Great thread.. finding it today has made me think of a mystery novel or something.. A couple people posting here have demonstrated knowledge and patience with loads of help...

My D16Z6 (93 Del Sol) had a problem for a couple years that I called "vapor lock or something".. seemed to not restart after short trips (a longer trip that more fully warmed the engine or a shorter one that did little to change overall temperature had no problems).. Then the problem worsened.. It would not start for a day -- then days -- until done starting...

I found the fuel pump (since I had heard then that I should hear the 'click' of the relay and the sound of the pump.. and heard neither) and tested the 2 wire connection to find hot and ground.. I found the ground but, the 'hot' was not, so I fed the hot to the pump with a wire from the dash fuse box that became hot with the key turned ON(II) and with ON(III).. fused it again by the pump and it has ran for over a year like this...

All full of confidence today and armed a ton of info from here I pulled and checked fuses for continuity, looked at and wiggled the ground near the thermostate, and found the main relay and opened it to see soldering that looked ok..

Rechecked for a main relay 'click' and it was there!.. Reconnected the factory fuel pump 2 wire connection and the pump hummed for prime and it runs again?.. perhaps the relay, one of the fuses, or the ground needed a better connection..? I still have the double fused hot on standby if things fail (since this just happened)...

Note: If you do try the new wire to regain use of your fuel pump ('test') leave all the spark retarding goop there and make it a Real snug fit.. I think too many are buying fuel pumps to then 'move on' to finding the problem(s).??

 

I have tried, in the past, to skip tinkering with this car's mechanics, and such, to leave it factory.. But, the timing belt recently broke.. replaced it and a little over 30 miles later the new belt shredded because the waterpump then 'screeched to a halt'..

So.. I still like factory, but plan to tinker more..

 

Update..

This evening the fuel pump would not run.. It was doing fine for a while (since last post here).. Hot humid today (it was warmer a few weeks ago, but rain and humid may have its part in my situation..? As before it would seem like a 'vapor-lock' deal..?

Rechecked the wires at the pump for hot with ignition on III, neither.. ground continuity real good on one of the 2.. so.. put the fuse back into the inline fused wire to regain hot back at the fuel pump from the wire I had ran through the console to the rear of the interior earlier from the interior fuse box after that fuse that is hot with ignition ON II and II (the fuel pump rests into the top of the fuel tank there on this model).. tested for current with ignition on (12 DC volt range),. then connected that hot to the pump..

Ran fine once again.. I had also rechecked the 101 ground prior to the reconnect of the alternive hot and it was snug and clean looking..

My pump problem may be a MAP sensor or something..?

 

btw I have been planning to come back with an update, but until now it would have been a boring 'nothing to report' kinda post.. ~ : )

 

Have you tried re-soldering the main relay?

 

I have been there and I have done that with my 93 Del Sol. Go find my old posts.
I bet it's your ECU. Water/condensation damage.
Borrow an ECU to test. I got a used one for $135

 

Is this your problem?

Won't start when cold and runs fine after it warms up. If so, it's the ECU - I repair this problem all the time...

 

Yes, I agree. If you are in a humid climate like I am (Florida) or where you are (PR) it may be won't start when damp (humid/condensation) but will start once warmed up (or dried out). How do you repair this? Are you familiar enough with the circuit board in the ECU to know what to replace/resolder or whatever? I would love to know how to fix my P28 ECU so I can keep it as a spare.

 

Yes, I have a solid understanding of OBD1 ECU electronics, possess P28 electrical schematics, and have been repairing them for over 6 years DBA EFI Logic.

I am not allowed to solicit on this forum but you can PM me for more information.

 

I had read in multiple Honda Tech posts/threads about the common cure of resoldering the main relay to get the fuel pump going (before I signed-up to become a member).

I examined each solder point and they all looked to have a clean shiny silver bubble with no cracks, so I just reinstalled it.

It does seem temperature related. Though cold and cool, or the hot of miles of driving, are not the times it decides not to pump fuel / start.

It is when there is a short trip of a couple/few miles, and then the engine is shut off, that it will not restart. Or if it is a hot day, and parked in in the sun, it will have the same risk of not starting. Much like Goldilocks in the old story. This ones too hot, this ones too cold, this ones just right (to make it not start).. once running it keeps going.

 

Try swapping in a known good ECU, as mentioned.

 

It is a tricky spot.

I may find a volunteer to run my ECU in their car, to find nothing, or I run their's in mine, to find nothing. Since it seems to be a mid tempature zone of the engine that randomly won't restart, because the fuel pump receives no current to do so.?

 

Not sure what your question is.

 

I'm sure it's your ECU. If your friend lets you test your ECU in his car, you must do it after it sits overnight (cold). I guarantee it'll do the same thing in his car.

 

**Bump** David, what became of your issue? Did you solve it? I'm having similar problems with starting. Thank you.

 

I don't care how old this thread is Mr. Internet Police Man! BTW, who the heck cares how old a post is? What's the point in closing an old post? Especially if it's unsolved? I posted my comment to another thread that had no solution. It was one of the top results when I searched "1994 Honda Civic won't start", so I offered my suggestion, knowing full well it's an old post. Well, the Internet Police caught me red handed and issued a citation--not really, just pointed out the obvious that it's an old post. I figure, as long as I help someone out there, let it be man, let it be.

Here's my suggestion:
Could be a fuel issue caused by a bad MAP sensor.
To test this, unplug the wire going into the sensor. With the key on ACC (2nd position before starting the engine) plug the wire back in the sensor. You should immediately hear the sound of your fuel injectors working (priming). If not, try the steps again a couple of times, making sure the key is in the 2nd position. If you do hear the injectors come on right after you plug the wires, your car will now start. This means the MAP sensor needs to be replaced.
My 1994 honda civic engine would crank but intermittently wouldn't start. Replacing the MAP sensor (located right above the air intake manifold) solved the problem immediately.