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Hello fellow Z Enthusiasts, I'm at my whits end here from this Darn Datsun. I've got a 1983 Datsun Maxima, and I can't for the life of me figure out how to get this thing running properly.

 

A-little backstory on the car;

 

The car used to belong to my grandfather, and when he passed away my father inherited it and drove this old girl everyday for 5 years to work, All the way up until the point the engine slipped its timing gear, then it sat for another 7 years until I was old enough to understand cars and not hurt myself while working in the garage. After purchasing a new timing chain and replacing the old one, the car ran fine. Well, my brother was using the car while his was in the shop during this last summer, but the dummy doesn't know a THING about cars and never checked the oil, water/coolant level, etc.; pretty much everything that you need to check on old cars to make sure they dont explode while driving them. Well, this time he didn't check the water level, called my father asking "why it was overheating all the time". And as he was driving it back to our house, the poor car blew the head gasket. Months of work down the drain (and wallet, mind you). It sat for another 2 months, until we managed to get the money to buy a new gasket. (Now THAT was one heck of a time, trying to figure out how to take the head off) We eventually got it replaced, but and hooked everything back up, but upon starting the engine we realized it wouldn't drive correctly.

 

Let me explain;

 

When you started the engine, it would idle great. It revved in idle like a dream as well. Then you'd try driving it; Ohhh boy, was there a problem. The thing would lurch and pop forward worse then a dang blender paired with a v8 engine runnin on 3 cylinders.

 

Back to the garage I suppose.

 

Everything looked fine, but we read in the manual that the oil pump timing gear needs to be 5 degrees past the time marks at 8degrees past TDC. Well, we were off, so we tried setting it how the book looked.

 

Tried again.

 

Cranked and backfired, and eventually got it started that way, but even then it ran so bad that it would die when you gave it just a tiny bit of gas.

 

Back to the garage...

 

We noticed that when we turned the distributer clockwise, it would run better, so we decided that instead of setting the Oil Pump Timing Gear at 5 degrees PAST the timing marks, we'd set it 5 degrees BEFORE the timing mark, still at 8 degrees TDC.

 

Started it up, and amazingly it ran. It ran actually pretty good, which was surprising because it was the complete opposite of what the book called for. Our engine, a L24E non-Cali engine runs OUT of time, not IN time. But it was still out of time and not "drive able" (still lurched) and after hooking up a timing light to the engine, we discovered that the car would idle at 20 degrees, then drop down to 0 when you gave it gas, which would explain the lurching and backfiring.

 

We thought we'd messed up on timing chain, so we checked that but it looks just like its supposed to.

 

After a month of trying to time the car with the Oil Pump Timing Gear, we called 9 to 9 and Tom said that we needed to reset the computer. He said no matter what we did, the engine was fighting to put the engine back in time, so after a quick reset, we'd need to retime the engine again and it should be good.

 

Well after resetting the computer and retiming the engine, the engine wouldn't even start this time. After fiddling with the Distributer and Timing Gear again, we got it running, and the engine now advances correctly when you give it gas. It no longer drops to 0, it goes up with the RPMs.

 

We then tried driving it...

 

Same thing again, only this time worse. It lurches so bad it could give you whiplash if you weren't careful. We think it may be a vacuum line, but they look hooked up correctly and we can't find any leaks, so we are literally going insane trying to figure out this engine.

 

If anyone's been through the same problem or has an idea on what the problem might be, let me know what I could do to try and fix this.

 

Thanks!

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This may seem like an extremely simple question, and apologies if you have already thought of this.

 

But....Are you sure the issue is timing related? Rust in the gas tank and fuel pump cavitation will absolutely cause those sort of problems.

 

Seems that your timing was off originally, which you have since remedied, that's good. But if you're experiencing the same symptoms, that leads me to believe it is not ignition related, but fuel delivery instead. You also noted the car has sat for various extended periods of time. Another potential clue.

 

This happened to me once. I had sediment in the tank. Car would idle wonderfully, but under load it would backfire, pop, and gasp until I stopped moving. The particulate would then settle enough to idle normally again..until I tried moving. This was before I installed a pre fuel pump filter. Drained the tank. Inline filter. Problem went way.

 

 

Rust/detritus in the tank, leading to clogged filters, or line blockage can definitely lead to what you are encountering.

 

Again, apologies if you have already confirmed fuel pressure.

Edited by OldAndyAndTheSea
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Just looking at the vacuum lines is probably insufficient, a small slit or crack is awfully hard to find.

 

Try the carb cleaner trick and see if the RPM's kick up at idle

 

If the timing issue has been solved, which still not 100% sure it is (have you put it at top dead center and checked the cam position and the distributor clocking angle), then it does fall onto more of a fuel issue.

 

Like with all help threads, can we get some positives? 

 

Have you looked at the fuel filter to see if it is letting sufficient fuel in? A simple test would be to pop it off and try to blow through it. 

 

What state are the spark plugs in? I suspect awfully whitish or light grey.

 

Sufficient gas present in the tank?

 

Keep the info coming, and try not to drive it too much, if it is popping and lurching because it is running lean you can hurt the motor if you put it under load under that condition.

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The computers don't reset on those old cars.  Whoever Tom is, he might be a nice guy,but he doesn't know anything about your car.

 

You said that timing chain was correctly installed but you didn't mention the notch and groove.  You might be looking at the wrong things on the timing chain to determine correct installation.

 

It's been said that the L6 can warp a head after one overheat.  You described many.  Have you checked the plugs for coolant or pressure leakage?  A cylinder pressure test would tell you if things are right or not.

 

ThE 280ZX FSM's should be close enough to the L24E engine to help you out.  Check Engine Mechanical and Engine Fuel and Emissions Control. The 1981 Fuel Injection Guide is good also.

 

http://www.nicoclub.com/FSM/280z/

 

http://www.xenons130.com/reference.html

 

Edit - could also be something simple like firing order.  These engines will run with the wires placed in reverse, on just the two or three cylinders that fire.  Best to confirm the basics.

 

And this part sounds like you have your vacuum advance line connected to full time vacuum instead of ported.  " the car would idle at 20 degrees, then drop down to 0 when you gave it gas".  Basics.

Edited by NewZed
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