Car question - nothing to do with audio, but...

[mzeitlin3348]

I figure since you all are so technically inclined regarding audio - and you are about my age - you might just know something about cars ....

My vintage car - yep ... just like my audio gear -old-..., keeps stalling after 5 minutes run time and won't immediately start again. It doesn't matter if it is warm or cold, just run time. After about 30 minutes, the car starts right up. This started happening after I let the car sit in the garage all winter. I wanted to take it out today for a spin. Started up....backed out...a few minutes later. dies.....There is about 1/4 tank of Shell gas in the tank. I usually run it down an 1/8th so I keep cycling with fresher gasoline.

Can a bad fuel filter cause this? The filter is relatively new, but unchanged since I replaced the fuel injectors a year ago. The car was running fine then.
Has anyone experienced this and changed the fuel filter and problem went away?

Additional info: 1983 280zx turbo. Run once a month or so except over the winter.

 

[gearhead]

Could be a fuel pump.
Is it EFI?
If so, it may have a place to screw on a fuel pressure gauge to check it.
You'll have to find the pressure specs somewhere.
If there's an Autozone near you, they may rent you a gauge and supply specs.
Wish I could be more helpful, but I'm more knowlegeable about pushrod-equipped Chryslers.

 

[Chad Hauris]

I am not familiar with this particular model but could there be an ignition problem such as the pick up coil in distributor, ignition module, coil, etc. Is it TBI injection or multi-port? You could also check that the fuel injectors are receiving power, there should be a test light for this.

I wouldn't think the problem is in the fuel filter because this would cause trouble when starting up.

 

[usedto]

I had a 55 Chevy in 1966 that gave me fits for 3 years. The problem was similar, but sporatic. The first thing I would do (which is the last thing I did) is swap the coil. Heat can make them break down. Cool off, and they get better......temporarily.

Worked for me.

Larry

 

[mzeitlin3348]

I'll check it out. The strange thing is it starts right up after 15 or so minutes., whether warm or cold. The injectors are new and sound great (clicking sound). Could be the computer giving a bad signal because of a sensor somewhere.

The engine is EFI.

 

[Ghog]

Autozone has the equipment to read the computer codes on many cars. I don't know if yours has diagnostic codes, or if they could read them on a 1983 Nissan, but it's free if they can. They do this in hopes of selling you a replacement for the faulty part. I have had good experiences with them reading codes on my truck.

Ghog

 

[OvenMaster]

My vintage car - yep ... just like my audio gear -old-..., keeps stalling after 5 minutes run time and won't immediately start again. It doesn't matter if it is warm or cold, just run time. After about 30 minutes, the car starts right up. This started happening after I let the car sit in the garage all winter. I wanted to take it out today for a spin. Started up....backed out...a few minutes later. dies.....There is about 1/4 tank of Shell gas in the tank. I usually run it down an 1/8th so I keep cycling with fresher gasoline.

Can a bad fuel filter cause this? The filter is relatively new, but unchanged since I replaced the fuel injectors a year ago. The car was running fine then.
Has anyone experienced this and changed the fuel filter and problem went away?

Additional info: 1983 280zx turbo. Run once a month or so except over the winter.

I'd look at a weak fuel pump, weak or leaking fuel pressure regulator, water in the fuel lines, and gum in the fuel, especially if the fuel is not fresh, and yes, a fuel filter.
Tom

 

[blue_lateral]

My best guess would be the ignition module, or whatever it is that contains the transistor that fires the coil on that particular model. Thats only a guess, though and probably not a very good one. Unfortunately you are probably going to have to get a wiring diagram and troubleshoot it with a DVM, while the problem is occuring, just like you would a piece of vintage audio gear.

Best of luck,

John

 

[mzeitlin3348]

I am going to try the fuel filter first - and then get a fuel pressure gauge to make sure the fuel pressure is fine when it happens again. I have a hunch, though, that it is the fuel filter. NOt starting the car up I'm sure is causing this....

 

[cabinover]

Just pull a spark plug wire from the distributor when it quits, if there is still spark it's gotta be a fuel problem.

Just for chits and giggles, did you pop the fuel cap off to see if it's getting vapor locked?

When it dies does it just up and quit like shutting off the key or more slowly like running out of fuel?

 

[mzeitlin3348]

when it dies, it does so as if I shut the key off - or like a vapor lock, both act the same way.

Electrical is working, plenty of spark.

