Brain teaser for the Brain Trust

I had a 2000 Ford F150, I know that's not the same year or vehicle type, and it was running rough, but only sometimes, which made diagnosing it a real PITA. What I ended up doing was replacing the plugs, coil packs, and spark plug wires. After that it ran smooth as butter. When your son replaced the plugs he had to move the wiring around to get to them. It is possible that while removing the coil packs and the spark plug wires to make room he damaged the coil packs or, more likely, the spark plug wires. It gets hot under the hood and the plug wires dry out and don't like to be moved. And you can't tell by looking at them if they're damaged or not. I would have started here before anything else. Fuel, air, or spark gets you running and of course the computers in these things have now gotten in the way and can either prevent that from happening or make it work better.

Sounds like one of the coil packs is bad to me.  It got moved, now when it heats up it malfunctions.
-=theron

Ignition wires can go bad after a number of miles.  When I had my 1991 Miata, it was recommended to change the plug wires frequently.  Where they were on the engine tended to overheat them.

Theron's diagnosis sounds good, also.

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This might be a better place to look for help:

https://www.focusfanatics.com/...-tech-discussions.64

Looking at some similar discussions there, one guy suggested tracing the battery ground terminal to where it grounds to the body (and to the engine block, too, while you're checking). Do the usual drill of remove, sand down to bare metal, replace. I guess some things do apply to any car, after all.

Also, they note that an intermittent ground over a long period can teach the CPU bad habits. They suggest clearing the cache and letting the CPU learn new patterns by driving the car slowly in around-town traffic. They explain 'clearing the cache', but I would only get it wrong if I tried to repeat the explanation. You could look it up.

Full disclosure: I don't drive a Ford Focus, not even on TV.

PS: Another guy said his loose/worn out motor mount made the whole car shake in a way that sounded like the engine was running rough. (Don't laugh. I know a guy with a Speedster who found a front bumper bracket hitting the fiberglass body, and he thought all the noise was coming from the front suspension. Sometimes, you just never know.)

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Kelly, I'd change the coilpacks on that Ford.

I'm about to go through this on my 2009 Dodge 5.7 Hemi. It has 144k on the clock.

Runs totally fine(with one caveat), until this past weekend. This truck has the cylinder deactivation under light load. Cylinders 1,4,6,and 7 are deactivated under light load to save gas. Lately, the truck has sounded very slightly rough when this "feature" comes on(there is an indicator light "mileage saver" or something when the system is on). It's easy enough to deactivate, just slide the shifter sideways to semi-manual mode(dash says "5" for 5th gear instead of "D"). You have to do this every time the truck comes out of park.

I think I might be onto something here, maybe?

I was traveling back home through Westbury CT on the interstate. I was moving along at 80 mph for a while(30-45 minutes) and all the sudden she got REALLY rough, breaking up, misfiring, check engine flashing intermittently etc. All temps and pressures read NORMAL: oil, water, trans. The truck balked at any application of throttle, so I carefully eased over from the left lane to the slow lane.

I slowed down and pulled over and read a pending code of "multiple cylinder misfire" even though the check engine went out and she smoothed out.(I have a bluetooth code reader in every modern vehicle I own).

So I proceeded to finish driving home, but at 70 mph instead. Everything OK, no misfires, spitting, sputtering, etc.

I was thinking plugs and coil packs. I have no idea if anything was ever changed before.

FYI, the hemi has 16 plugs and 8 COP packs. The coilpacks look original, plugs unknown. I've had the truck for 35k since 2020.

Thoughts?

I think the "plugs and coil packs" idea is a good one.  The BMWCCA magazine has a maintenance/repair column by a fellow who provides a better maintenance schedule than the factory and he always recommends replacing plugs and coil packs around 90k miles.  I would think it'd be similar for other vehicles.

"It is possible that while removing the coil packs and the spark plug wires to make room he damaged the coil packs or,more likely, the spark plug wires."

This.

