COP's . . . resistor plugs on 355? 308 cop still don't work

Hey all,

Still didn't get my COP conversion working . . . I have yet to shield all the wires although I did wrap most of the loom in tin foil which should've simulated things pretty well . . . couldn't get to the entire loom but I may cut the loom up to shield everything better if this doesn't work . . .

Do the 355's have resistor plugs?

I'm running stock plugs in my 308 which I don't think are resistor . . . resistance is in wires . . . right? Should I order NGK resistor plugs with the same number as what I have? I think they're BP7ES if I'm remembering right.

Just in case you're wondering why I'm asking about the 355 is because there's been several successful COP installations on them . . . and some unsuccessful though.

Thanks,

Sean

 

I think I'm on to something here . . . there would be a ton noise affecting the Haltech ECU using the cop's on standard plugs . . . going to try it.

Sean

 

Sean,

Original 308 plugs are not resistor-type because the wires and extenders ARE. The extenders should have about 1100 ohms and frequently go bad. The carbon-core wires won't last forever, either. My 308 ran fairly well on just four cylinders.


Tom

 

Another reason I'm hoping to get this COP working . . . no more distributor caps, wires, or extenders.

I'm real hopeful the resistor plugs do it.

Sean

 

What pray tell is a 'COP' ??

 

Coil On Plug conversion.

 

Resistor plugs did it!

 

I believe I'm the first to concieve and perform this conversion and it's been running absolutely perfect over 2 years now with absolutely no problems on the street or track.

JD

 

Yes you were and thanks!!! . . . your thread motivated me and even got me 4 coils from another chatter!!!


Glad to hear all is still working properly. I thought I recall several other people having problems to the point that $1k+ for plug wires seemed cheap again. A guy with a Countach, aftermarket EFI, and two DIS4's never could get it working. I started thinking it was shielding (I think you used shielded wire) and had numerous conversations with MSD about it. Switching to resistor plugs from the standard plugs seems to have solved my problems. I'm also using a Haltech ECU which I'm sure is more sensitive to high voltage than the 355 ECU.


So do the 355's use resistor plugs?



Sean

 

There's an output on the DIS4 box for rpm but the stock tach reads double . . . isn't there some "tach signal conditoining box" that I can use instead of having the tach recalibrated?

Thanks,

Sean

 

Yes, 355's use resistor plugs. NGK PMR7A is the stock oem plug.

 

Sean, just use an output from the haltech to drive the tach if any are available. The 308 tach is tough because it's a 4 cylinder tach, not an 8 due to the twin distributors. They used to sell an adapter to cure this in the motorcyle world, you could search there too.

 

Still need the adapter to split the number of pulses in half. I'm surprised I couldn't adjust this in the Haltech software. Anyway, looks like I found what I needed on another Fchat thread . . . Dakotadigital.com has "universal tach signal interface".

Another interesting development . . . I've been able to dial in another 8 degrees of advance with this ignition system (36 degrees full advance with 10.5:1 compression, was pinging with dizzy's over 28 degrees) . . . maybe some cross talk or noise from the plug wires was causing some erratic spark or does the CDI spark help suppress detonation?

Sean