S/C MM knocks and vibrates help

[tdotcv]

At a red light I slowly accelerated and the MM vibrated then I reversed parked it and it knocked hard. No check engine light. Any ideas what it could be.

[justbob]

Oil pressure? Coolant temp?


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[tdotcv]

Its not overheating... I checked trans fluid its topped up...always something goes wrong and I was saving for a suspension kit...

[tdotcv]

Ok I just took it for another test ride. Three things happened. First when I come to a stop then start driving it vibrates like crazy from the rear. Then when I let it rip it seems to hit a wall at 60mph and knocks. Then I let it rip again and it wouldn't go past 60mph even with the gas pedal to the floor.

[Blackened300a]

Sounds like what happened to my car on the dyno when my catalytic convertor let go and blocked the exhaust off. What exhaust are you running?

[tdotcv]

How did you know it was your CC did a check engine light tell you? I have stock exhaust I just noticed last week my muffler has a hole in it the size of a nickel. I just did my emissions road test three weeks ago and passed with flying colors.[/COLOR][/B][/B]

[justbob]

Coil pack grounding out?


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[JohnE]

Flooring a supercharged car that is acting up, really? You just desire to blow rotating parts through your hood don't you?

Start doing basic troubleshooting. If you are not capable, take it to someone qualified.


Could be many things: fuel pump, bad coil, bad MAF sensor, etc.

[tdotcv]

I floored it to check for symptoms...its not the best idea but I needed to check for signs...

[MOTOWN]

Flooring a supercharged car that is acting up, really? You just desire to blow rotating parts through your hood don't you?

Start doing basic troubleshooting. If you are not capable, take it to someone qualified.


Could be many things: fuel pump, bad coil, bad MAF sensor, etc.

Agreed! your only going to make it worse, or blow up your motor flooring it, and its already knocking!:shake:

[Blackened300a]

How did you know it was your CC did a check engine light tell you? I have stock exhaust I just noticed last week my muffler has a hole in it the size of a nickel. I just did my emissions road test three weeks ago and passed with flying colors.[/COLOR][/B][/B]

We pulled the exhaust apart and saw the cat unraveled and blocked the mid-pipe. It wouldn't rev and had no power. Also the boost went up because it had no where to go with the clogged exhaust. Do you have a boost gauge? Did the boost go up as the power is down?

[sailsmen]

Sounds like Carbon Build Up. Go 0 to 117mph back to back w/ the OD turned off until the problems stop or the engine lite comes on.;)

[clmrt]

Ah, the old "Italian Tune-Up."

[chief455]

Sounds like Carbon Build Up. Go 0 to 117mph back to back w/ the OD turned off until the problems stop or the engine lite comes on.;)
:lol: Oh boy, that'll find the issue!

[tdotcv]

We pulled the exhaust apart and saw the cat unraveled and blocked the mid-pipe. It wouldn't rev and had no power. Also the boost went up because it had no where to go with the clogged exhaust. Do you have a boost gauge? Did the boost go up as the power is down?

I have boost gauge I will keep my eye on it. I took a look at the drivers side coils and the connections look fine and boots look clean. One boot had a few drops or oil probably from me topping it up two weeks ago. I didnt have time to check the passengers side...I wish I knew a competant mechanic...I went to a shop for some work and they had drop the exhaust...when they bolted the cats to h pipe on they used blue sealant because I can see how it spread. I'm beginning to wonder if that is causing a leak or if putting sealant is a good idea.

[DarthLord]

Check the oil to make sure you don't have a milkshake (blown head gasket) or water out the tailpipes.

[tdotcv]

New symptom...revs up by itself, now along with vibrations after acceleration and significant loss of power.

I checked all the coils they look to be in great condition. There is no CEL but I'm going to have it scanned anyways.

[RF Overlord]

I checked all the coils they look to be in great condition. There is no CEL but I'm going to have it scanned anyways.Bad COPs won't always set a CEL or even a pending code, so just because you don't find anything doesn't mean one of more aren't bad.

[Blackened300a]

I drove 20 miles with a miss and no CEL. Loss of power, idle surge and vibration makes me think it's major vacuum or boost leak.

[whitey]

I dont see how a bad cop would cause a knock? A bad fuel injector or fuel pump going bad would cause a lean condition, but fuel and no spark would just be a loss of power.

[justbob]

I drove 20 miles with a miss and no CEL. Loss of power, idle surge and vibration makes me think it's major vacuum or boost leak.


+1


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[chief455]

+1


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+2
the 'knock' is unclear though.....

[justbob]

+2
the 'knock' is unclear though.....


Driven dead lean it will cause a knock. And much higher engine temps from lack of fuel to cool the cylinder. Add retarded timing to the mix, followed by boost... BOOM.


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[tdotcv]

I checked all the hoses but maybe I missed something they all look good. Isn't there a way to check for vacuum leaks like spraying WD-40 from inside the car through a vent or another way spraying from under the hood.

