Electrical Question 1991 Honda


wizarddrummer
05-30-2011, 03:08 PM
Is it possible to bypass the Master Relay?


The car is a 1991 Honda Accord SE

Several weeks ago the car was running normally and then one day I went to start it and it would not start. I could tell something was different when I was turning the key.

I used to hear clicks; the gas pump engaging and there was a spark because there were a few occasions in the last three years where the electronic ignition didn't get it right the first time, the car would sputter and die and then start on the second try.

Now when I try to start the car it just turns over. No clicks, no fuel pump and definitely no spark.

I knew more about electrical circuit wiring when I was in 7th grade electronics 48 years ago then I do now.

I'm just wondering if I can bypass the master relay by cutting some wires and then splice them together or put some kind of ... I don't know ... light switch or something in there that'll work so I can start the car?

I don't have the cash to fix it by going to the parts store or even a junk yard to get the part; and I'm not sure if that's even the problem. I just read about other's with similar starting problems and the "experts" seemed to point to the master relay.

Here are some recollections over the last year or so that might help someone diagnose this thing. Don't know if any of these things are related or not.

-- on several occasions while driving around if I stopped to go into a store to buy a soda, I would come out and the car would not start or even try to start. The remedy? I would take the cable off the battery; let it sit for a few minutes, reconnect the battery and it would start.

-- Occasionally when I stepped on the gas while in drive the transmission would feel like it's trying to upchuck itself on the street with lots of rumbling and vibration with very little forward motion. Sometimes the green [S] light would be flashing and sometimes not. Remedy: Sometimes moving the shift lever back and forth would set it right and then it would work normally. Sometimes I had to remove the cable like I had to do when it wouldn't start.

I can program computers with large scale applications but my knowledge of cars is limited to the days of points with gap settings and dwell and timing lights.

Appreciate any help or advice.

jeffcoslacker
06-08-2011, 10:02 PM
Saw this a little late, I guess you could, although I wouldn't consider it a permanent solution, that relay is there for a reason.

Don't know about these, but most relays have a diagram of their internal structure stamped on them. It should show the two terminals that energize the relay coil and close it, and then the incoming power and outgoing terminals that are energized once the relay's coil closes their contacts. You should be able to determine how to bypass and power all the circuits based on this....

wizarddrummer
06-08-2011, 10:19 PM
Saw this a little late, I guess you could, although I wouldn't consider it a permanent solution, that relay is there for a reason.

Don't know about these, but most relays have a diagram of their internal structure stamped on them. It should show the two terminals that energize the relay coil and close it, and then the incoming power and outgoing terminals that are energized once the relay's coil closes their contacts. You should be able to determine how to bypass and power all the circuits based on this....

Appreciate the reply... I don't have to many tools anymore. I have to try and get the thing out of the car first :) I've seen a site that shows the electrical schematic with the various stages of starting, (highlighted in differnet colors) but it's kind of greek to me. How many computers does a Honda have anyways? Anyone know?

wiseguy01
08-28-2011, 12:04 AM
there are many variables in this motor one you said it sounds different than it used to and ther is no spark does the engine sound like its under load cause one time i started a 95 civic it started then died never started again just kept cranking long story short the timing belt went out and it sounded like the motor had no load sounded like the motor was turning faster than it was supposed to and on my 93 accord the icm- ignition control module went out which is located in the distributor and it died and wouldnt start had to replace the distributor so more details is needed and on my 93 i cant hear the fuel pump engaging but it works fine so the 3 main checks are fuel spark and air so you need to get fuel pressure tester test fuel rail and then check for spark and go from there because for spark there are like 4 things that can cause no spark icm cps timing belt bad rotor in the distributor so more info is needed for further diagnosis

wizarddrummer
08-28-2011, 03:14 AM
there are many variables in this motor one you said it sounds different than it used to and ther is no spark does the engine sound like its under load cause one time i started a 95 civic it started then died never started again just kept cranking long story short the timing belt went out and it sounded like the motor had no load sounded like the motor was turning faster than it was supposed to and on my 93 accord the icm- ignition control module went out which is located in the distributor and it died and wouldnt start had to replace the distributor so more details is needed and on my 93 i cant hear the fuel pump engaging but it works fine so the 3 main checks are fuel spark and air so you need to get fuel pressure tester test fuel rail and then check for spark and go from there because for spark there are like 4 things that can cause no spark icm cps timing belt bad rotor in the distributor so more info is needed for further diagnosis

