Honda Concerto '89 Fuel Delivery Problem

[VH770]

Hello,

I have a 1989 Honda Concerto, engine number D16Z21******, VIN number JHMMA286**.

It will not start. Through initial troubleshooting it's clear that it is a fuel supply issue. There is spark at the plugs and when I spray fuel-ether (start'ya'bastard) directly into the throttle body passed the throttle valve, the engine will start and run as long as i continually supply the aerosol fuel.

When the issue first started, there is a chance the fuel tank was empty - I'm not 100% sure but it is possible, however i think i had enough fuel at that time based on previous experience. At that first moment, it cranked and the engine started fine, ran for about 2 seconds, and then just cut out instantly, and would not start again. I have since put 10L into it via a jerry can, so there is plenty of fuel in the tank at the moment. Apart from that, i temporarily disconnected what I assume to be the fuel supply line to the fuel rail from the tank/pump (marked as A in the diagram below) and i found fuel at this hose, not much, not under pressure? but some fuel trickling out of this hose. does this sound right for this hose, or should it be under high pressure?

http://i59.tinypic.com/23m1sa9.jpg

Also, i do not have a workshop manual for this car, can anyone please tell me the locations of the following:
- fuel pump
- fuel filter
- fuel line rough location from tank to engine bay
- pressure regulator/2nd filter/anything like that. Perhaps if any of you had a diagram of the fuel supply system you could upload it for me? I would be very grateful.

Thanks! :)

Charlie

[VH770]

OK i found a manual online, and found this diagram which helps me a lot.

http://i57.tinypic.com/apeebl.jpg

My questions now are:

1. if i turn the ignition key to ON (not starting the engine, just ON), should i be able to hear the fuel pump turning on? The manual suggests i should be able to hear the pump turn on for 2 seconds after switching to the ON position, if i put my ear next to the fuel filler at the rear of the car (with the filler cap removed). is this a true reflection of how to tell if the pump is on or not, or is there another way?

2. following on from this (in a backyard way to test the fuel pump), if i disconnect the fuel feed pipe from the fuel filter (diagram above), with the ignition ON (not engine running), should the fuel be at high pressure (30-40psi)? if it is not at high pressure, is it fair to assume the fuel pump is faulty, or would there be another reason that there'd be low pressure (apart from low fuel)?

I do not want to go to the hassle of removing and replacing the fuel pump unless i can be absolutely sure it is faulty. If i find the fuel pump is working, i will replace the fuel filter and hopefully that is what is causing poor fuel supply.

thanks

[Jasemas]

1. Sit in the back seat, get someone to put the car into POS II
If the fuel pump is good, you'll hear a whirring kinda of sound thats the fuel pump priming
If you don't hear it prime then
A - check your fuse box
B - check your main relay
C - remove back seat and check ground to fuel pump with a multimeter

[VH770]

Thank you very much! I just went out and did the diagnostic you described; i cannot hear anything (quiet as a mouse) when turning the key to ON and listening at (a) the back seat and also (b) at the fuel filler (cap removed). So i suspect this is a good indication that the fuel pump is not working.

1. I am aware of the fuse panel location, but on the fuse panel (under dash) there is no fuel pump fuse. where are the fuel pump fuse and main relays located?
2. Please let me know the easiest way to remove the back seat.

Thanks :)

[ECU-MAN]

Have you checked the Main PGMFI Relay ? You should be abled to hear it click when you turn on the ignition

[VH770]

Have you checked the Main PGMFI Relay ? You should be abled to hear it click when you turn on the ignition

Where is the PGMFI relay located? What does it do?

Thanks

[ECU-MAN]

It drives the fuel pump and powers the ECU.


It is located under the dash, drivers side

[grifty]

Actually on a Concerto, its located behind the stereo.

[VH770]

I've had a look through the manual and it shows the PGMFI relay to be inside the console. Bit of fun getting to it i'm sure. Interestingly I've also had a further look through the electrical section of the manual and it shows a fuse at the engine-bay-fuse-panel (fuse #38) which is a fuse for the PGMFI relay, i'll go and check that hasn't blown.

http://i61.tinypic.com/es92cm.jpg

Question: if this PGMFI relay is faulty (thus causing the fuel pump to remain de-activated when ign ON), would it also result in loss of spark (assumedly because it powers the ECU)? I do have spark, just no fuel. Or is it a dual relay that triggers the fuel pump separately to the ECU?

thanks

[Jasemas]

Isn't the fuel pump fuse in the engine bay fuse compartment?
It's a big fuse when compared to the small 7.5/10 amp etc. ones

[VH770]

I'll have a look at all the fuses in the engine-bay-fuse-panel but from what i'm reading in the manual, it looks like there's nothing that is specifically labelled as a "fuel pump fuse" or anything like that. it's only referring fuses to the PGMFI relay.

