You are correct, as soon as the key is turned, the computer cycles the fuel pump relay to prime the fuel system. After that, the computer looks for signals from the ignition module to verify the engine is actually running. If the computer loses the ignition module signals, it assumes the engine has stopped and for safety reasons, it cuts the fuel pump relay off.

So a faulty ignition module can mess up the fuel pump circuit. But the fuel pump not priming would pretty much elimnate that as the cause I would think.

 

Dave, I am not quite sure I understand you here. What would pretty much eliminate that as the cause? The pump does not prime when the problem occurs. So the pump could be failing or there is a bad signal and the pump doesn't run?

The problem I have seems it almost runs as if it has some fuel or is trying to fuel and spark is being supplied because with what little fuel there is it tries to run.

I have a broken fuel pressure gauge and need to replace it. I had a problem with it on the trip and couldn't be sure it was accurate. I recall it reading 20 PSI running good or having the problem and still showing 20 PSI so the reading is unreliable.

Hall effect pickups are either good or bad and I did have a spark. Having a spark would indicate that the ignition is working and can determine engine rotation and energize the pump if I am correct. So this points me to a defective pump unless the distributer pickup now sparks at the wrong time and just won't allow the engine to run. I remember the old ford external ignition module boxes with to harness's and plugs from the 70's-80's and when they got hot they just stopped making spark I recall.

So what are you leaning towards, pump or dist pickup module?

 

Is the part in the dizzy the pickup coil, I know to replace that you have to knock the drive gear off and pretty much tare down the whole thing

 

Not sure what you mean by "in the dizzy"

The part in question is this.. it is called Distributor Ignition Pickup, you likely know how it works and is based on the Hall Effect. I know how to replace it, no big deal actually!

The choices are get a rebuilt distributor and risk a bad part that has never been replaced or a new distributor for $$$ or $25 for a new Ignition Pickup and my labor. This is of course less cost and labor then a fuel pump! IF this does not fix it then I believe my only choice would then come down to a new fuel pump assembly.

 

The ignition module interlock has nothing to do with the priming routine when the key is first turned, so I would lean toward a fuel pump problem, not a ignition problem.

 

I have a 1994 Mazda B-3000 with a Ford 3.0 V6 ive had a vapor lock in the cooling System because Ford put a 16lb Radiator cap if you fill the Radiator full then it misses like a Fuel Issue and use a lot of gas its all the 16lbs in the radiator pressure then it don't circulate the water put a 13lb cap on then it runs better. And ive read up on posts on here about vapor lock some say it has to do with air Bubbles in the fuel and I think most of you's take the myth's on vapor lock the wrong way and with Ford using the 16lb cap it will cause the heads to crack or the head gaskets blow out then your spending tons of money fixing Fords Mistake.

 

I just came across this thread again, and thought I'd give an update.

The truck ran better in cold weather. When it got hot again, the problem was back. I could spray the distributor-mounted ICM with cold air from a can and it would be okay again. This time I bought an actual Motorcraft ICM. I was reluctant to pull the distributor, so I had the shop do it--surprisingly cheap on the labor. They also said the pickup coil was bad and replaced it too. Truck ran great for a long time. I still have it, and am currently working on a new problem that may be water in the gas, but that's another story.

 

So this is an old thread, but I'm leaving bread crumbs in threads as I find them.

I am having the exact same issue. I have been battling this for about a year now. Just blew a nice week-long trip to Virginia because the RV died 2 hours into the trip. All this time I have been thinking I had a heat-related component failure, but I no loner think this is the case.

My RV is a 1990 Winnebago Warrior, based on an E-350 Chassis with an EFI 460 engine.

Here is what I think is happening. I believe that these engines and vehicles were designed before the prevalence of ethanol-blended gasoline. Ethanol gas has a lower boiling point that pure gas. Like others, I have only had this problem in very hot weather (95F+), usually with the AC going. I replaced the ICM first, last fall, and the vehicle ran fine all winter. I figured I had it licked. Problem returned in the summer. So I replaced the Distributor, which also replaces the PIP sensor.

