Simple test of the return fuel line

[White Lincoln]

In my efforts to make this car run better (without an engine swap) I came across some tests to see why the O2's are putting out code 137 and 173, running rich. One of the tests was to see if the return fuel line is backing up back into the injectors. What is an easy way to check? I was thinking to remove the return line at the fuel rail and apply pressure to the return line to see if it has resistance. If it does, I would move along the line to the tank. The theory behind this is extra fuel is coming from somewhere into the injectors. Also put tubing from the fuel rail return and see if fuel is indeed being pushed out under various conditions.

Next idea was to check if fuel comes out of the vacuum line at the regulator to see if is somehow leaking out of the regulator.

THe next few items are to test the fuel pressure at the rail, which i did again and it is steady at 38, engine warm, idle and only increases during reve's. It also stayed at 38 for the longest time after the engine was shut off.

Another test, which may be fruitful is to test voltages at the O2's during three states, cold, key on, engine running cold, engine running warn. That would show if the 02s get the hint to change voltages under these conditions. Is it a closed loop when the engine is warm or an open loop when the engine is warm? I read two different explanations, then I just got confused and figured a beer was better than a headache.

For shitz and grins, I pulled the engine IAC connector at warm idle and sure enough it is working. The engine dropped in RPM and ran like crap. If the TPS was acting up, I would get irregular idle, which that is not an issue. I also sprayed some brake cleaner on the vacuum lines while under warm idle and no, and I mean no flucuation in idle.

One question I have is if you swap a new MAF with the old one, the reaction should be instant, right? Which leads to one more question, when a code is corrected, such as running rich, how long does it take the car to adjust? 20 miles of contius driving? I did clear codes after correcting the distributor issue but the codes came back. Which leads me back to the O2's or some bad timming pulses from the PCM to the injectors. Frack, I really don;t know what the f is wrong here. As mentined in another post, my tranny is acting up, which could be related. That will require a good diagnostic by a trustworthy tranny mechanic (is there such a thing?).

Thought i would offer something to the site to think about instead of beer, boobs and engines....

 

[White Lincoln]

Well, I will be darned if anything. in my search for rich output codes, I started checking what injectors I had bought last year and everything I looked into for what this year, model and engine required and it seems that when I purchased them from Amazon, they said they fit. When I went back to my purchase I made on Amazon, they now say they won't fit. I sent a message to the vendor enquiring of the difference in fit. As I dug more into this, it seems the 9F-593A or B fit newer model engines. But I see that other purchasers of the product had no issues with putting them in 94-95 3.8l V6.

I bought F1ZE-B4C F1ZZ9F593B from Amazon.
According to RockAuto, the OEM numbers for this car are: OEM / Interchange Numbers: F3DE9F593B4C, F3DE9F593B4D, F3DZ9F593B, FJ81T

Ah, it'll be alright.... yeah.... No, I'm screwed. I have an older set that did not get the codes 137/173 before I added these new injectors. I bought the new ones thinking the ones I purchased from eBay 6 years ago were the wrong ones. And I was right. After learning more about injectors last year, I found out the numbers of the injectors from 6 years ago were for a 93 Cougar, which did not have a V6. But eBay does not lie!

This stuff is draining.

More to come as I do more tests, starting with the O2's voltages.

 

[1997ThunderbirdLXV6]

Two things:

1.
Forgive my ignorance, but why is it that the PCM can't correct for a rich condition? I mean if it knows it's running rich, why doesn't it simply command less fuel?

2.
About parts purchases: I always look up Thunderbird and Cougar. Should be exactly the same, but I had one or two experiences where the part specifications did not match, one of them being the wrong part.

 

[dDUBb]

@White Lincoln ..

I'm guessing you have a 94/95 ?

Ok .. closed loop means the engine is up to operating temp and adjusting fuel based on feedback from the o2 sensors.

How were you planning on checking the o2 sensors ? You'll need an oscilloscope or graphing multimeter to watch the sin wave. But that only tells you the sensor is relaying information - the engine is in a constant balance between rich and lean, it's always adjusting. When those adjustments are out of the PCMs normal working range, it will add or subtract fuel in the long term. Ford is pretty generous on their thresholds - it's 30% .. so when you have a rich code, it's adjusted to the point where it can't subtract any less fuel. Now if this were a mechanical condition ie; wrong injector size .. it may be over compensating to make up the difference. Only way to know is to verify the # is correct .. most 3.8L NA engines used the same size.

