TCCoA Forums banner

1 - 19 of 19 Posts

·
Beer and Cheese
Joined
·
7,386 Posts
Discussion Starter #1 (Edited)
I've been doing so many vacuum leak tests my mind is going to explode! Every now and then a hissing sound will pop up in and around the fuel rails. I don't notice a fuel leak with the smell of fuel, but when I do the vacuum test with water around the base of my injectors there is a noticeable sign of air bubbles blowing at the bottom of the injector o-ring. Is this a big enough leak to throw off idle and stalling out the car at start?

Thanks,
 

·
Registered
Joined
·
96 Posts
yes i know fel-pro makes a set, it is a small box, with enough 4 injectors. i had to buy two boxes when i did my new intake gaskets.
 

·
Beer and Cheese
Joined
·
7,386 Posts
Discussion Starter #4
I bought my 60 injectors used, had them flow tested and cleaned before I put them on. You're supposed to use engine oil to lube them before you put them on. I did all that. I just bought new Fel-Pro gaskets this morning. I'll swap out those and see if the leak goes away.
 

·
Beer and Cheese
Joined
·
7,386 Posts
Discussion Starter #5
Another question, is it normal for a little bit of air to leak at the TPS and Spring side of the TB?




This is a Cobra IAC valve, the top cap in the picture leaks a little bit of air as well is this supposed to leak?

 

·
Super Moderator
Joined
·
11,961 Posts
To put it simply, no there are to be ZERO air leaks anywhere.

My guess is that you have enough vacuum leaks to let the engine idle, but when you pop into gear it dies because even your 20 vacuum leaks can't keep up.

What are those red and black doohickeys on the inlet tube right after the throttle body??? ....and what is a bungee cord doing anywhere near your engine??

 

·
Beer and Cheese
Joined
·
7,386 Posts
Discussion Starter #7
Haha the red and black doohickeys are rubber plugs. Vacuum test bro! By putting a rubber glove over the TB and blowing in a vacuum line I'm creating negative pressure. If there is a leak in the system some where you can hear and see it with soapy water.
 

·
Super Moderator
Joined
·
11,961 Posts
Why is there an IAC mounting flange on the inlet right after the TB, and another one that seems to be on the rear of the supercharger casing? .....and how exactly did you go from needing injector spacers to NOT needing them? Where were they installed in the first place?
 

·
Registered
Joined
·
2,435 Posts
The problem is the airfuel is way off I guarantee it, I've never done any of these vaccuam test and u will leak very little air by the shaft on the throttle body, the injected prongs should not be leaking period
 

·
Super Moderator
Joined
·
11,961 Posts
The problem is the airfuel is way off I guarantee it, I've never done any of these vaccuam test and u will leak very little air by the shaft on the throttle body, the injected prongs should not be leaking period
thats pretty much a given. He's been trying to tune it WITH vacuum leaks, lol.
 

·
Beer and Cheese
Joined
·
7,386 Posts
Discussion Starter #11
Why is there an IAC mounting flange on the inlet right after the TB, and another one that seems to be on the rear of the supercharger casing? .....and how exactly did you go from needing injector spacers to NOT needing them? Where were they installed in the first place?
That's where the IAC is located on a Cobra plenum.

What are you talking about?! Look at the picture, the IAC is just laying on top of the SC, it's not bolted to anything. I was taking a reference picture to show where air is leaking out.

The injector spacers would not fit, the base of the spacer is too fat and would not seat in the injector hole.
 

·
Beer and Cheese
Joined
·
7,386 Posts
Discussion Starter #13
So it turns out my plugs were so fouled that it would even start up. I guess after the few hours of running ruch after dataloging they must have went bad.

Here









Best picture of the day!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I have over 1300 seconds of datalog running at 900 rpm. Everything seems to look good.





 

·
Registered
Joined
·
3,902 Posts
Btw, almost every car I smoke test the intake system on shows small leakage a the throttle shaft. Also on fords I always have smoke leaking from the cap on the iac valve and a small bit coming from the egr valve. And yes this is on egr valves whose diaphragm does hold vacuum. For that reason i would venture to say that this is "normal." Glad to see you got it figured out though.
 

·
The Parts Guy
Joined
·
7,268 Posts
Btw, almost every car I smoke test the intake system on shows small leakage a the throttle shaft. Also on fords I always have smoke leaking from the cap on the iac valve...
I've seen this a few times as well.
 

·
Registered
Joined
·
5,408 Posts
I do a lot of smoke testing on various cars at work for emissions repairs, leaking at the IAC vent is fairly normal, depending on how much it's leaking. The throttle shaft seal and TPS I personally have never seen leaking, however I wouldn't doubt it's possible. The fuel injector to intake manifold leak is definitely a problem.
 

·
Registered
Joined
·
96 Posts
um different subject here, but OXMAN, are your front wheels canted??? or is this a optical illusion?
 

·
Super Moderator
Joined
·
9,142 Posts
FWIW I just checked mine. I have no leaks anywhere except a very minor one at the IAC vent. I'm not particularly concerned since it's a brand new Ford unit...
 
1 - 19 of 19 Posts
Top