So far I have replaced:
ICM
Distributor/PIP
Catalytic Converter
Spark plugs and wires
Engine temperature sensor
Idle Air Valve
Radiator
Thermostat

The in-tank fuel pump burned up about 5 years ago and so is about 5 years old.

I have never replaced the fuel filter (said in Ford manual to be good for life of vehicle) or the external high-pressure pump. I am going to replace the fuel filter this weekend.

I am also going to install a digital fuel pressure gauge this weekend.

This fellow caught the condition in the act, with a pressure gauge:

460 FI problem

Like this fellow, my engine was running 190F-195F (I have a 195F thermostat in it). But as we crested slight rises in the road, it would peak to 202F or so. Then, the stumbling would start. The engine would stumble, and any attempts to give gas would result in worse stumbling and backfiring through the intake manifold. I would coast to the shoulder, and it would idle (barely), and then die. After waiting 20 minutes or so, it would fire up with no problem. Before I replaced the distributor, I saw this problem when running at interstate speeds for hours, and then slowing down either due to traffic or getting off onto surface streets. I suspect reduced under-hood airflow was the culprit then. With this last crash last week, I think it was just the high temperatures and running the freshly-charged AC, combined with hitting hills.

The internet is rife with these kinds of reports. The usual responses are that EFI systems cannot vapor lock, and I have seen videos and reports that the problem is "fixed" by replacing the fuel pump(s), fuel filter, or the fuel pressure regulator. Many times the poster vanishes with no update.

My suspicion is that replacing components may bump the pressure back up a few PSI, which may be enough to defeat the ethanol gas from boiling. Or, more likely, they simply do not hit the right combination of high ambient temperatures and engine loads to cause the problem.

What I am going to do is first of all, install a GlowShift digital fuel pressure gauge. It's actually a dual-reading gauge, so I'm going to also wire into the fuel pressure sending unit with a T fitting so I will now have a digital readout of the fuel pressure and the oil pressure. I'm going to install the fuel pressure sending unit on the schraeder valve on the fuel rail.

This will give me a baseline pressure reading.

I am then going to replace the fuel filter, and see if the pressure changes. I will also replace the fuel pressure regulator on the fuel rail, and see if pressure changes again.

Sadly, fall temperatures seem to have arrived just this week, so I may not have a chance to road test this at high ambient temperatures again until next summer.

I have also ordered some "hood louvers" that I am going to install on either side of the hood. Actual hood louver are expensive as heck - these are generic louvered vents:


I considered running louvered vents all along the back edge of the hood, but the cabin air intake is right in front of the windshield, and I don't want to feed hot engine air right into the cabin air intake. So, I will install these near the back of the hood, on the sides. The goal here is to reduce under-hood temperatures.

I am also going to slip some rubber tubing over the fuel rails on top of the engine, in an attempt to insulate them.

Depending on the results of the fuel pressure reading, I may replace the high-pressure external fuel pump also.

I'm also considering installing a cooler on the fuel return line back under the chassis:


I would position this horizontally out of the way and fashion a sheet metal scoop to catch air and duct it through the fins of the device.

I've got another trip the first weekend of November - 4 hours each way. But I'm betting temperatures will be cool enough that I won't have to run the AC and I won't have any problems.

Steve

 

How could underhood temperatures affect the fuel in a EFI engine? The fuel recirculates continuously back to the tank, with the fuel moving like that you would not think it would have a problem unless the fuel tank itself was hot. The fuel regulator is at the far end of the fuel rail, so it should keep most of the fuel in the fuel rail exhanged with the fuel in the tank. Also, the more pressure you run the fuel at, the less likely it is to turn to vapor. Unlike the old school carbed pumps on the engine that actually put a slight vacuum on the fuel as it was pulling it up from the tank. If the ethanol fuel could not stand the temps back at the tank, then I could see that being a problem.