However, the fuel stuff could have been it. Coincidences do happen.

At any rate, the coil packs, plugs (and wires?) have all been swapped out now right? As well as the fuel pump and its minders? So anything that happens from here would have to be some other component.

I’m a bit surprised that no one has replaced the fuel filter by now.  It’s a cheap common denominator.  

@edsnova posted:

"It is possible that while removing the coil packs and the spark plug wires to make room he damaged the coil packs or,more likely, the spark plug wires."

This.

However, the fuel stuff could have been it. Coincidences do happen.

At any rate, the coil packs, plugs (and wires?) have all been swapped out now right? As well as the fuel pump and its minders? So anything that happens from here would have to be some other component.

I think it's possible to get fuel reading problem codes with bad coil packs and spark plug wires. If a cylinder isn't firing all of the fuel going into that cylinder is coming out unburned and the O2 sensors are going to detect a fuel rich condition.

Here's one thing to check. This happened to a friend who changed his plugs and immediately experienced similar unpredictable results, mostly misfires. I suggested replacing coil packs and went over to help install them. When we took off the old coil packs what I saw was the tops of the plugs and inside the coil boots smeared right full of dilectric silicone.  I cleaned the silicone out of old coil boots (what a pain) and off the tops of the plugs. We put it all back together with the old coil packs, and it ran like a top.

I little of that stuff on the ceramic ribs of the plug is all you need. It's not to be smeared all over everything! More is not always better, even though this is America.

OK, guys, excellent thinking here.  You may have missed the part where we did put on new coil packs, but NOT new wires.  I'll suggest he do that.  I also finally tumbled to the idea that if the sensor(s) were feeding bad info to the ECU and it was then giving improper info to the injectors, and the mixture was getting hosed, then that could have upset the O2 sensor.  In any event, the O2 sensor was replace as one of the steps we took. I'll get him to do new plug wires.  And I think were good on battery terminals and grounding, but easy enough to check that too.  The idea that the ECU remembers shyt and stores some of that history in a cache, is news.  Will have to go look that up.  My son has gone so far as to understand where the ECU is and how one might replace it.  Although he and I both do NOT want to go there. --$$--

Thanks for the good thoughts and vibes.  Will keep you posted.

@El Frazoo posted:

OK, guys, excellent thinking here.  You may have missed the part where we did put on new coil packs, but NOT new wires.  I'll suggest he do that.  I also finally tumbled to the idea that if the sensor(s) were feeding bad info to the ECU and it was then giving improper info to the injectors, and the mixture was getting hosed, then that could have upset the O2 sensor.  In any event, the O2 sensor was replace as one of the steps we took. I'll get him to do new plug wires.  And I think were good on battery terminals and grounding, but easy enough to check that too.  The idea that the ECU remembers shyt and stores some of that history in a cache, is news.  Will have to go look that up.  My son has gone so far as to understand where the ECU is and how one might replace it.  Although he and I both do NOT want to go there. --$$--

Thanks for the good thoughts and vibes.  Will keep you posted.

I thought I read that he replaced the coil packs but when I went back to look for it I missed it. Probably because it read "coil-overs" and my feeble brain interpreted that as a suspension component instead of the coil packs.

I opened the creaky door to my long term memory archives and came up with a couple of possibilities that are spark plug related.

1. Are the new plugs the right heat range?  I had an '83 Celica GTS that ran like crap after the dealer swapped out the pugs.  I took it to an independent shop that had been recommended to me and was shocked when they called me an hour later and said it was fixed.  I was expecting a big bill and wanted a chance to push the car into the river before spending the money, but they said it was just the wrong plugs.  Problem solved for very little money.
2. I once had some issues with an '88 Integra after washing the engine with Gunk.  It turns out that enough water had leaked past the boots on the plug wires to fill the deep holes they were in between the two camshafts and partially short them out.  I know you said nothing about washing engine, but I was wondering if there was a possibility of something (water, beer, whatever) having gotten around the plug(s).

