l20b wont idle, backfires, poor gas mileage...vacuum leak??

[rustrocket]

The other day, i was driving my 710 wagon when all of a sudden, it sounded like somebody threw a b ag of popcorn in the engine. At which point, it lost power and died.

 

I had it towed home and waited til the next day to deal with it. It turns over and starts, but it won't idle. It'll cough and sputter for a few seconds and then die. I can hear a light hissing sound somewhere, so i think it's a vacuum leak somewhere. Any idea what specifically could be causing the following:

*rough idle/wont idle

*backfiring while driving

*poor fuel economy

*poor power delivery.

 

I've checked all the ignition and fuel systems which appear to be fine. I just wont want to spend hours tracking down this little gremlin. Thanks for the help!!

 

-Cameron

[banzai510(hainz)]

I just wont want to spend hours tracking down this little gremlin

 

throwing the car away would be ezer I guess!!!!!!!!!

 

ck the points if its still a point car. maybe condensor.

 

fell around the intake if it seems loose. or gasket breaking apart, ck the carb area. maybe get some starter fluid and spray around.

 

Maybe ck to see a lash pad didnt fall out of the rocker arms(remove valve cover.

 

olddatsuns.com

[rustrocket]

I just wont want to spend hours tracking down this little gremlin

 

throwing the car away would be ezer I guess!!!!!!!!!

 

 

Perhaps i should rephrase...I don't have hours to spend. If somebody with similar experiences and a remedy or suggestion could help, it would be appreciated.

[420n620]

well you should check your compression to see if its up to par.

 

whats the plugs look like ???

 

run a ohms test on your spark plug wires.

 

is there a crack in your distrubutor.

 

points worn down

fuel filter plugged

check out what hainz said

this is going to be a process of alimitions because it can or will be one or more problems going on.

where are you located, maybe a ratsun member lives close to you and can come give you a hand.

[datzenmike]

Check the little glass bull's eye in the front of the carb; it should be in the middle. If too high or low you have a fuel delivery problem and can stop looking elsewhere. Easy and costs zero.

[racerx]

Check you coil....mine did that awhile back..and the coil went out. You can take it to Kragens or ohm it yourself..check your books for resistance reading. Yeh, if you still have points check that maybe it's pitted. and also your rotor and cap...

[freaky510]

check your cam i broke my cam sounded kind of like what yours did from what u said.It still ran only on 1 cyl it was realy weird it would start run real ruff.so i took off the vavle cover and hit the key and only my #1cyl was working lol

[rustrocket]

That's lots of helpful info, thanks guys. Now...i just need to get out of work during daylight so i can actually see what i'm doing.

[420n620]

you could go buy a extension trouble light or one of those headlight thing a ma bobs or a whats u ma calls it. No day light required.............. :D

[datsunaholic]

Funny, sounds very similar to what happened to my truck a couple weeks ago.

 

It was abnormally hard to start, but seemed to run OK until I got 3 blocks from the house. Coughed a couple times, but then ran OK until I got to half throttle then it acted like it was out of gas. At that point I was 7 blocks away and managed to get it turned around but it died out in the middle of the street 5 blocks from the house and wouldn't refire at all.

 

I pulled the fuel filter right there, wasn't clogged and was full. I pulled the fuel line at the carb, and had good pressure, but it still wouldn't fire (I have a Weber so no sight glass). The truck did have an all-over fuel smell though, but hard to pinpoint after I'd pulled so many hoses. Fortunately I'd broke down in front of someone's house who was nice and he towed me the 5 blocks back with his Mazda. Since I was in a hurry to get to Seattle I just left it there.

 

That night, when I got home it fired right up. I drove it up/down the block several times, no sputter. But it reeked of gas, I'd left the carb line loose and it was leaking all over the manifolds.

 

Then it rained for 2 weeks.

 

So, Saturday (2 days ago) I tried to fire it off again- it fired right up, ran OK, but then I remembered the fuel smell and yup I still handn't tightened the hose clamp at the carb. Tightened it up, and the truck wouldn't start. It would only run if the fuel was leaking.

 

Well, now I knew what the problem was. I have an electric pump and it provides more pressure than the Weber float valve can handle. So it was flooding and fuel-fouling the plugs. I pulled the fuel return line and it was plugged somewhere between the engine compartment and the tank- put 40PSI to it, it pressurized a bit then whatever was clogging it let go and was all clear. I hooked the hoses all back on, it ran fine, test drove it, and drove it to work today.

 

That would explain the bad idle and poor gas mileage I got the week before it stalled too.