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Engine Missfire on 04 BA Ford Falcon XR8


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SCOTLAND
New User

Apr 6, 2017, 3:10 AM

Post #1 of 3 (716 views)
post icon Engine Missfire on 04 BA Ford Falcon XR8 Sign In

Hi All

Need help diagnosing a misfire which is present at idle and on load throughout the rev range and has over time become worse and worse .. Vehicle is an 04 BA Ford Falcon XR8 with the 5.4 Boss 260 motor...

These are the things I have checked so far ...

Cats - Been removed

Spark plugs - Checked and in good condition

Coils - Checked and all seem to be firing

Vacuum Leaks on intake and manifold hoses - no smoke test done though

ECU Software - Original and Tuned Software checked ok

OBD Diagnostic - No codes relating to misfire present - tried on FCAR, Snap-On & Autel Scanner

Keen to hear if anyone has any other ideas?

Cheers


(This post was edited by SCOTLAND on Apr 6, 2017, 4:01 AM)


kev2
Veteran
kev2 profile image

Apr 6, 2017, 7:45 AM

Post #2 of 3 (695 views)
Re: Engine Missfire on 04 BA Ford Falcon XR8 Sign In

wow lots going on here -

Cats - Been removed -Is that legal - it is NOT legal in the states, AND can be problematic as codes are sure to arise. *

Spark plugs - Checked and in good condition - I always recommend OEM there are a lot 'gimmick" aftermarket products

Coils - Checked and all seem to be firing - Seem to be firing?

Vacuum Leaks on intake and manifold hoses - no smoke test done though - did you use old school 'carb cleaner spray trick" fast, easy, effective

ECU Software - Original and Tuned Software checked ok - STOCK is best and aftermarket is problematic *

OBD Diagnostic - No codes relating to misfire present - tried on FCAR, Snap-On & Autel Scanner - post ALL codes we can see if related or not.


THe misfire (post codes) can be ignition, FUEL, or mechanical.
Check your injectors, start by reading plugs, use a noid light, fuel pressure and pressure leak down, look at FT's and o2 sensor voltages.
you could enter mode 6 and look at misfire monitors... BUT basics first
Mechanical- might do a compression test. Again knowing ALL codes would be helpful.








* for off road, non registered ie racing this will be OK, you expect these problems.


SCOTLAND
New User

Apr 6, 2017, 2:15 PM

Post #3 of 3 (669 views)
Re: Engine Missfire on 04 BA Ford Falcon XR8 Sign In

Hi Mate

Cheers for your reply...


Cars pre 2011 aren't required to run a catalytic converter on them in New Zealand.. They are only passive cats anyways as the O2's are situated on the headers before the collector...wherase the cats are further downstream...

Plugs are OEM spec...

Coils - I did the pull test one by one and measured the resistance and they are all as they should be..

Regarding the vacuum leak possibility .. I'll give the carby sparay a whirl as you suggest...

Software wise the tuned software is sound as its only a few maps that have been adjusted and a pretty mild timing advance, but it makes a good difference to the drive of the car and numbers .. I've swapped it back to the stock software and the misfire is much worse...

Codes wise - the car doesn't present any codes at all when scanned with the previously mentioned scanners..

But i'll start looking at the bits you mentioned below.. cheers for your help..


Quote
THe misfire (post codes) can be ignition, FUEL, or mechanical.
Check your injectors, start by reading plugs, use a noid light, fuel pressure and pressure leak down, look at FT's and o2 sensor voltages.
you could enter mode 6 and look at misfire monitors... BUT basics first
Mechanical- might do a compression test. Again knowing ALL codes would be helpful.







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