I have a nice 280z car, blue 510 color. Too bad its sick and not running correctly. I have been reading these forums, and see lots and lots and lots of things that could be causing it. I have 3 separate mechanics talking to me about it, and some of them are not in agreement about what the problems are. Some say fuel injectors, wiring connections, fuel pump, low compression (and therefore need new piston rings, so they say they might as well rebuild it while they are at it)...etc .... I am in a tug of war here...stuck in the middle of all this. I am not complaining, but would like to get moving in the right direction.

I owned a 300 zx for 10 years. And drove a blue 1984 Z back in 1990. Oh yeah, I also test drove a 1976 260z car, that someone in my town was selling. It had dual carbs on it. So I do have some experience driving a few different z cars, but never had the pleasure of driving a different 1978 280Z car. So I have nothing to compare my poor running engine too.

Well anyway I am so glad I found these forums. They look extremely active!!!!!!!!!!

Edited January 10, 201114 yr by argniest

If you wish, there is a collection of documents for testing, adjustment, and general service here: http://atlanticz.ca/index.php/tech-tips.html

You should also have the Factory Service Manual (FSM) for your car to refer to: http://www.xenons30.com/reference.html

Also, the "280Z Fuel Injection Bible" is commonly helpful to many: http://www.xenons130.com/files/280zfuelinjectionbook.pdf

If you wish, there is a collection of documents for testing, adjustment, and general service here: http://atlanticz.ca/index.php/tech-tips.html

You should also have the Factory Service Manual (FSM) for your car to refer to: http://www.xenons30.com/reference.html

Also, the "280Z Fuel Injection Bible" is commonly helpful to many: http://www.xenons130.com/files/280zfuelinjectionbook.pdf

Yup, I have the FSM hard copy and electronic, and the 1975 Fuel Inj Bible too. Too bad it will take me a few years to understand all of it :-( because I am not a mechanic. But I suppose if I do all these things people are suggesting, in about 1 year I will be a Z car noob mechanic anyway he he

I will check out that first link ...thanks

To be clear, after you run SeaFoam through your intake and cylinders and knock down all the carbon/crud, you should change your oil anyway.

If I were you, I'd do a cheap oil change -- Wix filter (never skimp) and some Castrol GTX 10-40. Fill the oil carefully to the top mark, jot down your starting odometer reading, and drive it. Make certain you aren't losing oil from a leak. Always park it in the same spot at home, and watch for (big) oil spots on the ground. Also while the engine is running, lie on the ground and watch for oil drips. (Maybe you're leaking around the oil filter or oil pressure sensor?) If you're not leaking oil, and you're still losing oil, then your engine is burning it up. Personally I'd consider a rebuild if I were burning a quart every 1500 mi or so, especially if I had tired compression readings. If I were losing (and not leaking) a quart every few hundred miles, I wouldn't hesitate to rebuild the engine. To put it into perspective, your engine seems to be burning almost as much oil as a 2-cycle chainsaw.

Anyway, if you're looking for concensus, I think you have it from three of us on this list (again, if you're burning and not leaking the oil). Tell your three mechanics you're losing a quart every few hundred miles, and I think they'll reach a quick concensus too. You could nit pick over whether it's the valve guides or the rings that are leaking, but if I were you, I'd just do the whole engine.

Idaho's suggestion of a swap would be your cheapest alternative to getting the car running again, but if you go that route, save the original engine (assuming it's really the original engine, with a serial number matching the plate on the lefthand side of the engine compartment). Matching numbers are important for the value of the car.

From H to L on your dipstick is one quart. You might change the oil (no Seafoam or other additives) and start over, measuring oil consumption from a known mileage and new oil. Seafoam and other stuff dilutes the oil.

I don't want to divert your thread to a "best oil" competition but I did see a reduction in oil usage when I switched from Quaker State 10-40 to Pennzoil 20-50.

Most fuel pressure gauges come in a kit and look something like this - http://www.amazon.com/Actron-CP7838-Professional-Pressure-Tester/dp/B0009XQUKC/ref=sr_1_2?ie=UTF8&qid=1294694575&sr=8-2 - and cost about that much. They're usually in a bubble pack somewhere in the store.

My car too stunk things up, and got bad mileage, when the fuel pressure regulator was bad. It's always good to know fuel pressure on a fuel-injection system.

If your mechanics have not actually measured the fuel pressure yet, then they're not being very thorough, especially considering the symptoms you've described.

Edit - FastWoman beat me again!

Edited January 10, 201114 yr by Zed Head
Dang it!

:mad:Ahhhhhhh, then sooooo sorry it was not three quarts. It went from H to slightly above the low mark in 1000 miles. What I am saying is that it was maybe a 1/4 inch or more above the L mark. So that is my bad for saying it was 3 quarts low.

