knock sensor unplugged

[84svoinNE]

Ok, this is a response to my bod down post a few days ago, well i put a new coil and coil wire, cause I had a few problems the other day. So today I unplugged my knock sensor, because it was bogging under 14lbs of boost and not 9lbs, in 3rd, 4th, and 5th. after I unplugged it i took it out for a run. IT workeD!!!
but in the 3rd gear and up at 4500 or 5000 rpms it rattled... my friend thats another good svo guy, told me to NOT DO IT AGAIN, cause its causing detonation and could melt a piston blow a rod or blow my head gasket.... so im going to put it back on any suggestions why it was doing that and if it was that bad???

[LumbermanSVO]

Hey guys, he has left out a bit of important info....I'll just copy and paste from the first conversation we had (no I'm not a freak, Trillian automativcally logs conversations)

Tue Jul 23 2002
[22:06] youdumbkid3: so your svo likes to over heat too i see?
[22:06] LumbermanSVO: yeah, i think i had air in the system, its the first time its overheated
[22:06] LumbermanSVO: I'm gonna replace the t-stat and have the system flushed
[22:06] youdumbkid3: mine overheats alot too
[22:07] youdumbkid3: but i bypassed the heatercore, with some tubing
[22:07] youdumbkid3: but that shoudlnt be a problem
[22:07] youdumbkid3: just put a new t-stat in mine too
[22:07] youdumbkid3: still gets hot
[22:08] LumbermanSVO: have you flushed the cooling system?
[22:08] LumbermanSVO: checked the radiator?
[22:08] LumbermanSVO: purged the system?
[22:08] youdumbkid3: yep we just had the raditor refined and cleaned and such
[22:08] youdumbkid3: yep
[22:08] LumbermanSVO: is the fan workin right?
[22:08] youdumbkid3: we flushed it like 3 times lol cause we didn't bypass the heater core right
[22:08] youdumbkid3: yep jsut put a new one in
[22:09] youdumbkid3: like 3 months ago
[22:09] LumbermanSVO: have you checked the head gasket?
[22:09] youdumbkid3: well thats another thing
[22:09] youdumbkid3: its goes through oil alot.
[22:10] LumbermanSVO: do you have white smoke out the exhaust?
[22:10] youdumbkid3: im thinking its a gasket
[22:10] LumbermanSVO: is the oil milky?
[22:10] youdumbkid3: it puffs white smoke when i start it also
[22:10] youdumbkid3: no
[22:10] youdumbkid3: oil isnt milkly that is.
[22:10] youdumbkid3: but white smoke yet
[22:10] youdumbkid3: yes
[22:10] LumbermanSVO: yeah, replace the head gasket, should fix it and you should be able to run 15lbs boost again
[22:11] youdumbkid3: how hard is it to replace a head gasket
[22:11] LumbermanSVO: not too bad, some guys clain to have done it in under an hour
[22:11] LumbermanSVO: get a shop manual
[22:11] youdumbkid3: have one
[22:11] LumbermanSVO: follow the directions and it should be easy
[22:11] youdumbkid3: my dad can do it but just depends how long it akes


I keep telling him to replace the head gasket.......Maybe if I'm not the only one tellinghim to he will finally do it

[SVOeric]

Well, I'm not convinced it is a head gasket (yet)..

he said white smoke at startup... that's probably valve seals..

he also said it goes through a lot of oil ... that oil does have to go somewhere.. it is either

leaking out,

burning, or

leaking into the coolant.

the detonation can be caused by lots of things.

here are a few more questions, to help see if it is a headgasket --

Were you running 93 octane gas ? .. My SVO will knock like MAD at over 10 psi boost on "regular" gas

If you take the cap off the radiator, do you see oil in the anti-freze ?

Does your engine have any oil leakes?

Do you get white smoke while driving the car, not just at startup?

have you tested the fuel pressure (possible source of detonation)

have you done a compression check?

have you done a coolant system pressure test.

 

[84svoinNE]

i was running 92 octane
no oil in the antifreeze
and i can never find oil leaks anywhere
white smoke is only when i start it for like 4 or 5 seconds
I haven't tested the fuel pressure...
No compression test
NO coolant system pressure test...
It's going to be off the road for awhile now hah
i just got home and my brakes went out looked into the wheel well and there was fluid everywhere soo....... not good, im tired of having to put so much money in this!!!
new t-stat, radiator refinned, pretty much alot of stuff done to much to name

[SVOeric]

remember.. this is a 18 year old car.

it's not going to run forever without a little work.  I don't think anyone ever said this was a cheap hobby..

 

That oil MUST be going somewhere.. My bet is it is seeping into the combustion chambers, and burning, You just can't see it while yoiu are driving.

I would think at least a compression test would be about the best place to start.

 

[svono50]

It sounds like your knock sensor was working just fine, based on the results of your test with it disconnected. You can try a couple of "tricks" to stop tripping it before you tear the head off. 1) Gap the plugs to 0.028-0.030" and 2) Turn your base timing down to 8 deg BTDC from the factory setting of 10 deg. These will help your engine tolerate the higher boost with less detonation at the expense of a few HP.

Eric is right on the money. Don't just do a compression check, but also a leak down test. This will spot a bad ring or leaking head gasket that can pass a compression check. If you are getting oil into the combustion chamber, you will get detonation/pinging under high boost. Just my $0.02.

[gbeaird]

If he is sucking oil into the combustion chamber, that will lower the octane of the fuel and cause ping under load.

Oil could be getting in there from the turbo, intake valve seals, malfunctioning PCV valve and/or oil rings.

Do you have a _Motorcraft_ PCV valve on that car yet?

Gene Beaird
86 2R SVO
Pearland, Texas

[SVOeric]

that is some very good advice Gene...

 

Pull the intercooler hoses off, and the VAM hose off, and if everything is coated with oil, you know you are getting oil  sucked in

 

[84svoinNE]

vam's hose has oil in it

[SVOeric]

There is a good chance that is the problem (may not be the only problem, overheating could point to a headgasket, but that is probably best addressed in another thread)

As Gene said, what kind of PCV valve do you have, and when was the last time you changed it?

You really do have to use the Ford, or motorcraft part for this, the others just wont hold the boost.... 

You will need to clean all that oil out, and try to find where it is coming from.  Gene mentioned all the places it could be in his post.  If it is blow-by from the rings, there's not much you can do about it..

how many miles does that engine have on it?

[84svoinNE]

well, I suppose the pcv valve is what ever ford put on it in 89 when it got the whole under hood done in a engine fire... it's only had about 5 to 6,000 miles on it since then, engine has 114,000 on it.. its over heated 3 times last summer to where I wouldn't even drive the thing cause i was afraid it would blow up... after the radiator and new thermostat it helped a little still gets hot

[svocudd]

overheating

Your SVO definately has other issues. I agree with Eric and Lumberman that you need to do a compression test and a leak down test. SVO's do not overheat generally. The fan doesnt come on till they get very warm but they dont overheat unless something is wrong. You say white smoke on startup. Oil causes light blue smoke not white. White smoke indicates your burning anti-freeze.


Cudd