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what to do first?


Guest grunt0311

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Guest grunt0311

well no air leaks but still can't get it to stay started without flooring it and it just seems to idle then. Can smell alot of fuel. As I said earlier drained the tank, changed fuel oil and filters new plugs and wires cap looks good no air leaks on vacuum hoses. What next?

 

 

 

semper fi,

john

76 280x auto (dusty) still in ICU

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Hey John,

 

I`ll just throw so things at you (more than just this weekend)!

 

Buy a NISSAN repair manual for your year!

 

Drain old fuel from tank, change fuel filter, ck all fuel hoses (there are some in back under car by the tank) and once running have the injectors cleaned!

 

Ck drive belts /coolant hoses / water pump!

Change thremostat and coolant!

 

Ck ALL suspension parts, ftr & back!

Make sure you know the car is safe!

 

Pull the wheels, ck frt and rear brakes / ck brake hoses, replace if you see any cracks!

Change the brake fliud & bleed brake system!

 

Change ALL fliuds (trany / diff/ engine oil)!

 

I`m sure I missed items to do, others will probly add to, or give you other items that need to be done as well!

 

Anyway, enjoy it! Z`s are great and FUN cars to drive!!!

 

Pics

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Guest De Schmaydee

hell,

...somebody send this man an fsm (for free)...show a little appreciation for what they ("the military")have to do for us......i'd send you a 79-83 but it wouldnt do you any good.....s

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Guest grunt0311

Thanks everyone,

 

I drained and filled the engine with oil. Cleaned and gapped the plugs, drained and filled the tank. It turns over and backfires out the air filter, my neighbor says it is the timing. Cleaned the hell out of it this weekend to make me feel better. I had to close the garage door because I felt so stupid about washing this thing in front of everyone when it is old faded red primer but after it was done it did look better. Will keep everyone posted and again thanks for the help. I hope it is the timing. Oh anyone no how much a radiator should cost I think this one is leaking, junkyard is fine.

 

john smile.gif

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  • 3 weeks later...
Guest grunt0311

Found a radiator now to try and figure out the backfiring in the manifold. Someone told me check the timing, I also heard to check AFM and the cold start valve. I also found a fsm so I guess I have some reading to do.

 

john

76 just won't stay running unless floored

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One more thing to look at is the distributor cap...pull the 2 snap clips and look under to see if there is carbon scoring - if yes then repalce the cap & rotor. Then make sure you have all the plug wires going to the correct cylinders. Also check the wires as the probally are tired. If you can swing it I would go ahead and replace the wires, cap & rotor at the same time. If you get it running check for vacume leaks as they will have to be fixed before you can tune & adjust on it.

 

Good luck & thanks for your service! :D

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Backfiring out the intake is normally due to a lean mixture. Check all the electrical connections that are part of the fuel injection system (air & water temp sensors, AFM, injectors, ECU, thermotime switch, etc.)

 

As said above, check the dist. cap, rotor, plug wires, etc. and then set the timing.

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Get fresh gas in it first. Drain what's in there and replace with a full tank of fresh gas. History is very important in troubleshooting but you don't have that luxury with an impounded car. If there are plates on it you may be able to get an idea of just how long it has been sitting.

 

There are many things that could cause the problems you are having but try to keep the process focused, e.g., sure, timing can cause a backfire and since it's easy to check, go ahead; but realistically, unless there are signs that the distributor had been moved around just before it was parked, it's not way up on the algorhythm and is below checking the strength of the spark, insuring all injectors are functioning, there's adequate fuel pressure, the plug wires are on the correct plugs, etc. Establish the basics first and then start refining your troubleshooting. Otherwise, it's easy to get all muddled up. When you hear hoofbeats, think horses; not zebras. DAW

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Guest grunt0311

ok I have the oil changed , wires changed, cleaned the plugs, drained the tank and put in new gas now the darn battery lost its charge. I will get back with y'all after I give it a charge. Thanks for alll the input. While it is charging I did put in some of the door weather stripping from a Hundai Hyundai? excell almost fit perfect just a little trimming and cost almost nothing.

 

john

76 280z still trying

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Guest grunt0311

Ok, Here goes what happened. I try and crank without touching gas it just cranks. I pump it a few times and let go and it starts but quits shortly or if I try to feather the gas. When it ran for about 2 seconds it sounded good. If I hold down the gas while starting it will start and backfire through the manifold. Any ideas? The afm look like the black plate has been taken off and put back on because their silicone around the edges.

 

thanks

76 280 z still trying

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Guest grunt0311

--------------------------------------------------------------------------------

well no air leaks but still can't get it to stay started without flooring it and it just seems to idle then. Can smell alot of fuel. As I said earlier drained the tank, changed fuel oil and filters new plugs and wires cap looks good no air leaks on vacuum hoses. What next?

 

 

 

semper fi,

john

76 280x auto (dusty) still in ICU

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Smelling a lot of fuel is significant. I think the '76 had a cold start valve. Use the manual to locate the valve and unplug it, or better yet, pinch off the hose to it as it may be stuck open and dumping fuel. Check other things that would cause excess richness: on some engines around this vintage it is possible to cross-up the wires/connectors to the water temp sensor with other sensors which share the harness running along the intake manifold side of the valve cover. If the water temp sensor wire(s) are disconnected or crossed to another sensor, the message to the computer is that the engine is being started and run at sub-zero temps and the computer will send maximum fuel to the injectors, flooding it out. The wires I'm talking about are dark green and the one with a white stripe may be crossed with the one with a yellow stripe.

 

The AFM with the silicone sealer suggests it's been tampered with. Check the action of the flap/door: can it stick or is it stuck? The spring tension may have been fooled with and that will directly affect the mixture the engine sees.

Check the TPS per manual. Check the fuel pressure regulator...at least plug a test vacuum line to it, suck on the line and plug it with your tongue, and see if it holds vacuum pressure. If it doesn't, the diaphram is ruptured, and it will allow fuel fuel pressure at idle; flooding it out. Good luck and follow through with feedback. DAW

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Guest 240hybrid

If the AFM has been tampered with that might be a point of focus. I think I remember a guy having the same prob. with backfires through the intake, and if turned out to be his AFM. Like DAW said, is the silicone holding it up or causing it to stick??

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Guest grunt0311

Man this is turning into a nightmare! The afm looks new on the inside I can't tell that anyone has messed with it. Turns out I burned out the selonoid somehow so I am jumping it with a screw driver. All the wires have been painted or replaced in black but they seem to be in the correct place. The radiator I put in is full and after I crank it a few times I see water coming from the intake side of the block. I crawl under and it looks like the head gasket is leaking. The oil looks good but I have only cranked it and got it turn over a few times since I changed the oil. Still not running and I think I am going to go get a beer or 10. Oh yeah it still won't start but I guess I have a bigger problem now.

 

76 280z (driving me to drink)

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One more thing to look at is the distributor cap...pull the 2 snap clips and look under to see if there is carbon scoring -
Want to second this. "carbon scoring" means dirt on the inside of the cap is causing the cylinders to cross fire. If a plug fires when the intake is open, backfire through the intake. Same for cracked ignition parts (wires, coil, dist cap, etc.)

 

You're problem could be multiple things. Get the spark situated first. If it was carburated I would say stuck needle valve/float. Maybe stuck injector (or two?)

 

Wasn't there also a guy on here a week or two ago who could idle but died as soon as he touched the gas? Turned out to be the distributor module was bad (forget the name).

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