Rough idle start bad compression until warm up
Thread Starter
|
New User
Joined: Sep 2015
Posts: 3
Likes: 0
Rough idle start bad compression until warm up
Hello!
I have 2004 f150 small v8 (4.7?)
Has about 92000 miles.
When warm truck runs excellently.
At fiurst start up the idle is very rough and raw gas smell for about 4 minutes then truck runs like new. Will start and restart great until it cools down overnite.
My actron says missfire cyl 3.
Dealer did a lot of stuff ($1700).
Did not fix it. Dealer says that on start up compression is zero in cylinder three but is 100% when it warms up.
Suggested I run seafoam through it.
He thinks it has a vacuum leak or carbon at start.
In my limited knowledge I am thinking:
sticky lifter
bent push rods
warp valve
Any ideas on this appreciated.
I have 2004 f150 small v8 (4.7?)
Has about 92000 miles.
When warm truck runs excellently.
At fiurst start up the idle is very rough and raw gas smell for about 4 minutes then truck runs like new. Will start and restart great until it cools down overnite.
My actron says missfire cyl 3.
Dealer did a lot of stuff ($1700).
Did not fix it. Dealer says that on start up compression is zero in cylinder three but is 100% when it warms up.
Suggested I run seafoam through it.
He thinks it has a vacuum leak or carbon at start.
In my limited knowledge I am thinking:
sticky lifter
bent push rods
warp valve
Any ideas on this appreciated.
Junior User
Joined: Sep 2015
Posts: 53
Likes: 1
It has to have a valve sticking open if number 3 is dead then goes back to making compression.
You could try changing the valve springs and lifters on the intakes and exhaust valve on cylinder 3. New spring tension may help alleviate the issue.
New lifters of course as the old ones also may have issues
4.6 liter BTW
You could try changing the valve springs and lifters on the intakes and exhaust valve on cylinder 3. New spring tension may help alleviate the issue.
New lifters of course as the old ones also may have issues
4.6 liter BTW
Thread Starter
|
New User
Joined: Sep 2015
Posts: 3
Likes: 0
Thanks for reply.
Yeah. The dealer replaced coil, plug, and injector after I had already done the same things.
Dealer said the truck wasn't worth fixing. But a new truck is $40 k or more.
Mine has good paint, body , shell and pulls my liteweight trailer just fine.
So looking for info so I can check at some non dealer repair shops.
I was being optimistic on the 4.7 lol.
Yeah. The dealer replaced coil, plug, and injector after I had already done the same things.
Dealer said the truck wasn't worth fixing. But a new truck is $40 k or more.
Mine has good paint, body , shell and pulls my liteweight trailer just fine.
So looking for info so I can check at some non dealer repair shops.
I was being optimistic on the 4.7 lol.
Junior User
Joined: Sep 2015
Posts: 53
Likes: 1
Keep in mind , the spring lifter replacement may or may not work .
But you certainly need to look at the valve train and see if something is going on, so the cover needs to come off for inspection.
It could be the a valve has gauled in the guide, due to overheating or poor oiling.The head may need to come off.If it is an oiling problem that too will need to be addressed.
Putting a few new pieces may get you buy for quite a while and cold clear up the problem.It is worth a try.
But you certainly need to look at the valve train and see if something is going on, so the cover needs to come off for inspection.
It could be the a valve has gauled in the guide, due to overheating or poor oiling.The head may need to come off.If it is an oiling problem that too will need to be addressed.
Putting a few new pieces may get you buy for quite a while and cold clear up the problem.It is worth a try.
Thread
Thread Starter
Forum
Replies
Last Post
Handegard
Big Block V8 - 385 Series (6.1/370, 7.0/429, 7.5/460)
5
Jun 27, 2007 03:27 AM
2ndmouse
FE & FT Big Block V8 (332, 352, 360, 390, 406, 410, 427, 428)
7
Jan 30, 2005 12:16 PM
borin&strokin
Big Block V8 - 385 Series (6.1/370, 7.0/429, 7.5/460)
1
Feb 10, 2004 06:09 PM
