spitting noise under load

[7up.lmtd]

Hi all,

I am new to this forum. I have a question that I was wondering if anyone else has any ideas on.

I have a 90 Mustang 5.0 and when you put the car under load (just above idle while driving around 1,100 rpms) I hear a spitting noise.

I have taken off the h pipe and checked the surfaces there and don't see any signs of a leak there. When i put the car on ramps and have my wife put it in drive and put a small load on it I hear something closer to the headers. When I come up top I can't seem to hear it as loud.

I have looked around listened as close as I could and can't seem to pin point where this is coming from. I kinda sounds like an exhaust leak but also somewhat of a vacuum leak.

It has me puzzled. The stock mufflers on it are starting to develop holes so I was wondering is this a header issue or maybe an EGR Tubing issue. It's very puzzling as you hear it louder while under the car and in the fender wells than you do when your up top.

Any Ideas or suggestions on how to track this down would be greatly appreciated.

Erik
1990 Limited Edition (7up)

 

[HISSIN50]

Welcome to the boards!

What is a spitting noise to you? Is it like spitting phlegm (thew) or like how a little kid spits (tooh)? What I'm getting at: Does it sound like liquid hitting your exhaust? If you allow a drop of water to hit (condensation from AC or a coolant leak), it makes a sizzling sound.

Otherwise if you really think it's an exhaust leak, getting some smoke around the exhaust and seeing where it unnaturally is blown away can help.

Random weird thoughts.

Good luck Erik.

 

[MahFiVeOh]

My car does the same thing.....and it does sound like an exhaust leak.My exhaust is fairly new so i dont think its my exhaust. Just wondering where the egr tubing is? I'd like to take a look at that and see what condition its in.


Heres a bump for ya anyways.

 

[cjones]

you can also get a piece of rubber tubing put one end to your ear the other end to find the leak.

the egr tube should be by the #3 header tube and will rise up to the egr valve

 

[7up.lmtd]

The spitting noise does not sound wet. It's more of a pssstttt type of an exhaust sound rather than a throaty or tinge y noise. You could say it sounds like a big vacuum leak.

I have thought about the rubber tubing idea as i have already listened to the valve train and everything seems to be running smooth. I did grab a 1ft straight piece of pvc pipe I had laying and tried to listen near the exhaust manifold to head and didn't hear anything there that was out of the ordinary.

This thing is just frustrating.

The EGR Tubing I am referencing to goes from the h-pipe up and over the transmission. It then disappears to where I can't see it for a while. I have also followed back the air pipe for the smog pump and from the places I can physically see and reach my hand into, without getting burned, there does not seem to be a leak there.

I will have to take a closer look at it tomorrow as I am getting ready to head out to SF for the day with my kids. . . . Minus the Stang

Thanks for the input so far. Hopefully someone will have experienced this before and know what I am up against. If not then I will end up tracking it down somehow and will have to report back as to the problems and the solution so that others might be able to avoid the frustration.

Thanks again !

Erik

 

[HISSIN50]

Erik, worst case I suppose you could use a smoke machine up the tailpipes (if you have a buddy with access to one or you have access to one). You should find any leaks with escaping smoke.

 

[BigHairyMonkey]

if it sounds like a metallic sound its prob exhaust leaks, from the flanges

 

[FordGuy88]

They way you discribe it it sounds like an exhaust manifold gasket.

 

[7up.lmtd]

Ok. So after listening with the hose I could not pin point exactly where it was coming from. I could only tell the sound was coming from the back of the engine and sounded like it was coming around the flange.

I replaced the stock headers with BBK Shorty Headers and everything went in smooth. I inspected the original gaskets and headers and could not see any signs of leak.

After install I drove it around for about 45 min and the sound came back. ARGGGGHHH.

I crawled under and re tightened the flange bolts and rechecked the Header bots too. They were all tight and looked good.

In looking closer at the back of the engine I followed the EGR Tube and it looks like the noise could possibly coming from that.

I am talking about the Tube that runs along the back side of the motor and bolts into the back of the heads. Next thing to check is if there are gaskets for this or if it's metal to metal. Then I will have to try tightening the bolts, if I can get me hands back there, and see if they are loose.

