chad911sc

Just purchased a 1998 C5 and motor runs excellent. Drove it 3 hrs home but could only go 80 mph due to the F45 suspension codes and also the oil pressure gauge not showing anything. It goes up over half way when turning the key on then back to 0 and that is where it stays entire time the vehicle is running. I know it has oil pressure it runs perfect and purrs like a kitten. What should I check first? Sending unit, wiring ect.... Thanks for any help, Chad.

tblu92

Almost always when the sending unit goes bad ( and they always do) the oil pressure gets stuck at 80 PSI----Never seen one stuck at "0" but it has to be the gauge or sensor
You can also read the oil pressure on the digital gauge screen on the dash by scrolling thru all the other gauges such as trans temp-oil temp coolant temp etc
PS: There IS a built in safety device in your computer that will automatically shut the engine OFF if the oil pressure goes below like 3 PSI---

73Corvette

If you do a search in the TECH forum on OPS replacement there are a ton of threads with various options and the DIY's... remove manifold, access port, it can be done by mechanical prowess...
here is one of the bigger threads

https://www.corvetteforum.com/forums...-relocate.html

The relocate is recommended because of where the OPS lives... it's a very hostile place for a pretty high tech little component. The heat usually gets them...
it's just a gamble... the new one might last for another 10 or 20 years or it may last 10 minutes and you have to do it again IF you don't do the relocate... not saying it CAN'T go bad even if you relocate, but it should be much simpler to change the next time... if there is one.

lionelhutz

Try the sensor replacement first. Actually, make sure it looks plugged in properly first.

I don't think there is....

73Corvette

If you just do the replacement be sure you don't OVER TIGHTEN the sensor... you can crack or destroy the new one just putting it in...

chad911sc

after spending the morning reading the different ways of changing the sender I think I am going to do the hole in the cowl methed and buick sensor change out. Great info on the site!! By the way on the digital dash reading it is showing XXX does this run off of the same sensor as well? and will the buick sensor show the digital reading as well if changed over?

Chad.

73Corvette

1 yes I believe so...
2 I don't have a clue...
If you going to do a neat job of the access port... would you post pics that it CAN be done neatly?
If your relocating any of the OPS should work fine...I will be watching to see if the Buick Sensor shows the DIC pressure also...I don't think it would mentioned as an alternative or replacement part unless it did...
but, stranger things have happened.

73Corvette

FYI ... things change, when I first started on the forum I thought there is NO way I would pull the intake manifold off as opposed to the other methods... I am pretty old school and have never seen one off in person.... after over a year on the forum and seeing how it seals as opposed to the old nasty troublesome gaskets... it looks like it's actually a fairly simple way to do it...SO, I probably would pull the intake now myself rather than the other methods and DO the relocate... just sayin.
At one time I vehemently defended the access port method... and had actually tried the replacement method (without success) I know it can be done I just couldn't do it.
From all indications, if your much of a shade tree it only takes about 15 to 20 minutes to take off the intake and then you have FULL access to everything you need to get at and even some room to look at other things that tend to be issues that live behind the intake... anyway... Good luck be looking forward to hearing how it turns out for you.

lionelhutz

Yes, its really easy to pull the intake. I don't understand cutting the car just to avoid pulling the intake.

73Corvette

I didn't either, but nobody took the time, that I remember to explain WHY...
Maybe I couldn't see the forest for the trees...although it seems pretty obvious to me now that the manifold removal is a piece of cake and there are some other benefits to doing the removal...
I guess the biggest concern I had heard or thought about myself was trying or messing with re- installing the manifold more than the removal...
The possible problems with...Leaks,Cleanliness, pinching wires, getting it back on RIGHT... but, it appears that most of that isn't really an issue... if your conscience and careful.
I haven't been able to find a GOOD video of the C5 Intake Manifold removal... it would be cool to actually see someone do it.... it might not be so intimidating and take some of the fear of doing it out and make the access port a thing of the past...

BigGun

There is no safety device like this on a C5. There are also several reports of the sensor failing at "0", mine was one of them. If the oil pressure gauge on the dash doesn't read correctly the digital reading will not work correctly either.

tblu92

OK looking into this more deeply---In EFILIVE they do show a low oil pressure table----You are correct It will not shut off the engine --But it will flash a "low oil pressure warning " on the dash----Not quite sure if this warning will put the engine into " reduced power mode " mostly because I have never seen this warning---But at the least---you will get a "low oil pressure warning" if the pressure drops below the values in your stock tune-- normally between 0 and 15 PSI at idle

73Corvette

Even most of the older cars had idiot lights on them... usually by that time it's almost or is TOO late I wonder why they STILL put dipsticks on them?

chad911sc

Yeah I read the manual last night and it said that there would be a warning if oil pressure was low. I wasn't really worried about it not having oil pressure because it runs far too well to have any oil pressure issues. I drove it 3.5 hrs home from where I bought it and it was 103 degrees outside temp. I have been around hi performance engines most of my life and can tell by ear if a motor is sick and dying or running in its happy spot. I wasn't really worried about pulling the intake off because lack of experience or time constraints its just I have been burned once by a piece of small metal bracket someone had previously engineered into a spot where there was not suppose to be and it fell down into the cylinder without me knowing until it was too late. Had to pull engine and well I'm sure you can figure out the rest.:-( I am going to be putting in a new A\C compressor, dryer and filter very soon as well so might as well just do the intake too and clean out everything. Thanks for all the chatter guys its always better with more minds involved.

73Corvette

I hear ya... I think if and when I have to do mine I'll probably put some masking tape over the intake ports... and any other possible OH $H1+ Moments