[Zack]

I checked all the hoses but maybe I missed something they all look good. Isn't there a way to check for vacuum leaks like spraying WD-40 from inside the car through a vent or another way spraying from under the hood.

How bout a vacuum gauge?
lol

[whitey]

I checked all the hoses but maybe I missed something they all look good. Isn't there a way to check for vacuum leaks like spraying WD-40 from inside the car through a vent or another way spraying from under the hood.

Take your car to a mechanic.

[stevengerard]

I dont see how a bad cop would cause a knock? A bad fuel injector or fuel pump going bad would cause a lean condition, but fuel and no spark would just be a loss of power.

Mine did this a few years back and that was the issue

[tdotcv]

How bout a vacuum gauge?
lol

Where is there a good line to check for vaccum leaks, maybe on the Eaton somewhere?

[tdotcv]

Mine did this a few years back and that was the issue

I could swap the 39lb injectors because I have a set of 60lb injectors already and see if that works. My fuel pump has only 300 miles so its probably not that. But the injectors I can swap are bigger so does that mean it needs a tune.

[justbob]

What does your boost gauge say at idle?


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[tdotcv]

Boost gauge works stays at 15

[justbob]

Boost gauge works stays at 15


Well there is your issue. You should be at or around 21. Unless you have cams, you sir have a vacuum leak.


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[chief455]

Well there is your issue. You should be at or around 21. Unless you have cams, you sir have a vacuum leak.


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+1 on vacuum leak.
Intake gaskets? Vacuum hoses/fittings? yes, can spray around the area while running to see if the boost/vacuum gauge changes, but it's not the most precise method.

[tdotcv]

Well there is your issue. You should be at or around 21. Unless you have cams, you sir have a vacuum leak.


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I don't know if I have cams I have an 03 cobra motor. I went for a test drive on the highway. I reached 60 mph and the boost gauge hit 20. Then I got off and cruised at 50 mph and it stayed at 20. At low speeds or at idle it stays at around 16-18.

One thing I should mention is that my fuel pump assembly is messed up. It leaks a lot of gas when the tank is more than half full. I ordered a new assembly and it should be in any day. Would that be causing all these problems. I can't see a hole but the bottom of it is warpped and thats where gas leaks from but would a fuel pump assembly that's opened or cracked or has a hole cause these problems.

I am thinking of swapping injectors because I have a set laying around and its easy. But they are larger and does it require a tune if I do that.

[justbob]

Injectors require a tune. BTW, if this is a Trilogy by chance, they are not "easy". Also, injectors rarely got bad. What is your exact set up? Idle numbers off the boost (glorified vacuum gauge) are the only numbers I need to know. First you said 15, now your saying 16-18, that is telling me a small vacuum leak is present.

Once again, besides cobra block, what all do you have including pulley sizes, porting, fuel pumps, headers???

You would know if you had cams big enough to effect your vacuum like I do, it's quite pronounced.

You should also go pick up a cheap vacuum gauge and plug it in just about anywhere to verify your boost gauge is accurate. A very common leak is on the line to the gauge, therefor spraying chemicals I the engine will not always find the leak.

As for your fuel pump leak, how in the world did it get "warped"?? I bet the bank your seal is just not seated right. Your evap will be effected by escaped air, but I don't believe you would notice unless it is causing some kind of vapor lock. Did all your symptoms start when you did the FP? Or were you guessing the FP was the cause?


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[tdotcv]

Set up is cobra motor with ported Eaton pulley size I dont know nothing is written on it I'm guessing 2.9-3.1, single focus pump stock headers.

I tried to make a video but my phone sucks... boost stays at consistent 20 on highway when I let go of gas pedal. At lower speeds and when my foot is on brake like at a red light boost is lower at 15-16 range is that normal. I bought a vaccum gauge but where I live its going to be dark very soon maybe I will check it tomorrow morning.

I've had the leak for at least a month but car was running amazing. I don't know if its related.

[justbob]

Once again, only the vacuum at idle is needed. Verify the accuracy of the gauge and report back.

No, 15-16 is not normal. 21 is average of a good running engine.


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[tdotcv]

I hooked up the gauge to the brake booster for the power brakes and the gauge reads a healthy 21. What the hell is going on. That should rule out a vacuum leak.

[justbob]

I hooked up the gauge to the brake booster for the power brakes and the gauge reads a healthy 21. What the hell is going on. That should rule out a vacuum leak.


Unhook your boost gauge now and hook up the vacuum gauge to the tubing. Sounds like your boost gauge is whack. I would also start data logging a few things on your Xcal such as inj. Pulse drop, FP duty cycle, MAF counts, and ECT.

Average readings for all are only a google away.


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[tdotcv]

I swapped the spark plugs still the same issues. No check engine light so I think it might be catalytic converters. I'm planning on ordering SW exhaust entire set up but only installing the converters to see if that fixes the problem. If it does then I will install the full set up and get a tune...the reason I don't want to I stall the complete set up now is because I have to book an appointment and cross the boarder and take time off work just for a tune!

