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Having either fuel or spark related problem


Guest ZmeFly

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At least thats how it acts yet I cant find a cause. My 83 ZXT, after being warmed up runs and drives fine, idle is good as well but only when i shut the car off and let the turbo timer take over. This will not happen all the time but most of the time, the car will idle like it has a huge miss, watching the air/fuel gauge notes it from running right on the edge of rich and dropping to lean when this "MISS" happens.

 

Its as bad as to where the car almost seems like for the split second it shuts off. I cant figure this out everything is new less the fuel filter, but I cant see how this is the culprit concidering how well it runs any other time.

 

Fuel mileage has not suffered at all. All but the fuel filter being new on a almost complete tune up. The turbo timer I have is a Blitz Dual TT.

 

Anyone have any recommendations?

 

Thanks

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That might be the problem.. some aftermarket O2 sensors are just 'one unit fits 5 different cars' kind of things, but it may not be quite right for the Nissan.. or it could have failed prematurly (also a problem with some aftermarket non-OE sensors and elecrtonics) Something else I thought of.. what kind of plugs are you using?

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Almost sounds like an electrical short, whereby the short is resulting in electrical feedback to another component: which somehow affects either your ignition or your fuel, or both.

 

This component, at certain conditions, will build up w/this unengineered and unexpected electricity; it then builds up w/this electrical charge to the point where it either has to overheat (fail) or discharge that extra electricity. To which this component then releases that electrical charge and voila-everything runs fine again: until the next cycle.

 

I once had an electrical gremlin on my Z: bone stock 280Z 2+2 whereby the engine would miss. I discovered it would do so at any rpm but it was only when my A/C was on: this miss also corresponded to the exact moment when the A/C compressor clutch would magnetize (click on). Upon closer inspection I found that someone, prior to my owning the car, had rerouted the feed wire to the distributor incorrectly. By doing so the distributor feed wire was sitting on the compressor clutch pulley. Thru time the turning of the pulley ground the wire bare-so everytime the clutch was engaged-the distributor signal was interrupted...shorted, which caused me to lose power.

 

Just a long story to basically say-dont give up and keep looking. Your problem sounds like the signal to your ignition or fuel system is being interrupted for some unk reason. Can you think of any other variables when this problem occurs? Is your A/C on? Is it only at higher rpms/lower rpms? Is it only in the daytime/night time? Are your turn signals on/off...ect.

 

Sorry, no actual solutions-just more thinking out loud: it definately sounds like a wiring short of some kind. Have you checked all your grounds to all electrical components that your new wiring harness connects?

 

Kevin,

(Yea,Still an Inliner)

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datsunlover yes its a (dont hate me, it was all I had the money for at the time) GP Sorenson O2 sensor. I use only NGK plugs and wires, the plugs are BPR7ES11's gapped at .38 or .40 I cant remember what I set them at.

 

Kevin, the ac is gone, the time that this happens is ONLY during cool down when the turbo timer is running the car. Before I shut the ignition off I make sure all other items (as prescribed by Blitz) are off, ie radio, heaters, lights and so on.

 

While Im driving the car all is well, even at stop lights, though if I am at a long light it will do it slightly but not to as high of a degree that it does when cooling down.

 

Could the relay for the TT be causing this, ie going bad or on the brink of just shutting down completly? I just cant understand this, its making me nutz

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Separate the TT and its realy from getting any power.

 

Drive the car for a day or two (and just stay out of the accelerator-dont push the turbo any harder than needed to comute).

 

See it the problem shows up or not.

 

If the problem doesnt surface after isolating it from the rest of the car/engine's circutry then you have found the source: then either the TT & its relay are defective or they have been installed in such a manner that they are getting/giving electrical feedback from/to your ignition system.

 

Have you tried calling the mfg of the TT & its relay-perhaps they will know exactly what the problem is....maybe a diode in the harness somewhere is all that is needed :?:

 

Kevin,

(Yea,Still an Inliner)

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