Idle/Timing problem

[festivBS]

Can you think of any big electrical things i should check?

[JohnGunn]

Can you think of any big electrical things i should check?

I'm assuming you mean in the context of your current starting problems, which seem to be traceable to a failure in the fuel supply system.

The whole purpose of the electrical components of the fuel delivery system is to turn on the fuel pump and trigger the injectors at the right time for the correct pulse length.

I'll skip the part about the injectors. It's not likely that all four of your injectors have failed at exactly the same moment. So what follows concerns the fuel pump.

You could start at the battery and trace the circuit through the "Main" fusible link, ignition switch, clutch switch, and fuel pump relay to the pump itself, but you have said you hear the pump running when you turn the switch to start. I would say that's hard to do with the starter turning over, but, to be sure your ears are not deceiving you, you could check that you have power to the green/yellow wire at the electrical connector that leads into the fuel tank, whenever the ignition switch is in the start position.

From there it's a straight path to the pump, which you could check physically by pulling the pump and testing for continuity.

From the pump forward to the injectors all is mechanical. I've talked about that in an earlier post so I needn't repeat myself.

It must seem that you're having a lot of bad luck, with the new pump appearing to have failed, but there are lessons to be learned from everything. And, once you get beyond these problems you'll have an extremely reliable car that gives you more pleasure than any amusement ride. And what I think, in the long run, is more important, what you learn in solving these complex car problems will serve you well in solving problems in an infinitely more complex system, life.

Careful observation, patient thought and analysis, simple experiments to test the results of your analysis, deliberate action, followed by more, careful observation, etc.

Good luck.

John Gunn
Coronado, CA

[festivBS]

I heard the pump cuz i pulled the cover off the tank and touched the key to the on position and it ran. the only thing that makes me think it could be an electrical problem rather than the pump itself is because last time i checked when the key was in the on position my power wire at the plug showed no power when pluged in but when unplugged the wire from the "hot side" (i guess you would call it) showed power. if that could be due to a faulty fuel pump then i will most definitely get a new one.

i really appreciate all the help and advice you've given me, it seems you have been thinking about my problems as much as i have! haha

[JohnGunn]

it seems you have been thinking about my problems as much as i have! haha

I can see how you might think that. But I have to confess, I think I enjoy the process of understanding the problem as much as the satisfaction of finding the solution and fixing it. To me it is all a very rich experience.

There are four positions on the ignition switch, off, acc, on, and start. When you say "on" do you really mean "start"? I ask because, according to my 1990 Festiva electrical manual, power to the fuel pump relay and thus to the fuel pump only comes from a circuit activated when the switch is in the start position. But that is the same circuit that turns the starter which normally makes a lot of noise.

Further, you should be testing power to the pump at the connector just outside the tank when the key is in start position. When you measure the voltage of a wire that is not connected to ground, as when you unplug the connector, there is no current flow. When you apply your meter, the meter internally creates a high-resistance circuit to ground so that it can read the voltage, but that can be a very weak source of power and show full voltage. Rig up a circuit tester with a 12 volt bulb and two wires, or buy one for a couple of dollars. The brightness of the light will tell you how much power is available from that disconnected wire.

If there is not enough power to turn the light on clearly, when the pump is connected it will bring the value of that weak power source down to nothing immediately.

What I would do is forget trying to measure the ungrounded wire. Measure the voltage with the key at start. If it shows 10 to 12 volts, there is no lack of power. The pump should run and there should be a pretty strong flow of fuel coming out of the input hose that attaches to the fuel filter in the engine compartment.

But for this to work the pump has to be grounded through the inertia switch so make sure that button is pressed in.

How far you want to take this is up to you. To get a good flow of fuel at the filter requires that the filter in the tank be open and that the hose from the fuel pump to the inline filter be unclogged. I would think problems there to be unlikely, but it wouldn't take much time to blow through the hose and look at the filter in the tank. The bottom line is, if you have power to the pump and no, or very weak, flow to the filter, the pump is defective. It is for you to do whatever it takes to convince yourself that the pump is either good or bad and then go from there.

