The V8 Owners Forum -

Mate in the SD1 club has fitted a MegaJolt and EDIS to his 4.6 engined SD1. Kit supplied by Trigger Wheels. Running EDIS only - MJ disconnected - it misfires badly at around 2000 rpm. Starts and idles ok. His timing light says it is running at 12 BTDC. He's tried another EDIS8 module. Coils are new. Plug leads supplied by TW, and resistor plugs used. He's experimented with the VR sensor gap, but that made no difference within the limits given.
TW don't supply the capacitors that I have on my EDIS at the coils - but say they aren't needed anyway.

The trigger wheel and sensor can't be fitted as TW says on an SD1 with air-con, so he's re-engineered things himself. His skills for this sort of thing are pretty good, so I'd guess that part's ok, but I haven't actually seen it.

Hi Dave, has he used proper screened cable from VR sensor to EDIS 8 module earthing screen only at the EDIS end? and sounds obvious but try reversing the VR sensor wires in the plug I have never tried the later some say it crates a no signal situation some don't

Revserning the VR wires would be my suggestion too.

All the screens seem to have been done by the book - only connected at one end. He tried reversing the VR connections and said it wouldn't start.

With the MJ disconnected it probably dosen't like 2000 RPM with only 12 degrees advance. It's in Limp home mode really.

Regards Denis

Without the MJ, the EDIS module will be running at 10 degrees limp home mode. The fact that it runs at all means the VR sensor is wired correctly. The 12 degrees is probably a 2 degree misalignment on the wheel/sensor/TDC mark.

Why has he got the MJ disconnected?

Because it is missing when that is connected too. It's a new installation, and he's trying to sort out why.

FWIW, if I disable SAW on my EDIS/MS set-up, it doesn't miss - just goes very 'flat' as you'd expect.

Even though you say the coils are new, it is possible that one is iffy.

Denis

DEVONMAN wrote:Even though you say the coils are new, it is possible that one is iffy.

Denis

That's a possibility personally i don't like pattern coils and EDIS probably due to the fact I have seen patterns fail yet since Ford introduced EDIS (inc the ECU internal EDIS based) I have never changed an OE Motorcraft coil (early clip tower type only) where as the later ones pattern or OE give plenty of aggro with HT faults & Fords its generally always HT leads related but shite garages change the coil too removing a perfectly serviceable OE to fit a pattern unit try a couple of scrap yard units Dave they can be had for a tenner a pair and always handy for spares and diagnostic purposes

Thanks, guys. Hadn't occurred new coils could be iffy. I've got some used genuine ones I could lend him to try - but sadly he's quite a long way off.
The only other thing I wondered about is the ground is to the body - on mine I ran it to the same ground point on the head as the EFI system.

Hi
might you have resistive plugs with resistive leads, because you don't get alot of spark out the end if you do! won't say how I know.
If they are multi post coils, you do not get alot out of them unless you have a grounded plug on both posts.
Best regards
Mike

lol - I know how you know

Now joined this forum, so can give info straight from the horse's mouth - thanks, Dave.

Dave's description of the problem was not quite correct, inasmuch as, the engine would rev above 2000 with MJ connected but would continually fluctuate if held at a steady throttle position, idle, 2000, 3000, etc.

After much head-scratching and fooling about in the garage, I can report that the installation is now up and running. I don't know about iffy coils, but I thank everyone for their input and other suggestions, most, if not all, had been investigated and proved negative.

At Dave's suggestion a weekend ago, I had removed all the plug leads and measured their resistance, then decided to whip the plugs out to check their visual condition. They were sooty but appeared OK. Gaps at 33 thou. Only done about 5000 miles.

As I had a new set of Denso plugs ready for the RR (which has coil-pack ignition) I decided to try them instead with 37 thou gap and...bingo!

The only thing I can put the uneven running down to, is the fact that the plugs I took out were NGK BPR6E (resistor, but not suppressed) and that allowed enough interference to upset things.

I should also say that throughout this unhappy saga, Chris at Trigger-Wheels has been most helpful.

You will find your original type NGK plugs were fine it was the fact they had fouled was your problem, the RV8 never seems to recover with failed plugs so I have read although some engines are content to flash off the carbon and make a full recovery of their plugs not the RV8 unfortunately, anyway glad its sorted now.

I was wondering if anyone would pick up on the sooty plugs aspect, and in different circumstances I might well have agreed that they were suspect.

However, while this has all been going on, and believe me it's been going on for several weeks - to convince myself that something else wasn't actually causing the problem, i.e. ECU, fuelling, fuel pressure, vacuum leaks, etc. - I swapped back to the original distributor ignition to reassure myself.

All was again sweetness and light, but when I returned to the MJ system the 'fault' also returned. At some time during this period I pulled one plug for a look-see - it was sooty, which didn't altogether surprise me as the engine had only been run in the garage with no load.

At some time in the future I'll try the (sooty) BPR6E's in my Scimitar (RV8) without cleaning them first and I shall be surprised if they don't work properly, but you never know.