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Hello guys! I'm new to this forum and recently new to the datsun world I purchased a 1981 280zx datsun that has been sitting outside a barn for about 4-6 years and since it still had the engine I decided to see if I can get it running before I even consider swapping the same l28e or if I get lucky the l28et. The first things I did was: change the oil, replace the fuel filter flush tank and replace gasoline (regular) replaced battery with terminals flush and replace coolant, spark plug wires (all in correct firing order) change ngk spark plugs (gaped .42 and added oil in each cylinder for lubrication) I cranked it with no luck, I heard the oil pump running loudly but decided to use starter fluid. Once started fluid was sprayed and the engine was cranked and the engine started and was running on starter fluid so my next steps were: clean injectors clean fuel rail replace o rings and insulation I cranked it again without starter fluid and it only cranked but didnt start. So I did a compression test and numbers were 140, 145, 145, 140,145, 155 so compression is pretty good being that 180psi is like new. I removed the fuel return line and cranked the engine and gasoline came rushing out, I tested the spark and its a blue with white tint, engine sounds like it wants to start so timing is good (?), exhaust smells like gasoline and has pulses, and it still doesnt want to start. Each time i remove the spark plugs after attempting to start it, i can see a little wetness on the tip and it smells like gas. It started once with starter fluid but now it just doesnt want to even with it. What do you guys think can be the problem? thank you!

I did a compression test on my recently rebuilt 260z engine. It has about 1500 miles on it. On the dry test with the carb fully open and the coil wire off I get the following results # 1 thru #5 came in at about 72 lbs but the # 6 came it at around 90lbs On the wet test all came in at 90 lbs including the # 6. I am rather new to this and this is the first time I have done a compression test, so my questions are- why would the # 6 not change from a dry to wet test. The warranty expires next week on this engine and I wanted to do this test prior to the warranty expiring.Is this something to be concerned about? Thnaks zdude1967

I recently completed a compression check on my 1976 280z It's all original from what I was told when I bought the car... Engine Has 103xxx Miles on it... and the Last 3xxx I have driven. It hasn't had any major issues in the past that I am aware of, but I did have to reseal the fuel tank and clean out and replace a few fuel Injectors. Results: Cylinder Pressure ..............(Dry).....(Wet) 1 ... 130 ... 140 2 ... 120 ... 130 3 ... 80 ... 90 4 ... 110 ... 120 5 ... 120 ... 130 6 ... 110 ... 120 I don't Know what the pressure should be but, I'm pretty sure 80/90 on one cylinder isn't right. The car accelerates kind of slow and always has(its an old automatic transmission never really expected anything super amazing). It tops out at about 35/40mph(which isn't right I was getting to 70 on the highways before this issue). And It makes a Metallic clicking sound once it hits 3000-4000rpm. Any help or advice would be appreciated.

The other day I had my 260 out and the pedal got stuck under the floor mat. In any case it revved pretty high before I could release it. Now I have a loud valve tap and the # 5 cylinder seems to have lost compression. I did not do a compression test but rather a simple finger over the spark plug hole. Could I have bent a valve? It over revved for maybe 20 to 30 seconds. Can these Z engines typically have piston to valve contact. The head was rebuilt 500 miles ago, timing chain etc all new. Any ideas or suggestions would be appreciated Thanks Glenn

Hi, I just had my 260 engine rebuilt. It is running like s**T. I did a poor mans compression test (finger over the spark plugs while cranking engine) and the # 5 seemed to have no compression. In any case the engine is under warranty and the company that rebuilt it seems to be rather clueless. I say this because they want to check the carbs as they think this may be the issue. Now I do not claim to be Mr. Goodwrench but my understanding of this engine leeds me to believe that if there is no compression or very weak compression it would either be the valves or the rings. Would someone please let me know if there could be other reasons besides the rings or valves or if I am clueless with my ring/valve theory. By the way they claimed they checked the valves and that they are fine which is why they are moving to the carbs. Thanks Glenn

