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new 240 rebuild, will not start.


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I am restoring a 71 240z. I just put the motor back in after the rebuild , basically everything is new or rebuilt, rebuilt SU's from Z therepy. new coil, rebuilt distributer, rebuilt fuel pump, the car started and ran badly for about 10 minutes. turned it off to address an oil leak, went to start it back up and it wouldnt start. I noticed the fuel filter was only half full, should it be full? I checked the lines from the tank , I thought maybe it was sucking in air from the rubber lines at the tank. also bypassed the tank and had the fuel filter draw gas from a gas can. still didnt start. I adjusted the distributer timing from full retarded to full advance. checked for spark, its there but doesnt seem that stong, it is only stock coil and distributer but the car ran for 10 minutes before so thats probably not an issue. there is 6 and a half volts on the coil's positive side. not sure where to go at this point. the engine acts as if its going to start but does not. fuel, spark, timing?

 

Chris

 

 

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try a fresh battery. you should have about 8 volts at the coil. Check your plug order 153624. You might stop and check your timing. Put engine at TDC, put Dist at #1, Cam lobes should be pointing up at a V on cyl 1. All that should say you're okay.. Next check the AFM. it's got a flap inside, push it up and down a few times, and see if that makes a difference. Let us know what you find out.

 

Phar

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honestly having rebuilt a few different cars and truck I find that you almost never have a new componant related isue it's always something stupid like a disconnected cable, a missing ground or something along those lines. I recomend combing through, assuming nothing and just follow everything to it's completion

good luck

Edited by drive185mph
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Thanks for the replys,

 

It is a new battery, new distributer, Points, cap , rotor, litterally new everything. Today I found compression in all cylinders is 120, ther is NO vaccume when I am turning the engine over. From what I have read there should be 5-10 of vaccume? when I could get it running for a couple seconds. using the throttle had no effect. also some of the plugs were blackish semi wet. Steve at Ztherepy told me to change the plugs. I did that today, didnt seem to have an effect. A massive vaccume leak? out of ideas.

 

 

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Fuel Pressure is 3-4 pounds, I have checked the timing at least 20 times, started at center, retard, advance. have spark, unless I am doing it wrong. when the crank is on TDC (this is the first big timing mark correct? ) the lighter chain links is on the 1 mark on the cam timing sprocket, distributer rotor is pointed at #1. when it initialy ran for those few minutes it was very uneven, but did respond to the throttle. shouldent there be some vaccume when cranking it over?

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Fuel Pressure is 3-4 pounds, I have checked the timing at least 20 times, started at center, retard, advance. have spark, unless I am doing it wrong. when the crank is on TDC (this is the first big timing mark correct? ) the lighter chain links is on the 1 mark on the cam timing sprocket, distributer rotor is pointed at #1. when it initialy ran for those few minutes it was very uneven, but did respond to the throttle. shouldent there be some vaccume when cranking it over?

 

Yes there should be some vacuum.  Are the plug wires crossed?  Mixed firing order can produce those symptoms.  Sorry if my advice is basic, but it sounds like something basic is off. 

Edited by cygnusx1
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double, tripple , quadrupple checked all things timing. I reran the wires just to be sure. I am almost to the point of pulling the carbs an intake off just to check the gaskets. i am using a intake\exhaust gasket from MSA, stock intake, 3 into 2 headers. everything on the intake has been plugged off. I only know how to check for intake leaks if the engine were running. Used no sealer on the carb gaskets or intake.

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  • 1 year later...

Ok, The car has basically sat for a year while I moved. looking for any help I can get.

 

The car will not idle consistently. I can play with the choke to get it to start. it will then run(sometimes) it will usually start climbing in rpm's. even if I play with it and can get it to idle at 1200 rpm, it will occasionally spit throuh the carbs and will still die eventually. very inconsistent.

 

Again the carbs are from ztherepy, basically everything is new. if it was just a carb issue. you would think I would be able to get it to at least stay running. I cant seem to find any obvious vaccume leaks.

 

Any Help is Greatly appreciated.

 

Chris

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Ok, The car has basically sat for a year while I moved. looking for any help I can get.

 

The car will not idle consistently. I can play with the choke to get it to start. it will then run(sometimes) it will usually start climbing in rpm's. even if I play with it and can get it to idle at 1200 rpm, it will occasionally spit throuh the carbs and will still die eventually. very inconsistent.

 

Again the carbs are from ztherepy, basically everything is new. if it was just a carb issue. you would think I would be able to get it to at least stay running. I cant seem to find any obvious vaccume leaks.

 

Any Help is Greatly appreciated.

 

Chris

 

It sounds like the idle mixture is too lean. Check for vacuum leaks. Use a spray cleaner or starting ether to locate vacuum leaks. Spray it at likely places such as the intake manifold gasket, carb base gaskets, and so on. Do this when the engine is cold if possible to minimize the risk of starting a fire on the exhaust.

 

Check the PCV and the brake booster. Disconnect their hoses at the manifold and plug the ports.

 

Other things to check:

 

Throttle opener adjustment (if it is still installed).

Ignition timing.

Make sure the vacuum advance is connected to "ported" vacuum, not manifold vacuum.

Choke cable adjustment.

Throttle linkage adjustment.

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OK, Not sure why this made a difference, I move the distributer shaft over a tooth and reset the distributer to center. it stopped sputtering and with the choke on it will run 2000 to 2500 rpm. it will stay running now but will not idle or run at all with the choke off.

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I Checked all the above recomendations and nothing. Does the distributer drive look like it could be a tooth off?

this happened to me on my rebuild, it looked right just like in the pic, but i was a tooth off, after i moved it a tooth, no more problems...i went thru the exact same symptoms as you..try moving it a tooth, u can always move it back..

hope u get it figured out!

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i moved it a tooth, it stopped suttering but will not run unless the choke is on.

 

Will it run with the choke off if you hold the throttle open?

 

How are you setting the ignition timing?

 

A large vacuum leak would explain this. Are you sure there is no vacuum leak? Is the PCV installed? Correctly? How about the Master-Vac? Perhaps it is leaking. Try unhooking the vacuum hoses for these at the manifold and plugging the ports.

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