1970s 1979 425 engine, won't stay running.

[NickD]

Problem:
1979 DeVille 425 carbureted engine. Engine starts and shuts right off. After a couple of ON/OFF cycles it will not even cycle, just cranks. I noticed that the oil pressure light does not go out. Does the vehicle have to be running for the light to go out or should it go out after cranking the engine a few times?

Background information:
I truly believe the car to be a 49,183 original mile car. I have numerous receipts and documents to support the mileage. Last oil change was 48,850 miles on October 29, 2006. The last time the vehicle was on the road was June 25, 2009, at 49140 miles. I have no idea how long it sat dormant. I do know that it was stored inside until about a month ago. The dealer that I got it from told me that it did run. He also told me that it ran out of gas and he put gas in it and now it won't stay running.

What I did so far:
I removed the oil pressure switch and installed an oil pressure gauge, cranked the engine and did not get a reading, the gauge did not move from 0 psi. I next changed the oil and replaced the oil filter. I cut the old filter apart and noticed a little sludge (about a tablespoon) in the bottom of the filter. The pleated paper inside the filter was intact. The old oil felt fine. I did not notice any metal whatsoever in the oil or filter. I also pushed the oil pressure regulator relief spring in and out to be sure it was not stuck, it moved freely back and forth in its bore.

My thoughts:
I thought before I start looking for a fuel or fuel system problem that maybe the oil pump lost its prime, from sitting all those years, so I was going to remove the pump check the tolerances and prime the pump as per the service manual and see what happens.

Your thoughts
I am not the brightest bulb in the box so I figured I would ask you guys/gals for your thoughts before I continue on. If the consensus is a fuel issue and not an oil pressure issue I will redirect and start with the fuel system. Any and all comments, thoughts and ideas would be greatly appreciated. Thanks in advance.

[35-709]

  #1.  Never try to start a car (you care about) that has been sitting for that long without giving it a thorough check over.  You need to attend to both the gas flow and the oil.  If it were mine, I would, at the very least, pull the plugs, spray some Marvel Mystery Oil in the cylinders (or any good oil) and crank the engine (plugs out) with a good battery until you got oil pressure and then crank a little more after that.
You might try pouring a small amount of gas down the carburetor (no more than a shot glass, after the plugs are reinstalled), if it fires and runs on that and shuts off, you have a fuel delivery problem.  With a car that has sat that long, it could be in the carb --- stuck needle and seat, stuck floats, neither allowing fuel in.  The fuel filter could be full of crap from having run out of gas (how old IS that gas?), the fuel pump diaphragm could be dried out and not able to pump.  Disconnect the fuel line at the carb and direct any fuel you might get into a good sized container, crank the engine and see that you are getting fuel into the container, if not you'll have to find out why.
Of course, it is never a good idea to run without oil pressure, but the engine will stand a little.  There is no low oil pressure "shut-off" that won't allow it to run.  Actually, if it were mine (more so than just pulling the plugs and cranking it), I would have pulled the distributor and spun the oil pump with a drill motor and a made up tool to get down into the slot and spin the pump to get oil flow and pressure to the engine.  I have seen a wood boring bit with the point ground off work just fine.  It will take a larger drill motor (1/2 inch drive) to spin the pump once it picks up the prime.
It is always a good idea, especially in this case, to fill the new oil filter with oil before installing it, it helps the pump pick up the prime much faster.  Pour fresh oil into the filter and let it sit a minute as the oil is absorbed into the filter material, then pour in some more.  You won't be able to fill it completely because the filter installs at an slight angle but it helps immensely.   

 

[bcroe]

I would not run an engine that cannot immediately
show some oil pressure.  I prime those by connecting
a high pressure hose (trans pressure gauge) between
the pressure port and that of another engine.  Run
that one for 30 seconds to pressurize your engine,
watch that no more than a quart of oil get transfered
between engines.   

If gas in the carb runs it, you have a fuel problem,
I have started using a fuel pressure gauge on old cars. 
If gas does not start it, likely ignition.  AND before
all that, check that the timing chain set is reasonably
doing its job.  Bruce Roe

[TJ Hopland]

I would agree that the oil problem needs to be figured out first.  You should be able to generate some pressure cranking and if you are getting zero that isn't good.
 

Once the oil is figured out on to fuel, A common problem other than just old age with these cars was for one reason or another the charcoal canisters have a failure that lets charcoal bits get into the float bowl of the carb.  Don't know why 77-79 seemed especially bad for this issue.   Those bits are just perfect size to plug up the jet holes.  Kinda a pain to clean out and even worse when you just assume it was just random crap and don't fix the problem and have to do it again right away.   Quick patch was to just install an inline fuel filter in the line from the canister to the carb to catch the bits.  Real fix is to replace the canister.

[hotrod095]

Sounds like the engine is not getting fuel. Will the engine run if you give it fuel down the float bowl vent? Could be the fuel filter could be backward when it was installed (happened once to me) and the car will start for 2 seconds then sputter. Then no fuel will make it to the bowl of the carb and you will just keep cranking.

Also could just be a bad fuel pump all together.

[NickD]

Thanks, guys, for all the advice. I will do some more diagnostic testing and let you know how I make out.

[Dave Shepherd]

Dont forget the inline filter in the carb inlet fitting , often overlooked.

[Koa]

And? Does Your baby already run?

What was the problem?