Perhaps a "fuel pump fuse" is any fuse that protects the PGMFI relay? does that sound right?

unfortunately i cannot find wiring diagrams for the PGMFI relay so that i may understand it better; i'll keep looking.

[VH770]

OK - had a look at all fuses, none are blown. fuse #14 is not blown (i half expected it to be, because my battery charge light has been constantly on for months even though the battery charges fine). all fuses in the engine bay are fine, too.

I noticed this morning (car having sat overnight) that when i turned the key to II, i heard a whirring sound for about a second and then it stopped, it could have been the fuel pump but i'm just not sure. When i turn the key to II again, no sound; it only happened that first time.

question: should the fuel pump whirr to life every time you turn the key to II?

question: if the fuel pump is working correctly, is it right to assume that the fuel at the fuel filter will be under high pressure (30-40psi) at all times, even when the engine/electricals are turned off? even when the engine has been shut down for several hours/days? Or would fuel drain back into the tank and only be pressurised in the supply line when the ignition key is in the II position?

thanks

[ECU-MAN]

check your relay, sounds like its the problem


http://www.ozhonda.com/forum/showthread.php?31796-DIY-Main-PGMFI-Relay-repair&highlight=relay

[VH770]

I decided to disconnect the fuel inlet hose from the fuel filter (theoretically this should be the pressurised fuel directly from the tank/pump), and test if the pump worked when turning to ign ON. What i found was that the inlet hose would not spurt any fuel when the ign switch was put to RUN (position II), nor did it spurt any fuel when i first disconnected it. After about a minute of waiting with ign on RUN, for some unknown reason, about 100ml of fuel spurted out the inlet hose, but then stopped abruptly, and i could not get it to repeat itself. I was baffled, but decided to fit the hose back onto the fuel filter and re-install the filter. I then attempted to start the engine, and what do you know, it starts and runs perfectly well now. Furthermore, when i turn the ign to run (position II), every time i can hear the fuel pump whirring for a few seconds before stopping. This was not happening before.

http://i61.tinypic.com/6pyg7r.jpg

Is it possible that i ran out of fuel, and the fuel pump was starved of fuel (had an air bubble in the line, or inside the pump), and was unable to compensate for this until i disconnected the fuel line (at the filter) and exposed the line to the atmosphere, thus allowing air in the line to escape? Or is it more likely that my relay or pump need replacing? Perhaps if there is air in the pump, the current supplied by the relay cannot trigger the pump (threshold too high). I might be clutching at straws, but i just don't know why it would be an electrical issue (relay or pump) if all i did was release air from the line and this rectified the problem. hmm.

thanks for all your help jasemas, grifty, and ECU-MAN :)

[VH770]

had a read through that relay-DIY thread, thank you ECU-MAN. It certainly sounds like the relay could be contributing or the cause of this problem (perhaps opening the fuel line and then car starting was a coincidence). Any tips on where is best to buy a new relay, apart from contacting honda directly? (always going to be a super expensive option).

[ECU-MAN]

repair your existing relay, that is the point of the DIY

[VH770]

I understand the point of the DIY, and i will attempt it, i am just wondering where a relay can be purchased if the DIY fails?

Can you please clarify that bridging 2 with 7 will activate the fuel pump?

http://i58.tinypic.com/2nuq41t.jpg

[VH770]

OK well i removed the PGMFI relay (located behind and under the CD player in the 89 concerto), resoldered it's circuit board and re-installed it. i also wired in a switch to connect wires 7 (fuel pump) and 5 (ign12v) if i ever find the fuel pump doesn't activate with ign12v normally in future. Turning this switch on will activate the fuel pump (essentially bypassing the PGMFI relay). This way, in future if this ever happens again, i will at least be able to determine if the relay is causing problems with fuel pump activation or if it is something else. will just have to wait and see if this problem surfaces again.

http://i61.tinypic.com/2u589qu.jpg

http://i59.tinypic.com/ejbwbp.jpg

thanks for your help :)

[ECU-MAN]

did you find dry joints on the relay ?, if you did there is a good chance you found your problem and the switch will not be necessary.

[VH770]

what do you mean exactly by "dry joints"?

[ECU-MAN]

bad solder joints

[VH770]

No i didn't find them to be particularly bad, they looked more or less fine to me.

[Jasemas]

Did it all work all good and dandy?
Replace fuel filter bro :P

[grifty]

I had a similar issue as well, soldered the main relay and has never happened again