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O2 Sensor - 1992 F150 4.9 VIN Y Automatic

Kaajot

Micro Machine Manager
Hi all-

Never really had any feedback on all of the other threads, but I did "fix" everything for about two months.

Now the truck is dead on the side of the road with codes 126 and 327. I've replaced the MAP sensor four times in a year now (under warranty and swapping brands).

126 is the MAP sensor code again.
327 is EGR low voltage.

I changed EGR solenoid, TAB/TAD solenoids, and everything out in 2015 and 2016. We also replaced the TPS last month along with the MAP warranty. I think there is a new EGR valve was replaced in 2016 also, if not 2015.

I've been going through YouTube and Online looking up symptoms, causes, etc. So far one very possible cause for the EGR and MAP "effect" is a bad 02 Sensor. I have smelled rotten eggs occasionally over the last two months.

My mechanic just put an new O2 Sensor on for me a few months ago. I think I purchased it off RockAuto, or from NAPA.

Does anyone have any advice here? Can an O2 Sensor fail so quickly? It appears that if the O2 Sensor has gone bad that it will fail to send voltage up to the components that were a problem (MAP, TPS, EGR). Is this correct?

Appreciate any advice. I'm trying to have this truck stop breaking on me so I can take picture of it, cleaned up. I just had a bath but needs another one. Under the hood is pretty but the motor mounts are worn and the engine moves 4-12 inches right now at times (we're changing those out soon when I change the oil pump and oil pan). Hopefully will take photos after that phase of "rebuild."

There is light rust on the wheel wells. This Summer, if it's alive, I'll buy replacements and start fixing the body since the rust is now becoming evident.

Thanks again.

-KJ
 

Fellro

Moderator
Staff member
Is your cat intact? The rotten egg smell is indicative of a cat problem. If it gets plugged, you will initially lose power, then no go. It is generally initially caused by an overfueling condition, whether vacuum leak or a bad regulator.
 

dustybumpers

don't play well w others
Bad 02 sensor will fry a cat
Could be 02 sensor is good, you have a fuel problem, just o2 sensor picking it up
Checked the fuel pressure lately?

Did you ever do anything about having 2 intake gaskets on? I recall you saying you did that at one point
That is a problem there
 

Kaajot

Micro Machine Manager
Hey Dusty & Fellro-

Yep, we took care of the double gasket the dude that owes me $1500 put in about a year ago (January 2018). So now it's a single and seems to be holding together.

Actually, we put in a new Cat Converter in 2017 also and a new egr tube that mates up that way. There was a HUGE hole in the old cat (rust/blown out). Rock Auto purchases.

I believe we did check the fuel pressure, but I can recommend that check again. When I was TS'n the fuel issues before the new MAP and TPS we checked the Safety Inertia Switch (it's good), voltage at the pumps (they're good) and ran the new ground to the the front fuel pump directly to negative just to see if that made a difference. Also replaced the fuel selector switch on the dash because it was showing bad earlier Fall 2018, Napa part.

I was thinking O2 sensor fried itself (defective?) because ScannerDanner (YouTube) showed the O2 fried would cause the rotten egg smell, but maybe the O2 fried the cat. It's a brand new cat! :-(

The other problem is the motor mounts rocking everything and I really need to get a day on the lift where we support the engine and fix that -- have new motor mounts, so it's happening sooner than later. Wondering if the motor mounts can be agitating the O2 sensor or the Cat and causing this?

The only other thing I can think of is maybe the Ignition Control Module or my PCM went bad and is causing the low voltage at the O2 sensor? PCM was replaced Fall 2016, still under warranty can get them to send me a new one.

Appreciate the fast responses.

-KJ
 

dustybumpers

don't play well w others
Motor mounts

When it jumps up, it unhooks the vacuum for the map. and there is all the codes.
 

Kaajot

Micro Machine Manager
Motor mounts

When it jumps up, it unhooks the vacuum for the map. and there is all the codes.

smiliewhathesaid It's on the immediate short list. Got the parts already.


I think the map is connected though, I can check. Eventually I think it would do what you're saying though given the way it was moving near the end.

