Notices
Modular V10 (6.8l)  
Sponsored by:
Sponsored by:

Misfires on 4,5,8. Iím going to document what I try.

 
  #1  
Old 04-09-2019, 10:57 PM
wbubble
wbubble is offline
Freshman User
Thread Starter
Join Date: Apr 2019
Location: Richland, WA
Posts: 38
wbubble is starting off with a positive reputation.
Misfires on 4,5,8. Iím going to document what I try.

Hi all, my first post! Ive has a few Ford trucks but this week I picked up a project.

2000 F250 4x4 v10.

I picked it up cheap knowing it was misfiring. The previous owner said heíd been given 2 different possible diagnosis by 2 different mechanics.

One mechanic said he had burnt valves and low compression on a cylinder (although he couldnít recall which).

The second mechanic told him that compression was fine, then took $1500 ďto run a bunch of testsĒ and ended up using the truck as his personal vehicle for a few months. Yikes.

No check engine light but when I got her home I plugged in the scanner and read 3 codes indicating misfires on cylinders 4,5 and 8.

I had already bought 2 new coils, 2 motor craft plugs and 2 new boots and started farting around with the cylinders in question.

Cylinder 8 plug looked normal but old, so I gave it a new coil and plug.

Cylinder 5 plug was wet with gas. I cleaned and gapped it and put it back in with a fresh boot. I wish Iíd bought 3 of everything.

Cylinder 4 plug was so gooked up with goo/grease that I couldnít see the electrode and there was no way that cylinder had been firing. It got a new plug and coil.

i started her up and while she felt the same, only cylinders 4 and 5 were still reading misfires. I took a spirited drive around the block with no change.

Iím not sure my compression tester will work with the deep plug holes so I think I may swap plugs, coils and injectors from cylinders 1 and 2 with 4 and 5 to see if the misfires follow the parts. I donít see any holes in the pcv hose and the valve rattles when I shake it.

Any suggestions are appreciated. Iíll report back as I try different things.

Heres the cylinder 4 plug.

 
  #2  
Old 04-10-2019, 05:41 AM
JWA's Avatar
JWA
JWA is online now
Post Fiend
Join Date: Aug 2010
Location: Reynoldsburg, Ohio
Posts: 11,458
JWA has a superb reputationJWA has a superb reputationJWA has a superb reputationJWA has a superb reputationJWA has a superb reputationJWA has a superb reputationJWA has a superb reputationJWA has a superb reputationJWA has a superb reputationJWA has a superb reputationJWA has a superb reputation
OTC makes a compression testing kit with one fitting specifically mentioned as used on Triton or Modular Motors---someone somewhere makes an adapter for these engines your current tester could use for that test.

Good gravy that #4 plug is just plain ugly---are those metal particles that have become magnetized? I wonder if a valve or ring hasn't failed and spewing metal debris?
 
  #3  
Old 04-10-2019, 07:39 AM
Krewat's Avatar
Krewat
Krewat is offline
Admin Newbie
Join Date: Jul 2002
Location: Long Island USA
Posts: 39,882
Krewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputation
i got $5 on a physical failure in #4
 
  #4  
Old 04-10-2019, 07:52 PM
wbubble
wbubble is offline
Freshman User
Thread Starter
Join Date: Apr 2019
Location: Richland, WA
Posts: 38
wbubble is starting off with a positive reputation.
Originally Posted by JWA View Post

Good gravy that #4 plug is just plain ugly---are those metal particles that have become magnetized? I wonder if a valve or ring hasn't failed and spewing metal debris?
As far as I can tell, itís just sludge.
 
  #5  
Old 04-10-2019, 07:53 PM
wbubble
wbubble is offline
Freshman User
Thread Starter
Join Date: Apr 2019
Location: Richland, WA
Posts: 38
wbubble is starting off with a positive reputation.
Originally Posted by Krewat View Post
i got $5 on a physical failure in #4
I canít take that bet because youíre probably right. Fingers crossed though.
 
  #6  
Old 04-11-2019, 06:06 AM
JWA's Avatar
JWA
JWA is online now
Post Fiend
Join Date: Aug 2010
Location: Reynoldsburg, Ohio
Posts: 11,458
JWA has a superb reputationJWA has a superb reputationJWA has a superb reputationJWA has a superb reputationJWA has a superb reputationJWA has a superb reputationJWA has a superb reputationJWA has a superb reputationJWA has a superb reputationJWA has a superb reputationJWA has a superb reputation
I'm sure a compression test will reveal a lot---at minimum you'll probably be pulling the heads off. Then again pulling the valve covers might reveal something as well.

Hope this is a relatively simply repair but it doesn't look to be so far................
 
  #7  
Old 04-11-2019, 09:02 AM
johnfist
johnfist is offline
Senior User
Join Date: Dec 2017
Posts: 417
johnfist is starting off with a positive reputation.
I'd definitely yank the valve covers and inspect the areas. Aside from #4, which looks dicey, you may have some failed rockers and a wrecked cam. Happened to me.
 
