Can't get my rebuilt DE to start.

[slipnfall]

Hi everyone, I know these topics pop up all the time, and I'v done my best to help when I can. Now I really need some help getting my own DE to start! This is a '92 BTW, stock rebuild.

Let me first tell you what I have checked/done:I'm *very* sure on my timing chain timing. Turns very smoothly. I paid very close attention installing my distributor, knowing that it actually kicks back a notch. I verified, with cap off, that the rotor was pointing to the cyl-1 plug wire. Plug wires are in as labeled.New battery.Starter checked at local auto store before installing.Fuel pressure checks good.I smell fuel after cranking 10-15seconds. I pulled plugs to verify.Spark *seems* ok: checked by holding spark plug/wire to block. New plugs are gapped to FSM spec's, like 0.039-0.043" IIRC.Checked power/gnd on MAF, TPS, and CPS.With key ON, unplugging/plugging in the CPS makes the fuel rail 'tick'.Can create/hold vacuum on FPR vacuum loop with hand pump.Had fuel stabilizer in tank while sitting w/~2gals left. Just added 6gals of '87.Checked ECU for codes after each attempt: none but 55(OK).

I can crank and crank, but not even a spudder! Sometimes I hear a 'poot', but It's certainly not a cyl firing. After I crank enough to smell gas, I pull the fuel pump plug and force out the gas. I'm afraid if I continue trying with no luck I'm going to start washing my cyl walls down.

Fluid levels are solid.

Anyone? I'm really starting to get frustrated. Can a vac leak cause it to not fire? I should *only* need fuel, spark, crank pos, TPS and MAF, right? Is there anything I can unplug to eliminate the possibility that it's bad(and still get it to start).

Also FWIW, when I was cleaning the idle-air-adjust valve, I didn't put the set screw back to it's original position, but this shouldn't matter that much(?)

The only modification I'v done is to remove the AIV/PAIR system. I capped both the atmo and vac lines, plugged the exh. header, and the hole in the filter box.

Thanks for anything anyone can offer.-Jamie

[nab911]

Ok, if you have air, fuel and spark it will fire. First Pull the plugs and make sure they are sparking and you should also see fuel sprays coming out of the spark plug holes.

[slipnfall]

Thanks for the reply: here's an update.

I double checked my fuel lines, and they are correct(return and feed).

The engine is flooding after 3-4 attempts. I can look down into the cyl w/a flashlight and see *just* the edge of a puddle of fuel(since the engine sits cocked). I clear the floods by pulling all plugs, unplugging distrib, and removing fuel pump fuse. Crank for 45sec's.

Also buttoned up my battery terminals: got some top-post shims, ground off the oxidation w/a dremel, and installed some anti-corrosive doughnuts.(been meaning to do this anyways).

Also I checked my coolant temp sensor: it was out of spec(read 4.1kohm, FSM said 2.something was the max). I unplugged it. Now I get a 'poot' more often from the exhaust, but def not a sure-fire fire(he he). I'm going to try inserting a resistor in place of the coolant temp sensor temporarily.

I also tried disconnecting my MAF, no luck.

ECU reflects MAF and temp sensor problems(12/13).

I'm still stuck: I have a feeling my spark is getting extinguished. When I tested the plugs, they were arcing about 1-2mm away from the ground tip FWIW(I think this is because I didn't gap them w/a proper tool).

Also I have a spare coil/power transistor that I tried, with no difference. I considered buying a compression tester, but I know from turning it over on the stand that the compression 'sounded' good enough to get a fire.

Oh and I'm beginning to smell gas on my dip stick. I hope I don't damage anything before I get it running; I certainly can't afford another teardown/rebuild!!!

Thanks again!-Jamie

[slipnfall]

Oh I meant to ask: on the throttle position sensor, which direction do I turn it to 'reset' the position?(to correspond with closed-throttle). There's an arrow on the back FWIW. The FSM lists the voltage output that you should expect, but since it's a waterproof connector, it's hard to get to the terminals.

I thought maybe if it was reading full-throttle, the ECU would dump extra fuel in.

[nab911]

the tps screw i think moves the sensor and the actualy valve. If you turn it, the entire throttle will open with it IIRC.

[slipnfall]

I just got a good desciption of testing the TPS on 240sx.org... I'll let you know how that and the coolant temp sensor rig goes.

-Jamie

[leper421]

Ok, if you have air, fuel and spark it will fire.

You forgot one thing: Compression. Get a compression gauge and check each cylinder. It will be lower than normal because the engine is cold, and the piston rings arent fully seated yet, but you should have some compression in each cylinder.

I verified, with cap off, that the rotor was pointing to the cyl-1 plug wire.

The rotor should actually be a little bit(10 degrees) before the contact for cylinder 1. Although I would think you'd still be able to start the car with the ignition timing set at 0 degrees, it may be worth trying to advance the timing a little and see if that helps.

[slipnfall]

Guys... I'm a moron...

The distributor timing _was_ set correctly from the start. The rotor was so worn that it wouldn't fire. Between getting a new rotor, there were some other problems, like TPS and CPS not hooked up. Well when I put the new rotor on, I installed it off-time. It was one cylinder off. I was really out of ideas tonight and just decided to pull the valve cover and re-set it.

Can't believe it was something so simple... Lesson learned here.

Thanks for the help guys. Once you mentioned that fuel+compression+spark=fire, I knew one of the three had to be off. Idled a little high(1600rpm), but I didn't give it full time to warm up(only about 1min).

<sigh of relief>

So from here, I'm gonna change the oil(not taking any chances on thinned oil), top off the coolant, adjust the idle, and tweak the timing.

Best regards,-Jamie