These are long shots but possibly worth investigating.

@El Frazoo posted:

My son has gone so far as to understand where the ECU is and how one might replace it.  Although he and I both do NOT want to go there. --$$--

This reminds me of the guy who tell the doctor that when he touches his elbow it hurts (and his knee, toe, and head). The doctor says "Broken finger."

It could be the ECU, but my bet is the ignition wires, or your past efforts were successful and it will continue to run well.

Not to muddy the water, but it may not be "ignition" related.  Mopar's Pentastar 3.6L v6 (used in millions of Jeep, Chrysler, Dodge) has a similar issue of "multiple random misfire" that can be related to 1. oil viscosity & 2. rocker arms.   Apparently, either the oil doesn't activate the rocker because of some pressure switch or the arm doesn't activate to the correct lift mode because of broken internal on the arm, thus creating a random misfire.   I don't see how oil viscosity would cause a misfire, but that's what the forums are saying. I'm still researching this one.  I wouldn't ordinarily think the Focus' 4-banger wouldn't have similar issues but anything is possible.  I'm just indicating it could be another issue that 'happened' to somewhat coincide with the service interval.  I know that doesn't help and it's probably more likely a wires/plugs/coil/ecu issue, but when you eliminate all those things...

And really, good luck, and know there's others dealing with similar diagnostics(me on the 3.6L), I'm using Jeep & Mopar forums for the "knowledge" specific to the 3.6L and it's already helped me on 3 other unrelated issues...   I heavily use the BMW forums for the E46 wagon & E93 vert, I really would suggest looking into a Focus forum or another Ford product that uses this engine.  (not that the brains on this forum aren't great, they are just less product specific for your case) ---   My.005 (my .02 adjusted for post-covid inflation)

Those various owner forums can be super helpful.  I used an F250 forum to find out what was going on with my truck's climate control system.  Every so often it would freeze and do nothing.  Turning the key off and on did nothing to clear it.  This seemed to be a common problem with no identified dealer service fix, but the forum folks said to "Get the engine running, then turn on the headlights and then step on the brake pedal twice - That should clear it".

I looked at that and thought who the heck are they trying to kid?

But I tried and Son-of-a-gun, it worked.  Don't know how they found that, but I used it a couple of times a year as needed.

Stand on one foot, put your right index finger to the top of your head, spin clockwise three and a half times, put both hands behind your back and say Kitchy kitchy boo boo, four times.  That will fix it.

Meanwhile back on planet Earth, with the coil packs installed there are no high tension plug wires to break down, right?  and no dizzy.  But still wires that could have been screwed with, unintentionally.  We will give that a careful look.  And so far since the high pressure fuel sensor replacement a few days ago, as I hear it, the car is working OK.  So maybe that was it??  As to having the right plug heat range, I can only surmise that young son (he's 50-something) got proper replacements.  i can check on that too.

I gave him the link to the owners forum that was posted above, maybe that has helped??  The idea the the ECU might need a reboot is interesting.  As a DIY adventure, Sounds like a good way to render the car useless.

@El Frazoo posted:

Meanwhile back on planet Earth, with the coil packs installed there are no high tension plug wires to break down, right?  and no dizzy.  But still wires that could have been screwed with, unintentionally.  We will give that a careful look.  And so far since the high pressure fuel sensor replacement a few days ago, as I hear it, the car is working OK.  So maybe that was it??  As to having the right plug heat range, I can only surmise that young son (he's 50-something) got proper replacements.  i can check on that too.

Hoping the fuel pressure sensor does it.    since he was in there moving things around.. check all the vacuum hoses for a loose one....  

during my recent E46 power steering pump replacement I found a vacuum hose to the purge valve not seated  (the cause of my gas smell and random CEL) that I had been looking for (for way to long).  Apparently I didn't get the hose back on good enough when I replaced the purge valve. 🤦‍♂️   it happens.

