'93 240SX wont start (same post as in "93 240SX dies on decel.")

[stratmatt777]

I just realized that I posted this last night in the wrong forum- 240SX technical.

Here it is again now in this proper forum. This is the exact same thing I just posted as a reply to the 3 year old "93 240SX dies on deceleration" thread, but I want to make sure that people with expertise on starting problems see it so here it is again with the proper thread title. Sorry for the double post, but I am desperate!

thanks for the help!

I read some of the threads on the cars that wont start so you guys don't have to repeat yourselves over and over! I bought this car in 2002 with 54,000 miles on it. It now has 112,000. -It has been making the "marbles in a can" noise that I read about on here probably for months but I coudn't afford to have it fixed. -When I take it out of gear on the freeway exit ramp, if the lights are on, it often drops to 300rpms and almost dies or does die. The more electrical accs running the more likely it dies. I put it in gear to restart it and then have to catch it and give it gas before it dies while pulling up to the stop sign. The rest of the way home I notice that the headlights dim ever-so-slightly when I apply brakes (brake lights using power, I guess). The car has a 90's era Viper alarm but I've never had a problem with it.

About a week ago I tried to start it and it sounded normal for the first two truns- like it was gonna start maybe- but then it didn't. It just turns over and nothing happens. I replaced the spark plugs and observed spark from plug #1. The old plug's threads were wet and smelled of fuel.

I called a mechanic and told him about the "marbles in a can sound" and he said that my engine may be destroyed. He said to stick my finger in a spark plug hole and crank it- if my finger is blown out from the compression the engine is not destroyed from bad valve timing. It passed this test.

The air filter is pretty new. So the dieing/electrical problems probably indicate an alternator problem? Several months ago when I replaced the bad starter I hooked my batt up to AAA's tester and it said that my batt and alternator were both in excellent condition (maybe the tow truck driver misread the tester machine?).

I have never replaced the oxygen sensor in 50,000 miles- that wouldn't cause this would it (I have one I'll install tomorrow)?

To troubleshoot this thing tomorrow I'm going to do the following things that I've read about in a couple threads here:Check for tear in hose on valve coverCheck groundsCheck fusesCheck fuel line pressure/filter/priming with key in run pos.I should replace the cap, rotor and wires for routine maintenance since I have not done anything routine like that in 50,000 miles due to lake of $.Is replacing the coil routine maintenance at 112,000?

What are all the things I should replace for routine maintenance?All filters everywhere I suppose?

How do you check fuel injectors (when do they wear out)?

I do have a DMM and understand how electricity works in general (simple V=IR knowledge).

I saw qat727 mentioned jumped timing. How does that happen? Maybe it happened to my car with a failing timing chain tensioner?

One thing is for sure- I am having the timing chain replaced on Monday so that I my engine doesn't self-destruct (assuming it hasn't already). The mechanic I calle dsaid that timing chain engines are not non-interference engines (which seems like a really stupid design decision to someone who doesn't know everything about car engines).

Alternator?

The PCV valve has never been replaced either. All that's ever been done is oil and filter, brakes, air filter, a thermostat, a starter 5 months ago, and I just did the plugs.