When I unscrew the gas cap, there's a pressure relief sound, but it does this whenever I shut off the engine, as for example, when I go to fill up the tank. I suspect that's normal.

At this point I am thinking clogged fuel filter and/or clogged screen in the gas tank. Changing the filter is no problem.

Cleaning the screen in the gas tank.....(#*$&)?? How to do that?

 

[SPL db]

When you say that you leave 1/8th of a tank of gas in the car, is that by the gas gauge?

Is the car level? Just wondering if there is enough fuel to keep the PSI up...

Just a thought, might want to go and fill up a gas can and add some fresh fuel...

Scott

 

[Adam]

Tried cleaning the spark plugs? This doesn't really sound like a problem caused by dirty plugs, but it can't hurt, I've had several mysterious car problems go away by just cleaning the spark plugs in the past.

 

[blue_lateral]

Are the Injectors clicking when it has a problem? You can put a really long screwdriver on one of them and put the handle end up to your ear to hear them. Try it when it's running to see what it sounds like. Then try it again while someone is cranking it when it wont start.

 

[Clarence]

if you dont use stabil in the tank when it sits, the gas decomposes and turns to varnish, which can plug filters, injectors, and the like... it is so important to use stabil intanks sitting for more than 6 months.

 

[fotno]

Sounds like bad fuel in the tank, lines, filter(s), injectors etc... Especially since the car sat for so long before the proble started. Might be worthwhile to run a course of injector cleaner through after you get the filter(s) changed out. Good luck buddy.

 

[mzeitlin3348]

I thought I'd update you on what the problem was - now that I fixed it.

Turns out it was my distributor. After I replaced it with a new one, the car ran fine - no more stall. I have no idea why the old distributor would fail gradually - it finally died altogether which is what enabled me to trace it. Intermittent problems are a pain in the butt - just like in vintage audio.

I do have a new problem - now that the car is running - when it gets to full operating temperature - good and hot - (but normal water temp, etc.) - the hot idle sputters - and usually the engine stalls because the engine goes very rich. I can re-start, but have to keep my foot on the gas at 1000 rpm. Everything that has to do with temperature has either been changed (cylinder head temp sensor) or checked (resistance values are o.k.).

Something is telling the computer to add more gas when the car is very very hot. I thought the injectors were bad - but all six of them? Every spark plug is black. I can keep the car running (without my foot on the gas) if I open a vacuum line and let air enter - then it perks up and idles - poorly, but stays running at about 900 rpm. Re-connect the vacuum line and it sputters and usually dies.

Come back the next day when the engine is cold - and she fires right up and idles fine ... until it gets hot and then sputter.

I don't know what else to check ...

 

[blue_lateral]

Maybe pull the vacuum hose off the fuel regulator. if theres gas in there, the regulator is bad.

Has the temp sensor for the fuel injection been checked while it was hot and in sputtering mode?

Check voltage coming off the oxygen sensor when the car is hot and sputtering. Use a DVM. The voltage would be varying normally between something like 300mv (lean) and 900mv (rich). Try this with the car hot at both idle and about 2500 rpm.

If the sensor is working when the car is sputtering rich, it should be stuck high, probably over a volt.

If it is stuck high, youre barking up the wrong tree and this isn't the problem.

On the other hand if its stuck low, like below 500 mv, the signal from this sensor is telling the fuel injection system to go full rich. There are about 4 possibilities why.

(1) The oxygen sensor is bad.

(2) The oxygen sensor has air leaking on it. Check the air injection system if you have one. All air injection that is ahead of the sensor needs to be shut off with the engine hot. An exhaust leak upstream of the sensor could cause this, too.

(3) A "point" vacuum leak, that is one that affects only one cylinder, is causing one cylinder to operate way leaner that the rest. The system richens up all the way trying to get that one cylinder rich enough. It cannot, so the system runs full rich.

(4) A mechanical or ignition problem causes a dead miss in one cylinder. The system interprets this as a lean miss because of the oxygen that got through because the cylinder didnt fire. Result is the same as number three.

All that above about the oxygen sensor assumes that the car is actually running rich. Are you sure of that?


John

 

[mzeitlin3348]

The temp sensor is brand new - installed today. The engine is doing the exact same thing as when I had the old sensor installed. The wiring checks out o.k. (i.e. continuity) to the computer.

Interestingly - the resistance profile of both sensors is the same. I would think after 23 years, the old one would have changed somewhat.

 

[blue_lateral]

Oops.. My edit and your reply crossed in the mail