Prelude no wanna start

Here's my situation, I have a 1992 Prelude (5spd manual) that I bought almost two years ago. Like my previous Prelude of the same year, it occasionally cranks strong but does not start. Unfortunately the other Prelude was not around long enough for me to diagnose, as a lady turned in front of me and totaled it a month after I got it. So this new one had this occasional not-starting issue as well, but after I let it sit for a minute it would start right up like there was nothing wrong. It was fairly infrequent so I was not super motivated to chase it down. It did not seem related to weather or sitting for long periods unused, it would be just as likely to do it if I just ran into a store and came right back out.

Recently it has gotten more frequent, to the point where I ask myself "Is it going to start?" when I unlock the door. And this past week it refused to start after waiting for quite a while, unlike the other times where it just needed "a rest" before starting. Now, I am sure it will leave me stranded if I don't begin the chase to find the issue. I just did a mini tune-up on the car, replacing plugs, cap and rotor, and noticed quite a bit of corrosion on the coil wire, which I cleaned off but I do plan to replace. However, I still have the starting problem. So, I checked the fuel pressure, a nice solid 40psi and it got there in a hurry, so the fuel pump and pressure regulator don't seem to be the issue. I got a nice blue spark when I checked that, so that also seems good. I keep reading on various web pages about a main relay for the fuel pump and I would love to know your thoughts on this, or any other things you think would be worth diagnosing as well.

Thanks!

Hmmm. It spins over and doesn't start, right? You have fuel pressure and a hot blue spark and I'm going to assume that means you checked those while the problem was happening. If so, that pretty much leaves a problem with no fuel injector pulse.

There are 'noid lights' which you can use to check for injector pulse. They aren't cheap, but you can do the same thing with a 12V LED from Radio Shack. Remember that the 'long' leg of the LED is the '+' side and needs to go to the injector power source wire, the other to the ground which goes back to the computer. Pick any injector, obviously the easiest one to get to is the way to go. While the problem is happening, disconnect the injector connector, connect the LED across the injector leads, try to start the engine and look for a pulse. LED flashing = good injector pulse and you need to look elsewhere. LED no flash = need to investigate this further.

I dunno if Honda used this back then (the Accord we have doesn't have a factory alarm), but many OE alarm/anti theft systems use a fuel cut, meaning you'll have spark etc but no fuel injector pulse if the alarm system thought someone was trying to steal the car. Does the car have a 'security' light? If so, is it flashing when this happens?

FWIW: I have seen OE antitheft systems which if you use the power locks to lock the car you have to unlock it with a keyless remote. Unlocking it with a key will set the alarm off, unless you locked it with the key. If someone got POed and disconnected the horn/lamp flash you may have an alarm going off and not realize it.

Well, that sounds fun, I like flashing LEDs.

It does spin over, and sounds strong, but does not crank. In the past I have either had to key it off and try again or key it off and wait a minute or two and try again for it to start right up.

To be honest, I don't know if we checked these things "when it was happening" because I went out to start it, it didn't start, and a few days later we start diagnosing things without trying to start it again first, so I might be back at square one, waiting for it to do it again to test it. After we tested the fuel pressure I tried to start it for squirts and giggles and it fired right up. When it runs, it runs too good for it to have jumped time, as I have considered that also.

I can at least rule out the alarm system as it did not come with one, thank goodness, I hate those things.

Thanks! I will let you know how it goes with the LED

Good luck with it.

By the way, the proper term is 'for gits and shiggles'.

I read that as "grits and shingles", but that's something completely different.

OK, this time I can happily say that I got annoyed at Auto Zone. A NOID that is They had a kit that was $20, and that was within my budget so I picked it up and tried it out. So, of course The 'Lude is not having "the issue' at the moment, so I did get a nice strobe-y flash from the LED when I hooked it up. I guess now I need to hook it up everytime I am going to crank the car and see what happens, eh?

Any other thoughts about what to pursue until this avenue yields some more information?

How is the compression ? I assume you checked the timing.

Compression is fine. Like I said, once she's running she runs too darn good for her to have jumped time. I appreciate the ideas, keep 'em coming please!

EastCoastMojo wrote: OK, this time I can happily say that I got annoyed at Auto Zone. A NOID that is They had a kit that was $20, and that was within my budget so I picked it up and tried it out. So, of course The 'Lude is not having "the issue' at the moment, so I did get a nice strobe-y flash from the LED when I hooked it up. I guess now I need to hook it up everytime I am going to crank the car and see what happens, eh? Any other thoughts about what to pursue until this avenue yields some more information?

Yep, that's what I'd do. Plug that puppy in and spin 'er over, if you get flash but no start joy then it's time to look elsewhere.

Something I just thought about; IIRC some Honda dizzys have an integral ignition module that'll quit making sparks in a 'hot soak' condition (run the engine till warm, shut it off, try to restart 10 min or so later). That means being ready to check for spark at the same time as you check for injector pulse. There are spark plugs made which have a alligator clip hickey so you can clamp them easily to something metal while you spin 'er over. Next time you go by the 'Zone might want to grab one of those as well.

Excellent suggestion, Chuck has one of those alligator thingys so I will pack that with my NOID.

OK, that came out sounding kinda dirty.

Thanks for the help dude! I really appreciate it!

Main relay, very common problem on all older Hondas. Solder joints crack. You can open it up and re-solder them or replace it.

Next time it doesn't start, try hitting the underside of the dash (drivers side) with your fist while cranking it over. When mine started going out, it wouldn't start if the car had been sitting in the sun. If I opened the doors and let it sit for 5 minutes it would normally start. Otherwise if I smacked the dash while cranking it over it would fire instantly as soon as my hand contacted the dash.

+1 on the main relay, a common and easy issue on Hondas of that vintage. On Civics, it is under the dash on the right side, not sure where it is in Preludes.

Run_Away wrote: Main relay, very common problem on all older Hondas. Solder joints crack. You can open it up and re-solder them or replace it. Next time it doesn't start, try hitting the underside of the dash (drivers side) with your fist while cranking it over. When mine started going out, it wouldn't start if the car had been sitting in the sun. If I opened the doors and let it sit for 5 minutes it would normally start. Otherwise if I smacked the dash while cranking it over it would fire instantly as soon as my hand contacted the dash.

The Fonzie approach, I like that

On these Preludes it is under the dash on the left, above the clutch pedal. I will try whacking it next time.

Thanks!

Sonic wrote: +1 on the main relay, a common and easy issue on Hondas of that vintage. On Civics, it is under the dash on the right side, not sure where it is in Preludes.

I'll give another +1 on that, though a screwdriver handle seems to work better than the fist.

That's a heckuva lot easier than noids and spark tests and all that crap.

Well, I'm glad we're all on the same page LOL. I bought a main relay yesterday, along with a new set of wires to take care of that corroded coil wire. I plan on just installing the relay and wires this weekend and see how it goes. Guy at the parts store gave me a funny look when I came in asking for that relay. He said it was the third one he sold that day. I got the last one!