But yes, it's jumping all over the place. What about the low voltage at the EGR (327 code) and the return to low economy (2-6 mpg) and burnt eggs?

smiliestirthepot
 

Kaajot

Micro Machine Manager
We'll take a look at it, fatherdoug.

I don't know why the low voltage codes to things like the EGR and fuel pumps are occurring though, but I'm not a CAT expert so maybe a plugged CAT causes the voltage drop that's damaging components/throwing faults?

Going to throw a quesiton up on the 1997-2001 forum -- looking at a spare vehicle because of this, F350 or F550 for hauling/dumping.

Will keep all posted as the F150 hybrid "250" gets worked. Motor mounts are probably my first target to isolate breaking and stop new breaks from the engine jumping around.
 

dustybumpers

don't play well w others
Voltage at the egr is a measurement how much the diaphragm in the egr is moving

Have you checked the egr with vacuum to see if it is functional?


My guess it is probably filled with carbon, or rust, and not moving properly.
 

Kaajot

Micro Machine Manager
I've not done the test, but I ironically watched a guy on YouTube show how to test the vacuum. Talking about opening it up and covering it with your thumb type test on the solenoid?

We did rebuild last January all of the vacuum tubes during the manifold intake and exhaust reseals.

I found one last vacuum tube that was busted December or January 2019 when I installed a new heater core and blower motor, repaired that too.
 

Kaajot

Micro Machine Manager
Hey Dusty-

Although we're gonna check that egr, I keep thinking about that I may have smelled some wires burn. I think maybe my darn ECM computer may have fried again, and we just changed it out in 2017 (rebuild from A1 Cardone via Rock Auto).

I was checking to make sure the catalytic converter we installed afterwards was a Federal and not a CA-emissions, as that may have required a different serial number ECM. It says we put a Federal Emissions Catalytic Converter -- old one had a HUGE hole in it where the erg used to mate up. We replaced the EGR Tube too, so it's all new.

BOSAL 0794032 (Daily Driver) is the Catalytic Converter installed after the new ECM. Put a Bosch O2 Sensor in, may need to be replaced with a better part since I've smelled rotten eggs a few times before the truck completely died.

It's worth noting I had a K&N Air Filter and Throttle Spacer from AutoAnything.com installed prior to both of these maintenance tasks. I am wondering if that Throttle Spacer is causing the problems but really can't be sure until the motor mounts are replaced and the engine stops swinging. The battery's mount position is also loose, but the ground should be tight. Apparently the rack not supported where the battery is at, possibly due to bolts rattling out from the motor mount movement.

I think we're going to clean the Throttle Spacer, EGR Valve, etc, check the Ignition Control Module (it's not been tested and we did repair a wire 2 years ago to it during the ECM swap) and get the motor mounts/oil pan & oil pump changed, and check the ECM board itself for any faults or blown capacitors. That's an expensive $229 part from Rock Auto, but I see they're just under $100 form PartsGeek. Is there a different brand or reman shop I should be looking if the ECM is what's fried again? (ie not A1 Cardone, better warranty than 1 year?)

https://www.partsgeek.com/catalog/1992/ford/f150/engine_electrical/electronic_control_unit.html for reference, cheap A1 Cardone reman ECMs.

The ECM is mounted to the firewall of the cab, but could the engine's movement be somehow shorting/frying it out prematurely?


ALSO, anyone got instructions or a link on how to test an Ignition Control Module before I start replacing the ECM? We've not replaced the ICM yet and I was told Autozone can test these to see if they're good, but if there's a way to test with a tester, definitely would like that in my trouble shooting kit since the part is much easier to get at than the ECM and should be ruled out first as good or bad.

