ENRKyle20

I was driving my Z just now and I have been havin a problem not getting over 5500rpm in 1st great (rev limiter is set at 6800) So for the first time I tried revving it with the clutch in (in hopes that it would making me think that the ignition was ok). SO i did rev up just fine to 6800RPM.. So I kept driving, 30 seconds later or so I notice the check gauges light come on, I checked the gauges and everything looked fine. Then it went out. 10 seconds later it came back on, gauges looked good, then it went off. I figured it was something to do with the fact that I just spun the motor way over the gauges red line and it was telling me. Then it happened again, this time I had no oil pressure. So I switched the car off and pulled over. I checked the oil level and it was fine. I also checked the oil pressure sender to be sure the wire was hooked up and it was. So I tried starting it and it started fine, but the lifters were ticking telling me there was indeed no oil pressure. So I called a tow truck and got her home.


No a few things come to mind. First, why the heck didn't the fuel pump shut off, I thought these cars were wired to kill the fuel pump with no oil pressure?.. is it timed and It was not low for long enough to kill the pump?


Next what went wrong. I did not replace the plastic oil pump drive thing, wish I did. I hope that is the problem. If it Is I can avoid taking the pan off and just get to it with the intake manifold off. fishing any broken parts out with a magnet or something with grease on it to the stick. I fell like if that is what broke it would act exactly how it was, not a clean break right away, it broke and somehow kept turning the pump a little, when it caught.. then it didn't grab anymore. That sound logical?

the only other option I can think is maybe a oil galley plug came out? any easy way to check this? There is no oil leaking out under the car at all, and the level is still fine.

BTW, the motor has a hair over 700 miles on it, I have drove it fairly rough, up to 5000rpm, and a little past sometimes when it does not misfire.

Thanks


Edit. I hope its not a spun bearing. I would imagine it would be hard to crank over, and I would hear something if this was the case correct? I mean I did hear something but it was pretty distinctive oil less lifters



Also. I am running 10W30, cold pressure is about 65-70 or a bit higher, then it steeles about 55-60 unless im at low rpm, then it about 25.



something else im thinking about is.. the plastic that holds the distributor dummy gear in was cracked, could have broke completely and worked it way off the cam gear. either way, intake manifold is coming off. I will be able to spin the pump with a drill then and see if I'm getting pressure.

Injuneer

There is no interlock between the oil pressure sensor and the fuel pump on the F-Bodys. I think that only on the Corvettes. And the "check guages" light does not come on because you put the tach above red line.

shoebox

Probably the oil pump drive. You installed a cracked drive in a brand new engine? If you are also using and HV oil pump, that can cause oil pump drive issues, too. Spinning to 6800 with inadequate oil pressure is likely to cause bearing damage. If it does not show up now, it may very soon.

mzgp5x

I noticed a problem with the oil pump drive retainer (Plastic piece with single bolt) under the intake manifold. The fastener can come loose, thus, allowing the drive shaft to lift due to cam drive load. This can cause it to become disengaged under load. Result... no oil pump drive. I lock tite all fasteners with red. Yes, I do not like the gm design. It is a high potential failure point (along with many others). Next time I'm in there, it gets modified so it can never come loose. Also, lock tite your lifter retainer spyder fasteners with red.
HTH. B. (97ss 383ci D1 MM6 Moser_12)

sbs

There is no "kill the fuel pump" functionality on the vette, either. Or any car I've ever heard of. I seriously doubt that DOT would allow a manufacturer to do that.

The vette does have an "if there's oil pressure then enable the fuel pump" circuit, so if the primary fuel pump enable logic goes haywire while driving, the pump won't cut out.

sbs

That's what I thought he said, but then I thought 'surely I read that wrong'...

bw_hunter

I can show you a number of oil pressure senders for American cars that cut voltage to the fuel pump when the pressure drops below 2.5 psi. The J-cars, X-cars and whatever the Olds Cutlass was called all had them.

ENRKyle20

The shaft inself was not cracked. it was just the oil pump drive gear for the cam shaft, the bolt hole had a small crack it. I did use blue locktite on that bolt.




here is why i thought that the fuel pump would shut off, but I didn't look closely at why the oil pressure switch was there.

budgetlt1

[QUOTE=steve9899;6009535]There is no "kill the fuel pump" functionality on the vette, either. Or any car I've ever heard of. I seriously doubt that DOT would allow a manufacturer to do that.


lots of vehicle have an oil pressure cutoff where if oil pressure gets too low it will shut off the pump. its sort of like an early inertia switch. but no, the f bodys do not have this.

WS6T3RROR

Pull the oil filter off and then cut it open. Sometimes they can fail internally. Good practice right now anyway just to look for signs of damage.

A lifter galley plug could have blown out, they should always be tapped for pipe plugs during a rebuild imo. If this is true if your timing set isnt hurt consider yourself very lucky.

Until you do some pull and peek its all just wild speculation.

Injuneer

That looks like the Corvette schematic, not an F-Body.

http://shbox.com/1/1995_pcm3.jpg

shoebox

Right, that is not an f-body schematic.

ENRKyle20

AllData V10.10 says that's for my 95 Z28. I will check Mitchell On Demand and compare

Injuneer

If you want to argue about it, go right ahead. There is no oil pressure switch on an LT1 F-Body.

Also not so sure why "DOT" would not permit the fuel system to shut down on loss of oil pressure. The LT1 fuel system shuts down (PCM cuts the fuel pump and injectors) when it loses the low res pulse from the Opti optical cam position sensor.

ENRKyle20

as i found out from experience. Either way even if that was the correct diagram (not sure if it is or not) the wiring diagram does not indicate that with no oil pressure the pump would shut off. Only that the oil pressure sender is seeing voltage from when the fuel pump is running.