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MarvinG · 01-09-2021, 05:57 PM

This was a problem when I purchased this several years ago, and I’m circling back making another stab at repair. I’ve put around 10,000 very happy miles on this rig, with the light on.

When I first purchased I read the code per the flashing light method and, if memory serves, it indicated lean fuel mixture. I replaced the O2 sensor with no improvement. I also sprayed ether all around every fitting and possible vacuum leak I could find with no change in engine rpm. When shutting the engine off, I do hear some kind of whining/vacuum like sound apparently on one of the little black devices (with wires and vacuum hoses) mounted on top of the driver’s side valve cover. But I never determined exactly where, no results spraying ether there, and don’t know if what I heard was abnormal or not. I then took it to a local shop who does all manner of auto and some truck repairs. I was told they had a mechanic with some Ford expertise. They replaced the O2 sensor again, EGR valve, Fuel filter, and ran some Seafoam or equivalent through it, had me drive it with the muffler disconnected to see if the problem was there, reconnected the muffler and gave up. Cost about $500 for their attempts. At that point I also gave up, at least temporarily.

Now, I’d like to tackle it again. Rarely, like when I forgot to take it out of overdrive lockout, so that the engine is roaring down the freeway, the check engine light didn’t come on. Most of the time, though it comes on.

Thank you in advance for your help. I know some real experts on this system are on this forum.

subford · 01-09-2021, 09:27 PM

Just replacing parts very seldom works and the O2 sensor gets replaced for doing its job.
Most of the time the lean code is because you have low fuel pressure. Operating in third gear will send the RPM up with lower vacuum that sends the fuel pressure higher.

You need to do tests to find out what is going on. You need more than just KOEO codes you to find out what the CONTINUOUS MEMORY DIAGNOSTIC TROUBLE CODES (CM) are.
The CM codes readout after the KOEO codes are done reading out twice and with a separator code and then the CM codes will readout twice.

Also you need to put a fuel pressure gauge on it to see what is happening with the fuel system.

MarvinG · 01-09-2021, 10:48 PM

Subford, thanks for getting me started.

OK I’ll get a gauge and do a pressure test. (At one point the mechanic who tried wanted to drop the tank and put a pump on. I believe he said I had pressure but he wondered if I had pressure but not volume. My understanding of pressure/volume relationships made me question his logic. I was willing at that point to let him do it, but he got discouraged after starting to drop the tank, and bailed out.)

Regarding the CM codes, to clarify can I pull those by counting the flashes or do I need to get a quality OBD1 reader to get them?

rustyrim · 01-09-2021, 11:30 PM

the obd 1 readers now available for less than $30.00 are well worth it.

the readers are manufacturer specific . Autozone , Amazon ,type places all have them. If you google obd1 reader ford you can shop for price i think there is only one manufacturer.

subford · 01-10-2021, 06:59 AM

Quote:

Originally Posted by MarvinG

Regarding the CM codes, to clarify can I pull those by counting the flashes or do I need to get a quality OBD1 reader to get them?

You can count the flashes but the reader is much easier with the digital read out.

Here is the reader that "rustyrim" was talking about. The INNOVA-3145.

You can get it on amazon in the link below or at most auto part stores.

https://www.amazon.com/INNOVA-3145-Ford-Digital-Reader/dp/B000EW0KHW/ref=sr_1_5?crid=JUJ89OWHAWK5&dchild=1&keywords=for d+code+reader&qid=1610283556&sprefix=ford+code%2Ca ps%2C207&sr=8-5

Make sure you get the adapter with the fuel pressure gauge if you rent it.

/

MarvinG · 01-10-2021, 10:06 AM

Is there a simple/easy place to connect the fuel pressure gauge? Or maybe I should ask, where I connect it? I understand the concept, just looking for the tap location.

Should I check it with engine running or key on, engine off?

GypsyR · 01-10-2021, 12:18 PM

The gauge connects the the passenger side fuel rail on top of the engine. The fuel rail is chromed and easy to spot. The fitting on it looks just like the valve on a car tire and if no one has lost it, will have a black plastic tire valve cap on it too.

subford · 01-10-2021, 03:32 PM

The location is in the photo below like GypsyR said above.
You can run the engine and take it for a ride while someone watches the gauge.
It should be 30-33psi at idle and about 40psi at wide open throttle or by pulling the vacuum line off the regulator while at idle.
Just turning the key on and off will tell you nothing.
Grounding pin #6 of the self-test connector and turning the key to run should show 40psi.

mpaton · 01-10-2021, 04:55 PM

Quote:

Originally Posted by subford

The location is in the photo below like GypsyR said above.
You can run the engine and take it for a ride while someone watches the gauge.
It should be 30-33psi at idle and about 40psi at wide open throttle

I'll add much emphasis to subford's advice and say you MUST drive it while someone watches the gauge. You have not mentioned any symptoms of stumbling or loss of power, so it is probable that you will manage to read 30-33psi at idle. Many people stop there and insist that their fuel pressure is fine. It is not, you must drive it and verify fuel pressure when the engine is consuming significant quantities of fuel. Only then will you learn how well your pump is working.

