This 2.3 has got me stumped.

[John Smith]

gettin bak 2 basics..

if this unit is "new 2 u"..the usual checks of "grounds"..might b n order also the puter won't fire the injectors if it don't hear from the sensors etc...again grounds...also from personal experience..starting from the battery terminals...I think we're all making the assumption that this is all good..and also FP relays....good TFI module..good sender in the Diz etc...

 

[Off Road SHO]

It starts up just fine and runs for 30-40 seconds and then dies. Trying to keep it running with the throttle doesn't help; still dies.

I did watch the pressure as it died; While running it was 25-26 psi and as it died it started to creep up. I'm sure that was caused by the regulator doing it's job. When I disconnected the return line after the rail and plugged it up, the pressure shot up to at least 50 psi, so I thought the new looking regulator was bad, ie: 25 running and 35 running with the vacuum disconnected.

I put a new regulator on and it still does the same thing.

I will try and monitor the in-tank lift pump's voltage next, to make sure it is constanly getting 12 volts. I have no way to feed the HP pump with pressurized fuel so I might try putting 4 or 5 psi on the gas tank and see if that keeps it running.

I probably should just bite the bullet and drop the tank or raise the bed (probably easier) and see what's up with the lift pump.

Thanks for the suggestions guys.

Tom

 

[SMTGREG]

With over 25 psi fuel pressure the engine should run with no load.Will small blasts of starting ether keep the engine running? If it DOES NOT... start look elsewhere. Not a fuel problem. Test the voltage to the injectors as the engine dies. It should stay at 12 volts. I just replaced the EEC relay for the same concern as yours on a truck about a week ago. Another way to test injector power is get a #194 bulb (small license bulb) disconnect one injector and place each of the connector wires in the injector connector with the engine running the light should be flashing. Watch what happens when the engine dies. Normally it should flash until the engine stops turning. If it stops before that you have an EEC problem. Have you checked for spark as the engine dies. Does the spark go away then the engine dies or does the spark fade with engine RPM.

 

[John Smith]

Is this an 86 truck?

Is this an 85 truck with a complete factory 2.3 EFI install?..I wasn't aware that EFI started in 85 ..but 86. If it has ever been changed does it have all it's spots?..sensors, wires, etc..(still curious about that apparent possible patch in the high pressure line) also have you done the basics of checking for codes?..it should give off some clue as to what may be under par possibly. I remember my 88 had gone thru an engine swap..and many of the grounds were loose or not hooked up correctly..took a while..i still think you should have a good 39+ lbs when primed w key on. do you hear both pumps running at key on? It WILL work hang in there...

 

[Off Road SHO]

John,

I can get upwards of 50-55 psi of fuel pressure if I block off the return line of the rail.

The only codes I get are two that deal with an engine that is not at operating temperature (duh! It won't stay running for more than 30-40 seconds at a time). And the EGR code. EGR solenoids are bad; are open all the time. Have disconnected them and blocked off the vacuum line.

It's sure doesn't look like a "patch" in the fuel line. It is connected in a factory like manner in the middle of the nylon fuel line between the HP pump and the rail. The outer protective rubber sleeve (also factory looking) can be slid back from this cylinder quite easily, allowing a visual inspection of the cylinder/nylon tubing interface.

I don't know the history of the vehicle. In fact, I'm assuming it's an 85 because that's what the title says. I can look on the door plate to get the date of manufacture.

SMTGreg,

I have not started on electrical troubleshooting since this low fuel pressure thing has me already stumped. The truck does have some poor wiring but it doesn't look like there are any potentialy loose or missing grounds. The "starting and running fine for 30 seconds" seems to rule out an electrical issue in my book, but I'm not an expert of electronic fuel injected vehicles either. If it is a 60 pin computer like the EEC-IV in the Ford SHO, I have a "break-out box" that I can install if need be; otherwise, it's easy enough to check for common 12 volts on the injector's red wire.

Are these engine sequentially injected or batch injected?

I don't have any ether in the shop but will pick some up today and try your "keep it fueled" trick.

One thing I noticed while replacing the fuel pressure regulator: the triangular mounting plate on the rail is not perfectly flat. One of the points is bent up slightly. There isn't any gas leakage at all so it more than likely is sealing well, but at this point, I thought I throw that out there.

Tom

 

[John Smith]

In my limited experience

In getting one of these 80's vintage Fords to run with TFI....

It's ALL electrical....if you have a breakout box..by all means trace whats happening while this fails..i have a hunch you'l see puter shut down the injectors for some reason..they DO tell'm when to fire based on all of the input...including the main sensor the DIZ/TFI/etc etc..

A good refresher for me occasionally is

http://fordfuelinjection.com/?p=64

not to be demeaning with the reminder of the basics but..
then of course no massive vacuum leaks...

 

[Mark_88]

Here is a shot of that little metal canister. The rubber protector hose just loosely slips over the ends.

Tom

That looks EXACTLY like a fuel filter from my carbed engine...and if the line is fitting "loosely" you are not getting proper fuel pressure...

When I put my 6.5 psi pump onto the back of the filter (like the one in the picture) without a clamp and turned on the pump the fuel sprayed out all around the fitting...if that happened on mine and not on yours then you are not getting enough fuel pressure coming into that connection...unless, of course, you don't have a pump on the other side of that filter (coming into the fuel filter)...

Edit: looks like I missed a few posts before this...I'll leave it up in case you haven't cleared that matter already...

