Running Rich

[Hrududu]

Sorry if this is pretty basic, but im still pretty new to the Z (and most engines) I know that my car is running rich. A friend of mine who is a mojor in car repair has told me thats the problem. All i need to know is what i need to do to fix this and get the Gas-air ratio right. Its a 77' 280 that is all original. I have looked and cant find any instructions on what needs to be adjusted or fixed. Thanks in advance. I know you guys here are great!

[Gee]

Search for how to tune your car, there's been plenty of posts on this topic.

[TomoHawk]

Sorry to tell you, but, There's no easy or direct answer to your question, except, "Check everything." I have a 78 280Z with the e.f.i, and the Nissan dealer guy said mine is rich too. You can check/service/replace the AFM, the thermotime switch, even the wiring. "Original" doesn't really mean anything good, except it has all the parts that it had when new. Most of those parts are now old and maybe even worn out or the performance has degraded. That means you'll have to fudge things someplace, if just replacing some simple things doesn't help, like the thermotime switch.

I think the best thing we can do is to replace the wiring, but you can't get those either.

[sonofzzzap]

Hey there buddy, you and I are in the same boat

About two weeks ago I bought myself a 77 280, my first Z, the same as yours, not all original mechanically, but a very sound running car. I have done some tweeking to mine so far, maybe we can help each other since we're both newbs.

Ok, why dont you gimme a semi-detailed describtion of how your z is running (idle and so forth) etc... and we can compare notes here.

[sonofzzzap]

also get the efi bible and print it out, its a great resource http://www.72hours.net/~zcar/

check ebay for a 77 factory service manual too, im still lookin for one so good luck

[beandip]

ever heard of the story of the BLIND LEADING THE BLIND ? I bought a really good 240 that the PO tinkired with to the point that it wouldent even make it up a normal driveway ramp with out a running start. Before you start tinkering , buy some books like the shop manual , and read about what you are about to take on. Ask questions of people that really know what they are talking about and are not guessing. Then you can enjoy the ride. All the best of luck . Gary

[sonofzzzap]

thanks for the encouragement.... heh

well, I just thought that some of my troubleshooting might help him some with getting his little things worked out, I know it has helped me alot

[TomoHawk]

Before you start tinkering yourself, don't you think it would be a good idea to make surethat all the consumable or replaceable stuff is either replaced, checked or cleaned? I mean like, new air filter, oil change & filter, a GOOD coil, spark plugs & wires. I even had my L28 engine decarbonized, which seemed to help some.

I think next, I would want to remove the AFM (or carburettors) and either carefully clean them or rebuild, then the same to the other stuff, then finally the wiring, if possible.

FWIW

[Hrududu]

Well, everything was tuned up when i got the car in July. New plugs, wires, filters (air, oil, fuel) and all freash fluids, so i have checked all those things. I also cleaned all of the electical plugs under the hood. i checked the AFM and it is running about as lean as it can get. The car has really been acting strange since the cold weather started, but has been doing this even in the warmer months. it will run ok when cold, but when the clutch is pressed to shift, the RPMs drop and fluctuate between 500 and 1k. Once the car warms up though, it stops doing this. The car idles ok, but a little rough when cold. when running, it blows black drops out the pipe and if revved, it smokes black for a few seconds. I have noticed it seems to be running a bit better after cleaning the electrical contacts, but it is still too early to tell. These plugs only have about 600 miles on them and are quite black. I think i will replace the plugs if the car continues to keep running better. Today it was not spitting un burned fuel.

[beandip]

Most likely what you are seeing comming out of the exhoust as liquid is water condensation . You might check the coolent temp with a candy thermometer when the temp gague is showing normal driving temp. Dont remove the rad cap on a warmed up engine , do it when it is cold and leave it off untill the engine warms up . You could have a bad thermostat and the engine is running on a cold start setting. That is the same as the choke being on.

[Hrududu]

Most likely what you are seeing comming out of the exhoust as liquid is water condensation . You might check the coolent temp with a candy thermometer when the temp gague is showing normal driving temp. Dont remove the rad cap on a warmed up engine , do it when it is cold and leave it off untill the engine warms up . You could have a bad thermostat and the engine is running on a cold start setting. That is the same as the choke being on.

its odd that you would say that, because i was thinking of replacing the thermostat. I noticed that it seems to bee messed up and got a new one to install and just need to do so. Once when i got out of the car, i heard a terrible thumping sound under the hood. I opened it and found it was coolant being sloshed from the rad to the engine. I figured the thermostat needed replaced so i got one a few days ago and just have not had the time to put it in yet. Will do so tomorrow when i change the oil.

[TomoHawk]

How much coolant do you let out when you change the thermostat? I think it's about a gallon (3 qts.) And where does it come out? I think my radiator has a valve on the bottom tank. I should probably replace my thermotime switch.

thx