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78 280 z L28 Wont Start


TieFighter88

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Bought a 78 280z from a dude for 1000, fresh L28 engine in there apparently... she had been sitting for almost 2 years and now I am trying to get the engine started.

 

I replaced all of the fluids and serviced pretty much everything: Oil, radiator, fuel pump/lines, air hoses, electrical connections, injectors, relays, fresh battery, plugs...

 

Just wont start; dull backfiring when I turn it over...

 

I have spark on all the plugs, the distributor is fine, injectors are fine, fuel pump is fine, fuel pressure is fine, fuel relays are fine, ignition relay is new. The ECU harness satisfies all the tests from the service manual, I checked the whole harness for bad connections and she is clean now. Tried 2 different ECU units...

 

Still inspecting the accessory harness, the only symptoms I am conscious of now are:

 

No dash lights (except the map light)

the engine temperature gauge reads maxed

the radio doesn't work now

 

All the fuses are ok ... I am totally confused... are their any common simple checks that I am missing? This EFI is killing me... still working through the EFI bible also...

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yep, full mouth full of starting fluid, just makes backfiring more violent and loud. AFM is clean and connectors are all good and checked. I was worried that it was impeding the air flow to the throttle chamber. I can see it barely moves past half way open when attempting to start. I open the AFM myself and spray the starter fluid in there and when it ignited it just came back out from the intake...

 

so stumped...

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There are a few guy in Holly hill that were nissan techs in the late 70's early 80's. Amor tech on hand ave, right off of ridgewood.

 

Amor tech

268 Hand Ave

Ormond Beach, FL 32174 (7567)

386-672-6307

 

Pull out the fuel rail along with injectors and try and start it and see if the injectors squirt.

 

As for the temp gauge maxed out, that means the wire is grounding on something. Could be a clue, or just a corroded to hell temp gauge.

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You didn't mention timing. The backfires show that your ignition system functions. Check firing order, make sure the order is in the right rotation, CCW, and set your timing. 10 degrees is a good ballpark number.

 

I once had an engine that sat for only one year and wouldn't start until we squirted about a teaspoon full of oil in to each cylinder. They were dry, so there was no compression. Another possibility.

 

And make sure that every vacuum hose is connected, the oil filler cap is on, and the dip stick is in its tube. Plus no cracks in the AFM intake hoses. The crankcase and intake system have to be completely sealed so that all air goes through the AFM. If there's a leak to the crankcase, the PCV system will let air in and cause the mixture to lean out. A sign of lean is intake backfires.

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I did experiment with the timing, I have it set all the way to the bottom, this caused the most life in the engine while attempting to start... The firing order I have wired up is according to the typical L28 1-5-3-6-2-4 counter clockwise... All the spark plug wires are good and sparking consistently...

 

Triple checked for air leaks... First thing I eliminated after I could hear the backfiring.

 

I put a good 5ml squirt of mystery oil in each cylinder to sit overnight when I first tried to wake her up after the 2 year sleep... will add more oil and try again, the oil pressure gauge inside is moving but on the low end... although the dip stick reads full...

 

I did consider to pull off the rail and check to see if the injectors were actually squirting, I already serviced them tho and they are clicking nicely... will triple check from the rail tho...

 

Will rip the carpet up tomorrow and finalize the rest of the wiring before I start crying to the guys in Holly Hill, I know it has to be some simple electrical issue...

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Oil pressure on S30's will almost always read low, until its revved past 1500rpm. Do a compression test also.

 

I may also be able to lend a hand before you head to the shop. I have a 280zx, but all the EFI principles are the same.

 

The shop owner is ....eccentric. There are two, Sil and Juan. If you want you could even give them a call and chat up what could possible be wrong.

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I did experiment with the timing, I have it set all the way to the bottom,

 

These engines are known for having the oil pump gear off a tooth, which moves the distributor drive shaft off its mark also, putting you out of adjustment range at the distributor. You can at least eyeball a tooth on the reluctor (the six point iron wheel on the distributor) with the timing mark at 10 degrees, on the compression stroke. A tooth should be about centered on the pickup coil. Easy to do, and timing's important. Looks like you've done everything else.

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Did the car run prior to it sitting for 2 years? Who rebuilt the engine and are they a trustworthy source?