@1997ThunderbirdLXV6 ..

See above. The same goes for Lean codes. When the PCM has to add more than 30% it will throw a code.

I have lean codes on my SS right now. Too much air. .. it defaults to stock fueling tables at WOT. Apples and oranges.

 

[White Lincoln]

Two things:

1.
Forgive my ignorance, but why is it that the PCM can't correct for a rich condition? I mean if it knows it's running rich, why doesn't it simply command less fuel?

2.
About parts purchases: I always look up Thunderbird and Cougar. Should be exactly the same, but I had one or two experiences where the part specifications did not match, one of them being the wrong part.

Great minds think alike.

 

[White Lincoln]

@White Lincoln ..

I'm guessing you have a 94/95 ?

Ok .. closed loop means the engine is up to operating temp and adjusting fuel based on feedback from the o2 sensors.

How were you planning on checking the o2 sensors ? You'll need an oscilloscope or graphing multimeter to watch the sin wave. But that only tells you the sensor is relaying information - the engine is in a constant balance between rich and lean, it's always adjusting. When those adjustments are out of the PCMs normal working range, it will add or subtract fuel in the long term. Ford is pretty generous on their thresholds - it's 30% .. so when you have a rich code, it's adjusted to the point where it can't subtract any less fuel. Now if this were a mechanical condition ie; wrong injector size .. it may be over compensating to make up the difference. Only way to know is to verify the # is correct .. most 3.8L NA engines used the same size.

@1997ThunderbirdLXV6 ..

See above. The same goes for Lean codes. When the PCM has to add more than 30% it will throw a code.

I have lean codes on my SS right now. Too much air. .. it defaults to stock fueling tables at WOT. Apples and oranges.

So, could the engine be running lean and the o2s are over compensating by running rich? Hmmmm....

I was going to see what voltages i would get from the o2 sensors, per some instructions i read on the net. And i have not used an oscilloscope since tech school. My scanner is not much help as OBD1 does not say much. So I guess the volt meter won't help much then. I could unplug the 02s and see if it changes the codes! lol

As mentioned, looking back in my spread sheet on what I have done to this car over the years, the 137/173 codes started around the time I put in the new injectors. And I just replaced the 02's being so stupid to think they may have gone bad since my last head gasket work I did. Turns out, o2 sensors can get pretty messed up if you let coolant go down the exhaust and fowl up the cats. But that was not the case, I had replaced them just a few years back. I have fixed so much stuff on this car in just one year (I hit genius status at 63), but still am back tracking on what I did over the years to lead to this issue. Last time I had a 173 (and two other codes) was when the 1-2 actuator in the tranny went out.

 

[dDUBb]

No .. when the code says Rich, it means that it's reduced the amount of fuel to the point where it sets the code. ( not enough air ) In a perfect world, the computer might be able to go to 50% for example to make up for a larger injector size without needing a different tune.

Same goes for Lean codes .. a vacuum leak would introduce more "unmetered" air and the computer adds fuel to the point where it indicates a problem (code).

False lean ? Yeah that's a thing .. more of a false sensor reading; but it will adjust fuel and throw a code that points you in the wrong direction. The last time I discussed this was when I took advanced automotive diagnostics courses ( 2005 ) but say you had a fried wire with excessive resistance on a sensor ( MAF or O2 sensor for example) .. by the time that signal gets to the PCM its not the same as what the sensor is actually reading; so it may compensate and end up making the problem worse.

I agree .. obd1 sucks.

Volt meter won't do anything except give you an average voltage.. they switch between 0-5 volts; so you might see 2.5 Volts which doesn't tell you much except that they are "working"

Why did you change the injectors - my philosophy usually goes along the lines, if it isn't broken, don't fix it.

The 1-2 accumulator would have nothing to do with lean or rich codes - those might come up if there was an issue related to the o2 sensors or the wiring harness at the transmission when it was being worked on.

 

[Grog6]

Where did you get the injectors? what color?
What kind of 02 sensor?
Check the rear o2 wires near the exhaust for melted spots.
If you never replaced the rear o2s, now is the time. I usually buy new front ones, and move the old fronts back.
Only use NTK sensors; bosch don't work for us.