:disappoin I was warned and worried about fouled/contaminated fuel so I wanted to do a lot more fuel-prep work than just drain and refill the gas tank. I pulled the gas tank, got it cleaned at a local shop who gave it a Castic acid bath for a day, got it back last week but haven't reinstalled it yet. Blew all the bad gas out of both the feed and return lines with an air compressor (the feed line between the fuel damper and the fuel filter; the return line between the fuel rail and the fuel tank). The fuel in the feed line had some black flakes in it, the fuel in the return line had a bit of thick white junk similar to a jelly but otherwise the decade old gas looked clean and new in color. Changed the fuel filter, changed the oil and oil filter, drained and replaced coolant, replaced a bad fuel hose, replaced the leaky bypass hose(s) (why I stopped running it long ago in the first place), got some 93 octane gas with some gumout fuel system cleaner in it, and here I am. I have a 2-gallon fuel container sitting on a box right behind the fuel pump I'm feeding the fuel hose with gas. Incidentally, I have the rear of the car up on jack stands (using the proper jack stand points as instructed by the repair manual). The rear wheels and drums are off (bad break hoses and brake fitting nightmare but that's another story) and I don't think this has anything to do with why the car won't start. :stupid: The hole on the container was wide enough to put the return hose in there as well, I've already verified the fuel pump is pulling fuel at a good rate, and there is fuel coming out the return hose when I'm cranking the engine. I verified there is spark in #2 and #3 cylinders by using a test light. I hooked the negative alligator clip up to ground and stuck the needle up against the metal contact inside the rubber boot of the spark plug wire and when someone else was cranking the engine I could see sparks in there. The cranking is really healthy sounding. Not too fast, not too slow, just like I remember it when it was running. It just won't fire up. I lifted the distributor cap to inspect inside. There was a bit of corrosion on the rotor head and contact points. Nothing to keep the car from starting I would think. I cleaned them up and put the cap back on. I felt air pulling into the air filter housing when the car was cranking. I know these are rudimentary checks I'm doing but I'm afraid I don't know much. Most of what I know about my Z I've learned in the past three weeks just reading the repair manual and hobbying away on it. Suffice it to say removing the fuel tank was a challenge for me, especially the venting vapor lines, but I succeeded at it without breaking anything. Not looking forward to putting the tank back on. I presumed it would be running by the time I got to that point. Anyway, I read elsewhere on the site that vacuum hoses can prevent the car from starting. There are some small rubber hoses around the distributor I observed today that were cracked and hardened and didn't seat together that good. I'm not sure why the timing would be off, it's only sat in the garage for 10 years. Not sure how to check for a bad timing chain or even set the timing. I see the adjustment screw on the distributor and I see the two little plates with the lines on them, and that they're offset from each other by a certain angle. If the rotor head spins counter-clockwise, the little bit of white corrosion on it would have been closer to the leading edge of the head rather than the trailing edge (relative to the middle of the rotor head). I presume this would signify a more "advanced" timing than "retarded" timing. Which is what I figured already anyway: The car is advanced and I'm retarded, it's okay, it doesn't mean that life is unbearable. I pulled the spark plugs out last night. They were all blackened on the electrodes and the insulators. I lightly sanded them and wiped them all clean and checked their gaps with a feeler gauge I bought. Not really sure how tight the fit is supposed to be but they all seemed to be gapped around 0.8mm. Anyway the car should be getting fuel as the pump draws the fuel out of the container nicely and I have fuel coming out the return hose. Doesn't mean the injectors are good but I don't know how to check the injectors and wouldn't they go bad one at a time? Would two or three bad injectors keep the motor from starting? I have spark inside the spark plug wires by using my test light probe grounded to the (-) battery terminal, but that doesn't mean it's a "good enough" spark. I haven't done a compression check. Seems self explanatory enough to put a compression gauge into the spark plug holes and check the cylinder compression but I don't know if this is a likely culprit of why it won't start at all. Seems implausible to me that it would prevent the car from starting when it ran very well the last time it ran a decade ago. Anyway, any general wisdom of what/how to check next, or most-likely-culprit information would be greatly appreciated. :stupid: Thank you in advance! Shawn