4.0L OHV & SOHC V6 Tech General discussion of 4.0L OHV and SOHC V6 Ford Ranger engines.

Engine Jerking while accelerating

Old Jul 15, 2016
  #51  
Jeff R 1's Avatar
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Originally Posted by cheese_man
the newer models have more sophisticated ECM software now then back then in 1999
Maybe so, but I'm still going to maintain that you don't have to have a hard reset done by a Mazda dealer when installing a new oxygen sensor.

Here's a quote from Ron...

"it should only take 3 to 6 days for LTFT to correctly reflect new O2 sensors."

I think what ever dealership you spoke to is trying to drum up some business.

Mechanics and dealerships don't know everything or if they do they are taking advantage of their position.

I know a lady who had a 2002 Lexus SUV.
Check engine light came on, but still ran fine or at least she didn't notice anything wrong.
The dealer spent 10 hours trying to track the problem and never did find it.
He said "we can try and put in a new PCM in, but once it's plugged in, it's yours"
He gave her 4 of the 10 hours free, but the new PCM was still 1500.00 bucks ! (dealership price of course)
The mechanic was grasping at straws.
The lady didn't say what the code(s) were, she just said "after all that, the so called factory trained mechanic couldn't figure it out".

Shortly after that she traded it in on a Subaru and got 1500.00 for it.
The Subaru dealer didn't even want the Lexus on the lot, it got sold in an auction.

My point is that the Mazda mechanic doesn't know what he's talking about, or he's being dishonest.
At least at this stage, that's what it looks like.

When ever I hear things where one has to bring in a vehicle to have the PCM reset at the dealer to factory specs, my alarm goes off.

Anyways I won't be commenting on this anymore unless someone asks me a specific question, you may get the last word in, if you want.
 

Last edited by Jeff R 1; Jul 15, 2016 at 10:08 AM.
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Old Sep 20, 2016
  #52  
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I forgot my password and the site would never send me the email to reset it so I made a new account and added a 1 to the end of the name.

I still have not found the cause of this issue yet. I had no luck so I just kept driving it. somedays it would drive fine and others it was bad. recently it got really bad and also found not idle very well. whenever the compressor kicked on for the ac it would idle even worse. I am getting tired of dealing with this and not being able to figure it out. I bought a new IAC valve (which was probably not needed, but oh well) and I also changed all the spark plugs again. I changed them about a year ago maybe less. I took a picture to show everyone what they looked like. now that they are changed, I took it on a short drive and it idled and ran great. I believe they were the cause of the misfires, idling and jerking on acceleration. 4 of the spark plugs look fine and the other two are really gummed up. one bad plug on each side of the motor. bad plug is on passenger side rear of the motor and another bad plus on driver side front of motor. Not sure what caused them to go bad like this and also not set off any codes for rich or lean or anything. Any suggestions?

I'm thinking dirty injectors on the good spark plugs on that bank of the motor adding extra fuel and the cylinder that isn't clogged is getting too much fuel and fouling the plugs. Does this sound possible??
 
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Old Sep 20, 2016
  #53  
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I wish I could post the picture I took but it won't let me without uploading it on another website then posting the link here.......
 
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Old Sep 20, 2016
  #54  
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the site also deleted my long comment explaining an update to my problem. Guess i'll type it all out again....
 
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Old Sep 20, 2016
  #55  
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haven't been able to get my truck repaired yet and kinda gave up on it for a while. I kept driving it since sometimes it would run ok. recently it has started not idling well on top of the jerking when the motor is under load (like going up a hill on the highway when just cruising along). I replaced the IAC, which might not have been needed. I'm just tired of this problem and wanted to eliminate the possibility. I changed all the plugs. They were a year or less old. 4 of them looked ok to me. one plug on each side was dark and really gummy. the pass rear plug and the driver side front were the gummed up plugs.


Any one have any ideas on what is causing the plugs to get like this? There are still no check engine lights.


after the plugs and IAC valve, I took it on a short drive and it ran great, no issues.
 
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Old Sep 20, 2016
  #56  
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how hard is it to get the fuel injectors out on this motor so I can clean them?


1997 mazda b4000 4x4 4.0L
 
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Old Sep 20, 2016
  #57  
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If it's like my 3 litre, the upper intake manifold will have to be removed to gain access.
About your plugs; dark and gummy sounds like they're getting "oil" fouled.
Replacing the valve seals will solve that.
Unless the valve guides/stems are really worn, then the new valve seals will wear out sooner.
Dry and sooty plugs means that it's running too rich, but that would affect all the plugs.
I don't think that the injectors need cleaning though from what you described about the plugs.
It probably wouldn't hurt, but I don't think that's going to solve your fowling problem.


I use Photo Bucket to upload pictures here.
 
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Old Sep 20, 2016
  #58  
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Replacing the valve seals? Is that where the intake or exhaust valve seal around the head in the combustion chamber?
 
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Old Sep 20, 2016
  #59  
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Sort off, it's not in the combustion chamber, it's on top of the heads.
After the valve covers are taken off the rocker arms, keepers, and springs are removed to access the seal.
You use a tool like this to compress and remove the springs, so you don't have to take the heads off.


eToolsCity | Options for a Quality Valve Spring Compressor Tool to Save Time and Money


You can use compressed air to hold the valves in place or Ron's rope method.
What ever method is used, the engine must be rotated so the piston is at TDC, the wheels blocked up and the transmission in gear.
The battery is also disconnected so there is no chance the engine will accidently turn over.
With Ron's rope method, the rope is fed into the spark plug hole to form a coil on the top of the piston.
The engine is then rotated so the coil of rope is pressed up against the underside of the valves so they stay in place while the seal is replaced.