 

[dDUBb]

There are no rear o2 sensors on obd1 grog.

 

[Grog6]

I looked up the 137 code, and I thought it said after cat...

What Does the Code P0137 Mean? In short, there's an issue with your vehicle's oxygen sensors. Specifically, the diagnostic trouble code P0137 yields the following message: “O2 Sensor Circuit Low Voltage (Bank 1, Sensor 2).”
That's what I read ,BUT, I see the problem; google made 137 0137, which is obd2. My bad.
Other places,it was correct .

 

[White Lincoln]

Why did you change the injectors - my philosophy usually goes along the lines, if it isn't broken, don't fix it.

After some 100k miles (120/130?) I was doing my usual "WTF is wrong with this POS now?" and started reading a lot on the net about the symptoms I had and most matched the injectors are not spraying right. It was cheaper to replace them than have them cleaned. Stupid 'A' me threw out the OEM yellow ones. SOB. The car did run better and more stable after replacing them. A few years later trying to track down another "WTF is wrong NOW" issue, I started digging into the injectors I bought and found out the injector number says they are for 93 Cougar, (eBay said different, of course) they did not have a V6 in 93. So, I did more research and found the ones I have now from Amazon and were approved by Amazon to fit my car and the numbers seemed to match acording to other sites. Ah... damn long story.

dBUBd:
"The 1-2 accumulator would have nothing to do with lean or rich codes - those might come up if there was an issue related to the o2 sensors or the wiring harness at the transmission when it was being worked on."

Correct, but the codes that showed up when the broken 1-2 main spring went (common on the 4r70w) showed up with Codes 136 / 172 / 173. After fixing the accumulator, the codes cleared. Not a lot of notes on what else I might have been testing... Maybe I left the O2 unplugged when I ran the scan.

 

[White Lincoln]

Where did you get the injectors? what color?
What kind of 02 sensor?
Check the rear o2 wires near the exhaust for melted spots.
If you never replaced the rear o2s, now is the time. I usually buy new front ones, and move the old fronts back.
Only use NTK sensors; bosch don't work for us.

Hey Grog,
I got the current injectors from Amazon, F1ZE-B4C F1ZZ9F593B. They are chrome / grey plastic. O2 sensors are Bosch 15716 Premium Original Equipment Oxygen Sensors. I have only two o2's.

Interesting about Bosch not working for you. Never heard that before. I always read Bosch was like, "the schitz man!"

​

 

[White Lincoln]

I looked up the 137 code, and I thought it said after cat...

What Does the Code P0137 Mean? In short, there's an issue with your vehicle's oxygen sensors. Specifically, the diagnostic trouble code P0137 yields the following message: “O2 Sensor Circuit Low Voltage (Bank 1, Sensor 2).”
That's what I read ,BUT, I see the problem; google made 137 0137, which is obd2. My bad.
Other places,it was correct .

I found this article:
"If you are getting "too rich bank 1" codes, it means that the computer believes the engine is warm enough that it should switch to closed loop operation. At this point the computer believes the ACT and ECT sensors are saying "warmed up", so those sensors are probably fine in your truck......
So if the computer is trying to lean out the mixture, yet it is still too rich, why is this?
The answer is that extra, uncommanded fuel is coming from somewhere. Common causes are a failed fuel pressure regulator, a leaking injector, or a blocked fuel return line."

EGO not switching and rich bank #1 - Ford Truck Enthusiasts Forums

1987 - 1996 F150 & Larger F-Series Trucks - EGO not switching and rich bank #1 - Hi Ho, Im at my wits end and in hopes that SOMEONE out there can help me with this. Okay the facts. 1991 Bronco 5.8L E40D trans with air. 140K miles Problem: Okay a couple of months ago it started running REAL bad...

www.ford-trucks.com

So this is why I wanted to check my voltages on the o2's and have checked my fuel pressure and I doubt the regulator is at fault, it is brand new Walker regulator. Well, 10 months old.

Anyway, that is where I am now. I need to check the o2's and check the wiring and while I am under there, check my line to the starter and that the starter contact bolts are tight.

 

[White Lincoln]

I pulled the driver side plugs and not only are they burning perfect, they are Iridium plugs! I could have sworn I was using copper.

 

[Grog6]

save old platinum and iridium plugs, you can reclaim the platinum, or iridium.