@El Frazoo wrote: "The idea the the ECU might need a reboot is interesting.  As a DIY adventure, Sounds like a good way to render the car useless."

Yeah - DON'T MESS WITH THE FACTORY ECU UNLESS YOU KNOW WHAT YOU ARE DOING!

It can be amazingly easy to do something simple, and instantly turn your car into a very big brick, unable to move.

Unless, of course, you have a Ford F250 where they want to "re-flash the ECU" seemingly every time you come in to service anything on the engine (usually followed by a bill for $1,500 or more).  

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I hesitate to comment here without legal representation, but...

The post I read referred to a simple 'reset' procedure that was only this:

- Disconnect both main battery leads completely from the battery.

- Touch together the power (plus) and ground leads you have just disconnected from the battery.

- Reconnect the leads to the battery and start driving the car.

Supposedly, that clears some sort of volatile memory cache in the computer, and the computer then starts 'relearning' proper behavior.

I have no idea if this is a good idea or not, if it accomplishes anything or not, or if it is the first step into a deep abyss.

What it does seem to suggest (to me, anyway) is that the computer might need some sort of reset after the car has been driven for a while with an intermittent ground. It's somewhere to start researching if you're otherwise out of answers. I'd look for a whole bunch of corroborating opinion from trusted sources before doing anything at all.

But I'd also look for a car without a computer. Anyone know where you can still find such a thing today?

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I hate new(er) cars for their complexity.

@Sacto Mitch posted:

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But I'd also look for a car without a computer. Anyone know where you can still find such a thing today?

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Nope, none of that here.

No ECU?  I have one in my garage.  Kind of burgundy red, low to the ground, rag top, air cooled.  Very fun to drive.  And I can generally fix it.  Full disclosure: I did put in a MagnaSpark dizzy, coil and I'm guessing some kind of solid state electronics, that I suppose does not involve what we would generally call a CPU with memory.  At least I hope not.

OTOH, the salesman at the Honda dealer said he thought my 2018 Accord had about 36 CPUs in it to run everything.  So far so good with that bad boy.

@Gordon Nichols posted:

Unless, of course, you have a Ford F250 where they want to "re-flash the ECU" seemingly every time you come in to service anything on the engine (usually followed by a bill for $1,500 or more).  

It was a diesel. Everything is $1500 with a diesel.

I bought my first one in 2003. A friend in the trade said, "it'll be a love/hate relationship". I thought he was crazy - what's not to love? Torque for days. Good fuel economy. Tow anything. A diesel is fabulous at everything it does.

Fuel available at about 1/10 as many places and generally $1.00+/gal more than gas. 16 qt. oil changes. Block heaters. 2 batteries. 10,000 lb GVWR. Gelled fuel. Running out of fuel is a really, really bad experience (and remember, the fuel is available at 10% of the places gas is sold)

... and at least $1500 every time anything was wrong, and there was always something wrong.

I sold my last one in 2013. It was one of the happiest days of my life.

Yeah, the time to own a diesel passenger car was 300D/25¢ per gallon era back in the 80’s and 90’s. Both my son’s A3 and my brother’s Sportwagon are looking at ~$1500-$2,000 DPF replacements. Diesel is even more expensive than the efree I run in my cars, although my brother swears the MPG even it out. (Until your DPF filter outs your car in limo mod3 until you cough up for a new one)

Dad had a diesel Chevette. You don't know crapbox until you drive a diesel Chevette.

@Stan Galat posted:

Dad had a diesel Chevette. You don't know crapbox until you drive a diesel Chevette.

Wow, a shiver just ran up my spine!

Bought my first rabbit diesel 5 speed in 1979 50 miles per gallon was great, 40 below weather and jelled fuel, propane torch in hand to melt the filter or heated garage to do the same, add regular fuel a bit or diesel conditioner to remove water. No heat … either even with a blanket for the front grill.  Row a lot with 50 hp but it was cheap to run.  A sibling did 500K  Km on one then another 500K Km on another Jetta.  NO TURBOS….