EDIT:
Don't go ahead with this until you show the forum a picture of your gummed up plugs, but at this point that sounds like what's happening.
 

Last edited by Jeff R 1; Sep 20, 2016 at 06:38 PM.
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Old Sep 20, 2016
  #60  
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Old Sep 20, 2016
  #61  
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From: arthur
1 of the coils in the pack is barely firing both plugs

time for a new coil pack
 
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Old Sep 20, 2016
  #62  
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Plugs are not oil fouled, just black and sooty.
I agree with cheese_man.

EDIT:
The coil pack was replaced along with plugs and wires.
The only thing left are the injectors.
 
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Old Sep 21, 2016
  #63  
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From: arthur
it is not uncommon for faulty coils to make it past inspection

try can of seafoam 1st , the injector just may be partially stuck open from carbon build up
 
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Old Sep 21, 2016
  #64  
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When it wasn't running correctly I ohmed the old coil pack and one of the sets ohmed a little different than the others so I replaced the coil pack with one that ohmed out almost exactly as the others in the pack. I can't remember the numbers but I think they may have even been the exactly same resistance as each other. Did the same with the wires. Removed them and visually inspected them and tested resistance and the longer the wire the greater the resistance. The resistance in them was proportional to their length.

I thought that it looked like oil fouling but I don't know much about it. I'll try looking up pictures of oil fouled plugs. If it was the four better looking plugs had a clogged injector and the bank was adding more fuel to compensate, wouldn't that make the dark plugs foul and the other two ok that bank look ok? But wouldn't there be lean codes?
 
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Old Sep 21, 2016
  #65  
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Do you mean seafoam in the gas tank?
 
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Old Sep 21, 2016
  #66  
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From: arthur
you are using platinum spark plugs on a coil pack that is not powerful enough to fire 2 platinum spark plugs at the same time

you should install regular nickel spark plugs

yes add seafoam to the fuel tank and drive , the seafoam should clean out the partially clogged injectors
 
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Old Sep 21, 2016
  #67  
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The new plugs are nickel coated ngk. I've been using fuel injector cleaner in the tank every 3 tanks probably but I'll get the Lucas kind next time.
 
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Old Sep 21, 2016
  #68  
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From: arthur
nickel coated platinum BAD!

just plain nickel plugs are what the engine requires
 
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Old Sep 23, 2016
  #69  
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I noticed that the plug that is in the close up picture is missing the porcelain around the bottom piece! The other plugs are not missing this piece. How could this have happened and does it mean anything about that plug going bad?
 
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Old Sep 23, 2016
  #70  
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As pointed out spark plugs for cylinders 3 and 4 share one coil in that coil pack.
3 4
2 6
1 5
These are spark plug Pairs, each sharing 1 coil in the 3 coil pack

They are wired in series so if one spark plug or spark plug wire has a problem, then BOTH spark plugs can be effected.

Yes, missing porcelain will cause low spark voltage from multiple arcs to ground, or in series wiring ground to center, instead of one strong spark you get multiple weak sparks and it would rob spark power from the other plug.
Electricity is like ME.............easiest path to ground or the aptly named Lazyboy in my case
 

Last edited by RonD; Sep 23, 2016 at 03:22 PM.
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Old Sep 27, 2016
  #71  
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I understand but the bad spark plugs are at opposite corners of the motor, Passenger rear plug and drivers front plug. they don't share a coil pack. are you saying that these two plugs going bad is directly related to each other from the coil pack they are connected to?

The bad plugs are in position 3 and 5 according to your chart. Or maybe position 1 and 4. I thought the passenger side was bank 1 since it has cylinder number one on that side.
 
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Old Sep 27, 2016
  #72  
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Ford V6 engine numbering
3 6
2 5
1 4
front

3 and 4 are on the same coil in the 3 coil pack
They are a "matched pair" used to balance the engine
3 and 4 are both at Top Dead Center(TDC) at the same time

As are 2 and 6, and 1 and 5, this is why coil pack is wired the way it is
3 4
2 6
1 5

3 "matched pairs" are used to balance a V6 engine

You can see the "match pairs" for any engine by looking at the firing order
Ford V6 firing order is 1-4-2-5-3-6
Split it in half and put one half below the other
1-4-2-
5-3-6

And that's the "matched pairs"
1-5
4-3
2-6

4cyl = 1-3-4-2
1-3-
4-2

Matched pairs are 1-4, and 3-2
 

Last edited by RonD; Sep 27, 2016 at 11:39 AM.
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Old Oct 7, 2016
  #73  
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Thanks Ron but I still am not following what you're saying. I didn't think those two cylinders would fire at the same time from the same coil. After looking at my coil packs they wire directly to the same position as the cylinders are located. None of the plug wires cross over the others. So I would think that cylinder 3 and 6 would share a coil. And 4 and 1 would share a coil. And 2 and 5 would share a coil. When I tested the coil for resistance this is how I tested them. The side of the coil that the plug wire connected to. One test lead on each side, then test the next two leads down, then the last two leads down. If those two sides werent in the same circuit then they would show open. How could cylinder 3 and 4 be on the same coil?
 
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Old Oct 7, 2016
  #74  
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From: arthur
purchase a spark plug tester

and try each cylinder

coil packs do fail over time , have you swapped in the regular nickel plugs
 
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Old Oct 7, 2016
  #75  
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Yes nickel plugs now. Everything is good so far and I've drove on a trip that was 8 hours one way, then back. Plus other driving.
 
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