Trouble with rough idle 1978 280Z

[dbullard]

OK, here goes a long car story -

I recently decided to get my 1978 280Z 2+2 running again after sitting in a garage for about 5 years. The car was purchased new in 1978 by my mother, and became mine in my teenage years. It stayed at home when I went to college, and other than being started occasionally in the summer months, it has sat in place for about 5 years.

After getting insurance put back on it, I replaced the previously frozen battery that wouldn't hold a charge. The gasoline had varnished so I drained that, replaced the fuel filter, and eventually ended up replacing the fuel pump as I wasn't getting any gas to the engine. I cleaned out the lines, replaced rubber hoses, and blew out the fuel pressure regulator by the fuel pump.

I can get it to turn over and start for short period, sometimes it was able to maintain an idle, but if the gas was applied it would die.

I read on this forum to replace the varnished spark plugs and I was able to get it to start run a little better.

What I am experiencing is, the car will start from a cold start idle about 750 RPM just as the would back in the day! Once the car warms up however, it starts idling very low and eventually dies. It is then difficult to get started again. I tried adjusting the idle screw and that doesn't seem to make any difference of whether it will run or sputter to a stop.

I have checked and filled the radiator, engine oil, all that good stuff, but it wants to die. If I get it running and try to increase the RPM, it hesistates and sputters and dies. It is making a ping noise like it is backfiring in the manifold.

Now it has started a slow leak of antifreeze from some location under the engine. I don't know if this is a seal or just an old hose leaking.

Has anyone ever experienced anything like this after sitting for a few years? I am at a loss and would really like to get this up and running this summer. Any common things to check out?

Thanks in advance!

[dbullard]

Also - would the temp sensor issues I read about in another thread be a likely culprit of it dying when it warms up like it is? I runs rough like a muscle car with a huge cam in it.

[grantf]

try checking the fuel pressure. Also go over the whole engine and look for worn rubber like the vacume lines and the hose leaving the air flow meter. this is just the easy things that should be done anyhow for what it's worth.

[d240zx2]

A couple of things:

1) You didn't mention if you dropped and cleaned the gas tank. If you didn't do that, now is the time. Old gas can contaminate new gas and cause problems like you've described.

2) The coolant leak is likely from a failed water pump. Often, those pumps will fail after being "put up" for a few years. It's common, but aggravating.

Frank

[dbullard]

Thanks for the input Grant and Frank! I will hopefully get some time to try those things out this weekend. It has alway run so smoothly up until it sat for a few years. The body is a little rough (typical for the rust belt), but the engine has 65k original miles on it. I am eager to get it running for a little summer nostalgia.

RE: Fuel pressure, would I just get a gauge dial from somewhere and tap off of the fuel like near the engine to check that? Is there a preferred location to check this at? I know I was getting fuel to the engine because when I turn the engine over gas trickles out of the hose near the block, and when I disconnect the hose it releases the pressure.

RE: Vaccum lines - on my Audi I made a leak detector device for checking for vaccuum leaks. Basically a PVC cap with a NPT air tool chuck threaded in. I know this isn't a turbocharged engine, but has anyone ever checked for leaks on the engine? I am wondering if very low pressure hooked up to the hose coming off the airflow meter could help find some leaks? Any thoughts? It worked really slick on that car - I found an intercooler leak, a PCV hose leak, and a cracked diverter valve leak!

RE: Gas tank - I did not drop it, but I did drain it through the plug in the bottom, and since I was worried about rust and scum, I put an inline fuel filter coming from the tank going to my new fuel pump. I figured a $4 filter and some hose clamps were cheaper than another crudded up fuel pump. I have since filled the tank up about half ful with fresh gas. The gas I removed smelled lurid like turpentine and was a nasty beer-like color.

RE: Water Pump - I'll have to check into that. My goal is to get it running long enough to drive to my garage on the other side of town where I have access to more tools. It is a pretty minor leak so far, but worth fixing for sure!