FirstGenRunner

This is in regards to a 3vz engine. I'm not sure about the 22re

There are three lines on the regulator. Starting from the top down. (I'm assuming this is right) The one at the top is a vacuum line. The next line down is the fuel return line. And then when it bolts to the rail that's where the main fuel will input from. In between a the vacuum line and the return line is a diaphragm.

When you start a cold engine there should be no vacuum. The diaphragm will be concave closing a valve inside and not allowing the flow of gas to the return line. Thus building up pressure for the fuel rail to then help push through the injectors. (I could be wrong, but you never want the fuel to flow back through the return line off the regulator...right?)

When the pressure on the rail drops, and something creates the vacuum that'll then make the diaphragm go from concave to convex, pulling the piston up and allowing the fuel to flow to the return line and back to the tank.

Now, again I'm assuming the Fuel Pressure VSValve will be the part that controls the vacuum to the regulator. Again, I need to confirm this in the FSM.

Main questions...
1. When you have a cold start on the engine is there any vacuum to the pressure regulator?
2. Is the vacuum supplied to the pressure regulator coming from the fuel pressure VSV?

Thanks in advance

scope103

Here, take a look at this: http://www.autoshop101.com/forms/h22.pdf

The purpose of the regulator is to keep the pressure in the fuel rail a fixed amount above the pressure in the intake manifold (the pressure in the intake goes up and down with throttle position). This way, the volume of fuel injected is solely a function of how long the injector is open -- open time is easy for a computer to calculate.

Fuel is constantly flowing back to the tank in the return line. The pump produces more than enough pressure for all situations, and the regulator returns "what it doesn't want." This is true even if the engine is not running, and the you're powering the fuel pump through the "FP" connector on the diagnostic connector.

There is vacuum in the intake manifold as soon as the piston starts to move -- otherwise no air would enter the engine. It has nothing to do with "cold start."

The FPU (Fuel Pressure Up) VSV (Vacuum Switching Valve) is used for hot starts to reduce the chance of vapor lock in the fuel rail. It does make the engine run rich, but only for a minute or two. By bleeding atmospheric air into the pressure regulator line, it makes the regulator raise the rail pressure. (The vacuum doesn't come "from" the FPU, it comes from the intake manifold, and the VSV bleeds air into the line, reducing the vacuum.)

Are these academic questions (the best kind!), or do you have a problem related to fuel pressure?

FirstGenRunner

Problem with fuel pressure...or best guess is fuel pressure. I can't find a fuel pressure tester around. Well one that comes with a banjo bolt. I picked up the standard type that uses the shrader valve as i heard there is a valve on the passenger side on a tube coming off the fuel rail. Not sure if this will work there.

The runner won't start at all. Actually, It'll sound like it's going to start, give maybe a one second rev up at the beginning and then die out. I've let the motor crank a good 5-10 seconds and then pulled a plug to find/smell no gas on it, and find the end of it to be white.

I know my injectors are firing or are at least getting a voltage to fire. I've hooked up a multimeter and cranked the motor and watch the voltage go up. I'm guessing not all 6 injectors died at the same time. One i could imagine, but not all six.

I took some quick start and spayed it into the intake pipe. When I tried to start it after that it started up and ran for a few seconds...long enough for the wipers to go up and down. This telling me that I'm getting spark and air.

I know I have spark at the plugs.

I've tested the MAF, and everything is within tolerance.

The FSU VSV is within tolerance.

I just installed a new fuel pump and filter a couple weeks back.

I'm guessing there isn't enough pressure building up on the rails for the injectors to spray into the cylinders.

As soon as I jump out the connectors on the status box to make the fuel pump start working as described in the manual it is automatically flowing out of the regulator. I would have thought nothing would come out of this unless pressure was too high on the rail.

TNRabbit

Have you checked for ECU codes yet?

scope103

Try starting it with the FP connector jumped to force the pump to run. If the switch in the VAF fails it won't detect air flow, which is necessary to keep the pump running after you turn the key from the start to run posn.

If it runs that way, your problem is in the VAF, or the COR (Circuit Opening Relay).

Those are easy tests, and you should do them before breaking open the fuel line. But since your problem came up after replacing the fuel pump and filter, I agree that you may may knocked some dirt loose which is blocking flow. So you need the correct banjo-bolt to schrader adapter to hook up your pressure gauge.

FirstGenRunner

The ecu is coming back with code 14 but I don't entirely believe it. The main reason is that is a break in the ignition circuit, and the motor did run with the started fluid in there. Telling me it's not an ignition issue.