 

It could be that the damper inertial ring has slipped causing incorrect timing. Verify timing with a timing wheel and piston stop. A 7 or 8 inch wheel will fit so you don't have to remove the engine.

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Apparently she ran great, but again this is just from a dude on craigslist. He took my offer of 1000, I knew it was a gamble so I didn't offer any more. Plenty of bling throughout the car otherwise, so shouldn't be too burned if the L28 is dead...

 

After seeing the really poor wiring job I have to pursue all the harnesses and relays first, as they need love regardless if the L28 is running. Will get into more mechanics after I finish ripping up all the electrical tap hiding these finger twist splices...

 

More and more life in the electronics as I clean up the wiring one step at a time, only the dash lights/turning signals and radio are out that I can see now...

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I'm leaning towards timing after reading all the replys. You eliminated fuel by using the starting fluid.

 

Having you checked the rotor in relation to the motor at TDC? Pretty Sure the Rotor should be pointing very slightly above one. Someone else chime in here. I recall a pic somewhere in the FSM or maybe that was the drive spindle.

 

Is the stock distributor in place? Wondering if possible the Transistor is bad? Did you visibly see clean spark on all 6 spark plugs?

Edited by JSM
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Just tried putting a 5ml shot of oil into each cylinder to up the compression, felt like she had more kick and a soft putter. I adjusted the timing on the distributor just slightly with each attempt and could only flirt with the engine starting. Sounds so close.

 

The injectors are definitely squirting, the plugs were filmed up in gas when I pulled them. Will let her sit for a while tonight while I rip up the rest of the wiring in the interior.

 

I open the AFM and squirt starting fluid in there, to sit between the AFM valve and the throttle chamber and it just ignites and pops back out ... :0

 

Found two random wires spliced into the fuse box, will follow them back to see what this idiot has wired them to... please see below.

 

(how do I post an image on this forum?) only allows me to add a weblink...

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I'm leaning towards timing after reading all the replys. You eliminated fuel by using the starting fluid.

 

Is the stock distributor in place? Wondering if possible the Transistor is bad? Did you visibly see clean spark on all 6 spark plugs?

 

Visibly confirmed spark from each plug, consistent and not erratic. I have cleaned all the pickups and checked out the distributor and freshened up the spark plug wires...

 

The ignition timing must be off, but I have attempted to start with every possible timing setting on the distributor...

 

The fuse box has a splice to the AC fuse, and one to the Fuel Gauge fuse. The center console has switches to power the fan/AC compressor ... And the FUel Gauge works fine... Although these wires could lead somewhere else... worst wiring cluster dance I have ever experienced...

post-28059-056810500 1340233136_thumb.jpg

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I checked out and cleaned up the Ignition transistor, the FSM says there isn't really a way to test it; like the ECU "just replace with another unit"... I have a spare ECU that came with the car and I swap them out with each attempt to see if the ECU is the issue...

 

I was happy to find that the Ignition Relay is the new one, Nissan released a different pair of relays to supersede the factory original (had a faulty ground or something)...

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Can you see where the rotor is in relation to TDC? This is out of an 82 FSM. I don't think the rotor relation is different from year to year for the Motors themselves. The left circle is NA, the other with the X is turbo.

 

ZX_DIST.jpg

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SOLVED - Incorrect Distributor Orientation: counter-clock 153624 sequence starts at 2 o'Clock, rather than from the original marked notch on the cap / FSM stock configuration starting from 10 o'clock...

 

I removed the Rocker cover and plugs so I could physically observe the valves whilst establishing TDC / monitoring the each of the pistons compression cycles.

 

Felt the compression from each piston and confirmed the correct 153624 cycle and mapped it on the distributor, which was mounted in a fashion fit to this retard that put her together...

 

Pushing the whole car in 3rd gear up and down the driveway, I don't have the 27mm socket for the crank... great workout.

 

Will tune her up tomorrow, not everybody in the neighborhood shares my enthusiasm for this car at this time of the morning...

 

Did notice smoke from somewhere in the bay though, I couldn't discern if it was oil or water... was immediate from this cold start, could just be gunk cooking from the outside of the block / headers or a bad gasket... but will pursue this issue in a separate thread as it shouldn't be related to what we have been chasing in this one.

 

!!!THANK YOU VERY MUCH !!! EXCELLENT INPUT MATES!!!

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