No Oil Pressure..

[Cerulean]

This has been happening for a little while now.. I noticed that whenever I come to a stop my

oil pressure gauge in my 1990 Bronco, (351W), would competely go down

to the "L" in the red. I checked the oil, it was a little low so I

topped it off, but the problem continued. After a while it seemed to

get worse. Whenever I would slow down and stop the oil pressure gauge

went all the way down, the red Engine light would come on, and the

truck would start to sputter as though it wanted to stall out.

All these problems went away whenever I gave it a little gas, and

there were no problems at all when I was actually driving, only when I

stopped. It does it mostly when the truck is in Drive, though if I let

it idle in Park for a few moments the oil gauge and RPM gauge start to

go down then as well and the truck tries to stall.

Also, it doesn't do it at all until the truck gets fully warmed up,

reaching operating temperature. The first 15 minutes or so of driving

the oil pressure seems fine.

While I'm sure the truck is due for a tune-up anyway, I was hoping

someone may have encountered this before and could give me some

thoughts on what this may be caused from.

These are the codes I was able to pull. Any more thoughts or explanations of the codes themselves would be greatly appreciated. Thanks.

21: ECT out of self test range 0.3 to 3.7 volts.

24: ACT sensor out of self test range 0.3 to 3.7 volts.

33: EGR valve opening not detected.

12: Cannot control RPM during ER Self-Test high RPM check.

41: No HEGO switching detected always lean (right side).

52: Power steering pressure switch always open or closed.

77: System failed to recognize brief WOT during Dynamic Response Test (user error).

Please keep in mind, I am quite possibly the single most mechanically-challenged person on the planet, so feel free to explain things in as simple terms as possible when it comes to the engine... hehe

Thanks.

C.

 

[Seabronc]

That is a common problem with Broncos. When did you change the oil filter last? It can be caused by the bypass valve in the filter being open. I have heard numerous complaints about Fram filters and have had problems with them myself. I now use Baldwin filters and 20W50 oil, it goes low at idle but maintains about 5 lb while hot and at idle. Acceptable readings, I am told is about 10 lb or better per 1000 RPM, which is what I get. The oil pressure sending unit which is located on the driver side, front, lower portion of the engine may be bad, (picture attached, the line coming off the T is to a wet oil gauge, yours will have an electrical connection on the top of the sender, I use both), it is notorious for going bad. Low, (main bearings and rod bearings), engine wear as well as the oil poump getting weak is another place that can cause low oil pressure readings.

If it is not knocking when you see the low reading, you at least have some oil pressure. I'd take care of the other problems associated with the codes you pulled also. I'd start with the EGR sensor and HEGO (O2 sensor).

Good luck,

>-

 

[mbtech2003]

i've always used 15w40gtx oil with never any problems!! i used 5w30 once and the lifters made some noise but that is before i put in the new cam.

 

[snowman74]

I use 10W40 Quaker State year round. I change every 3000-4000 miles. Been using Napa Gold oil filters...sometimes I use K&N filters, but who can afford those on a regular basis?

Fred,

Isn't 20W50 a little stout for the EFI 5.0 engines? I know your's has a carb. Just curious.

Snowman74 >-

 

[Seabronc]

I use 10W40 Quaker State year round. I change every 3000-4000 miles. Been using Napa Gold oil filters...sometimes I use K&N filters, but who can afford those on a regular basis?
Fred,

Isn't 20W50 a little stout for the EFI 5.0 engines? I know your's has a carb. Just curious.

Snowman74 >-

lots of people use 20W50, both engines here are 351, but I can't think of any reason it would be too heavy for a 302 or why a carb vs EFI would make a difference. It is probably too stiff for real cold weather like in your area or even here on a real cold winter morning.

>-

 

[snowman74]

The reason I thought the carb engine might make a difference is because of speed density programming on the 5.0 engines...I think Ford recommends 10W30...not certain...but wouldn't the original engine set up be affected by getting the oil too thick? Just a thought.

Snowman74 >-

 

[Seabronc]

The reason I thought the carb engine might make a difference is because of speed density programming on the 5.0 engines...I think Ford recommends 10W30...not certain...but wouldn't the original engine set up be affected by getting the oil too thick? Just a thought.Snowman74 >-

I seriously doubt that it will matter. I'm certainly no authority on oil and can only act based on what I have read. It certainly works for me. I tried different things and am currently following the suggestions of a site the does a lot of testing and has years of practical experience as far as oil and gas goes. I haven't implemented all of their suggestions yet, but every time I do work in one of their suggestions, I have been very satisfied with the results.

http://www.lubedev.com see the article labeled "Great Mileage with Lubricity "

>-

 

[mbtech2003]

5-20 and 5-30 are reccomended but as allways its mostly your climate. ford says these for better fuel millage.

