loss of oil pressure

I have a 1990 bronco 5.8 i put a new timing chain , oil pump & oil switch. In reverse after driving for a minute oil pressure gauge which is stock drops to LOW from the M in NORMAL which is half way from HIGH and the check engine light comes on.But when i put it in drive it goes back up to M and back & forth between M&R but doesn't drop back to LOW positive replies please??? this is the best way i can describe whats going on.

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i have a 1990 bronco 5.8 i put a new timing chain , oil pump & oil switch in reverse after driver for a minute oil pressure gauge drops in drive its up and down sum 1 please help ?

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The best I can decifer out of this is that it drops in reverse, and jumps up and down in forward. Sounds like it is jumping all over the place.

Maybe an erratic engine speed with marginal bearings (he replaced his pump), a bad sensor, or loose wires.

Comments not considered POSITIVE enough have been deleted. My apologies, the intention was not to post STUPID A-- NEGATIVE SH-- replies. I can *assure* you that it will not happen again, and once more I apologize. Best of luck with figuring things out.

post deleted

firstford said:

i have a 1990 bronco 5.8 i put a new timing chain , oil pump & oil switch in reverse after driver for a minute oil pressure gauge drops in drive its up and down sum 1 please help ?

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I believe your truck has an oil switch rather than a sender. If the switch or it's connection is poor it will cause the gauge to read eraticly. If you put Teflon tape on the threads of the switch it will not make good contact. When Ford went to the oil switch in place of the sender unit, it was a step further backward in regard to a usable instrument. All an oil switch does is show a middle gauge indication when it makes to let you know you have an oil pressure of 5 PSI. Most people who get frustrated with the Ford gauge go to a separate wet gauge. That is the only way you can get a reasonable feel for what the pressure actually is. The better quality gauge the more accurate the reading. as a general rule of thumb 10 lb per 1000 RPM is what you are looking for. The pressure will drop some as the oil heats up and thins out so on the wet gauge you will see it drop at idle and increase at cruise speed. If it appears to be low you may have worn mains. or just a oil filter stuck in bypass mode. Use good filters, avoid Fram, I use Baldwin which is one of the premium brands and used quite extensively in heavy equipment.

Good luck,

>-

Thanks seabronc that was helpful. ALL THE NEGATIVE SH-- YOU GUYS COULD'VE KEEP IF YOUR NOT GOING TO HELP DONT MAKE STUPID A-- REPLY some of us might know alot of this stuff.

this topic, and my response, has obviously caused alot of inrest. I did not mean to offend antone, nor start an arguement about the grammar, spelling, or lack there of of the original post. I also do not believe that a reasonable nor constructive answer can come out of a question that is not properly worded to a point where no one can understand it. My comment was solely for the purpose of having someone ask a question in such a manner that it could be responded to with a legitimate response that would help not only the person that asked, but also anyone that looked it up on the past as well. I did feel that this site was not only one of learning and help, but also of free speech and opinion. If I am to be repremanded for asking someone to ask a clear question, Instead of having enough skills to not only find a PC, pull up a search engine, Find us online, and then register, yet not be able to type a perfectly good question in english?, then I no longer want anypart of this forum. So for the moderator that felt so empowered to warn me about MY OPINION, delete my account. Because my opinion is just that. Mine. And I will not opologize nor recant, just because someone doesn't like it.

firstford said:

I have a 1990 bronco 5.8 i put a new timing chain , oil pump & oil switch. In reverse after driving for a minute oil pressure gauge which is stock drops to LOW from the M in NORMAL which is half way from HIGH and the check engine light comes on.But when i put it in drive it goes back up to M and back & forth between M&R but doesn't drop back to LOW positive replies please??? this is the best way i can describe whats going on.

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And all do apologies, but it sounds like more of a short in the electrical than an actual oil pressure problem. If you have acess to an actual oil pressure gague you can hook up manually, you can find out what is really going on. The factory gagues never have been the most reliable, and with a manual gague, you can get the best info to work with

So, if I might ask a question relating to the subject..

On a PSI gauge, what are good pressures for idling and cruising?

I have a minor leak in the back of the transfer case, and want to know if/when it's out of control..

& knowing ideal pressures would tell me just that.

Thank you.

jstevenson509 said:

So, if I might ask a question relating to the subject..On a PSI gauge, what are good pressures for idling and cruising?

