Need help diagnosing problem. Thx!!

[JrdnsEdu]

Is it possible that my new starter (AcDelco) can cause a metalic like clicking noise when the car is in gear and I'm on the gas??
Here's why:
About 2 weeks after I had a new custom exhaust system put on, I starting hearing this metal like clicking noise from under the car. It gets louder and louder when driving and on the gas. So I took the car over the the exhasut guys who spent 30 minutes under the car and driving it with me even, trying to figure out where the nosie is coming from. They swear they cannot find any gasket leaks, loose screws, missing welds, or anything wrong with the exhaust system.
One of the exhaust guys thinks he hears some clicking like noise around the starter, but did not exactly know if that was the problem.
I'm at a total loss as to where to turn next. Spend another 100 bucks for antoher starter and see if that really is it and then try to return the other one?
Valve problem maybe, but wouldn't I hear that at idle?
Any ideas,suggestions are much appreicated.

 

[Pancho]

Hi, some more information might be helpful --

Does it only happen when moving, or stopped also? (You said it happens when on the gas, but that doesn't necessarily mean moving...)

If only while moving, is it the same if coasting in neutral or clutch depressed? Or only when accelerating/decelerating in gear ?

Is the frequency related to anything? I doubt it could be once every engine rev, but maybe every other, or related to wheel RPM, or ? Does the frequency change when trying different things (turns, coasting, etc.)

The more info the better !

 

[Pancho]

...Guess I shoulda' read it twice (...maybe three times) before asking some of the questions, I see now you say in gear on the gas.....

 

[JrdnsEdu]

Thanks for the quick replies. Yes, you can hear it faintly at idle(clutch not depressed), but when on the road...it is much louder and easier to hear when in gear. Louder at lower gears but that is prob due to less road noise I'll assume.
I also thought gasket and that's why I brought it back to the muffler shop, but they swear that's not it.
I'll try the duct tape idea and check again to see if the anything is loose and report back... I cant do it until the weekend so if anyone else has any input, I'll take it..
Thanks again!

 

[cruzer99]

I agree with C5D about the exhaust leak. The only good thing is that it will get louder and you will know for sure. You might check your motor mounts also. If they are broke or loose it will allow the engine to move and maybe open a gap at the header under power (just a thought).
Good luck........

 

[clar2001]

Could be a heat sheild rattle that can be very decieving, I would say no to the starter.

 

[Eric]

If the noise is coming from near the starter, maybe it's the passenger side donut gasket on the exhaust manifold. If it was overtightened when the new exhaust was installed, it may have split.

 

[69MyWay]

When you say new CUSTOM exhaust....what did this include?

Headers
Pipes
Mufflers

Etc..............

Where you there the WHOLE time the exhaust shop had the car?

Is it in anyway possible they had some fun reving the car up hard when you were not around....over reving it and bending a push rod, or pulling a rocker stud loose?

Did you rev it hard right after picking it up...maybe a little too hard?

If Headers are on the car, has the gasket been changed?

If stock manfolds....I agree with Eric, you need to really suspect that heat riser unit and the donut gasket around it.

Any chance they cracked the exhaused manifold with the studs being over tight, etc? A crack will do exactly what you are describing...as well as the other things listed above.

 

[JrdnsEdu]

You guys I think are right on the money with this... This issue was driving me so crazy that when I got home late last nite, I had to figure out what was causing this.
I finally used a little common sense thanks to you folks!! Not sure where my head was at.
I was at the shop the whole time the car was there and made a point of not driving it hard afterwards.
I didn't notice until last nite that there is little pressure out of the passenger tail pipe. When I put my hand over the passenger tail pipe...no change in sound coming from engine, but when I put my hand over the driver pipe, you can hear the difference. So I popped the hood again not just focusing my attention on listening for the mystery noise, but looking for engine heat loss. The passenger side is way hot and the driver side is totally cool.
It has to be that heat riser unit and the donut gasket around it that 71Shark and 69MyWay are descibing then.?

I do not have headers on the car yet, ( I just got new pipes and mufflers) but I was thinking this might be a good opportunity to add them at this point. I was planning on eventually doing it anyway. Any suggested packages from any particualar source(s) I should be looking for? I guess Ceramic or stainless are my best bets??
Or if it gets too expensive, maybe I'll just run over to Autozone and get a new gasket...
Thanks again for everyones help and input!!

 

[JohnZ]

They may have put the heat riser valve on upside down; the valve is flat on one side (goes against the manifold with a gasket), and chamfered on the other side where it meets the top side of the "donut". Also, there's supposed to be either a separate or welded-in extension sleeve on the exhaust pipe where the flange holds it against the bottom of the "donut"; the sleeve supports the inside diameter of the "donut" so it doesn't split or crumble. Those are the two most common causes of exhaust leaks. Also, if the heat riser valve is on either upside-down or oriented wrong so the weight interferes with the manifold, the valve can't open, and all the exhaust gases from the passenger side manifold are being forced through the little intake manifold crossover passage and out the driver's side manifold.