Eventually they got better,  2012 was the last jetta but with a turbo, with egr and particulate filter, the 2012 passat diesel with adblue. … the adblue tank went $1200, Egr $700 issues a lot with the jetta, there was a 5K invoice waiting with time for both cars so the cars had to go with time so Dieselgate vw payout helped.

I agree that Diesel has been short circuited by the powers to be but cars throwing a code is no fun, and dealers charge just to read a code… Finally, VW GTI went in 2022 with capacitor controls on the steering wheel … there was so much dislike and complaints that VW decided to go back to analog controls DUH…finally something went through.

@Michael Pickett posted:

Wow, a shiver just ran up my spine!

I owned a silver 1981 Chevette Scooter, purchased in the fall of 1981 with 3000 miles for $3000 out the door, so we were the rare 2 'vette family.

Mine was 52 hp of Isuzu fury -- 4 sp manual, no radio, a/c, back seat, or passenger seat adjustment (the driver's seat moved fore and aft). It did however have a heater and a 3-speed fan. Even hubcaps were an extravagance the General decided to forgo, the car made do with center caps to dress up the silver-painted 13" steelies. I bought some black spray-paint for the wheels, and 4 chrome trim rings, blacked out the trim, and installed black side moldings. No other modifications were made.

Mine was faster than dad's, which is really saying something. He traded a 1976 Nova with the police package 350/4-bbl. I had put headers on that car "to improve the mileage", but by 1983 dad had been through a really tough time in business and was entering into a phase of deep frugality. That 'vette was like a hairshirt of self-hatred, but it did have A/C for mom, which had the net effect of making a glacially slow car even more snail-like. I'm pretty sure I could have personally outrun it in a 1/8 mile drag-race, and I've never been fleet of foot.

My car wasn't as bad because it was unencumbered by anything other than a size-tiny alternator and a waterpump the size of a walnut. Mine was reasonably reliable, dad's was not.

It was the last American car he ever owned.

My F250 Diesel (6 liter) didn't really see snow or cold weather until we moved back to New England and by then the idea of being "Snowbirds" was behind us, including trailering Pearl 1,100 miles each way, twice a year.  Stan is absolutely right - Hitch up a loaded trailer and you didn't see any change in performance.  None.  It just pulled and pulled and pulled and I got 16.5mpg while pulling the trailer at 70mph in cruise with the AC on and another 600 lbs of "stuff" in the truck bed.  It was a refined beast.

There were five things that failed on the Ford 6-liter engines.

1. Fuel Injection Computer Module (on top of a hot engine, so it cooked - $1,500)
2. Fuel pressure pump (actually an oil pump, buried behind the engine $1,500)
3. Fuel pressure sensor ($27 part that took over 6 hours to change so, $1,500)
4. EGR/cooler failure (Equally buried but cost $300 so totals out to $1,800)
5. Fuel injection Pump failure (easy to swap, but the part was $900)

And if you were smart enough to "chip" the engine, you could get over 500 ft lbs of torque out of it with better fuel mileage at the cost of blowing the heads off (repairing that was around $8,000)

I had 1-3 fail and repaired and then sold the truck to a young Diesel kid and I was very happy to see it driving away.  

And on @Stan Galat's Dad's Chevette, a guy I once worked for had a Mercedes 190D, while I was driving a '66 Mustang 289/4-speed.  The Mercedes was a very cool looking little sedan and he bragged and bragged about getting 52 miles per gallon with it.  I volunteered to go get lunch one day and, with a twinkle in his eye he offered his beautiful little Mercedes for me to drive.  I take off from the store and the first thing I noticed, when I stepped on the "go" pedal, was that this car was entirely and utterly GUTLESS!  I mean, NOTHING!  Even worse, it was an AUTOMATIC!  It made all sorts of little growling noises, but it didn't GO!  It just sort of bumbled and vibrated along.

