355 misfire when engine is hot? ignition wire reroute shows some relief.

While testing and confirming Goths theory I used some plastic marine wire standoff's
I went a little further to get the wires totally out in the air


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+1 on that. Provide some info (or do you want a PM?), Goth, and I'll be all over them for my F1.

 

Tim that's brilliant! Goth should design some covers for the channel that lets the wires exit straight out from the plug holes like the 348. End the channel wire crossfire now!

 

where can I order these from also...

 

Hi folks
My 96 F355 spider with 19k miles on just started to misfire yesterday after sitting in the garage while I warmed the engine prior to setting off. It started fine although had a loud squeak which disappeared after about 3 minutes, then after around 10 minutes it started to misfire. No warning lights on and I suspect a wiring or bad connection issue. Any ideas?

 

Tracking down this issue over the past month, ended up taking a number of steps to address the situation.

1. Pulled plugs, all looked good with no wet plugs, but it looked like the gasket was leaking as the plugs looked like they experienced a bit of water damage - replaced with PMR7A;
2. Checked wires, they were old and had some heat damage from close proximity to headers - thanks Ricambi;
3. Replaced gaskets on covers to help prevent water damage to plugs and wires - thanks Ricambi; and
4. Saw this post from Oz, ordered the wire looms he designed - thank you Oz.

Problem solved, runs smooth and steps taken to minimize potential damage in the future.
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What are the blue items in your picture?

 

Interesting as I have a similar problem with my 308. Runs great for 20 minutes then breaks up once hot. Wonder if my plug wires are getting hot too. I was at a muscle car show this weekend and saw some insulator boots meant to shield the plug wires from heat. Looked to be about five inches long and slid over the end of the wire. Can't find by searching on the internet.

 

I installed these over the weekend. I also placed wire heat shield material around the wire bunch. Not sure if it is my imagination, but the car seemed to sound smoother when driving back to San Diego from LA after I installed it during stoogiepalooza. The blue spark plug wire seperators looks cool. I may have to get some black ones.

 

Plastic wire looms from summit. Before replacing the plug wires I pulled the wires from the stock routing system (in place looms as well as covers above actual plugs) to determine if heat was my problem. I left a couple on just to keep the wires in order.

I found heat damage to two wires from headers (melted) and simple water corrosion to the exposed area of the plugs. The new boots from Ricambi have additional rubber flanges that may provide a bit more water protection, not to mention the new gaskets, mine were very damaged and missing in several areas. Funny, also had missing Allen screws on the covers to the plug covers (those that were most difficult to access).

 

Just ordered the wire loom from Amazon. I'll place it before entering the GothSpeed spark plug cable management plate to make things look even more organized.

Amazon.com: Spectre Performance 4631 Black Pro Wire Separator: Automotive

 

I am interested to know more about the wire heat shield and where you placed it. Also, would appreciate some pics of your final install. I am looking to go this route also.

 

This are what I'm asking about.

Anyone think they'd do any good?

Titanium Spark Plug Boot Protector - Automotive - BSTFLEX fire sleeve, firesleeve, exhaust wrap, turbo blanket, fabric, tape

 

That set is plastic. I tried them on other cars I have and they crack easily.

This set is aluminum... I ordered several sets as I need the four wire connector and they have to be purchased in sets. If you need the three or two wire connectors let me know!

Amazon.com: 3pc piece GUNMETAL Billet Aluminum HIGH QUALITY Spark Plug Wires Cables Separators Dividers Organizers Holders Kit Set Grey Gray Silver: Automotive

 

Bummer.. I get these in the mail today. I'll have to order the aluminum ones from your link. Thanks for the info.

 

Considering the crazy money Ferrari wants for wires, coils etc. and the fact that wires touch until they leave the cam covers isn't a COP conversion the way to go?

 

100%, if you can find COP's that fit under the covers. That's my biggest issue but when major service time comes, I'll be doing it one way or another. I'm not going to bother with ridiculously priced wires when a better setup is available and easy to implement for less money. You don't even need a fancy ignition box, just wire the cop pairs in series and add a resistor if impedence doesn't match the factory coils.

 

Yes simple and elegant. That is what John did for the 550's. The whole 12 COP's was cheaper and more robust than 12 Ferrari wires sold each by the way since they are so ridiculously expensive. I rebuilt a set once from kingborne stuff and even that was not cheap considering the labor put in. I think spacing the wires is a great evolutionary step in the right direction. The typical COP used are Japanese robust units. I think COP is a great way to improve 355 reliability to the next level. Later Ferraris went that route for good reason.

 

Yep COP's for sure. I have my setup ready to install with the denso COPs. just need to make a few items for a near oem look
I will be using a spark box, MSD as this motor really needs one in my opinion with those hairy hydraulic cams she has.

 

I attached some pics of the spark plug wire re-route and the heat shield material. I placed the heat shield material where the spark plug cables enter the engine since it is fairly close still to the headers.
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Well, it looks like my brand new set of wires from Ricambi have an issue. #1 has melted and shorted to the block. I wonder if I can just order the #1 wire.

I'm thinking of developing an aluminum standoff that is roughly the same dimensions as the gasket that will set the cover plate about 1/4" to 1/2" higher and allow me to route the wires up towards the intake instead of bundling them together. Thoughts? Maybe if it's made thick enough, it would allow for COPs to be used.

- Tom
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Thanks

 

I think that is a good idea. Seeing that others report seeing the crossfire in the dark I would expect as much if not more with the valve cover lid off and wires jammed in the channel. At the very least getting some space will allow you to take Goth's good idea one step further and help the wiring under the cover. Goth needs to fab some kind of perforated metal standoff spacer that the OEM cover screws on top of sort of like a chimney cap.

 

I know someone that works at a local metal fab shop. I'm going to see if I can get him to fab some prototype spacers.