-KJ
 

dustybumpers

don't play well w others
I am not a fan of the K&N air filter. It is an oil base filter, and allows fine dust to enter the engine
fine dust compression engines = premature failure IMHO
I am not telling you to use a paper filter, just telling you I do

The spacer for the throttlebody is another fail
Here is a throttlebody being heated by the engine coolant and being cooled by a spacer?
Huh?
Ya. I can sell you a bridge in the desert by father Doug's house.....LOL

FIX THE DAM MOTOR MOUNTS
 

fatherdoug

Tonto Papadapolous
I am not a fan of the K&N air filter. It is an oil base filter, and allows fine dust to enter the engine
fine dust compression engines = premature failure IMHO
I am not telling you to use a paper filter, just telling you I do

The spacer for the throttlebody is another fail
Here is a throttlebody being heated by the engine coolant and being cooled by a spacer?
Huh?
Ya. I can sell you a bridge in the desert by father Doug's house.....LOL

FIX THE DAM MOTOR MOUNTS

I still have a few PREMIUM locations left! :D
 

Kaajot

Micro Machine Manager
Motor Mounts, got it. TS ICM Procedurally?

You guys are a trip!

I'm actually headed to Florida to get that Dump Truck (1992 F-700) next week, hope I won't be posting regarding that journey back to New York. smilieFordlogo

Yes, we're gonna get at the motor mounts this week, yay! :guns:

So, good news. I knew the wires were a little frayed, but the ignition coil wires to the distributor had corroded badly from water and poor deflection of any moisture. They got it running again. There are still other codes, but this was probably the big short in the system. Ice doesn't short it out really, and when it was really cold it worked reliably, but once it warmed up the water just killed everything and no fused conductor was able to bridge the gap. Meanwhile of course that ice was pushing things apart every time the wiring froze and thawed.

Autozone here says they can't test Ignition Control Modules. Don't think my ECM needs to be looked at now that they found the major smoking gun (besides the motor mounts) regarding the no-start.

Any idea how to check the ICM, procedurally?
 

dustybumpers

don't play well w others
Naaaa, his are all out there where the time zone has changed for the 3rd time.
 

Kaajot

Micro Machine Manager
I sense a bit of geographic rivalry. If I get out to Arizona some day, definitely interested in one of dem bridges to park my truck on. You know, keep it out of the moisture n such. No need to rust it more than it already has!

So, we got the truck running today and then it died again, but looks like it's a combination going from the PIP sensor/wiring to the ICM, from the ICM to the Ignition Switch, and backfeeding that routing it affects EVERYTHING. Turns out that's why I've got a fault in my towing computer at times, a fault in my MAP sensor and it blowing out constantly, throwing grounding faults at the O2, EGR, and Fuel Pumps even though they're working as advertised. It's the damn Ignition Switch under the steering wheel column.

And of course the MAP sensor got fried again in the process. The ICM shows bubbling on its board solder (we checked) as well as potential breaks in the circuit routes at 2 locations, and the Ignition Coil Bundle was super corroded. It's all water. I wash my truck like I wash my bum, a lot, and it was not as good a deal for the truck as it was for me. I used to spray out the entire cab (carefully) in Arkansas and believe that's when I really jacked up that Ignition Switch which doesn't have a lot of protection to begin with if you're spraying water in the cab.

Five MAP sensors later.... NAPA says this is the last one, then I have to buy a new one for a new warranty. :p

Think I'll just call the truck 5 MAPS from now on. It was RED IX, but this is much more fitting.
 

Kaajot

Micro Machine Manager
The guy that did my engine swap is to blame from 4 years ago. Found the underlying problem that was even why the ICM and Ignition Switch (now both replaced) were failing and damaging the MAP as well.

Engine Ground was to Battery Ground, sharing same terminal on frame, since 2015.

I have put so many solenoids, sensors, switches, etc and replaced things in this truck because of that crap. The guy owes me $1500 too and I took him to court, won a judgement for only $495 and he's yet to pay.

Backyard mechanic con artist. Feh. What a learning experience. And all of this time, effort, learning paid for by lending him cash to pay his tickets so he didn't get escorted off to jail and could keep working at Advance Auto Parts. I truly was the fool, but at least I know better about grounding.

I'm not a mechanic, but I'm learning. I won't do something I don't know how to do properly and can't reasonably do safely and with a good backup plan if it goes wrong.

Just a little floored. Truck is now driving as good as it did in 2011 and 2012 when it made many 500 mile journeys between Little Rock and Atlanta for TDYs.
 

dustybumpers

don't play well w others
Glad you found the issue. Sorry it was such a headache

Sent from my SM-N960U using Tapatalk
 

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