Let me know if this is correct: Are we saying I only used about 1/2 or 3/4 of a quart because it went from H to 1/4" above the "L" mark on the dipstick?Also, nope, its not leaking much oil at all. I see a small drip coming from the oil drain plug, but that never happened until a more recent oil change. Before that she never leaked one drip of anything onto my new garage floor. I would have noticed. I am still amazed its not leaking more.

Also, my relative also changed the exhaust manifold gasket a while ago, when he was working on other stuff. He also said the fuel pressure was fine. He measured it in a few places he said. Also he removed fuel pump and did a volume test, and said it didnt have any problems pumping a lot of fuel like he felt it should be. That tells me the fuel pump and screen in the inlet were OK. Of course that was a year ago.

We never measured fuel pressure, after the fuel pressure regulator. I am not sure how to do that?? They are cheap enough I should just buy a new one. Fuel pumps (good ones) are not cheap of course. I think my source has bosch type replacements.

Also, I did just change the oil and havent driven it much at all...because of the icky snowy bad roads. I did put in some sea foam over the winter per direction from a mechanic. Since I didnt think I would be driving it at all until March. And I filled the tank (and the new tires) all the way up.

Who knew all the snow was gonna melt and get upto 54 and 60 degrees in two days.Thats when I drove it, and found out it was dying on me. I attribute that dying to the cold weather. Something about the cold weather is exposing a weakness in the car!!!!!!!! that never happened during 1000 miles test driving in the summer.

OH YEAH, and when I added seafoam, I put it in the gas tank (not anywhere else since I didnt know how to do that). I put 5 cans in there over the summmer. Each time I filled up the tank. I was not thinking about how much was or could have been leaking down into the oil because of the bad rings that I am sure must be there.

Edited January 11, 201114 yr by argniest

3/4 qt. per 1000 miles is not too bad. Seafoam is a once every ten or twenty thousand miles kind of thing, it doesn't repair anything it just loosens up "stuff" that has built up over the miles. It doesn't preserve things either. I would stop with the Seafoam for now. I'm pretty sure that the previous owner of my car had Seafoam in the oil when I got it and that it was contributing to the the eye-burning exhaust. The exhaust smelled cleaner after I changed the oil. You need to get to a clean, normal baseline to work from.

Your relative sounds like the sharpest mechanic that has worked on or looked at your car, of all those that you have described.

I don't want to divert your thread to a "best oil" competition but I did see a reduction in oil usage when I switched from Quaker State 10-40 to Pennzoil 20-50.

Dumb question, but can I change oil if the car is jacked up on a 3 ton hydralic jack? that would mean it is angled backwards...of course I have some 6 ton jack stands which I could put under there too. I dont want to get squished when changing oil.

Yes I have heard that before. I dont mind using penzoil 20-50 year round. That is what someone else told me to use too.

Most fuel pressure gauges come in a kit and look something like this - http://www.amazon.com/Actron-CP7838-Professional-Pressure-Tester/dp/B0009XQUKC/ref=sr_1_2?ie=UTF8&qid=1294694575&sr=8-2 - and cost about that much. They're usually in a bubble pack somewhere in the store.

OK, well I have seen those kind in my local stores, however, I didnt think they could be used on the 1978 z car. I mean there isnt any port to hook it into on the fuel rail, right? Can I use this acton version that you showed, on the Z car. I want to leave it in there, while I go for a test drive. That hose looks pretty long. I just wanted to use like a few inches of fuel injector hose, right after the fuel filter. Can I hook that one in the URL, up to the 78 z car right after fuel filter?

My car too stunk things up, and got bad mileage, when the fuel pressure regulator was bad. It's always good to know fuel pressure on a fuel-injection system.

I may just go ahead and order one of those, or see if my local foreign car parts store has one. Once in a while I get lucky and they have a few parts for my car. I mean it cant hurt to change it right? And how easy is it to change anyway???

Edited January 10, 201114 yr by argniest

3/4 qt. per 1000 miles is not too bad. Seafoam is a once every ten or twenty thousand miles kind of thing, it doesn't repair anything it just loosens up "stuff" that has built up over the miles. It doesn't preserve things either. I would stop with the Seafoam for now. I'm pretty sure that the previous owner of my car had Seafoam in the oil when I got it and that it was contributing to the the eye-burning exhaust. The exhaust smelled cleaner after I changed the oil. You need to get to a clean, normal baseline to work from.

Your relative sounds like the sharpest mechanic that has worked on or looked at your car, of all those that you have described.