I have tried starting it with the fuel pump jumped (by accident at the time) and no luck starting it that way either.

scope103

No, 14 is "IGF signal from igniter is not input to ECM for 4 consecutive ignition." You can get 14 if the igniter doesn't generate anything at all (including the IGF signal and the spark triggers), but the code is telling you something very specific.

More importantly, the injector signal is triggered by the IGF signal. So when the ignition is working but the ECM doesn't hear about it (no IGF at the ECM) the injectors don't open.

You could try listening at the injectors with a stethoscope (a paper-towel core is my tool of choice) to see if they are firing (it's an audible click). Or you might try hooking up your multimeter and watching it until it dies. (But a "noid" light would work much better looking for pulses.)

PatrickWJ

Did you find a solution?

I'm having the same problem. No start, I smell fuel, I jumped the FP/B terminals - I can hear the pump but I have no fuel pressure, spark is good. I can also hear the fuel pressure regulator as well when I hold my ear up to it while the terminals are jumped...doesn't start in jumped mode.

This all happened after changing my valve cover gaskets. WTF

greencactus3

i had a similar issue which ended up being a bent pin contacting where it shouldnt within the vafm. lucky i found the issue, no idea how it happened.

stroker393

FirstGenRunner - what was your fix or are you still down? I've got the same problem on my 90 V-6 before and after I replaced the fuel pump and filter.

FirstGenRunner

I haven't found the problem and it's extremely frustrating. So far changes have been:
Fuel Pump
Fuel Filter
Igniter
Ignition Coil
Distributor
Dist Cap
Rotor
ECM X 2
VAF

Mine started up about two months after doing the valve covers. It's definitely not the fuel pressure. I bought a noid light and can see the igniters being forced off. I tried disconnecting the wire off the igniter that sends the IGF signal to the ECM (which should kill the injectors) and it still runs. It's hard since it's an intermittent problem. Running through the tests and measurements in the FSM, everything seems to be within tolerance or super close. I had PM'd with another member and he was able to fix his problem by repairing his VAF. My next goal is to record each of the measurements in a spreadsheet and measure them twice. Once when it's running, and then again when/if I can get it to fail. If everything checks out there, I can only thing it'll be the wiring harness. I've gone through the bay and tried to ensure that I didn't pinch any wires when putting everything back and that everything had clearance and no sheathing had been removed from the wires. Everything looks as it should. To double check this, I tried misting water into the engine bay with it running, and no luck tried moving the wires to force a short, no luck. Tried misting and moving the wires. No luck. There is no rhyme or reason at this point. I'm lost.

I'm afraid it's going to be the wiring harness and I REALLY don't want to pull that apart.

93toyrunner2

I suggest checking resistance on your engine bay related wiring to the ECM, using the FSM for reference. I did this with my 3vze, and was able to replace poor resistance wiring as needed. One thing that made it easier was the alligator clips I found that had "bed of nails" inside the clip. I got them from the MAC tools truck. You can connect the bed of nails directly into the wire at any exposed area.

FirstGenRunner

So what you are saying is testing the resistance of each wire coming out of the ECM wiring harness. Basically test the resistance going from the harness at the ECM end to the opposite end at the component end right? I did this for the igniter and figured it was a waste of time. I guess I understand what you are going for here. It'll prove out if there are any shorts or if the wires are corroded. I did test the grounds and everything was as expected.

93toyrunner2

Exactly!

abecedarian

IGF is "I Got Fire".
IGF will not keep the engine from running since the distributor generates the triggers which the igniter passes through to the ECU for calculating RPM and timing once the engine is running: the igniter controls spark when cranking to start. IGF is not one of those signals- it's generated specifically by the igniter and sent to the ECU.

If I remember correctly, on the V6, the distributor has two pickup coils: one tells the igniter/ECU when a cylinder is at TDC and is also used by the ECU to trigger injection, and the other is used to calculate crankshaft angle so the ECU can accurately control ignition timing advance

What happens is the ECU triggers a spark event, the igniter collapses the field in the ignition coil which causes a spark plug to fire and through some clever electronics the igniter can determine if the cylinder actually fired. If the cylinder fires, the igniter signals the ECU "IGF". If the ECU doesn't get IGF back from the igniter, it assumes a cylinder misfired and after a certain number of misfires occur in a row, the code is thrown.

If the igniter and ECU have been checked / swapped with no solution to the problem, wiring is the next logical step. Check the terminals in the plugs, that they are corrosion free, firmly seated in the connector, and are actually making contact with the conductors in the wire. If those all pass, check the wire for continuity from end to end and check for continuity to ground, power and other wires in the harness, obviously with the ECU and igniter disconnected.