348 Check Engine light / rock rattling sound

I just finished looking for the "bunch of rocks in a blender" in my F355 and it turned out to be a bad left cat. I do not have a check engine light yet. But I am not going to wait for it. Any mechanic with a stethoscope should be able to find where the noise is coming from.

I called Tubi and they told me that they are not approved in the US. I am now in search of aftermarket cats.

--tony

 

I don't have them but have seen Hyper-flow cats as a suggested replacement. Not cheap but I think less expensive than OEM.

http://hyper-flow.com/355.htm

Cheers
Kevin

 

Well, I took my cats off (both of them) and have also disconnected the exhaust ECUs...I still get the "Check Engine 5/8" light on ALL the time....I don't have any noises coming from the back and the car is running a little rich on the left bank of cyliders but it runs well...When I start the car after sitting overnight, I can see a little dark smoke coming out of the left exhaust (the right exhaust does not smoke at all)...I don't know why yet but I'm working on troubleshooting the "Check Engine" light.

I also changed my O2 sensors thinking that it might correct my problem but no change...

You might want to try resetting your car ECUs (main Motronic ECUs) by disconnecting the battery overnight...Then connect the battery in the morning and let the car idle for about 15 min. before you start driving (ECUs learning procedure)....It might correct the "Check Engine" problem....It did not work in my case.

Some people suggest that the crank sensor wiring/plugs could be the source of the "Check Engine" problem...They need to be checked from underneeth the car. I have not checked mine yet. That will be next on my agenda of things to check.

Best regards - VK

 

If the cats have broken up. DO NOT DRIVE THE CAR. YOU WILL DAMAGE THE ENGINE. CATS PARTICULATES WILL ENTER THE ENGINE AND CAUSE DAMAGE.
THIS IS A NO NO !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

I have no cats on my 348 with by pass installed. Never had a problem with the check lights coming on. The cat ECU sensors and probes are still inserted in the by pass pipes. These sensors, probes measure the temperature of your cats.

Some times the check lights will come on because their is 9out 10 times a fault with the cat ECU's. They get moisture inside them from the back, beacuse they are located near to rear wheel arch. A solution is to rub grease on the back to keep out moisture.

One solution if the cats are OK is to reset the ECU's.
To do this do the following. This has worked for a number of 348 owners in the past.

To reset the ECU simply....

1. Disconnect battery leads from battery.
2. Leave off for a few minutes - kills all ecu's.
3. Reconnect battery leads to baterry.
4. Start car engine.
5. Leave to idle - DON NOT REV.
6. IDLE for 10 mins.
7. Siwtch off car engine.
8. Restart car engine and drive for 10 mins.

After this sequenece no check light should appear. If cats are damaged in anyway this will not work.

 

If your car is stalling it could be the cat's as others have said. Especially since the check engine light is coming on. What happens is that the busted up ceramic material is not alowing the exhaust gasses to be expelled properly. Kind of like the bannana in the tail pipe trick. Also the little busted parts can get into the muffler and rattle around in there too.

One other thing that you want to check is the condition of the flywheel. The flywheel will rattle like this when the grease has been flung out. There won't be anything inside to muffle the noise of the internal dampener. So when the engine is shut off you will hear it hitting up against the sides. Also if the grease is gone it will fry the little plastic guides that hold the dampening springs in place, and the grease will get on the clutch causing it to go out premateurly. Bad flywheels have been known to be the cause of hot start problems for other 348's.

So have both things checked out. Or you can do it yourself. Just get a mechanics stethiscope, they cost around $10 - $20. Get one and listen to the area you think is causing the noise. Just keep probing around till you find it.

 

You may want to try reading the fault code. There is a button
next to each ECU that will cause the check engine light to
flash in a sequence of pulses, a lot like reading morse code.
There are well over a dozen reasons why the check engine
light might be on. I have attached a list of fault codes.
The procedure for reading the codes takes a bit of
practice but is not hard.

I had a similar problem with stalling at stop lights a few
months ago. Was also getting the check engine intermittently.
The check engine light indicated an error with the lamda
(o2) sensor, however resetting the ECU as indicated in
the other posts cleared up the stalling issue. It turns
out that I had disconnected the battery at one point and
had not let the car idle for 15 mins after reconnecting it.
Therefore the ECU was confused as to what the right
baseline was for idle. The check engine light still complains
about the o2 sensors almost every day I drive it, but that
seems to be related to my lack of cats.



Lou
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Hi kenyon,

I don't understand how "CATS PARTICULATES WILL ENTER THE ENGINE".
Can you explain that?

thanks

cinquevalvole

 

I have read in several books on the 348 that if the Cats break up they can cause damage to the engine. I really do not know how...??? No mention about the 355.