I stopped at a light, pulling up at the front next to a VW 1,300 Beetle with three girls in it.....  The light goes green.  I stomp on it and it growls and crawls out of the light, shifting at around 1,800rpm.  For God's sake!  I could RUN faster than this car!  The Beetle, with the three young girls in it, pulls away like I'm in Fred Flintstone's car and I'm pushing it with my feet, all by myself!  Never been so embarrassed in my life.  The guy absolutely LOVED that car, but when I got back to the shop I never wanted to even ride in it ever again.

Ah, diesels. I've owned 3. The first was an 81 Peugeot 304 with a 4 speed. The thing was buller-proof and quite a bit quicker than the equivalent Mercedes. 35 mpg and it would cruise at 85 all day long. Sold it when I got a great deal on a Datsun 280 (old style, not the 2+2, ick).

Second was a work truck for the business, an Iveco 16' foot box truck with a great big turbo inline 6. I taught 3 people how to drive stick in it. Super reliable, but it introduced me to how stupidly folks drive around trucks. 9 tons doesn't stop that fast.

Right now I've got a '95 Toyota HIghAce 4X4 set up for overlanding and camping. So far so good. The same deisel powers the HILux and Land Cruiser in the rest of the world. Reknowned for going 300,000 miles without any attention. It's surpisingly quick and gets better mileage than one would expect for pushing a brick through the air.

I have only one diesel story, having never actually owned one. I think it was in the early '90s I had the great good fortune to take a three week fly-drive to Europe in late summer/early fall.  Wonderful vacation, saw and ate lots of really cool stuff.  Rented a Peugeot at the airport, four door sedan with a model number I forget. Beautiful car, plenty of room, easy cruiser, very responsive.  After a couple of days I was visiting a cool museum in some town somewhere that had a nice parking garage under the building.  A narrow driveway down to the kiosk to get your ticket from the machine.  It was a very narrow slot surrounded by concrete.  Had to roll the window down to grab the ticket. And since it was great warm weather, the window had been up all the time with A/C on.  Grabbing the ticket I suddenly wondered: what is that rattling noise bouncing off the surrounding walls??  Seems like its From the engine?  What's wrong there, I wondered.  Well, of course you know: turns out the car had a diesel engine that I had been driving for several days already (attesting to its excellent fuel mileage)  without the first clue.  This suspicion was certified when I did have to tank-up and so noticed the different arrangement of hardware at the filler.  Again I say: that was a very fine car, thoroughly enjoyed living in it for three weeks.

Euro cars in Paris were a step ahead, every taxi was a diesel.

Dad had a 1980 Diesel Pugeot 505 4spd...  34mpg, mid-size 4dr sedan, comfortable ride, good visibility out, but:

1. I had to go to 3rd gear to drive up the mountain to Asheville at a whopping 45mph on the floor.  Slow describes it well.   A turbo would have helped.  (a 350 swap would have helped even more)

2. tremendous body roll on curves (why it was so comfortable "cruising the vista")

3. did I mention slow?... well it was, my Beetle was faster.

This was another "lesson" in driving for my formative experiences.

Next diesel was much better- '83 F-250 6.9 International - it was still '80s so pre-turbo but really pulled much better than the 350 powered C-20 Chebby PU.

The F-250 was retired to farm use only  in favor of a Ram-3500 Cummins that is still "in the fleet".  (and with <85Kmiles will be for a long time-  20mpg on the last trip to south GA & back.)     

Wrenn-

My radar just went up. You said the F-250 was retired for "farm use only". Does your family farm?

I'm a total wannabe farmer. Grandpa had a small farm (160 acres, corn/beans) and was a seed corn salesman for Pioneer. I grew up across the hardroad from the farmstead, and benefited enormously from the experience.

@Stan Galat,  From hairless ape pipefitter to potato planter?  This is your retirement plan?

Thinking about a Mercedes 240D, just to slow my life down...almost to a stop.

Your a patient man !

@El Frazoo Do you have an answer yet as to the problem with your son’s car?