 

I think you are on the right track with psi gauge and here is why.
I have a John Deere garden tractor that has a 2cly 22hp water cooled FI motor.
When it was really hot out I would get about half done cutting the grass (4 acers) the tractor would start to surge till it stopped running and would not start up till it cooled off.

The web pointed to a spark issue but in testing spark was good.
So on to check the fuel system. Tractor has an in tank pump to a filter on the frame rail to the psi regulator and then a test port and the injector.
Note where the test port is .......... After the regulator so how do you know if it is the pump or regulator?

I checked with the local JD dealer and they said to pull the filter, install a tee and a gauge for testing.
I did and had the gauge where I could see it and went out cutting the grass. Yep about half way and the surging started and the gauge was bouncing all over the place till it went to 0 and motor stopped.
In checking the pump I could reach into the tank and the gas was boiling hot. I think the pump was heating the gas to the point the pump over heated and stopped working.

So if you can test after each pump and then after the regulator. This will tell you if the lift pump is failing or the high psi pump. If the test port is at the end like on my JD there is no way to know where the failure is.
If pumps and regulator are cheap and you can buy good one maybe just replace them?
Dave ----

 

This was always my assumption as well. And, as Dave noted, it is still possible that it is a fuel pump problem. Putting the pressure gauge on the fuel rail will show a low-pressure condition (see the quoted passage above). But it could be the pump failing, not fuel boiling in the line.

I am going to replace the high pressure pump, the regulator, and the filter. Then I'll have to watch my pressures come next summer. The in-tank pump was replaced with an Airtex E2060S pump about 5 years ago. When the original pump burned up, it took out the inertia switch and the relays. It's possible it damaged the high-pressure pump also.

Steve

 

So, is there a way I could monitor the current flow going to the pumps and determine whether or not they are running?

I could indeed install pressure taps before and after the pumps, but that would be difficult and expensive. Is it possible to wire up an indicator light somehow that taps into the fuel pump relays under the hood by the engine battery and tell whether they are running or not (and not just whether they are getting power or not!)?

Thanks,

Steve

 

You can have power to the pumps and they may not pump. Look at my JD tractor I am 100% sure there would have been power to the in tank pump but the pump would not pump when hot.
How did you find the low psi pump stopped working?
The way I look at it right now we are not 100% sure it is a fuel issue or spark issue we are only guessing it is fuel based on what?

I would say before getting into fuel psi taps because of what you said lets do a fuel system psi test and I am thinking it is at the end of the system like my JD.
If you find the fuel psi at the fuel rail test port is low then we need to dig deeper and maybe get tap(s) installed so we can test other items of the system.

I think for the regulator you pull off a vacuum line and it should change the psi? You need to check that but lets say that is true and you pull the hose and nothing then I would guess bad regulator but .........
What if the high psi pump is weak and is not boosting the psi up the regulator may be good no?

I think the low psi pump tap would be easy as I think you could use rubber hose & clamps to tee in a gauge.
What psi does the high pump put out? For testing could you do the same rubber hose & clamps?

I just wanted to point out when checking the fuel system you need to test each item to make sure it does not come back to bite you.
Dave ----

 

I know. That is why I said:

Obviously just having power is not an indication that the pump is actually running.

What I want to know is is there an electrical way to determine that they are running. By, say, current draw.

I am going to install a fuel pressure gauge this weekend that will monitor fuel pressure at the rail. But even if it shows zero, this does not tell me that the pump has failed.

I am trying to think of an electrical way to monitor the operational status of the pumps.

Steve

 

I guess you could if you knew what amps it pulls free flowing and when pumping and when it dead heads.
Once you have that information you might be able to tell but ......
What if the pump is having issues and the amps don't change or when you took your base line readings it was already showing issues?
Give it a try and report back your findings.
Dave ----