 

[broncobob58]

Mine does the same thing.The original owner said it happened to him and he had the oil pump changed but that didn't cure anything.I had assumed it was the sending unit on mine but I finally changed it and it had no effect,the engine doesn't knock and most driving conditions the gauge registers 1/2-5/8 of the way.I noticed for a long time it doesn't do it until the oil gets really nasty and it's been drive for awhile and at idle in drive.

 

[Seabronc]

5-20 and 5-30 are reccomended but as allways its mostly your climate. ford says these for better fuel millage.

That is news to me, what manufacturers spec that and for what year vehicles. I don't know aof any Bronco owner that uses that light viscosity oil, sort of like sand, but if that is what works for you, .

>-

 

[Desert Bronco]

This has been happening for a little while now.. I noticed that whenever I come to a stop myoil pressure gauge in my 1990 Bronco, (351W), would competely go down

to the "L" in the red. I checked the oil, it was a little low so I

topped it off, but the problem continued. After a while it seemed to

get worse. Whenever I would slow down and stop the oil pressure gauge

went all the way down, the red Engine light would come on, and the

truck would start to sputter as though it wanted to stall out.

All these problems went away whenever I gave it a little gas, and

there were no problems at all when I was actually driving, only when I

stopped. It does it mostly when the truck is in Drive, though if I let

it idle in Park for a few moments the oil gauge and RPM gauge start to

go down then as well and the truck tries to stall.

Also, it doesn't do it at all until the truck gets fully warmed up,

reaching operating temperature. The first 15 minutes or so of driving

the oil pressure seems fine.

While I'm sure the truck is due for a tune-up anyway, I was hoping

someone may have encountered this before and could give me some

thoughts on what this may be caused from.

These are the codes I was able to pull. Any more thoughts or explanations of the codes themselves would be greatly appreciated. Thanks.

21: ECT out of self test range 0.3 to 3.7 volts.

24: ACT sensor out of self test range 0.3 to 3.7 volts.

33: EGR valve opening not detected.

12: Cannot control RPM during ER Self-Test high RPM check.

41: No HEGO switching detected always lean (right side).

52: Power steering pressure switch always open or closed.

77: System failed to recognize brief WOT during Dynamic Response Test (user error).

Please keep in mind, I am quite possibly the single most mechanically-challenged person on the planet, so feel free to explain things in as simple terms as possible when it comes to the engine... hehe

Thanks.

C.

 

[Desert Bronco]

sorry about the Duplicate replies.

I just got my Bronco out of the shop for a complete head gasket job, and replacement of Valve lifters and cam shaft this morning. When i took it home to drive it, i noticed the EXACT same thing happen to the oil pressure gauge, then the truck stalled out while I was driving on the highway. Now its back in the shop and they are going to replace the oil pump, and possibily the rods and bearings. i would be interested to find out what happens if you get this solved.

 

[Cerulean]

I apologize for this waaaaaaaaay late reply. My computer blew up on me and I had to replace it and this kind of slipped my mind along the way. Again, I'm very sorry.

Good news though. All it took to fix my problem was a good old-fashioned oil change. Apparently the cruddy generic oil filter that the local quickie oil change place put on last time I had it done was... well.. cruddy and generic. I replaced it with a good Fram filter and replaced my oil (also cheap stuff from the quickie place.. ugh) with some name brand 20w-50, and I haven't had the problem again since. Though I haven't driven it very far since then. Planning a trip this weekend though so I'll let you all know if the problem comes back, indicating something else being the problem.

Sorry again.

C.

 

[bidibronco]

I'm glad someone brought this back up... it reminds me that the sweetie pie needs an oil change here soon.

 

[89Bronco58]

haha hey man dont beat yourself up, no need to apologize about the late reply, stuff happens. But glad you got it fixed, gotta love it when a seemingly big problem turns out to be soemthing super simple

 

[MatteF150]

This is a huge help!!!!

 

[MatteF150]

I've been chasing this same issue for 2 months bow

 

[nelbur]

Seabronk's reply in post #2 is hard to improve on, but it has been diluted to the point I feel someone needs to repeat that "this is a common problem with Broncos".    Actually it is a common problem with well worn engines in general.   When an engine's bearings wear, the increased slop in the bearings make it difficult for the oil pump to pressureize the oil system, particularly when the oil is hot and thin, and the engine is idling.    If you have this problem it just means that you need to ignore all the advice about "I use **W** oil in my Bronco, and determine what viscosity YOUR engine needs.   Start off by buying a quality oil filter as it will pass more oil than the cheaper filters with less filter area.   You then are looking for an oil thick enough to slow the leak from the worn bearings.   I would try a** W50 oil to see if it solves your problem as it is the thickest commonly available oil.   The 20W50 dino oil might be a problem in very cold, sub zero, weather.   If you live in such an area you can either use synthetic oil or see if 10W40 is thick enough to give some oil pressure at hot idle.   You do not need much oil pressure at idle but you need enough to **** the valve train and keep the lifters filled up.   Generally you will have plenty of oil pressure at cruising RPMs, and an engine can typically go a long way with this condition.