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

A couple of questions:

1. You reused the original ignition wires? IE the newly routed path is the same overall length as the original path?
2. I guess the brackets could be created in google sketchup and uploaded to be created online, like this?
http://www.ferrarichat.com/forum/139196638-post49.html

 

First, your reroute looks very nice and cleans up the lines. I like it.

Second, is there any possibility that this could happen with a fully hot car? I did not like how you said you reved it a little and nothing improved. I would run the test again to see if driving the car at normal operating temps and air moving through the engine bay reverse this plug wire cross talk assuming engine bay heat would decrease from the motion.

Third, several Fchaters over the years have gone to COP's. Could COP be the next gothspeed creation? Is there any reason to stick with plug wires?

 

OK boys, I'll sacrifice myself as being ignorant. Can you tell me whet the COP fix is all about? By the way, I love the new re-route on the wiring. Looks neat and efficient Goth. Great job.

Henry

 

Ah, so more of a coil-pack set up like nI have on my Toyota pick-up, eh? Thanks for the explanation.

 

What I really find interesting is all this issue with mixture control and cat death and header meltdown. You have hit on 2 great causes...heat induced plugwire crosstalk and coolant temp sensors. Helms thinks the problem is more global bad connections in general. Anyway 3 valid theories for which many Ferrari models can suffer but the 355 may suffer worse being closer built to the race car limit of it's day with 100hp/liter. What an awesome find!

This wire cross talk can be a real issue beyond excessive idle times. What if high ambient temps, like 355's living in Texas, suffer this under more conditions than living by the beach in california?

What about using non-oem wire? I can't remember my plug wire tech. larger diameter wires better? newer wires better? What else?

 

I had this problem when I went to the track, but one of my wires was actually touching the header heat shield. Problem manifested itself before I could even get the car on track. The car started up and ran fine, so I warmed it up, shut it off to go get ready to go on track and when I came back and started the car up, it was only running on 7 cylinders and fouled a plug. Cleaned the plug, put it back and it was fine. Shut it down, got ready to go on track and bam, 7 cylinders and a fouled plug again. That's when I found the wire touching the heat shield and zip tied all wires away from the headers and voila, no more misfire. Car ran great the rest of the day.

Moral of the story: Everyone go check your plug wire routing and make sure they're not near the headers.

 

Great information. I've been diagnosing a similar issue recently. I changed the spark plugs and, apparently, disturbing the wires caused it to become much worse. Although I live in Texas, the ambient temps were relatively cool a couple weeks ago when it really started acting up. However, exactly as you pointed out, the rough idle/miss was worst when heat built up in the engine compartment (I was stuck on city streets going from stoplight to stoplight with short 40mph stints between). Once I got on the freeway, it ran great.

 

I know were in dry SoCal...
We have used this for a little extra insulation on the wires to prevent crossfire/flashovers from humidity. That with dielectric on the connections really helped in the rain

Insulator Paste Wax Protector » Collinite

 

I'm glad I didn't go with the unshielded headers and that I live in a cooler climate. I like your update though and eagerly await your potential COP update

 

Nice Oz.

Simple, clean, and affective.

 

Looking at the pretty routing reminded me of something I came across while chasing gremlins in my Factory Five Cobra replica. Inductive crossfire. When wires are run right next to each other the pulse in one can create charge in its adjacent wires. If this happens at the wrong time, misfires can occur. It sounded a little old-wives-tale to me but I found a Ford TSB specifically describing what pairs of wires should be separated in their V8s, with different directions depending on the firing order.

 

I guess enough has been said about how effective the most recent Oz discovery is, and how it provides a simple and elegant solution to another one of our beloved cars' design quirks.

At the last Socal Stoogefest, Oz explains to me how I could have a problem with my car, and how the solution is easy and costs next to nothing to do. Hmmm, I like the "costs next to nothing" part, and since I am one of the odd ones without having to do anything to their car up to that point, I said let's just do it. He then took a minute and stole some zipties, and rerouted my plug wires, and sent me on my way home.

I was stuck in traffic for almost two hours, with the car idling for 10-15 minutes at a time, in the mid-afternoon sun with the A/C on. Granted I had the OEM shielded headers on, I knew the car would start to run a bit rough in these conditions, but never enough to bother me nor the car's electronics. But this time, the engine actually ran quite a bit smoother, without any misfires, with smoother on-off gas transitions. I actually enjoyed the drive home, in traffic, listening to tunes with the occasional interaction with the drivers (and passengers) around me (i.e. thumbs up, waves, etc.)

Bottom line is, this is one of the simplest, least costly mod one can do to our 355s that will have an impact not just on the overall drivability, but also on the other potential issues like overheating cats, slow down lights, disintegrating headers, etc. etc. Specially to those of you who like to let your cars warm up and idle for 15 minutes or more before taking off... :-D

Sure the COPs are more awesome, and I've tried it. While it is a great idea and it works, it is not without it's own set of quirks. But for now, get a set of Goth's awesomely designed Spark Plug Wire ReRouters for chump change; or if you are really cheap, zip ties work well, too! Either way, you will lose points at a concours... so Just Do It!

Cheers

PS: Almost forgot, here's how the F1 version looks like:
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Ok Goth, where can I order my set from??

 

I have decide the Kingsborne wires are not as good as preiously thought.

The "wasted spark" of the F355 doubles the possibility for crossfire, the parallel routing under the hot valve cover also does not help at all.

The weak coils are actually preventing misfires. If you were to put on 2 modern coils and 2 "MSD", the thing probably wouldnt even run.

 

+ 355 Either this or coil packs

My lawnmower has a more advanced ignition system then my 355 with better wire

 

Amazing fix. I always suspected the 355 plug wiring as being inefficient compared to the 348 because of the bundling and routing to close to each other. Remeber, Goth, the issues we had getting clean signals from the induction sensor at the dyno?

 

I see how they can be seperated with the holdlers but once they get to the valve cover, they are all on top of each other. Does this negate seperating the wires before they get to that point?

 

In a very old thread, a member mentioned that the cylinder pairs 1/4, 2/3, 6/7, and 5/8 ignition are fired at the same time instead of one spark per each single cylinder.

When placing the cables into the Gothspeed re-route plate, is it optimal to place the wires in the holder such that the cables are aligned 1, 4, 2, 3 for bank 1 and 6, 7, 5, 8 for bank 2?

 

PM sent to Goth. I think this are awesome just for the improved look of the engine bay!

 

where can I purchase these?