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Ok so last night i was sitting at a red light and i noticed the red Engine light on i then looked at my oil pressure gauge and the red light would come on when ever my oil pressure needle would go below the L. I then put it in neutral and the oil pressure guage went back to a good spot and the red engine light went off then i put it back in drive and it didnt happen the rest of my drive home.
 
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Is the oil level full? Did this just start?

These factory gauges can't be trusted. Your best bet is to put a mechanical gauge onto it and see what it reads.
 

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yea i should have put this in. But yes the oil level was fine and this was the first time it has ever happened
 

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im having a similar problem. i had aftermarket gauges(oil, volt, engine temp) installed after rebuilding the motor. i got the regular 30-45psi between idle and drive. in order to pass a smog test i had to go back to stock gauges oil and engine temp in order to turn the annoying RED ENGINE light off. i bought new sensors and installed them. i turned the truck on and got the RED ENGINE light on STILL, with no readings on the oil and engine temp gauges. i dont know what the problem could be. the mechanical gauges worked fine and showed regular operating tem/pressure. any one have any suggestions?
 

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if your engine light is on then pull codes and start there
 

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yo bsnow71
As Jason advised;
Check pressure w/gauge asap.
Test & Installation Tips in a 90; "...My oil pressure gauge was reading on the "N" of the NORMAL range. After doing some research it seemed like it could be the oil pressure switch, also known as a sensor or sending unit. Disconnect the wire from the switch, ground it to the truck and turn the key on. If your gauge quickly moves to the left, the problem is most likely the switch. The switch on my 5.8 is located near the oil filter. It is in a difficult spot to work on so I advise that you go to NAPA and get an Oil Pressure Switch socket to do the job. The cost is about $7-$8, this will save you time and will help you reinstall the new switch. Wrap some teflon tape around the threads and install. Make sure that it is in tight, I don't know about torque specs, I just put mine in quite snug. Hook the wire back on and start your engine. For me it was the cure. My oil pressure now reads over near the "M" on NORMAL..." miesk5 Note; The stock gauge & Sender will drop off after pressure reaches a certain level. You might actually have 5 psi, but the gauge will read 0 PSI & "...Technically all you need is 10 psi of oil pressure per 1,000 rpms . I still would not feel comfortable with less then 20 psi at idle. If it is lower then that, you can also get a thicker oil." by 420nitro
Source: by Canoeboy146 at FSB


Installation, Sunpro Mechanical in a 93; "As for the nylon capillary tubing.well I got rid of it, and used the kit from Sun Pro that comes with all adapters and 6' of 1/8" copper tubing. On my 93 I mounted a mechanical oil pressure gauge just below and left of the ash tray, using one of the dash fasteners to hook up the mounting bracket. I used the light from the ashtray for a 12V source. If you use this location the 6' copper will just make it, even with routing it well out of the way of everything......I did drill a hole in the fire wall to run the tubing, and the wires for the switch for my Hellas.....I just used a rubber grommet at the firewall to protect everything. On my 302, I did not have to remove anything on the engine to gain access to the oil pressure sending unit.....you do need a socket that is made for use on sending units (dont try pliers, or a regular 6 or 12 point socket). The sending unit is just forward of the oil filter.....you cant miss it.....you can get at it very easily from below.
Source: by Streetgang (Steven F) at http://fullsizebronco.com/forum/showthread.php?t=27589