Any suggestions from anyone would be greatly appreciated.

Thanks for all that have replied so far.

 

[fox-gt]

I have been dealing with the same issue for months. I have checked header gaskets, the joint where the headers meet the H-pipe, the joint where the H-pipe meet the catback. Mine definitely sounds like its in the exhaust and when I get under the car it sounds like it is coming from the back of the engine. From the side of the car, it sounds like it is coming from the Cats / H-Pipe. I don't hear it at high RPMs, only at idle.

subscribing to this thread...

 

[7up.lmtd]

I checked the EGR Tube at the back of the heads and they are secure. I used a tube and checked for noise coming from the bottom of the mounting points and I can't hear the noise there.

I am thinking that it is the cat's that are bad. I do have a couple rust spots on the mufflers and would expect that if I pulled the heat shields off I would find that there are some spots there as well. When I listen from the bottom of the car it sounds as if the noise is coming from the flange. If I listen from the top I really stuggle to hear it. If I listen in the wheel well I hear it really clear. When I put the tube past the flange I am now starting to hear it a little louder. ARGGGGHH.

I am going to see what I can track down for an stock h-pipe as I live in CA so removing the cat's at this point is not an option.

I will keep this thread updated just in case someone else has the same issues at least they have something to go on.

 

[daddystang]

I just posted a new thread that is pretty much word for word what you are dealing with yourself. I am hearing the exact same noise, and have started to think that it's the header gasket on the drivers side, but after you have replaced yours with no success I'm not too sure. I'm going to replace it anyway, keep us updated, and I'll do the same.

 

[daddystang]

I fixed the spitting/tapping/flapping etc... sound coming from under the hood on acceleration. It was in fact the drivers side header gasket. I was using metal type gaskets, and swapped it out for a paper type that I think came with the BBK headers, and poof, no more sound. 7up, which type of header gaskets did you switch to? The paper one I'm using now is much thicker than the metal one that was on there. Hope this helps someone else out. Good luck to you....

 

[7up.lmtd]

I am using the paper type that came with the BBK Headers. I have used a tube as a listening device and went over the gasket and flang area really slow and careful. I even checked the EGR Tube and Air Pump Tube.

The closer I get to the Top Drivers Side Cat the louder the noise gets. I have double checked all the bolts and it looks like it's coming from the cat.

The muffler on that same side does have some rust holes that are starting to appear so I am wondering if one of the welds for the cat is going bad. It's hard to see with the heat shield around that area and the fact that there is really no room to get a really good look at things without pulling everything out.

Thanks for your tips! !

 

[fox-gt]

I am starting to think mine is in the cats.

 

[MahFiVeOh]

I fixed the spitting/tapping/flapping etc... sound coming from under the hood on acceleration. It was in fact the drivers side header gasket. I was using metal type gaskets, and swapped it out for a paper type that I think came with the BBK headers, and poof, no more sound. 7up, which type of header gaskets did you switch to? The paper one I'm using now is much thicker than the metal one that was on there. Hope this helps someone else out. Good luck to you....

How hard is it to change the gaskets? I just had new headers installed last year and metal gaskets were used.I think i may attempt to put new ones on.Only thing is it looks like a pain in the a...... to do.

 

[Mr. Rustypwnz]

its not hard at all, go to advance or autozone and get some mr. gasket, gaskets I have them on my 86 and they seal up extremely nice, never had a problem with my 7up vert though, but all my emissions stuff, minus the catted hpipe are gone, when do you all get checked for emissions? If its like every year or 2 years I would get a 2.5" o/r pipe to get rid of the leak.

 

[7up.lmtd]

Based on the year of the 7up we get hit every 2 years for smog. As long as I have cats I am good for california emissions. I am looking into getting a new h-pipe as we speak. Hopefully I can get the resolved before the Fords in the Park show on the 14th but I doubt it.

As for replacing the gasket. It's pretty easy. The drivers side takes a little extra effort to remove the egr and smog pump hoses but that only takes about 10 min to handle and your home free.

 

[Mr. Rustypwnz]

oh yeah more pics of said 7up stang......