Thoughts on a Miss fire

whitmanink

Member
Joined
Dec 28, 2020
Posts
592
Reaction score
258
Location
denver pa
Ok so I did a hott compression test just so I know the cold want a fluke or anything ..
Results are as follows

#5~~~168
#6~~~169
#7~~~~165
#8~~~172

So again my thoughts are to replace the plugs I did not ..
Replace the fuel filter
And most likely get new sets on cop

And see what happens
 

whitmanink

Member
Joined
Dec 28, 2020
Posts
592
Reaction score
258
Location
denver pa
Fuel pump
What makes you want to say that?
I only ask because lito had me do a log and only said my fuel pump DC seems high but nothing crazy...

Fuel trims were normal ...
How would I go about testing that ?
 

Juice

Senior Member
Joined
Aug 24, 2017
Posts
5,024
Reaction score
2,149
Tell me what the fuel trims are when its breaking up
 

whitmanink

Member
Joined
Dec 28, 2020
Posts
592
Reaction score
258
Location
denver pa
Tell me what the fuel trims are when its breaking up
i cannot show the log but fuel trims were on ,and he said they weren't anything to worry about>?.

the only thing he said looked high was the dc current for the pump..

i know nothing about fuel pumps so im pretty much taking his word, as i do believe he is only trying to help and wouldn't steer me wrong ..

but im always open to others experience and knowledge as alot of times collectively, we solve our problems together ..


i just dont know how to test if its bad if its dont just stop pumping?
 

whitmanink

Member
Joined
Dec 28, 2020
Posts
592
Reaction score
258
Location
denver pa
I'm attaching this FoMoCo 2007 MY OBDII Summary sheet below to help you to better understand why you're seeing what you're seeing concerning the misfire monitor showing no last counts......what most of you are looking at to determine # of cyl misfires.

From my intuition, your car is a 07 MY & is why I've attached this FoMoCo OBDII Summary for a Ford 07 MY vehicle (includes all 07 S197's.....).

Go to pg 15 thru 16 of this report & read it all.............this is Ford explaining how the Spanish Oaks PCM detects & records misfires........and more importantly, what 1 HAS to do\perform once the batt has been disconnected OR the PCM's KAM gets reset (cleared) to RECALIBRATE the CKP sensor to trigger wheel so PCM can know the difference between a crank accel velocity pattern under load vs a crank decel velocity pattern under full DFCO operation BEFORE the PCM will start RECORDING misfires to Mode 6..........

This recalibration routine (60\40 Misfire Monitor recalibration) is built into the Spanish Oaks PCM calibration thus you don't need a separate tool to do this..........like all Ford vehicles >2010 do, but you DO need to perform this as it is laid out in this summary.

To help shorten this for you.............the 1st time you accel past 60 MPH in either 4th or 5th gear (manual) or D for autos (I'd disable overdrive prior so trans will stop in 4th gear.....), take your foot off APP & let engine coast & enter DFCO then DON'T touch the APP, brake pedal (auto or manual) or clutch pedal\gear shift (manual only) again until the vehicle MPH drops below 40 MPH then use the APP only & accel back above 60 MPH then repeat the prior instructions.........do this for a minimum of 3 consecutive times for Spanish Oaks PCM to complete this & save the learned CKP to trigger wheel pattern in the onboard AICE chip......then the Spanish Oaks PCM will start recording misfires into Mode 6 thus will be saved. This version I have found works the best & will cleanly complete every time it is done as explained.

For a manual trans (my car is a manual), I've found this works better\cleaner in 4th gear than 5th gear, even though 5th gear imparts more load on engine during this procedure.

Note: this is best done using a very remote stretch of road w\ very little traffic to interfere w\ procedure application..........so be advised.

I have a LOT of datalogs that will clearly demonstrate\ have recorded this showing the Spanish Oaks PCM not recording a single misfire event during the initial datalog drive cycle post KAM reset from tune reflash.......until after I've performed this procedure..........thus I know of what I say here.

If this isn't done, the Spanish Oaks PCM will only show all 0's for misfire counts........thus will never show any MILs for misfires...........until this procedure is completed & pattern is saved.

This is the main reason why you're not seeing misfires at this time..........you haven't done this recalibration yet.

Anyone that tries to tell you that this procedure is fully automated thus you don't need to do anything post batt disconnect or KAM reset.........is not exactly telling you the truth.


Now..................what work did you just finished doing..........with the batt disconnected while doing it?

This is showing to not be well understood among the community...............I have posted about this several times in other threads (w\ the link to fordmotorcraftservices.com provided & several copies of various MY Ford OBDII Summary sheets as well........like this 1.......), but the message is not getting learned\received.

Hope this helps you.

im not sure whats going on here ,, but i dont have the forscan dongle yet so i wanted to see if i could get a misfire,,
so i unplugged a cop while it was idling ..
it definitely, threw codes and pointed out that bank..

does this mean it will find misfires or i have to do what you described ?
 

StockishS197

Member
Joined
Dec 24, 2024
Posts
434
Reaction score
378
Location
Houston
im not sure whats going on here ,, but i dont have the forscan dongle yet so i wanted to see if i could get a misfire,,
so i unplugged a cop while it was idling ..
it definitely, threw codes and pointed out that bank..

does this mean it will find misfires or i have to do what you described ?
to me this shows your car is monitoring for misfires. You could have a partial misfire causing hesitation. When I had something similar, it was due to aftermarket coils and/or an improperly seated COP boots

The fuel pump DC being higher than normal just means the pump is working harder to hold the commanded fuel pressure. As long as your car is holding the commanded fuel rail pressure, probably isn’t causing the issue (Lito logs this too).
 

Support us!

Support Us - Become A Supporting Member Today!

Click Here For Details

Back
Top