Circuit Operation; "...In recent years, Ford Motor Company has been doing something I view as a bit sneaky. They have taken the oil pressure gauge and turned it into a glorified warning light. It says it's an oil pressure gauge, it looks like an oil pressure gauge, but in reality it is not. starting in 1986 a change was made on some models that altered the function of the oil pressure gauge as we knew it. The variable resistance sending unit was replaced with an open/closed switch and an in-line 20 ohm resistor was installed between the gauge and the switch. Anytime you have more than 4.5 psi of oil pressure, the switch closes, completing the circuit from the gauge (with the 20 ohm resistor in-line) to ground. This then results in a gauge that reads just above the middle. As you can see, there is no variation to the gauge needle in this circuit. It will either read no oil pressure or half-scale (normal oil pressure). On this style of gauge circuit, if the oil pressure gauge reads in the middle, it is telling you only one thing - you have more than 4.5 psi of oil pressure. How much more is anyone's guess at that point. When oil pressure drops below 4.5 psi, the gauge will return to 0 and alert the driver of a problem...Ford released a TSB (#88-5-14) for 1987-1988 F Series and Broncos that called for converting the variable resistive style oil pressure gauge circuit to the switch style circuit - if the customer complained of low or erratic oil pressure readings. The kit contains an oil pressure switch and an in-line 20 ohm resistor that is to be connected between the end of the existing sending unit signal wire and the new switch. The variable resistance oil pressure unit removed from the vehicle is then discarded. I want to point out some diagnostic problems that can arise from this circuit. First, if you are working on this switch style oil pressure circuit (with the in-line 20 ohm resistor) and install a variable resistive sending unit in place of the oil pressure switch, the result will be a gauge that reads lower than normal due to having two resistors in series, the fixed 20 ohm in-line resistor and the variable resistive sending unit. On the other hand, installing the open/closed switch on a vehicle that incorporates the conventional oil pressure gauge circuit will result in a pegged gauge needle after starting the engine. Sometimes you can tell that you need a switch instead of the variable resistive sending unit by the presence of the in-line resistor a few inches from the switch connector. This is not a good rule of thumb though, since many vehicles have the fixed resistor on the back of the cluster, and some of the digital dashes have that circuit built into the cluster. To determine what style circuit you have, simply ground the sending unit wire with the key on. If the gauge reads exactly half-scale, you can be fairly sure you need a switch-style sender. If you ground the sender wire and the gauge pegs, a variable resistor-style sender is needed..."



Oil Pressure Mod to Actual PSI "...short R in PCB..." info & NAPA Sender, etc.
Source: by Steve83 (Steve, That dirty old truck) at http://www.supermotors.net/vehicles/registry/media/281470


Try a Self Test for Diagnostic Trouble Codes (DTC)s by my pal, BroncoJoe19
The engine temperature must be greater than 50°F for the Key On Engine Off (KOEO) Test and greater than 180°F for the Key On Engine RUNNING (KOER) portion.
Run it around to heat the engine up and shift thru all gears incl Reverse. Then turn off all accessories/lights, etc.

Make sure A/C is off and transmission is in Park (automatic) or in Neutral for a Manual & release clutch.

Do Key On Engine Off (KOEO) portion first.

Look Codes up in my broncolinks.com site using the new Search function.

And Post em here according to:
KOEO
&
KOER
 

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turns out guys at autozone gave me the wrong switch. gave me an open/closed switch. i had the variable. replaced it and bam the engine light went off. i pulled codes and at KOEO i got 11-10-34 which is pass w/ a 34 continuous memory (EVAP control system fault / voltage higher than closed limit or Defective EGR pressure transducer sensor) i assume its the pressure sender cuz i had an egr fault prior that i replaced (got a 33 during KOER) when i did the KOER test i got 34-44. 44 being *Thermactor air system fault. im gonna replace the EGR PRESSURE TRANSDUCER SENSOR and go from there. any suggestion or any one have a similar problems/codes?
 

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i have an 89 and the same exact problem. theres no knocking or anything just the gauge goes crazy. im thinking a bad sending unit/sensor im gonna replace it here in a week or 2 when i have time.
 

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mine use to do that, i pulled codes and etc and it didn't work
(but i fixed alot of the codes themselves), then i replaced the Fuel Pressure regulator, and it fixed it.(didnt replace the sender because i couldn"t get to it)

but only 3 things i can think of that fixed it
1, fuel being dumped in the engine oil, thining it out, compined with the engine heat thining it out caused the engine to lose pressure at idle.(it was running rich and only getting 6-8mpg on highway, and now it 13-15mpg)
2. when moving parts of the harness out of the way to replace FPR, managed to bump the right wire.
3. because of the bad fpr, the idle bounced, but never noticed a corrilation of rpm the oil pressure.

i dont have any knocking problems, and i know my low oil pressure light has been gone since i replaced the fpr,and that was 3 months ago.
 