I have a minor leak in the back of the transfer case, and want to know if/when it's out of control..

& knowing ideal pressures would tell me just that.

Thank you.

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As a rule of thumb, 10 pounds per 1000 RPM. As long as the truck has more than 5 PSI at idle you should be OK. Don't forget the accuracy of some gauges isn't that great so if you want to really know get a good one. Check the responses above.

Good luck,

>-

Thanks for positive replies i was frustrated on the first message that why it was short and it was my fault for not being more detail. I've had the truck in 2 shop everybody in shops down here are in to newer models. Thats why i reach out to you guys because these is my first bronco and its alot i dont know but trying to learn.NOW THAT IM THREW SOUNDING LIKE A WHIMP IM GOING TO GO DRINK A BEER HUG MY WIFE AND KISS HER SISTER LOL thanks guys.

A GOOD oil pressure depends on a number of variables. Primarily what the revs are and whether you're using synthetic or natural oil. Synthetics tend to run at a lower pressure since they're more"slippery" than natural oils. Having a guage that gives you *actual* numbers is an important part of the equation. Now, having said that understand that the transfer case is two steps removed from the engine and *any* leakage there will have NO effect at all on the engine oil pressure. Many transfer cases leak, as a general rule the best thing to do is ck the fluid level, make sure it's level with the fill hole and then forget about it. If it's dropping a LOT of fluid that's one thing, but a small leak can be safely ignored as long as you ck the fluid level on a regular basis (ever month or two, depending on how bad the leak is).

Broncobill78 said:

A GOOD oil pressure depends on a number of variables. Primarily what the revs are and whether you're using synthetic or natural oil. Synthetics tend to run at a lower pressure since they're more"slippery" than natural oils. Having a guage that gives you *actual* numbers is an important part of the equation. Now, having said that understand that the transfer case is two steps removed from the engine and *any* leakage there will have NO effect at all on the engine oil pressure. Many transfer cases leak, as a general rule the best thing to do is ck the fluid level, make sure it's level with the fill hole and then forget about it. If it's dropping a LOT of fluid that's one thing, but a small leak can be safely ignored as long as you ck the fluid level on a regular basis (ever month or two, depending on how bad the leak is).

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Thank you Bill & Seabronk,

It was sitting for 2 days after a full day of driving, and the leak made a triangle about 4 inches tall and 3 wide at the base..

Sorry, I know this is vague for you, how bad do you think that is? It barely barely leaks when the engine's been cold for awhile.

Levels are fine.. I'll be sure to keep up on them, thank you, and would you recommend synthetic or regular with the leak?

I'd be inclined to go for natural just because it's cheaper..

Thank you!

Synthetic will find a leak anywhere possible. Now, are you leaking out the back of the t-case or engine? I'm confused? (sorry, I'm not that intelegent as you can see) As long as you stay on top of your levels you'll be fine, just don't run your truck out of fluid? Cool beans my man, cool beans!

jstevenson509 said:

Thank you Bill & Seabronk, It was sitting for 2 days after a full day of driving, and the leak made a triangle about 4 inches tall and 3 wide at the base..

Sorry, I know this is vague for you, how bad do you think that is? It barely barely leaks when the engine's been cold for awhile.

Levels are fine.. I'll be sure to keep up on them, thank you, and would you recommend synthetic or regular with the leak?

I'd be inclined to go for natural just because it's cheaper..

Thank you!

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That's not much of a leak (at least not to me, but I'm not a clean-freak).

I would unquestionably go with a synthetic, especially in the transfer case where you only need 2-3 qts. Natural oils ARE cheaper to purchase but in the long-run you're better off with a synthetic. When you weigh the advantages that you get with synthetic over the cost of natural it's a no-brainer. The only rub would be Bidi's comment. Synthetics *are* a lot "slipprier" than natural oils and will find every weak spot. An engine, tranny or Xfer case that was tight with naturals will sometimes (not as often now as when they first showed up) sprout a leak and an existing leak can become worse. But this does not ALWAYS happen, so it's definately worth the $15 to pick up 3qts of synthetic ATF and try it out. It will extend the life of the transfer case and make shifting much easier (by making the shifting easier it also extends the life of the electric shift motor & the linkages). In the end it's worth doing.