Well I was told I should keep seafoam in the gas over the winter (about 90 days long here where I cant drive unless I am lucky)

yes, my relative works on all kinds of awesome cars. easily $100,000 to more for those BMW's, mercedes, even classic muscle cars. He is known nation wide, and is a busy busy busy guy ....he fixes some, and restores them too, troubleshoots them, etc. I am very lucky to have him. However, he is sooooooooooooooo busy. It can be a month before I can even talk to him. And he doesnt email either. not a pc guy.

he has told me story after story about fixing all these crazy and difficult problems. And told me how fuel injectors have cured problems like what I am talking about. But he also told me about how a flakey fuel pump was causing a few car dying problems, like what i just experienced a few days ago. My head is spinning from all of this....

Edited January 10, 201114 yr by argniest

Well, I am reading over all your replies. Thank you. I have owned the car for two years.

I dont know what the percentages were for leak down test. I have it written down somewhere of course in my piles of notes and emails about this car. They were all within 10-20% of each other I believe.

All I know for sure, is that after he did those tests and the compression test, he said, hmmmmmmm, you need a rebuild. And he knew about the gassy/exhaust smell too.

Also, for many months at a time, my relative had the car in his shop working on the differential, transmission, suspension, welding, etc. So of course it couldnt be driven. He changed out the old gas and put in new gas as needed. In summer of 2010 I was driving the car. It was a blast. Dont get me wrong. I had it zooming down the interstate. And it was feelling pretty good. I drove it for hours at a time, no problems. Well, what I mean is until Jan 1st/2nd when it died on me 2 times...I never questioned if it was reliable or not. but now of course, I am scared to have it die in an intersection or worse. The cold weather must be effecting something which is causing this to happen. Because I drove it a lot in the summer and never a hint of this.

I will do whatever it takes to get this thing running. I invested in it heart and soul and checkbook too. But it seems like no one agrees on what to do exactly. So I am hoping to find more answers here. And things that I can do myself. I have the time nights weekends, and the patience too. Just need to know the proper procedure for doing various tests, so that I dont totally hose something up bad.

I can tell, this is going to be a long road for me. As I mentioned I have 3 good mechanics giving me advice and doing some work on it. But they dont all agree. And none of them seem to have time to really get down into the details, to figure out what is truely going on. Two of them are not locals. And I am not a mechanic. Although I have learned many things about my Z car. I still feel like an idiot. I have the original hard copy manual, and the elctronic version of it, on PDF, as well as the 1975 EFI handbook which looks very nice, well written and thorough.

I also bought every book published about the z cars.

So to summarize, the car was driven over the summertime. Now I realize the spark plugs were slowly getting fowled up, and as that happened slowly (or fastly depending on how you look at it), it lost its power. So now I know that is going on. But when it has new plugs and new oil, and the correct timing on the car...it was pretty good. But I am also 1000% sure it has quite a lot more spunk to give. And then there is that gassy/exhaust smell when you roll down windows. I hope that installing my new fuel injectors will help it get better. This is probably the case where there are multiple problems...and I am just going to have to eliminate them one at a time.

As far as burning that much oil, remember, I was adding a lot of sea foam and that star brite stuff. So we can assume the piston rings are somewhat shot, that means some of the seafoam and some gas is leaking down into the oil in the engine, and thinning it out. Which would make it burn up faster than it should. now that I am done using seafoam, it would be interesting to see if it still burns up that much oil. I am just guessing that it was 3 quarts based on how far down on the dipstick it was.

There are a couple of pics of it....before and after I added new tires and rims, and side louvers. I also added an air dam which definatley stablized it at interstate speeds. Also when I first saw it on the showroom floor in 2008 in chicago. Thats when I saw it, drove it, bought it.

But she is still definately sick and needs help. Its going to be along uphill battle.

If you're going to keep your Z and have the time and resources and attitude that you have here, you should sweat the To-Do list that the rest of us have done. A good and cheap place to start is to replace worn lines, and clean electrical connectors. I'm sure the MO for most people is to get their car running good ASAP. But if you don't mind some side projects...

Compression in all cylinders at least 75% of one another is fine for a street car. You're over 90% yourself, and are just fine. It seems to me that your compression numbers seem too agreeable to have oil ring leakage that severe. Are the numbers you have before or after they inserted oil into the holes. You can "make" tight numbers like yours by doing stuff like that...maybe you can get a compression tester and test your compression yourself?

I agree that changing your oil at this point would be a good idea. For a few other incentives: It would be good just for you to have a handle on exactly how much oil is in the car. I'd do a hot oil change and take your time. Let the oil drain awhile. Record how much comes out Inspect again for leaks. Observe how quickly the new oil fills the pan. How many miles are on the old oil? What color is it? How does the oil pan gasket look? Since you're identifying symptoms having to do with oil, it'd be a good idea to get yourself hands on with the oil maintenance for your car.

Inspecting a lot of things at this point will be good for you to learn about your car. It's amazing what having things right in front of your eyes under a lit flashlight can do for your wisdom. :bulb:

Presuming nothing major is wrong and just going by your compression numbers, if I had your car, and knew I was going to keep it, I'd be considering a rebuild somewhere down the road. 225-250k miles, perhaps.