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turns out guys at autozone gave me the wrong switch. gave me an open/closed switch. i had the variable. replaced it and bam the engine light went off. i pulled codes and at KOEO i got 11-10-34 which is pass w/ a 34 continuous memory (EVAP control system fault / voltage higher than closed limit or Defective EGR pressure transducer sensor) i assume its the pressure sender cuz i had an egr fault prior that i replaced (got a 33 during KOER) when i did the KOER test i got 34-44. 44 being *Thermactor air system fault. im gonna replace the EGR PRESSURE TRANSDUCER SENSOR and go from there. any suggestion or any one have a similar problems/codes?
yo,
DTC 33 & 34 "...DTC 33 is triggered when the EVP sensor is not closing.... To prevent the EGR valve from opening when the engine is cold, the vacuum line to the EGR valve may be connected to a parted vacuum switch or a computer-controlled solenoid. Vacuum is not allowed to pass to the valve until the engine is warm. EGR isn't needed when the engine is cold, only when it is warm and under load. Any of these codes could indicate a faulty EGR valve as well. as well as a problem in the ...vacuum solenoids' Miesk5 note; TAB & TAD; so repair those vac lines 1st..."
Source: by Larry C at aa1car.com
DTC 33 EGR valve opening not detected in KOER & CM = Continues Memory
Source: by Ford via Ben Watson in How to Tune and Modify Ford Fuel Injection @ http://books.google.com/books?id=-9W2U2fgp6IC&pg=PA79&lpg=PA79&dq=Code+18++ford&source=bl&ots=eaTeuXT5XE&sig=bR8lCPhsvmSpK9pqKqWD0vj89v8&hl=en&ei=7Le6Tb_0M9OBtgeps9DZBQ&sa=X&oi=book_result&ct=result&resnum=1&ved=0CBgQ6AEwADgU#v=onepage&q&f=false
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DTC 33 is triggered when the EVP sensor is not closing; so EZiest & cheapest checks are to inspect & repair/replace repair any bad vac lines. for a <$ vac line test; I pull em off and use the straw sucking test; one finger over one end; includes EVP testing & Links
Source: by miesk5 at FSB


DTC 34 "...in Key On Engine Off (KOEO) or Engine Running (KOER) Self-Test indicates that the EGR valve and/or EGR Valve Position (EVP) sensor may not be fully seated in the closed position. The EVP sensor voltage is greater than the closed limit voltage of 0.67 volt. Because of the preload on the installed EVP sensor, it is very difficult to determine whether the EGR valve is seated or the EVP sensor is in contact with the EGR valve stem..."
Source: by rla2005 (Randy) via miesk5

DTC 34- EGR voltage above closed limit - Failed sensor, carbon between EGR pintle valve and seat holding the valve off its seat. Remove the EGR valve and clean it with carbon remover. Prior to re-installing see if you can blow air through the flange side of the EGR by mouth. the egr is not closing properly which can cause detonation. remove the egr and clean off any carbon built up on it with carb cleaner and a brush if necessary.
Source: by miesk5


DTC 34;The EGR Vacuum Regulator (EVR) controls the opening and closing of the EGR valve. The EVR is an electromagnetic solenoid and should have between 20-70 ohms resistance between the pins. +12volts should be constant on one side from the EEC Relay, the computer controls the ground signal when EGR flow is needed.
When the EGR Vacuum Regulator (EVR) is off, both ports vent slowly to atsmophere.
To test it mechanically check to see if vacuum is present at the EGR valve with the electrical connector unplugged from the EVR. The top port should not have vacuum! Because that would open the EGR at the wrong times.
With everything connected and the engine running ground out the pin 33 side. The EGR vavle should open and the engine RPM should change. Read More
by Ryan M (Fireguy50) at
http://fordfuelinjection.com/index.php?p=43

=

EDIT:
SEE MY SITE @ http://www.broncolinks.com/index.php?index=146
for More Test LINKs... diagrams, etc.