It is important to retrieve all the codes from the PCM, and the Equus tool will be very helpful.

Spraying brake cleaner to look for vacuum leaks won't really help you on this engine. That is a test for lean mixture caused by unmetered air measured by a MAF (Mass Air Flow) sensor. You don't have one of those, your airflow is metered by a MAP (Manifold Air Pressure) sensor, and it meters all the air whether it came from a leak or not.

MarvinG · 01-10-2021, 07:59 PM

OK, I see the tap and will check that tomorrow if weather allows. Got it on checking fuel pressure under heavy throttle. And I hear what you are saying about leak-finding with ether isn’t satisfactory.

Three observations:
1) The codes I pulled today, using flashing light method, are 111 and 172. These are the same codes I pulled when I purchased it and first attempted repair

2) At idle the engine surges or hunts slightly. Not enough to see it on the dash tach but slightly revs up and back down. Just like the check engine light which has always been there since I purchased, the surge at idle has always been there. Don’t know if that has any significance or not.

3) I’ve attached a picture of the device that I think is the one I hear a vibrating, buzzing, probably air movement sound when the engine cuts off until it equalizes. This is located over the drivers side valve cover. This has always done that, and I wonder if it has any significance?

MarvinG · 01-11-2021, 07:53 AM

So as life goes, I picked up the loaner test gauge and fittings from the parts store. Told them to make sure I have the Ford adapter. Oh, yes sir! When I open the doghouse and start to connect the gauge. . . . Whoever used the kit previously, hasn’t returned the Ford adapter. So. . . . Back to the parts store to return the loaner and go to another store to get another!

subford · 01-11-2021, 09:16 AM

Quote:

Originally Posted by MarvinG

3) I’ve attached a picture of the device that I think is the one I hear a vibrating, buzzing, probably air movement sound when the engine cuts off until it equalizes. This is located over the drivers side valve cover. This has always done that, and I wonder if it has any significance?

That device is the EGR valve solenoid.
Yes it will bleed off when the engine is shut down from the engine running at mid throttle with a warm engine.
But it should not bleed off when an idling engine is shut down as the EGR valve should be closed at that point.

Sounds like the solenoid may be bad and opening your EGR valve at idle causing the surging.

Code 172:
Possible Causes:
-- Fuel injectors.
-- HO2S.
-- Secondary Air Injection (AIR) system.
-- PCV/Hose.
-- Vacuum.
-- CANP.
-- MAP sensor.
-- Electronic Ignition Coil Failure.

MarvinG · 01-11-2021, 07:01 PM

Can’t drive the vehicle due to a frozen bolt on a front shock I am changing. The shock is lose at the top and bolt still stuck at the bottom. So. . . .

I connected the fuel gauge and I read 32 at idle and 40 with the vacuum regulator hose pulled off. With the hose on the regulator the pressure modulates up as I open the throttle.

Of the possible causes of code 172, where would you start? What is the most likely or cheapest component to start with? Any way of testing the MAP, for example?

Regarding the vacuum bleeding at the EGR solenoid. . . I tried disconnecting the control wiring, thinking that might prevent the EGR from opening at idle and thus stop the solenoid bleeding. No change, still hear it bleeding on shutdown from idle. I reconnected the control wiring, and pulled the vacuum hose off the EGR valve. Then shut the engine off again, and as long as the vacuum line going to the EGR valve was shut off with my finger, or hooked back up to the EGR, the bleeding sounds continued. With the vacuum line lose from the EGR valve, it bled quietly through that line instead of noisily through the solenoid. What are your thoughts?

subford · 01-11-2021, 07:46 PM

I would disable the EGR valve and see if the it was still surging at idle.
I put a coin in the EGR tube at the valve for testing on my F53.
Do not over tighten the large nut with the coin in it or you may mess the tubes seat up.

If it runs OK at idle with the coin then I would replace the EGR solenoid valve.
If the solenoid dose not do it the valve may not be closing.
Then you would have to clean or replace the valve.