The tech from Link recommends that I try resistor sparkplugs to help cure my engine miss........

Are the stock plugs this type or are they standard??

Bosch WR7CC, NGK B6RES. Readily available at most autoparts stores that cater to European cars. The Cap'n

the "R" in the plug code # is usually reserved for resistor plugs.

what kind of miss do they think resistor plugs will cure?

or what kind of miss are you experiencing?

QUOTE (TimT @ Jul 8 2005, 05:32 PM)

the "R" in the plug code # is usually reserved for resistor plugs.

QUOTE (TimT @ Jul 8 2005, 06:32 PM)

the "R" in the plug code # is usually reserved for resistor plugs. what kind of miss do they think resistor plugs will cure? or what kind of miss are you experiencing?

I'm getting a consistant miss, at idle and pretty much everywhere, it's becoming a PITA to tune the motor with it.

LINK mentions (and so does the NGK website) that some aftermarket fuel/ignition controllers benifit from using Resistor equipped sparkplugs.

New wires, new everything.......plugs gapped at .045"

Hmm, might have to try some of those on my car... Worth the $5 or whatever for a set.

Mike

I had to battle noise myself. I found a couple of things.

Wire routing makes a big difference. I now run all of the FI wires at the front of the engine and spark plug wires at the flywheel end of the engine with as much separation as possible. That cured the noise from the TPS.

Even with that, I still get noise in the CHT sensor circuit. For a while I had warm up enrichment going on and off. The cure for that was to set the sensor failure point above the highest temp for warmup enrichment so, it really doesn't matter what happens. It can bounce around from above that point and won't affect the pulse width. I think this may be a product of the fact that the CHT grounds to the block and EDIS uses the block to conduct spark to the waste spark plug. You shouldn't be up against that though but, Mark may be.

The cure for the noise in the MAP sensor was a resistor in the signal wire (11K). I started with a pot and increased it until the signal smoothed out. Until I got a consistant MAP I couldn't tune at all.

I changed to MSD 8.5 mm wires and that helped a lot. The boots over the plugs are really substantial and the set I got are long enough that I can run them back near the rear tin.

I added a large capacitor on the positive side of the coil to ground (25uf if I remember). It was off of a 91 Escort and that cleaned up the AM radio noise.

I know that these aren't perfect solutions but, they work for me. Incidentally, when I ran the MSD 6A with pertronix trigger last year, I didn't have noise issues with the FI. Understand, the timing was with a dizzy but, I felt that combo was pretty clean.

Dave

I know Canadian Mark has been beating me up about electrical interference. I'm starting to believe it. I'm going to spend today making sure my timing is 100% spot on (including removing the fan and marking 10 degrees). Then the next step is to start looking at wiring and interference. I have an oscilloscope. Is there some way I can use that to evaluate if interference is an issue? Dave, how did you know when the signals "cleared up"?

Wont you have to replace all of the plug wires as well? At least the ends as the stock ones wont fit over the plug. I accidentally got a set while I was down at Scott's one day and found you can't take the big metal cap off of the resistor type.

QUOTE (McMark @ Jul 9 2005, 10:36 AM)

I know Canadian Mark has been beating me up about electrical interference. I'm starting to believe it. I'm going to spend today making sure my timing is 100% spot on (including removing the fan and marking 10 degrees). Then the next step is to start looking at wiring and interference. I have an oscilloscope. Is there some way I can use that to evaluate if interference is an issue? Dave, how did you know when the signals "cleared up"?

Mark, how does a Willey burger @ Hazels sound?? mmmmm

do you plan on being down in the area this week?

after this weekend I will not be touching my car (and will not need the LM-1) for 2 weeks...we are leaving next Friday to go down to Louisiana

in fact if I cannot get the car running decent and get rid of the miss, I am sending the LINK, the dizzy, and everything related to it but the motor and car down to So-Cal on Monday for them to troubleshoot it.

Mike you need to get rid of all sources of interference, use shielded plugs wires, use resistor plugs. Remove the unused trigger wires from the ECU, these act as antenna and can pick up stray signals. Im not sure which input is used with a distributor sync, or pulse, remove whichever your not using. Make sure the sielding on the trigger lead is well grounded.

The non resistor plugs are broadcasting all sort of noise. And can be picked up by the system.

QUOTE (McMark @ Jul 9 2005, 01:36 PM)

I know Canadian Mark has been beating me up about electrical interference.  I'm starting to believe it.

Yep coils, plug wires, plugs, etc. can be major sources of noise. Make sure all the wires and brain are well away from the plug wires/coils. Never use solid core wires

Also this problem can be a poor injector ground or any ground in your system.

From the SDS tech page

QUOTE

06/27/05 Interference on 4F Coil Packs and ECUs On two of our test cars, dirty power supplied to the new style coil packs have caused rough running problems and ECU resets. When the voltage supply was scoped, large noise spikes were evident. When we rewired the coil power and ECU directly to the battery via a relay, the problems disappeared. We recommend doing this if you experience these types of problems. The D manual contains a schematic for a typical hookup.

QUOTE

03/15/04 Resistor Spark Plugs For engines experiencing RPM ERR codes which cannot be solved by other means such as moving Hall sensor cables or changing spark plug wire types, it may be beneficial to switch to resistor type spark plugs.

QUOTE

08/13/02 Ignition Wires We have at least 7 reported cases of ECU ignition interference problems from people using Taylor ignition wire sets. Once replaced with a differrent brand, all these problems disappeared. As such, we cannot recommend the use of these wires with our systems. One user also reported severe RPM ERR codes and stumbling upon fitting replacement Bosch 7mm wires. The problems disappeared when the Accel wires were refitted.