  #8  
Old 04-11-2019, 03:54 PM
super 6.8
super 6.8 is offline
Posting Guru
Join Date: Oct 2004
Location: Southern KS
Posts: 1,027
super 6.8 has a good reputation on FTE.super 6.8 has a good reputation on FTE.super 6.8 has a good reputation on FTE.
If it has been misfiring that bad for very long your cats are toast and it will never run right by just fixing injectors, coils and plugs.

Just something to think about.
 
  #9  
Old 04-11-2019, 04:03 PM
wbubble
wbubble is offline
Freshman User
Thread Starter
Join Date: Apr 2019
Location: Richland, WA
Posts: 38
wbubble is starting off with a positive reputation.
Originally Posted by johnfist View Post
I'd definitely yank the valve covers and inspect the areas. Aside from #4, which looks dicey, you may have some failed rockers and a wrecked cam. Happened to me.
i was under the impression that this is an OHC engine. Are there really rockers?
 
  #10  
Old 04-11-2019, 04:06 PM
wbubble
wbubble is offline
Freshman User
Thread Starter
Join Date: Apr 2019
Location: Richland, WA
Posts: 38
wbubble is starting off with a positive reputation.
I put a can of injector cleaner in about 1/4 tank of gas and drove the truck to work. After clearing codes, #4 recoded right away and #5 was code free for about 15 minutes.

When i I put more gas in, I noticed that the gas cap is broken. Could that contribute? Still no Check engine light.

 
  #11  
Old 04-11-2019, 09:01 PM
super 6.8
super 6.8 is offline
Posting Guru
Join Date: Oct 2004
Location: Southern KS
Posts: 1,027
super 6.8 has a good reputation on FTE.super 6.8 has a good reputation on FTE.super 6.8 has a good reputation on FTE.
I would definitely replace the gas cap. That could cause some issues.
 
  #12  
Old 04-11-2019, 11:02 PM
wbubble
wbubble is offline
Freshman User
Thread Starter
Join Date: Apr 2019
Location: Richland, WA
Posts: 38
wbubble is starting off with a positive reputation.
Ok so tonight hereís what Iíve done. I removed and cleaned the throttle body (it wasnít horrible but definitely needed a cleaning). I also pulled the plugs, coils and injectors from 1,2,4 and 5.

I couldnít get by compression tester to screw in way down those holes so I attempted to compression test 1 ( a good running cylinder) and 4 ( my problematic cylinder) by using the ďpress it against the holeĒ attachment. I was able to get good pressure straight down on cyl 1 and got about 180. I couldnít confidently get a seal against cyl 4 and my gauge registered about 100 pounds.

I scoped all 4 open cylinders and was able to see crosshatch on all cylinder walls, but #4 was noticeably dirtier ( no clue if itís just because it hasnít had fire because of the fugly plug). The fuel injector from 4 was also very very dirty.

Next step is to reassemble with known good plug, coil and injectors in cylinders 4 and 5 and turn the key. From there it gets dirty.


This was the ďpress it against the holeĒ method way back on 4.

Scope down cylinder 4.

Injectors from #2 and #4.
 
  #13  
Old 04-12-2019, 06:31 AM
Im50fast's Avatar
Im50fast
Im50fast is offline
Humblest guy ever
Join Date: Apr 2013
Location: Central Florida
Posts: 3,009
Im50fast has a great reputation on FTE.Im50fast has a great reputation on FTE.Im50fast has a great reputation on FTE.Im50fast has a great reputation on FTE.Im50fast has a great reputation on FTE.
That one injector is scary-bad. No way will that cylinder run properly. I wouldnít run that injector until having it professionally cleaned and flow tested. (Might as well do the others while youíre at it)

The question is why/how it got that bad. You should use your scope to look into the intake passages- you have to find the cause of sludge on the injector tip.

Im subscribing to this thread - I want to see how this turns out.
 
  #14  
Old 04-12-2019, 08:03 AM
johnfist
johnfist is offline
Senior User
Join Date: Dec 2017
Posts: 417
johnfist is starting off with a positive reputation.
Originally Posted by wbubble View Post
i was under the impression that this is an OHC engine. Are there really rockers?
My understanding is any engine with a cam has rockers and lifters?

They're not cheap, or easy to replace. Might as well do them all when you do them as well.
 
  #15  
Old 04-12-2019, 08:24 AM
Krewat's Avatar
Krewat
Krewat is offline
Admin Newbie
Join Date: Jul 2002
Location: Long Island USA
Posts: 39,882
Krewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputationKrewat has a superb reputation
They're not "rockers" they are "followers".

4.6L head, but same thing as the v10:

 

Thread Tools
Search this Thread

Contact Us - About Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.