Such as EVP Location pic in an 89 5(part of his valve cover and oil pan gasket job); Miesk5 Note EVP is light gray & attached to the top of the EGR Valve
Location pic in an 89 5.0 (part of his valve cover and oil pan gasket job); Miesk5 Note EVP is light gray & attached to the top of the EGR Valve
Source: by Waltman at SuperMotors.net
 

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mieske5;
i replaced the EGR w/ a new one. i had gotten 33 prior to replacement. got 34 after replacing. im thinking i set the EVR on wrong. ima check it out today so hopefully all goes good. n try to rid of code 44 as well; lookin for a leak etc..
 

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i have to start working on mine too. the factory oil pressure gauge stays at the L all the time. and temp gauge doesnt even move i already changed the sending unit and temp sensor. is there a good spot to mount gauges so it can be monitored.
 

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mieske5;
i replaced the EGR w/ a new one. i had gotten 33 prior to replacement. got 34 after replacing. im thinking i set the EVR on wrong. ima check it out today so hopefully all goes good. n try to rid of code 44 as well; lookin for a leak etc..
yo c_bko89

Opps, I got you mixed-up with da OP (bsnow71) somehow.
OK.. gl.. see the Vac Leak Test at end of this reply.


also, ever rule out a bad new part. See my Defective Parts post here; it includes, "Went to Autozone and got a new EGR solenoid - constant code 34/35 started showing up- Replaced it with one from NAPA"


Vacuum Leak Test; On an idling engine check for vacuum leaks using a mechanic's stethoscope with the probe removed, or a ~3' garden hose section. On COLD ENGINE only, use propane torch w/rubber hose attached, UNLIT or spray carb cleaner, when it gets to the the leak the RPMs will rise. Also check: vacuum hoses; intake manifold gasket & throttle body; Tree Location pic in a 94 5.8 Source: by joelb23 at SuperMotors.net; PCV pic by Bbronco311. Vacuum Reservoirs: EGR Sys Vacuum Tank & 2ndry air (looks like a coffee can in earlier years) Depiction & Location in Parts Break-Out Diagram in a 96 w/Ford part numbers by Ford via miesk5 at http://www.broncolinks.com/gallery_i...6TABTAB5.0.jpg; Thermactor Air Bypass Solenoid (TAB, AIRB, AM1) w/Pink vacuum line & Air Bypass Valve (AIR BPV) & Thermactor Air Diverter Solenoid (TAD, AIRD, AM2) w/Yellow vacuum line & Air Diverter Valve or Air Control Valve (ACV) see my site @ http://www.broncolinks.com/index.php?index=416 & EGR Vacuum Regulator (EVR); also called EGR Vacuum Solenoid & EGR Valve Position (EVP) - MIESK5 NOTE: EVP is used on all years except for 95 5.8L California models & all 96, they use the DPFE Sensor instead of EGR Valve Position Sensor (EVP) etc, see my site @ http://www.broncolinks.com/index.php?index=146. AC, heater, defroster, vent control ckt & vacuum tank (plastic ball, or an irregular box glued to the evaporator cover), under dash & lines to heat/blend/etc. doors; & HVAC vacuum reservoir; Vacuum Tank pic, Ford part number 19A566; on side of evaporator housing by Ford via miesk5 at FSB. Carbon Canister (Charcoal Canister, Vapor Canister, Evaporative Emission (EVAP) Canister for the Evaporative System (see http://fullsizebronco.com/forum/atta...1&d=1315917794. & Line to & the power brake booster, Master Cylinder & Booster Location pic in a 93 by Steve83. ; and line to & Cruise Control sys in 86-91. Source: by miesk5 at http://fullsizebronco.com/forum/showthread.php?t=201323
 

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i have to start working on mine too. the factory oil pressure gauge stays at the L all the time. and temp gauge doesnt even move i already changed the sending unit and temp sensor. is there a good spot to mount gauges so it can be monitored.
yo thin blue line,
Run line from new sender (or Tee) through clutch blank and up to top of dash; I ran one along the instr cluster edge next to AC-Heater panel and to dash top
If you have the man shift BW 1356 Xfer case; you can mount the gauge to where the switch woule be placed for the ESOF xfer case
see gijoe4500's pic - place guage where indicator light and switches are shown.

or under dash or in an A pillar pod
 
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