No Power After Head Gasket Replacement?

Kris

Registered User
We replaced the head gaskets and port matched the intake and intake side of the heads, and i thought that i would be making a little more power now, but i am making a lot less.
the car will not break the tires loose from a standstill anymore, and the speedo is messed up (it goes up to 120km/h then stays there, and when i get back down to around 80 it jumps to 100 and then works fine?). i am making about 9psi or a little more at WOT. the check engine light comes on after driving the car for a while, but turns off when the car is shut off, and code 11 comes up when i scan for codes?

i think it may be vaccume hoses in the wrong spot, but i am not sure. would it be worth it to take it to a mechanic?

if i can not sort out the problems soon i am going to sell this car and go back to the mustang 5.0, so any help would be really appreciated.
 
Last edited:
here is my .02

If i were you. Id go back to the 5.0. I had a 90 SC and the upkeep is crazy for these cars and HG's go way to much. I had replaced mine also.

the 5.0 has proven to be a fast, reliable, fun car to drive and its comfortable. No it doesnt ride like a SC but its faster and costs tons less to upkeep
 
I agree .I like my SC, but I think it is just a bad mistake in enginerring.
I have a 95 lx runs great 88 & 85 turbo coupes they run great .The SC
cost more than the other three t birds put together to keep running
and the SC never runs right.And my 85 turbo is faster.
And I can change the plug on three of my t birds faster than one SC.
 
Make sure you have the vaccum line that goes from the backside of the manifold adapter to the fuel pressure regulator. It is a short line and you can't see it unless you really get up in there. This would explain a loss of boost and terrible power. Vaccum leaks are definately problematic on these cars. What did you use to seal your IC and tubes? Most people use RTV or a teflon gasket kit from one or our members 88bird.

Don't let the bad experiences of some people discourage you. You won't be able to sell it for any decent amount of money if it doesn't run right, and once it runs right you won't want to sell it! LOL
 
I think Dave's prob right.

As far as the speedo, I had the same prob and had to replace the speedo assembly. Find 1 in a junkyard, 'cause IF you can get one from Ford, it'll be expensive.
 
i thought the loss of boost would come from the ported exhaust manifolds and port matched heads and intake? should i still be making more boost?
 
Maybe you could try putting hose clamps or plactic ties on every vacum line you can
get to. This help my motor the most of all the things I did to it.

Opening your exhaust track will lower boost but not that much.but you should gain
some in power.

As the weather get warmer you will loose a lot of power.without a fan on the intercooler ,
or a larger intercooler.

Just get a big drink of your choice,& about 6 3/8in. & 2 1/2i. hose clamps some
plactic ties.you might need to take the wipers & two peice plastic cowl off under
your windsheild to get to the hoses easer.And start clamping vacum lines,pcv hose,
Put a clamp on the one that go's to the middle of the cold air intake pipe.

This WILL help.Then if you have problems you know it is not a vacum leak.

You need to remove the negative ground cable from your battery.Then drive it and
see if your check engine light comes on.then check codes again.

The speedo I don't know ,but you can buy a new one that go's to 145MPH new
from Ford for about $160.00 pat # p/nF4sz-17255-c www.fordpartsonline.com
Or your ford steelership.

Good luck.KEEP THE SC & BUY THE STANG.
 
Last edited:
I would never change my SC for an " everywhere you look, you see one (mustang)" I rather have a car that not even some ford techs know about, and work with it, and be patient with it till you figure it out and it will run better than anything. I've had my SC since summer of 2000 and with the help of people in this web site I fix everything that goes wrong with it; I, sometimes, get so pissed off when it breaks down that I just wanna wreck it and have the insurance pay me for it and buy me something more reliable, but i get to working on it, and after it runs again and I drive it again man it FEELS BETTER THAN SEX!
I would like to have a mustang 5.0 but I would never sale my SC for anything in the whole world
 
All I can say is don't get discouraged, and once everything gets up to par you will thank yourself for keeping it around. So far I've sunk more money into this car and everytime it breaks down I cuss it up and down, but once she's running I can't smile enough. I've dropped almost 7K into this baby since I've baught her but knowing that I'm 1 of maybe 2,000 LEFT to own a 91 SC with every option...that's worth it to me!

Perhaps I'm a different breed than some but it sure is fun when you out run another person in a "grandma car"!

-Tim
 
O2 Sensors

i dont know if this has anything to do with your problem, i dont know what code 11 is ( i guess i could look it up huh....) but anyway one thing not mentioned, and this is true with ANY car that has a head gasket failure.......you should always change the Oxygen Sensors after a head gasked failure. Coolant in the exhaust gas damages them. This may be part of your driveability problem.
 
Superloop said:


1. I would never change my SC for an " everywhere you look, you see one (mustang)"

2. but i get to working on it, and after it runs again and I drive it again man it FEELS BETTER THAN SEX!

3. I would never sale my SC for anything in the whole world

1. MY FEELINGS ABOUT AND SC / MUSTANG.........

2. I dont know what kinda sex your are having :eek: :D

3. AMEN to that brother!

And the 5.0 mustangs arent always faster........

Todd
 
kris, does the car idle smooth? how much vacume do you have at idle? my son mixed two plug wires once, it ran fairly smooth, but vacume was a little low at idle and no power. i do not rember witch wires. i made him figure it out. hang in there with the car, i have a 94 with an electrical problem tha is going to drive me nuts when i decide to fix it.
 
Silver90sc, you are my hero for the day.

i took your advice and went out and checked the wires for there location. they were all on the right spot, but i did notice one wire (the middle on the passanger side) was a little loose, so i crammed my hand in there, and low and behold it was not connected!!!!

this car went fairly good on 5 cylinders, so lets see how it goes on 6!!!!!
 
cool im glad you found your prob my ported heads helped a bunch and honestley it felt like the colder plugs app103 helped just as much as the porting
 
Last edited:
Back
Top