (DTCs) in your driveway
Howto Pull Codes 1983-1995 Broncos, Mustang, F series Trucks, Econolines, 302, 351 and more
Your engine and transmission are computer controlled.
The computer uses sensors to tell it a number of different things and it controls actuators that push or pull mechanical levers (kinda). If one or more sensors aren't working properly, the computer goes "blind" and doesn't know what to do. If the computer can "see" but one of the actuators is broken and therefore can't follow the commands of the computer; the engine won't run correctly. The computer is preprogrammed with set values for each of its sensors, and each of its actuators. It will run a self check of all systems, like the space shuttle; it will compare its set value(s) to the value(s) it recieves from its sensors, and actuators. If any sensor or acutator is out of the "normal" range the computer will generate a "code." It will generate some codes on the fly, and others will be stored while you are driving. There is a simple method to "pull codes" out of the computer for one to use for diagnostic purposes.
Earlier versions of On Board Diagnostics OBD 1983-1995 can flash the error code to the dash board and can be pulled in one's driveway without any special tools.
Later versions of On Board Diagnostics OBDII some 1995, and pretty much all 1996 and newer, require one to use a code reader or scanner tool.
Some auto parts stores will scan your engine codes for FREE, you may want to call around. Some will scan OBDII but not the older (prior to 1996) OBD systems.
SO here you go...
How to scan FORD on board Diagnostic Trouble Codes (DTCs) in your driveway
Howto Pull Codes 1983-1995 Broncos, Mustang, F series Trucks, Econolines, 302, 351 and more
truck gets to normal operating temp. will idle for roughly 5-10 min and then oil pressure bottoms out then just stalls. truck has exhaust leak at the doughnut but thats all. truck has roughly 150k miles and fires right up.