Edited January 10, 201114 yr by Jennys280Z

Good advice from everyone! Yeah, what they said!

I still think it's electrical! Fresh oil change, ignition, clean connectors. You should know a lot more after that.

About your "dumb question" -- If you have scrap lumber sitting around, try this: Set the emergency brake, and put your car in gear. Put a jack under the control arm of one of your front wheels, and jack several inches. Put a couple of 2x6 blocks under the tire, and release the jack. Jack the opposite control arm, and put 4 2x6 blocks under that tire. Jack the first control arm a few inches more, and add two more 2x6 blocks. Then you'll have 4 2x6 blocks under each tire. Change your oil, and then remove the blocks in the reverse order -- first two on one side, then four on the other, then the remaining two. You can also use jack stands, but they're frankly a bit difficult to get under there -- even the short ones.

If you want to get fancier, buy a pair of ramps, but be aware that they like to scoot when you're driving up on them, unless you somehow block them. Another method is to do the above with a couple of 2x6 blocks and two ramps. Substitute the ramps for the 4-block stack. When you're done, just back the car off of the ramps. Easy.

Edited January 11, 201114 yr by FastWoman

I definately want to learn a lot about the car. Its one of the reasons I bought it. :-) And yes I plan on keeping it a long time. And I have it insured for agreed value as stated in my policy. As I have done more work to it (or rather had more work done to it) I increase the insurance value more.

I have learned a lot, but nothing compared to how much I want and need to learn. I thought about the ramps but they seem way too dangerous and easy to drive off of. I am somewhat leery of using jack stands. So I will use your idea. I want to be able to get the car up in the air, as safely as I can...when I need to get under it. Thanks.

It does have fresh oil in it now. Maybe 100 miles on it, since the oil change. So its about as clean and shiny as its going to get. And then its been sitting since early december when the snowy roads happened. And I am trying to find connectors anywhere in the engine and pull them off and inspect them. I did see some corrosion on that water temp sensor, but not like it was caked on there and oozing out of it. But maybe a small thin layer on the male and female ends. So I scraped it off as best as I could, more down to the metal on the connectors.

I took a small pick and small screwdriver and cleaned the male and female ends of the connectors on the water temp sensor in the front of the engine. I heard if that one particular sensor gets green corrision...that can stop the car dead like I experienced. So now, I am thinking I should clean up all the other connectors in the car, in the same way using a pick and small screw driver to scrape off debris.

Is that an OK way to clean out those connectors? I dont know how else to do it.....because the connectors are mostly enclosed are hard to see. I dont want to do more damage than good.

Compression in all cylinders at least 75% of one another is fine for a street car. You're over 90% yourself, and are just fine. It seems to me that your compression numbers seem too agreeable to have oil ring leakage that severe. Are the numbers you have before or after they inserted oil into the holes. You can "make" tight numbers like yours by doing stuff like that...maybe you can get a compression tester and test your compression yourself?

I dont know if my relative who did the initial compression tests squirted a little oil in there before they did the tests. The next time I get to talk to him I will ask him. The fact that there were little puddles of oil underneath each spark plug seems to tell me that he did it, or maybe mechanic#2 did it too. But I swear I didnt see him putting any oil in those before doing the test.

Edited January 11, 201114 yr by argniest

Good advice from everyone! Yeah, what they said!

I still think it's electrical! Fresh oil change, ignition, clean connectors. You should know a lot more after that.

About your "dumb question" -- If you have scrap lumber sitting around, try this: Set the emergency brake, and put your car in gear. Put a jack under the control arm of one of your front wheels, and jack several inches. Put a couple of 2x6 blocks under the tire, and release the jack. Jack the opposite control arm, and put 4 2x6 blocks under that tire. Jack the first control arm a few inches more, and add two more 2x6 blocks. Then you'll have 4 2x6 blocks under each tire. Change your oil, and then remove the blocks in the reverse order -- first two on one side, then four on the other, then the remaining two. You can also use jack stands, but they're frankly a bit difficult to get under there -- even the short ones.

If you want to get fancier, buy a pair of ramps, but be aware that they like to scoot when you're driving up on them, unless you somehow block them. Another method is to do the above with a couple of 2x6 blocks and two ramps. Substitute the ramps for the 4-block stack. When you're done, just back the car off of the ramps. Easy.

Ramps scare me. Okay? I admit it.

But I don't like how high my jack stands makes me jack my car up either. I feel safe when I'm under the jack stands (though I've learned i have a mild claustrophobia)

I wish I had an elevated surface that was also really long I could easily drive up onto. Or better yet, one of those garages like they have at Minute Lube where I can stand up straight and access the bottom of my car! Why don't they rent garages like that out by the hour, btw? I'm sure crazy people like us would fill that niche of the market.