I'm guessing I don't need a tune for swapping converters and I'm guessing that they will fit on the stock h-pipe?

[Blackened300a]

I swapped the spark plugs still the same issues. No check engine light so I think it might be catalytic converters. I'm planning on ordering SW exhaust entire set up but only installing the converters to see if that fixes the problem. If it does then I will install the full set up and get a tune...the reason I don't want to I stall the complete set up now is because I have to book an appointment and cross the boarder and take time off work just for a tune!

I'm guessing I don't need a tune for swapping converters and I'm guessing that they will fit on the stock h-pipe?

The cats slide onto the header collectors and there is a pipe that slides into the cat that has a flange to bolt to the stock H pipe. Are you running SW headers?

[tdotcv]

Running stock header is that going to be a problem

[justbob]

Ah yeah. Stock pipes are around 2" and the SW is 3". To make it work it would look utterly ridiculous.


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[Blackened300a]

Running stock header is that going to be a problem

Yeah, the stock manifolds have flanges bolted to down pipes with both cats welded on which has a flange that bolts to the factory H pipe. The high flow cats won't mate up unless you are running SW headers.
Since you are running stock cats, I would think that they shouldn't be your issue. The SW cats are know for blowing out under boost.

[tdotcv]

Thanks for the info guys. I guess I will test the cats by removing them. If the car runs back to normal I know I found the problem. If it still rides horrible I guess I have to keep digging. What do you guys think about that idea. Should I remove cats to test them.

[justbob]

You could just pick up a cheap thermo gun for less than the labor to remove and test for equal readings side to side. Very doubtful anything is wrong with them.

[tdotcv]

I took the car to a performance shop today and had them look at the car. They suggested that I take the car to a transmission shop because they think that's my problem.

At this point I don't care what's wrong as long as the problem is found and fixed. The car is S/C so is there anything I can so to the transmission if that's the problem, maybe rebuild it stronger or adding some kind of kit.

[tdotcv]

Took it to a trans shop. Its definitely the trans because while I was there I put the car into D and it rolled back like a manual car.

He said he can rebuild it and have it ready tomorrow but it might break down again and suggested rebuilding it stronger so that's the route I am going.

[MOTOWN]

Took it to a trans shop. Its definitely the trans because while I was there I put the car into D and it rolled back like a manual car.

He said he can rebuild it and have it ready tomorrow but it might break down again and suggested rebuilding it stronger so that's the route I am going.

I would find another trans shop!

[tdotcv]

Why hes being honest. I have only driven the car for a month after installing the engine and SC. The trans lasted a month after the swap. I dont want to have it break down again and now is the time to have it rebuilt stronger. I wonder if doing to many burnouts had anything to do with this.

[jwibbity]

Why hes being honest. I have only driven the car for a month after installing the engine and SC. The trans lasted a month after the swap. I dont want to have it break down again and now is the time to have it rebuilt stronger. I wonder if doing to many burnouts had anything to do with this.

I think he said that only because why would any legit trans shop willingly tell you that they can fix it in a hurry and you could have it break on you. The fact that he even suggested that says what type of work he "supposedly" does on other customers cars.

I'm with MOTOWN, find another shop.

[MOTOWN]

I think he said that only because why would any legit trans shop willingly tell you that they can fix it in a hurry and you could have it break on you. The fact that he even suggested that says what type of work he "supposedly"

I'm with MOTOWN, find another shop.

My point exactly!

[tdotcv]

The trans broke down only a month after the swap. He has 20 years experience and rebuilding a trans in a day is nothing for him.

He is saying the trans didnt last 30 days after swap so why keep the same thing on it and why not leave the car upgrade with stronger parts and have the trans good for 600-700 HP. I think the 03 Cobras had stronger trans than we do also so swapping that engine on our trans and pushing it probably isn't a good idea. Why not upgrade now that I have the chance

[jwibbity]

The trans broke down only a month after the swap. He has 20 years experience and rebuilding a trans in a day is nothing for him.

He is saying the trans didnt last 30 days after swap so why keep the same thing on it and why not leave the car upgrade with stronger parts and have the trans good for 600-700 HP. I think the 03 Cobras had stronger trans than we do also so swapping that engine on our trans and pushing it probably isn't a good idea. Why not upgrade now that I have the chance

you need to re-word your posts better, you made it seem like he was going to do a temporary repair with a 24 hour turnaround OR get the trans built.

[justbob]

There's no reason he can't do a one day turn around and stuff it full of goodies.




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[tdotcv]

Well there is one reason he can't do it in one day, because I live in Canada and parts are hard to come by locally so we have to order them first. Remember I had to go to the US to buy my MM and 99% of my Eaton swap parts plus I bought the motor from the US also. I am limited to parts being in Canada, I have leaned to be patient with this car.

By the way does the car need to be tuned again when rebuilding the trans especially when rebuilding it stronger?