this is to my thirdgen veterans/experts will a drop in oil pressure to less than 4psi (as far as the computer is reading if the sender is bad) cause the FP to shut down and kill the engine?
yes or no?

 

No, the computer has no response to an oil pressure drop. It would just let the engine seize.

 

o.k. then I have a problem I was going down the road at about 80 when I had a total power loss (as far as the engine) no throttle response or anything until I let off the gas pedal then there a slight rev and the rpm gauge moved then nothing again.

then when it got down to about 45mpg the car cam back to life and ran normally until I got to about 70 then it did it again. no skipping no nothing. once again when it got to about 40 it roared back to life. I didn't turn the key off and back on or anything so please give me some things to check I'm sure somebody has had this problem before.

 

I posted in your other thread. I have an issue like this in my carb Bronco but it's because my engine is cold and it basically 'floods'. I stomp the pedal to the floor and it pops and chugs a little then nada. But if I take my foot off in time it comes back to life.

I would check your fpr for a leak.

 

fpr? what is that?
I feel like a dummy fuel pressure regulator
where is it located?

 

fpr = fuel pressure regulator

A drop in oil pressure could cause that problem, but there's only one reason why: The fuel pump relay is not functioning - in which case the oil pressure sending unit (OPSU) will take over control of the fuel pump and run it as long as there is oil pressure - so if the relay went bad, and the OPSU was bad, then that could possibly happen - since in that case there's nothing steadily controlling the fuel pump. It's not necessarily a drop in oil pressure as much as it is an instance where the OPSU isn't sensing oil pressure regularly as it should.

Another possibility, a clogged fuel filter. Sometimes, you'll get grime in the fuel filter (where it's supposed to be) ... but that grime can move around inside the filter. On low accelleration, the grime might settle to the bottom of the filter. But on higher accelerations, the increased fuel flow can 'pick up' that grime and clog the filter exit, reducing the pressure/flow. This can happen alot in a carbed car, since the mechanical fuel pump increases and decreases fuel flow with engine needs.

But, in theory ... since a FI car's fuel pump actually pumps the same amount of flow always, and the unused fuel is returned to the tank by the fuel pressure regulator, this 'picking up' of the dirt in the filter shouldn't occur - the fuel flow/pressure from the pump should be constant, and so if the dirt was to clog, it should clog always. But ya never really know.

 

thank you both for your help!! I will check the fuel filter, fp relay, opsu, fpr, and all. ohh and I did not have to shift into neutral and re-start the car while it was coasting. after it got down to about 45mph the car just came back to life. I will try to check this weekend.

 

I searched the haynes last night and from what I can see the fpr is under the throttle body AKA it has to be taken apart. please help I am handy with tools but never dealt with that before.

I drove it last night (under 65mph) w/o incident. and your right I unplugged the FP relay and it still fired up (took awhile ) but it did start and run. a little rough at first then it smoothed out.

A man told me that the car would only get about 85mph and then some type of limiter would kick in and make the car seem like it was dying until it comes down to a lower speed and rpm. But to be sure the car is supposed to do better than 85mph not only that but the second time the car did it I only made it back to 70mph any help is appreciated.

edit: the more I read the more it sounds like this "speed limiter" the tires I have on it came off of a 91 z28 so I don't know what the original tires were when i bought the car it had some dinky little 15in. tires on it (I hated them) I don't know what the orig. were. I have a way to test though I will drive it at 65 mph and see how long it rolls with no problem then I will kick it to the limit and see how long it goes before it hits the wall and report back.

unless yall say that won't work. Also will check the casting numbers this weekend. ohh I don't think these are the orig. gears either (pulling well over 3000 rpm at 70mph in final drive gear.

 

The speed limiter is set much higher - like 125mph - so that's not an issue.

It's quite possible your tach could be off as well - none of these gauges are very accurate.

15" wheel or 16" wheels won't make any difference.

 

o.k. one last time before I go home for the weekend and beat my head against the wall
1. check the casting numbers
2. try to blow thru the fuel filter
3. unplug the opsu and see if the fp relay is working
4. egr valve
5. see what gearing the rear has in 1:1 mode (70mph in 3rd not OD)
6. pull the vacume line off the fpr and look for gas to run out
7. last but not least the thing I know the least about take the throttle body apart and look at the 22 year old fpr
ohh and I use premium gas

 

Took the car down i40 it did real good 1st I cheked 4 vacume leaks with throttle body cleaner. I got it to 70 in 3rd gear and it got to 4700Rpm then I shifted into od and it dropped to 3500rpm. I kicked iT to 90mph with no problems. Drove about 12mi and came back when I came off the exit it shut off. I tried to restart but nothing I checked to hear the fp it did not prime. Tried to crank it and after about 6 seconds the opsu started the car. Let run for 30seconds then turned it off and then it started priming. Then no more problems.

Something else while I was driving at 70 the rpm's. Dropped about two hundred rpm even afterbeing in od for awhile. Giving me a little extra power and running a little smoother.Somebody talk to me and thank you.

 

The last little 200-300 drop in RPM was your torque converter locking, which is what it's supposed to do.

 

Thank you now I think the fp relay is trying to go or the fuel filter is clogged possibly the fpr now if it were the relay the opsu should have kept it running so what happened? ohh and it is a 5.0l

 

will replace fuel filter today or tomorrow (cheap part)

 

ok first off Newbie don"t laugh at me but this is a funny situation I did all this beating my head against the wall for nothing. My car is STOCK so why I thought I had a major problem I don't know. I drove my car to work and let the fellas ooogle over it and crack jokes. I let one guy drive it he came back and said that had a skip. I told him that I know that it's got a slight hesitation in it but nothing like what it had.

well that started a conversation and I fired it up for some more of the guys and one said that he smelled RAW gas. meaning that not all the cylinders were firing and I said "but it has so much power" they said that it would probably have more if it were running right. I mentioned this to an older guy that used to mess with some the older GM stuff and fired it up for him. he smelled it too. then one by one he went thru the pulling of the wires one at a time. 2 cyl.s weren't doing anything I said I would check it out tomorrow but he pulled out no. 2 plug and low and behold there was NO gap. None. just a gas soaked plug.

now the engine is stock like I said so there was no way that the piston hit the stock plugs and still runs as good as does so it must have been when I was trying to get the plug lined up so that it won't cross-thread and was bumping it around. Instantly the power increased the slight hesitation decreased when snapping the gas pedal. I will wait for it to cool off before trying to get to no.8 plug which by the way I remember having a hard time with also. to all my want to be mechanics "You live and you learn"
one last thing "IF you never make a mistakes YOU are not doing anything"

DON"T LAUGH!!!!!!!!!!!!!!

Edit:
ooohhhhhh!!!!!!!!!!!! my goodness if this is a LO3 then what the heck kind of monsters do you 350, 383, and 400+ cu. in. owners have under the hood. maybe I'm being over dramatic but who cares I just did no.8 cyl. and of course it was the same thing NO GAP and this thing woke up. Absolutely no skipping, hesitation, stumbling, the engine doesn't even shake when you rev it up, and it takes nothing to break traction ON DRY PAVEMENT. how in the world do you BB owners hold these things on the road. Now it's on to the front end and interior.