 

[dDUBb]

Hey Grog .. how many plug do you think it would take to recover an ounce of platinum ?

 

[Grog6]

20 years worth of plugs, and $20 worth of chemicals. There are videos, but I know chemistry.

 

[White Lincoln]

I may be on my way to riches! I have 12 iridium plugs now! WOOT! They are all good and if they really go 100k miles, then I can reuse them over and over and over....

I stuck the copper set in that I got for $0.50 each from a RockAuto closeout/sale.

 

[White Lincoln]

Okay guys, so it would seem that not only did eBay sell me the wrong injectors, (RIN-907 Fuel Injector - 93 V6 or whatever that would be) but Amazon at the time said the injectors i bought were correct, but now say they are not (F1ZE-B4C F1ZZ9F593B - Not 94 V6 but 97 and newer). When I pulled the fuel rail from the 94 Cougar in the junk yard, I took the injectors. I looked at the numbers today and they fit: F3DZ-9F593B according to all the research I did.

I have a rebuild kit in my Amazon cart and am debating a sonic cleaner or just fuel injector cleaner kit that pulses the injector open with cleaner fluid under pressure to blow through the injector.

Thoughts in cleaning the injectors from the junk yard?

 

[White Lincoln]

I pulled the driver side plugs and not only are they burning perfect, they are Iridium plugs! I could have sworn I was using copper.

Pulled and replaced the other three iridium's. All were burning fine, but either due to build up on the metal contact or not gapped correctly, they were not burning that great.

 

[Kidd-7]

I’ve used a 12v battery with a momentary push button wired in along with this adapter on a can of carb cleaner to work over junk yard injectors.

https://a.co/d/2jf9J7E

 

[White Lincoln]

You know, I made a whole system that had a compressed air canister with cleaning fluid, 12v connectors, switch to pulse the injector.... Some inventions just never turn out like you think they will. So for $25 I figured I would give those Chines another chance and see if their invention was better than mine. For a couple cans of Berryman's intake cleaner, GumOut or whatever is on sale, "It's a Unix system... I know this!!"

 

[Kidd-7]

One think I learned is to clean the injectors before putting the new screen in. I had a few that were sticky and had to sacrifice the new screen.

 

[Kidd-7]

Here’s the set up:

 

[White Lincoln]

Dang, that looks like my first attempt at making a cleaner device (and failed). Nice job. Glad yours worked.

 

[White Lincoln]

One think I learned is to clean the injectors before putting the new screen in. I had a few that were sticky and had to sacrifice the new screen.

Good to know. I saw several other people use a sonic cleaner several times before running the cleaner. Almost bought one this time, buy don't have any jewelry to speak of.

 

[Grog6]

What color are the injectors?
As long as the ones you bought are the same color you should be fine. If you bought sc injectors, that won't work.

I used a board that I got from Oscar, to pulse the injectors; a 20cc syringe body will go over the injector, and I used a 200cc syringe for feeding it chemtool b12. then I changed out the filters and o-rings.

 

[White Lincoln]

What color are the injectors?
As long as the ones you bought are the same color you should be fine. If you bought sc injectors, that won't work.

I used a board that I got from Oscar, to pulse the injectors; a 20cc syringe body will go over the injector, and I used a 200cc syringe for feeding it chemtool b12. then I changed out the filters and o-rings.

You didn't clean the injectors without the filter? And the injectors I will be cleaning came off of a 94 basic grandma, unscathed 3.8l Cougar. As mentioned, my OEM injectors where orange, but I have not seen this for sale in a long time. My wife only knows where i put the orange injectors. And she just keeps saying "I don't know what you did with them..." she's lying... I know she hid them from me.

So you did use the Berryman's juice...

"There are a thousand ways to get to Chicago from anywhere, but why would you?"

 

[Grog6]

I have a box of these injectors; I bought bigger ones to use for upgrades. I'd hook you up with those cheap. Well, cheaper than ford, lol.
Note I have the prp, and can chane it in the tune. It doesn't help to use bigger ones unless you need them. a pi engine is right at the edge at wot.

 

[White Lincoln]

I made this tonight. I am going to fill the cannister with gas first to test it. Putting the injector in the jar provides a place for the fuel to "eject" to and I an roughly see how it is spraying. It'll be fine....


....Probably blow a line and get fuel all over the garage.