Let me know how it goes.

[nitrofarm]

I heard the pump cuz i pulled the cover off the tank and touched the key to the on position and it ran. the only thing that makes me think it could be an electrical problem rather than the pump itself is because last time i checked when the key was in the on position my power wire at the plug showed no power when pluged in but when unplugged the wire from the "hot side" (i guess you would call it) showed power. if that could be due to a faulty fuel pump then i will most definitely get a new one.

i really appreciate all the help and advice you've given me, it seems you have been thinking about my problems as much as i have! haha

Do you have a schematic? You need one. You should NEVER be able to hear your fp run just by turning the key. Engine must be running.........

[resuwrecked]

If you did not rotate the engine between taking these pics it looks to me like your crank is btdc and the cams are atdc...

And btw your throttle cable hates your intake pipe.

[JohnGunn]

Do you have a schematic? You need one. You should NEVER be able to hear your fp run just by turning the key. Engine must be running.........

I don't know exactly what modifications festivaBS has made during his build, but on a stock EFI Festiva the pump comes on when the ignition switch is turned to the "start" position with the clutch switch closed.

There is another switch in the VAF meter that turns on the fuel pump. They both do that by activating the same fuel pump relay. That's why there are six terminals for that relay rather than the normal four. You are right when it comes to the VAF switch. It only comes on when the engine has started and air moves the vane in the VAF meter.

But when it comes to starting the engine, it is necessary that the fuel be under pressure so that the fuel can spray through the injectors in the proper pattern. That is why the pump comes on when the ignition switch is turned to "start" before the engine is actually running.

Once the engine starts, the VAF switch takes over and the ignition switch can be released from the "start" position to go back to the "on" position and the engine will continue running.

[nitrofarm]

I don't know exactly what modifications festivaBS has made during his build, but on a stock EFI Festiva the pump comes on when the ignition switch is turned to the "start" position with the clutch switch closed.

There is another switch in the VAF meter that turns on the fuel pump. They both do that by activating the same fuel pump relay. That's why there are six terminals for that relay rather than the normal four. You are right when it comes to the VAF switch. It only comes on when the engine has started and air moves the vane in the VAF meter.

But when it comes to starting the engine, it is necessary that the fuel be under pressure so that the fuel can spray through the injectors in the proper pattern. That is why the pump comes on when the ignition switch is turned to "start" before the engine is actually running.

Once the engine starts, the VAF switch takes over and the ignition switch can be released from the "start" position to go back to the "on" position and the engine will continue running.

John engine must be running or cranking to create enough air to close fp switch in vaf. The fuel "system" holds pressure from previous use. If the pistons arent moving the fuel shouldnt be moving either.

[nitrofarm]

If you did not rotate the engine between taking these pics it looks to me like your crank is btdc and the cams are atdc...

And btw your throttle cable hates your intake pipe.

Its hard to tell by that pic. I kinda see the two hash marks on the crank pulley.... I think And for sure that cable is hating life !

[JohnGunn]

John engine must be running or cranking to create enough air to close fp switch in vaf.

I believe this is correct.

The fuel "system" holds pressure from previous use.

There is a check valve in the pump whose purpose is to maintain fuel pressure between starts so that subsequent starts can be quicker. But that valve is not perfect. Eventually, pressure will decline to the point of no pressure. With zero pressure the engine will not start, unless the starter can turn the engine fast enough to move enough air through the VAF to close its fuel pump switch. I don't know if that is possible or at what cost that would be to the health of a battery.

That aside, lets take the case of a newly installed pump or fuel filter. When the engine is started after one of those procedures, there will be no pressure in the system and a considerable amount of air where there should be fuel. If your battery is not capable of turning the engine over fast enough to turn on the fuel pump and keep it running long enough to build up the required pressure, you're dead in the water. Your only recourse would be a new battery or to jumper the fuel pump to make it turn on before the engine starts. These are the kinds of problems designers are paid to anticipate and prevent.

If the pistons arent moving the fuel shouldnt be moving either.