Thanks for the reply. For a complete, detailed look at what the main relay does please navigate http://techauto.awardspace.com/index.html#overview

There is a lot of info there. After reading all of that I started to piece back what symptoms I had so I wrote them down in red.
Main relay symptoms are:


Car won't start when hot outside (fuel injected PGM-FI models only. Became more frequent; but not always.
Car won't start after parked for just a minute. Towards the end, just before it died, this usually happened after driving for about 30 minutes. but not always.
Car starts but quickly dies as the rpm shoots to 1300 rpm. A second cranking attempt will crank but no signs of catching or any strong rpm movements. Did not experience this.
Once started the car won't stall. After the car runs for a couple minutes, the symptoms return after shutting off the engine. Yes; after the car is started you can drive until you run out of gas, sometimes it would not start after shut off, but not always.
Windows have been rolled up on a hot day when problem occurred.Did not pay attention to this detail.
The heater was on before turning the car off. Did not pay attention to this detail either
Tapping your fingers or keys on the main relay will start the car. Didn't know where the relay was at that time
No (humming) sound from thefuel pump (http://techauto.awardspace.com/content/legendmainrelay.html) the moment the ignition switches ON. This I am experiencing now. No fuel pump sound at all.
No click sound after the ignition key turns on or
No click sound two seconds after the ignition turns on. Hearing a click but it seems less pronounced.
Check enginelight comes on (rare cases) or stays on longer than usual and no sparks (electronic timing only.) Can't say that I can tell the difference on length of time for the light; but after 43 years of driving I can say, with almost 100% certainty, I am not getting any spark.
10-15 of waiting and the car pushed to a shade, will usually start. My method, before I started researching the problem was to open the hood, take off a battery cable (my assumption was that the computer needed to be reset) this worked all of the time because the normal time I waited was long enough to cool the car down (something I did not know at the time.

As far as the timing chain is concerned, I can't say. Like I said before, the car (when it was running) was running fine when the intermittent transmission computer failure where the car would barely move when I applied the gas. Other times it would rumble like it wanted to cough up a planetary gear.

This was another problem that I was plagued with. Resetting the computer usually fixed this; sometimes just shifting from park to first gear very rapidly about 4 or 5 times would clear it up as well. When it was malfunctioning the green [S] light would blink. I believe this to be a computer problem as well, because in my experience when a part is malfunctioning it will do so all the time. When everything was in sync; all of the components (on board computers/relays, etc.) were behaving the car ran perfectly.

When the car is cranking it does not appear to be any faster than normal. That sounds the same.

No funny sounds, the engine had lots of power no hiccups or sputters; very smooth at 80 miles per hour.

As far as the fuel pump is concerned, it could be that is broken. Like I said before the car ran as it normally did (with a few of its idiosyncrasies) and the next day ... Nothing.

wizarddrummer
09-28-2011, 05:07 AM
The car started a few days ago for the first time in 4 months.

I should be elated but I can't pinpoint what I did to fix it.

Twice I resoldered the connections on top of the Master Relay.

I tried to start the car several times; but the engine turned over and didn't try to start.

A few days ago a friend stopped by to see if we could fix it. The battery was dead again after sitting for months from being weak from the previous starts that didn't work.

After 10 minutes of charging, I put the master relay back in and mentioned to my friend. Ok we're not going to hear the fuel pump engage; it's just going to crank.

I turned the key and to my utter astonishment it fired up almost instantly; it was as if I was starting the car after returning from buying some juice at a 7/11.

I have no idea why it started to work all of a sudden. NONE!

I should be elated, but I can't be.

Look, when you have a bad shock absorber that gives no resistance when moving in and out and you replace it with one that has resistence and the ride improves you can say it is fixed and be confident that the problem is solved.

After two sessions resoldering the parts of the master relay's printed circuit and numerous attempts to start the car... why does it now start reliably?

Magic... Wooooful Dust... the absense of Gremlins ... I don't know.

This is one for the books for me; that's for sure.

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