93 Altima stalling at random

pretty sure the 73 was carburetted - if it stopped on a grade with low oil, most likely you had partial seizure. once it had cooled, it released and you were able to continue.

Reply to
jim beam
Loading thread data ...

not by your previously stated criteria it wouldn't - a switch can still "work" when pressure drops. but it can be out of spec as to /what/ pressure, and the diaphragm leakage mentioned by steve w is exactly the kind of situation that illustrates this.

on the subject of pressure, if you will be so good as to link to a tool that will test such a switch with regard to switching pressure, i will be much obliged.

Reply to
jim beam

Wait a minute, you're telling me that it's possible to have normal oil pressure in a '71 Vega?

---scott

Reply to
Scott Dorsey

GM S series P/U and Blazers, Full sized GM trucks. Nissan started it on many of theirs in the late 80's. Ford has used it on the F series from around 96 or so. Not on the diesels though. Most of the German makes have a dual system BUT 1/2 of the ones I have worked on don't operate until the oil pressure is down in the 1-2 pound range.

Reply to
Steve W.

The Vega powered the pump through the switch like some modern versions.]

Reply to
Steve W.

Having owned 5 of them through the years and a couple Monza and a "slightly" modified Starfire, The only one that ever had problems was a first run 71 with the original block. Once they started the Durabilt engines they were not a bad little car. For an Opel Kadet based vehicle. The real problem was the total lack of rust proofing and sealers. You could just about hear them rot....

Reply to
Steve W.

Having owned 5 of them through the years and a couple Monza and a "slightly" modified Starfire, The only one that ever had problems was a first run 71 with the original block. Once they started the Durabilt engines they were not a bad little car. For an Opel Kadet based vehicle. The real problem was the total lack of rust proofing and sealers. You could just about hear them rot....

Reply to
Steve W.

Yep they had a carb BUT an electric pump. They used the O/P switch to turn off the light and power the pump. That was a carry over from the Opel Kadet design they were based on.

Reply to
Steve W.

The astute observer will note that the posed inquiry related solely to "one specific model car" and the above response didn't explicitly delineate so much as a single example. ;^)

Reply to
Heron

I'm not an expert in this area but, except for tractors and Model Ts, most vehicles such as the Vega have a fuel tank well below the carburetor so a fuel pump is necessary for engine operation. Did I miss something?

Reply to
AMuzi

Yes, the Trabant! They mount the fuel tank directly above the engine so that no fuel pump is needed.

This is why the Trabant is the most reliable car in the world. It has no radiator, no water pump, no fuel pump, no valves, valve train, or timing belt. There's nothing to go wrong except for catching fire a lot.

--scott

Reply to
Scott Dorsey

danielle, i'm sorry you decided to leave san francisco. but somehow, we all seem to manage without you. it's like you were never here.

Reply to
jim beam

i never really understood this on carburetted cars. with a mechanical pump, if you crash and the motor stops, you stop pumping gas. with electric pumps and the engine stops, it just keeps on pumping, potentially into a nice toasty engine compartment. unless you introduce more complexity/potential unreliability in the form of an inertial switch.

Reply to
jim beam

The ENTIRE line of GM S series from 1989 - end of production. That would be the S-10, T-10, S-15, T-15, Blazer, Jimmy, Bravada That specific enough?

Reply to
Steve W.

Isn't my newly established leg-humper precisely reminiscent of the never having anything of actual value to contribute ignored child, flailing his arms and screaming "PAY ATTENTION TO ME!".

Reply to
Heron

Is it the definition of the word car, as opposed to truck (or, by another term, sport utility vehicle), or the ability to parse the english language in general, that has you so flummoxed?

Reply to
Heron

Or even easier, power the fuel pump off a Tachometric relay running off the coil.

Cheers Dre

Reply to
Dre

even simpler yet! not.

personally, i'm all for electronic fuel injection where the computer runs the show. the computer is "complex", but is solid state, has a very low failure rate, and can be relied on much more than any electro-mechanical device.

Reply to
jim beam

"dear danielle, my 'friend' thinks she might be fat and has no [other] friends because she blames them for her being ugly. what should she do? signed: still living in mom's basement."

danielle responds: "dear mom's basement, your 'friend' is simply being dishonest if she's blaming others for her own faults. the first step to recovery is to end the denial, get out of that basement, and look forward to the onset of puberty with the hope that with it, the personality carbuncles currently afflicting them might pass."

Reply to
jim beam

Specific enough.

S-10 Tech:

formatting link
This is Tahoe, no chart, but I'll bet the same circuitry logic.
formatting link
One guy: "Yes they do. In fact most vehicles since about: 1988 have them. It is usually a function of oil pressure, meaning that if oil pressure drops below a predetermined level (usually about 6-8psi I think) it will cutoff power to the fuel pump." Different guy: "Completely wrong. The fuel pump oil Pressure switch is to provide power to the pump if the pump relay fails. If everything is working correctly and you lose oil pressure the only thing that will shut the engine down is when the engine locks up."

Pretty good discussion, some disagreement.

formatting link
Another explanation of the OP switch providing redundant power only.
formatting link
Here's my conclusion, take it or leave it. Except for the Chevy Vega, I haven't seen an OP switch fuel pump shutdown on common motor vehicles. Don't know about buses. On the vehicles you mention, a bad OP switch will only shut down the fuel pump if the pump relay is already bad. It's designed as a redundant power source, not for pump shutdown. There's always the odd stuff, like a shorted/grounded switch which screws the ECU circuits. Sometimes that's heat-induced, so checking/replacing the OP switch isn't a bad idea - IF THE FUEL PUMP ISN'T RUNNING. No idea if this GM OP switch circuitry relates at all to the Altima. Since the Altima was quitting (as I recall) after 5 minutes of running, a gage on the fuel rail easily would have told that story.

Reply to
Vic Smith

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.