 

[Bish0psaid]

My 95 Ranger stalled out all the time till I got a New Mass Aif Sensor!..any codes come up on that?

 

[Off Road SHO]

I don't think this Ranger has a MAF sensor, at least not that I can see.

If the little cannister IS a filter, it is an integral part of the NYLON hose that it is factory crimped onto. It isn't attached to the loose fitting protector hose that covers the entire length of the NYLON fuel line inside it. This is on the high pressure side that got up to 55psi when I blocked off the return line.

I'm wondering if maybe the PCM is telling the ISC motor to shut too far down. I'll put a DVOM on the signal lead ( I assume it's a 5 volt to 12 volt motor), and see what is happening.

And John, I did a smoke test first thing like I said and only found a small leak at the EGR solenoid, and fixed it.

Tom

 

[John Smith]

again about hearing the pumps prime..

Can u turn the key on and hear BOTH pumps operate?..(maybe having a helper turn on while u listen)..Also have you cleaned the accumulator..the little cartridge filter looking device tween the tank pump and the HP pump?...It has some check valves..possibly a filter etc..and controls the returns to the tank and input from lift pump?...this accumulator has to be full of fuel from the lift pump to make it run..also if it has fuel and you have 40lbs of pressure...from then on it's an electrical issue i believe..best wishes..

 

[Off Road SHO]

I only have 55 psi at the rail when I physically block off the return line with my finger tip; otherwise it's at 25 psi with the regulator plugged in and 34-36 with it un-plugged.

I have disconnected the feed to the "accumulator" and had lovely assistant turn the key to run and watched the fuel spurt 4 feet. But I can't hear the in-tank pump running very easily over the noise of the HP pump and the loud exhaust.

I wonder if I have an air pocket in the fuel run somewhere that is causing a cavitation somewhere.

Tom

 

[John Smith]

While ur there...

I'd clean out the accumulator..being careful to watch for any check valve issues inside..and move on to other things..again with the electric issues..where's that break out box?....ans also..do you have a spare tfi module?..they usually fail when warm i guess..but if the stator or tfi has issues..no fire or intermittant at best...

I only have 55 psi at the rail when I physically block off the return line with my finger tip; otherwise it's at 25 psi with the regulator plugged in and 34-36 with it un-plugged.

I have disconnected the feed to the "accumulator" and had lovely assistant turn the key to run and watched the fuel spurt 4 feet. But I can't hear the in-tank pump running very easily over the noise of the HP pump and the loud exhaust.

I wonder if I have an air pocket in the fuel run somewhere that is causing a cavitation somewhere.

Tom

 

[Off Road SHO]

John,

Accumulator has a new filter in it and the check valves "look" okay; don't know what to actually look for but they don't have any rust or cloggy looking stuff in them. The new filter came with two O-rings; one for the canister sealing was obvious, but the little 3/4" one, I haven't a clue where that goes in this application. Cloggy is a technical term I picked up while attending the School of Hard Knocks in central AZ ( Ima Gradiet).

And the fact that it shuts off with near precision timing kind of steers me away from the TFI.

I'm hesitant to break out the break out box because this thing runs great, for 30 seconds, AND, I don't have the EVTM that I bought off FleaBay last week. So I wouldn't know what pins to look at.

Tom

 

[John Smith]

Well at least we think the fuel primary stuff

is somewhat ready..

Assuming we have a usable EECIV puter and all necessary wiring and sensors present and functioning, The following list of events may occur....

"Start / Crank
This is the start (I know, bad joke). The EEC needs to senses several things to start an engine:
* Power to EEC and fuel pump(s)
* Slow and irregular PIP signal from the distributor
* MAF/MAP low and irregular
* TPS is closed
* HEGO shows lean

These tell the EEC that you have just checked the dash, want the engine to start, and have turned the key. Even though you�ve heard the fuel pumps whirr, the injectors haven�t released any fuel until it senses engine rotation. Even when the engine does turn over EEC hesitates almost a full second to begin fuel and spark; this is to support oil lubrication. ECT and ACT determine the amount of fuel; the colder it is the more fuel it dumps in. The Idle Air Bypass is opened 100% to allow for operator error free starting. Spark control is taken over by the TFI, as long as you hold the key in the start position. What if things go bad, your ignition system could not light the engine, and it become flooded? Press the accelerator to the floor while starting, the full open TPS reading will tell the EEC to cut the injectors back to almost nothing. When you decide the fuel has been flushed out release the pedal and the EEC will fire the injectors and the engine fires up. Once the key springs into run, timing is determined by ECT and ACT, the PIP steadies out, the MAF/MAP builds, and the system bumps into the next strategy."..end quote from

http://fordfuelinjection.com/?p=64

you did mention some "dodgy" wiring..have you checked and identified the fuel and eec relays?..or checked or change either?..again grounds, power feeds...

If you have a good coil, and solid wiring..grounded well...you should see it work..
hope it works for you...I'm outa suggestions except to go thru all of the above...even though you may be steered other wise...it's just basic stuff..and it generally works...
JS

 

[Off Road SHO]

John,

So do you think there is a relay that shuts it down after 30 seconds?

Is there a relay pack on these vehicles? I'm starting to lean towards either the lift pump is pumping air into the "accumulator and therefore causing the main HP pump to cavitate... or the Idle Air Control is closing down too far and shutting off the flow of air. No, that can't be it because I would be able to keep it running when I open the throttle plate.

It's gotta be a fuel issue.

Tom