This seems correct, but the fuel pump does more that just move fuel through the system to the cylinders. It runs constantly to build and maintain pressure. That pressure is what forces fuel through the injectors when they open. Without pressure, no fuel in cylinders. Without fuel in the cylinders, not ignition. Without ignition, no start.

Of course, this discussion is theoretical and involves a certain amount of speculation. In the end, what really matters is what is. And, in this case, what really happens, according to my 1990 Festiva electrical manual, is that the fuel pump is turned on when the ignition switch is turned to "start" and the clutch switch is closed at the same time.

Still, I think the kind of thinking you're doing is important. I believe, in all things, it is much better to resist what other people tell you and check whatever you are told against your own analysis. And even if you're wrong, as in this case, you will be preparing yourself for the time when you make your own, better, design one day.

If it would help, I could email you pictures of the relevant pages from my manual. [smile]Or you could just trust me.[/smile]

[festivBS]

got a new walboro 255 installed today and problems solved! gas flows like a champ now. now i'm waiting to get my ecu back so i can see how the timing looks and try to solve that problem again

[JohnGunn]

got a new walboro 255 installed today and problems solved! gas flows like a champ now. now i'm waiting to get my ecu back so i can see how the timing looks and try to solve that problem again

Glad to hear this. Nothing quite so encouraging as success.

[festivBS]

New problem- No start

I think my problem is my fuel pressure. without pressing the clutch but turning the key all the way, fuel will come out of the line disconnected at the fuel regulator but it takes a second to come through the line. and with a multimeter i am getting 11v

When i push the clutch in and crank the motor my power drops to 9v and the flow is alot slower. i looked at the b6t wiring guide over and i connected both of my green and red wires with both of the green with yellow for max power to fuel pump like it says.

When i spray starting fluid into the intake it will start and run pretty good and i can throttle it a little bit but it will eventually die (longest it will stay alive is maybe 8 seconds)

im thinking either a bad vaf or injectors.

sidenote: when i disconnect the fuel hose from the regulator and turn the key to the start position, it takes about 3 seconds before fuel comes out but when it comes out it has a pretty solid stream. Situation occurs both with clutch pushed in and not pushed in.

[JohnGunn]

I think my problem is my fuel pressure. without pressing the clutch but turning the key all the way, fuel will come out of the line disconnected at the fuel regulator but it takes a second to come through the line. and with a multimeter i am getting 11v

When i push the clutch in and crank the motor my power drops to 9v and the flow is alot slower. i looked at the b6t wiring guide over and i connected both of my green and red wires with both of the green with yellow for max power to fuel pump like it says.

When i spray starting fluid into the intake it will start and run pretty good and i can throttle it a little bit but it will eventually die (longest it will stay alive is maybe 8 seconds)

im thinking either a bad vaf or injectors.

sidenote: when i disconnect the fuel hose from the regulator and turn the key to the start position, it takes about 3 seconds before fuel comes out but when it comes out it has a pretty solid stream. Situation occurs both with clutch pushed in and not pushed in.

I just about decided that, since I don't know anything about the particular engine you are working with, my suggestions may have proven to be confusing. I know when you talk about wiring issues and the behavior of your fuel pump with and without the clutch pressed that what you are looking at does not match my 1990 Festiva Electrical Troubleshooting Manual. According to that manual if the clutch is not pressed there will be no power to the fuel pump relay. If this makes me confused, whatever I might say will inevitably pass my confusion along to you.

But, before moving on I decided to read your last post one more time and in the first paragraph I had a thought that might be worth mentioning.

You wrote about having fuel appear at the fuel regulator but having to wait second for it to come through the line. I can't speak for the engine you are working on, but on a stock EFI Festiva B3 the fuel line from the filter should go to the fuel rail first, the regulator is at the end of the that rail. Could you have switched the two lines that come from the tank?

With that, I'm done. Good luck. I'll remain subscribed to see how this turns out.

[festivBS]

i think i worded that wrong, our fuel is hooked up correctly cuz i've had that happen and i fixed it lol im wondering if maybe the fuel pressure regulator could be bad? causing the weird slowly dying out activity the car seems to have.