QUOTE

07/20/01 RPM Error Codes and Spark Plug Wires Several customers have reported RPM error codes and missing on E and F systems when using Taylor, Nology, Sparko and most brands of solid core spark plug wires. As a result, we cannot recommend the use of these wires with our systems. Good success has been obtained with Magnecor, NGK, MSD, ACCEL and most OE spiral wound and carbon string type wires.

QUOTE

11/13/00 Interference From MSD/HI6 Boxes When mounting MSD or Crane HI6 ignition boxes inside the vehicle with the SDS ECU, care should be taken to mount these at least 3 feet apart. More preferable, is to mount the ECU on one side of the vehicle and the the ignition box on the other. Better still, the ignition box should be on the other side of the firewall and a few feet away as well. These boxes generate extreme EMI and RFI which can interfere with data transfer from the ECU to the programmer. In extreme cases, they can cause the ECU to reset.

QUOTE

Strange Misses 09/27/99 A couple of things which you can check if you encounter random misses: On distributor equipped engines, be sure to check rotor to cap terminal phasing. Take half of your total timing and position the crankshaft at this figure (about 20 degrees BTDC), line up the rotor with the cap terminal. This will ensure the least posibble gap within the operating range. Excessive spark plug gap has been found to affect certain engines, especially if you are getting gibberish in the programmer LCD. Try closing the plug gap back to .030. Other causes for misses may be Hall sensor wires too close to ignition leads, MSD too close to the ECU and using ignition leads with insufficient supression qualities. Solid core, Taylor and Nology are NOT recommended.

QUOTE

Ignition Wires Proper operation of the SDS ECU requires the use of radio suppression type ignition leads. SOLID CORE WIRES CANNOT BE USED. Resistance type wires should measure a minimum of 3,000 ohms per foot. We highly recommend MAGNECOR OR NGK wires with the spiral wound conductor. We don't recommend the use of Taylor or Nology wires with our systems.

QUOTE

New wires, new everything.......plugs gapped at .045"

That gap is a tad large

I run .032 on my very healthy crankfire set-up.

my plug wires are from Aurora (made in Canada eh!!! )

Upon looking at my wiring harness, I was sorta lazy and for now just kept it 2 meters long and just wound it up until I figured out just how long to make the individual wires....I'll re-do it "correctly" and remove the extra trigger wires (I only need ING-1, so I can terminate or remove ING-2 and 3 completely since I know they still send out a signal)

New plugs and good idea on closing the gap a little, it couldn't hurt.

thanks for all the advice

Mark

I could see the noise on a graph of the datalogs. The signal looks all spikey. At first, the CHT, MAT MAP and TPS were all wacky and AM radio had a pop. The only thing that still is wacky is the CHT.

Take a look at the MS site for MS logviewer. MS saves datalogs as excel files. Maybe you can get it to open your excel logs. It's a pretty cool way to see whats going on. If it doesn't work for you maybe you can get one of those really smart peeps down there to massage the program or logs so it will. It's open source I think so you can have at it.

One thing I learned was only connect one end of a shield to ground and keep the number of ground points to a minimum. It's awful easy to create ground loops which may create signal problems. For instance, I had a ground loop involving the ground on the ground point on the case bolt through the ground plane of the MS relay box to the ground of the stock CHT in the head. I also had a ground to the - terminal of the battery. I eliminated the the ground on the case and now ground only through the CHT and the battery. I wish I could use a CHT that wasn't grounded to the head cause I think that is the source of the noise in that signal.

I made a 200 mile round trip today with no problems and it ran great all the way up to 2500 feet so, I'm really happy.

Dave

Mike: Don't they make resistor wires? the spark plug waire that have a carbon core, verses the solid copper core. I also know VW had resistor plug wire "ends" the end that actually snaps onto the plug. you would use these to stop radio interference. I think these were popular before resistor wires came around.


One thing, what is the theory on how the resistor plug, or wire or what ever helps reduce interference? i donot understand that part. metal sheilded wires that are grounded I can understand, but adding resistance i don't get, but it is supposed to work.

i be stumped on this one???????????????

QUOTE (DNHunt @ Jul 10 2005, 12:15 AM)

One thing I learned was only connect one end of a shield to ground and keep the number of ground points to a minimum. It's awful easy to create ground loops which may create signal problems......... I eliminated the the ground on the case and now ground only through the CHT and the battery.

Good point Dave, grounding to the case is not the best bet...even though the factory did it.

QUOTE

I also know VW had resistor plug wire "ends" the end that actually snaps onto the plug. you would use these to stop radio interference.

I had big problems with my crankfire with these ends. Seems that when you put double the stock volts through them they can burn out.

And the therory behind the resistor working to reduce interferance is?????? Anyone?????? i be all confused?????

While looking to see more information about this , found this link. Here is the part, looks to be a sheild for radio interference. Came off a 70 imported from Europe. Any thoughts?


Click to view attachment

Click to view attachment

Talk about digging up an old thread

I don't know what I'm looking at in your pic....

It's a sheild that fits around the distributor, the part is riveted to it. With a ground strap.
Notched for the distributor cap clamps.
Click to view attachment

Used on early VW Golfs,no longer supplied and the replacements work fine without the earth shielded setup,just saying ,no expert here so I don't really know a solution except for good quality replacement parts.