will faulty oil sending unit cause fuel pump to shut off

**98z28duval** · 09-12-2007, 01:01 PM

I have a 1998 Automatic Camaro Z28 LS1

...will the ecm shut off the fuel pump if it reads very low oil pressure for more than a few seconds? ...which stalls the car.

the reason i ask, is i am stalling out while in drive and after car is warm, at stop lights or when i am turning very slow.
bought the car a few weeks ago, oil pressure gauge was pegged out, a week later the car lot replaced it with a unit from napa. after - and positively only after this - is when the 'warmed up stalling while in drive and stopped at a light', issue started. the car was fine before. the engine is very strong and sounds good. no noises or signs indicating any sort of oil starvation. oil level is fine. the week i had the car with the pegged out guage, the car would have freakin' seized up on me that week if something was catastrophicly wrong with the engine, i drove it every day and no signs of any trouble.

i took it to MY mechanic, he knows the situation and he said(without testing it) - that the unit is faulty. ...so the car lot has ordered one from the dealership, and will be installed tomorrow.

will the ecm shut down the fuel pump if it detects low oil pressure for more than a few seconds? this makes sense doesnt it?

**0rion** · 09-12-2007, 10:45 PM

I can't recall ever reading anything like this and I've never ran into it myself. My gut tells me no (and it's a fairly large gut

) because people have had very low oil pressure from a spun bearing with no stalling. My first thoughts would be that when they put the intake back on after changing the sending unit the first time they messed up somewhere. Have you checked for vacuum leaks?? Either way please update the thread and let me know what the final word is.

**98z28duval** · 09-12-2007, 11:05 PM

the car lot called today and am taking it in saturday, everyone is convinced it is the oil sending unit, except me. ...i feel the same as you, a gut feeling. but regardless it has to be a result of something done when they replaced the pegged out unit.
i have read that the units have a fail safe that shuts the fuel pump down but there seems to be people on both sides of the fence, "yes it does" crowd and "no it doesnt" crowd. ...so, i dont knowww!! im in the dark. this is crazy i just want my new car to run like it did before the lot screwed with it and it not cost me in the long run to fix THEIR screw up! will post the results after i get the car back saturday afternoon, hoping for the best!!!
thank you for the reply and interest! love the site!

Originally Posted by 0rion

I can't recall ever reading anything like this and I've never ran into it myself. My gut tells me no (and it's a fairly large gut

) because people have had very low oil pressure from a spun bearing with no stalling. My first thoughts would be that when they put the intake back on after changing the sending unit the first time they messed up somewhere. Have you checked for vacuum leaks?? Either way please update the thread and let me know what the final word is.

**0rion** · 09-12-2007, 11:08 PM

I looked in my haynes manual and the oil level sensor shares a ground with the fuel pump relay but I didn't see the oil pressure sensor anywhere on there but it's late, I'm reading by lamp, and I'm tired.

**98z28duval** · 09-13-2007, 11:31 AM

same here, found out a few mins before i logged on here, youre correct its the oil LEVEL sensor that ties into the fuel pump not the sending unit. thanks for that bit of info!
ok...a little update. the coolant temp sensor was replaced, this has STOPPED the stalling. totally. it does not stall at all now. so the coolant sensor was the cause of the stalling evidently.

...the guage still reads weird when the car is fully warm to 210, the pressure on the gage drops to 0 for a second when stopped at a light and then bounces back to say 15-20 (the needle is kind of "jumpy". this does seem like the unit they had put in is faulty. engine is making no noises and oil level, coolant, etc all remain to be fine.
saturday when they replace the sending unit guess we'll know for sure.
the waiting sucks :/

Originally Posted by 0rion

I looked in my haynes manual and the oil level sensor shares a ground with the fuel pump relay but I didn't see the oil pressure sensor anywhere on there but it's late, I'm reading by lamp, and I'm tired.

**0rion** · 09-13-2007, 08:15 PM

yep, I shoulda caught that one. I was focusing more on the oil pressure. Something is definitely up there. I would get it taken care of asap though. If it's not the sender that's faulty and it is your oil pump going out it won't take long to do some bad stuff to your motor. When you hear it making noise it'll be to late.

**98z28duval** · 09-13-2007, 08:20 PM

leaving it with the car lot tomorrow afternoon so their mech can get on it first thing sat morning.
hoping its just the unit! i will update for sure saturday after i get home with it.
thanks for everything man!

Originally Posted by 0rion

yep, I shoulda caught that one. I was focusing more on the oil pressure. Something is definitely up there. I would get it taken care of asap though. If it's not the sender that's faulty and it is your oil pump going out it won't take long to do some bad stuff to your motor. When you hear it making noise it'll be to late.

**0rion** · 09-13-2007, 10:04 PM

no problem, keep me posted as to how everything works out for you. Got fingers crossed that it was just a bad sender out of the box.

**98z28duval** · 09-15-2007, 09:33 AM

took the car in this morning. they replaced the sending unit, but also found a vacuum leak!! took it out and drove it down I-10 for about 40 miles. the pressure does not drop to zero! i am now thinking the sending unit was not faulty, and it was the vacuum leak that was causing the sudden drop in oil pressure at stop lights. make sense? car lot was great the replaced everything at no charge.

when cold the car is a little over 40psi, when warm to full operating temp when i stop at a light it's at 20, a bit low, but within the 10psi per 1000rpms spec. down the road i'm thinking it may need an oil pump. but all the issues for right now are resolved. car is running great!
thanks for all the help man and any opinion on the above is greatly appreciated!!! i can breathe again!

Originally Posted by 0rion

no problem, keep me posted as to how everything works out for you. Got fingers crossed that it was just a bad sender out of the box.