[V63]

With a car sitting this long the existing fuel goes stale, diluting idea does not work because the bad gas is HEAVIER, the new fuel will sit on top.
You must remove all the existing stale fuel.
 If you run the engine on stale fuel it can (likely) seize the valves in the guides necessitates removing the heads to repair.

[Eric DeVirgilis CLC# 8621]

Firstly, the oil lamp will only extinguish with the engine running (assuming there are no oil pressure issues). The lamp will otherwise illuminate with the key on without engine running.

The rest as you described sounds like a clogged pickup screen in the tank. If the engine is able to fire up however briefly after it sat for a while, it means enough time had elapsed allowing rust/debris particles to fall off enabling fuel to pass through until it becomes choked up again. The tank should be removed, inspected and refurbished/replaced as necessary. Same for the pickup/sending unit. Fuel lines should be checked as well.

[Dave Shepherd]

The famous gas tank "sock", caused a lot of issues over the years.

[V63]

A plugged exhaust system will cause similar symptoms, restricted catalytic converter

[NickD]

Good morning, all. I have not been able to get back to the problem until yesterday. As I said in my original post, I changed the oil and filter and was still not able to start the car. So yesterday I figured I would unscrew the oil filter and see if there was any oil in it (as when I installed it, I did not fill it with oil) well the filter was full of oil. With that said I guess the oil pump is doing its job, so I moved on to fuel. I decided to drop the tank and take a look inside. Man did I find exactly what some of you guys said in the fuel tank. It was full of rusty and cloudy gas, debris and the sock was ¾ plugged. After removing all the stale gas from the tank there was so much rust inside that I figured the tank is shot. I am in the process of getting a new tank and sock. I have blown out the fuel lines with compressed air and I am moving up to the carburetor to replace the fuel filter. I figure the fuel pump is working since it was pumping fuel to the carburetor. I also do not want to touch the carburetor unless I have to. Do you guys have any thoughts on that? I will report back once the tank arrives and I get it installed, again thanks for all your help.

[V63]

The probability is the carburetor will need to be disassembled and cleaned of the varnish

[Chopper1942]

If fuel was left in the float bowl, it will have evaporated and probably left crusty deposits in the bowl.  It would be best to at least remove the top of the carb and inspect the float bowl for debris. Personally, I would remove the carb and overhaul it.  Get an OE manual for your car and follow the directions.  It is not that difficult.  Count the turns to bottom for the mixture screws and when you reassemble the carb install the screws to bottom and back out the to the original position.  I keep the mixture screws installed in the same side that I removed them from.  You should replace the float and check all the vacuum breaks.

[NickD]

UPDATE:
Car still not running, but I am making progress. I have installed the new tank and sender and added approximately 7 gallons of gas. After a bit of struggle and raising the rear of the vehicle I was able to get a good flow of fuel up to the fuel pump from the tank.  After connecting the fuel line (from the tank) to the pump I disconnected the steel line at the pump. I attempted to use the vehicle starter to pump fuel thru the pump. That did not work; no fuel flowed thru the fuel pump. Since this is the original pump (I'm guessing because it is painted blue) I figured the pump is bad, so I removed it. The new replacement pump (airtex 41204) is different from the old pump (see pics). The new pump arm does not appear to be close to the old pump arm. I was going to try and switch arms, but the new pump arm is retained in place different from the old pump arm. It looks like the pump will mount to the block, but I did not try it. Anyway, that's where I am as of yesterday. Any thoughts would be appreciated.

[Chopper1942]

Before condeming the old pump, I would reinstall it and do some testing. Disconnect the ign wire a the ign coil. If you have an air compressor, stick a rag in the fuel tank fill neck and with the line off the fuel pump blow air into the tank. You should get a solid stream of fuel from the line at the pump. Connect a vacuum gauge to the inlet fitting of the fuel pump and crank the engine. You should see 15+ inHg on the vacuum gauge. If it does not pull a vacuum, the pump is bad.  If it pulls a vacuum usually the pump is OK. Next, connect the inlet line to the pump, apply a small amount of air pressure to the tank to fill the fuel pump.  Crank the engine and see if you get some fuel out of the line to the carb.  If not, remove the fuel line at the fuel tank and connect the vacuum gauge to the line. Crank the engine. You should see and vacuum.  If not, you have a leak in the fuel line from the tank to the pump. If it pulls a vacuum and you get no fuel from the line to the carb, the valve inside the pump is bad.  If there is an issue with the pump diaphram, fuel will usuall come out of the vent hole in the pump.

I would try to get an AC Delco pump and compare it to your old pump.  I would be concerned that the Airtex pump would be damaged when you crank it over or when you install it.                                             

[TJ Hopland]

Stack the pumps and compare where the short part of the arm ends up.  The flat area where it rides on the cam may be in the same place it just may take a different route to get there.  Oldsmobile is a pretty similar pump but did have a different arm so its possible you got some olds parts.   

[Michael Petti]

Have you considered rebuilding the fuel pump you have. It's not that hard or expensive. You'll have a dependable unit you can have confidence in.

[TJ Hopland]

Michael, How do you rebuild that style of pump?  I know nothing is impossible given enough time and money but these seem pretty far on the impractical side.   First question is does anyone sell the replacement parts and then the 2nd problem is how do you install them?  Crimped housing, staked in valves, riveted on diaphragm?