RX-POP

Hello all! First post on the .com forums, I'm usually on the .au forums.

Anyway, I've had my 8 for about 5 months now. Love the thing to bits and its had its share of problems. First was a solenoid, fixed that, second was the cat, gutted that, third was the radiator, replaced that, and fourth were the coils, replaced those with BHR coils.

Its a 2004 6SP Manual

After I replaced the coils with BHR, car was running the best it ever has. Pulling all throughout the rev range, no backfires, just brilliant. Helped so much with starting issues, and starts perfectly like any other vehicle.

Went like that for about three days. Now its back to what it was like pre-BHR ignition. Still revs all the way to redline, just doesn't feel like its revving quite as quickly and seems to bog down a little bit at about 7k. Also much slower off the line and have timed it 0-100KMH (0-60MPH) at 7.2s and backfires when changing gears. Still idle's perfectly.

When it was running great with the BHR coils, it was doing 0-100kmh at 6.1s which is expected.


The car still starts great, so that tells me the coils are still doing something, its just this loss of power. Could it be the plugs have recently fouled with the stronger coils? They were not replaced.

I have cleaned the MAF, ESS, Reset ECU, 20 Brake stomp etc.

I have ordered new plugs as well as a new air filter and have done an oil change today. So I guess we'll see if they make the difference.

Had a compression test done by a rotary specialist BEFORE the BHR coils and numbers were fine.

I do premix approx 6 oz to a full tank of 98 RON.

Anyone have any suggestions or anyone with similar problems?

RIWWP

iTrader: (2)

Coils, plugs, and wires should be replaced at the same time. Replacing one of the 12 pieces without replacing the rest is only moderately effective. The ignition is only as effective as the weakest link. This includes the engine ground too.

LOTS of reasons for power loss though, including compression loss.

RX-POP

Did replace the wires a the same time as coils. I did also inspect plugs and they were pretty carboned up. Just seems strange that the coils made all that difference for a few days and then just suddenly went back to the way it was.

Like I said I've ordered new plugs and a new air filter (for good measure) and when they're replaced I'll get another comp test just to see.

Now grounds are something I probably need to inspect. Maybe they're dirty.. I think I'll do a little searching.

RIWWP

iTrader: (2)

Remember that your ignition is an electrical circuit. Just like replacing the light switch doesn't make the light turn on if the bulb is still burnt out.

Alternator produces voltage/current to the coils, coils build up and release high voltage charges, that charge travels down the plug wires and into the plugs, arcing across the electrode to the plug tip, where it grounds out on the block, travels through the block to the grounding cable, through the cable and/or chassis to the negative battery post.


All it takes is literally 1 component to degrade or break and the whole thing is suddenly not working.

Plug tips foul and/or burn away, grounds corrode, wires degrade, coils wear out, etc... And they do it at about the same rate as each other degradation, so they should be replaced at the same time. You can get away with replacing less, but typically not for long, because the unreplaced stuff is still just marking toward death.

Paco664

you mention the plugs were pretty carboned up.....

replace the plugs..... THEN if it doesn't run better go ahead with the comp test and other stuff....

IMHO the stronger coils made the plugs fire better for a few days BUT seeing as they were toast to begin with they are worn out...

RX-POP

This is exactly how the leading looked. Pretty bad.

RX-POP

I followed an installation guide for the BHR kit and grounded to the L/H fender. Is this the correct ground point or should I be grounding to the lower intake manifold?

Just trying to get everything correct here.

Paco664

you solved your problem right there with that photo...

RX-POP

Thanks for the reassurance there Paco. I'll replace the plugs when they come in and clean up ground points and I'll let you know how it goes.

RX-POP

Well, I got my new spark plugs in and its still underpowered. By underpowered I mean doing 0-100kmh in 7.2s measured through Torque (when I first changed to the BHR coils it was back to 6.1s).

I yet again did the 20 brake stomp and disconnect battery etc to no avail.

I had a compression test again and here are the results:

Rotor 1
7.2 / 7.3 / 7.3
Rotor 2
7.6 / 7.9 / 7.7

@250RPM

Within specs so I'm really not sure.. unless the BHR coils have died? I did buy them used.

Would a timing light help me here?

ShellDude

iTrader: (12)

I'm assuming AU 8s have a catalytic converter? Have you checked yours?

RX-POP

Yeah they do. Mines been gutted, I did take it off the other day just to inspect it and nothing has changed. Still nothing inside.

ShellDude

iTrader: (12)

just re-read your first post and saw you'd mentioned it there. hmm. seafoam for fun?

RX-POP

Did a carbon treatment using Subaru upper engine cleaner (no seafoam here in aus) before I changed the plugs. Didn't seem to change anything.

I'm thinking of doing this https://www.rx8club.com/series-i-do-...-wires-222641/
to test the coils... maybe that will turn up something.

RX-POP

Just to update anyone who happens to be following this thread, I removed the MSD ignition wires that came with my BHR coils and inspected them. They had a fair few scorch marks on them, but nothing going through to the wire, however they did look past their use by date.

I changed back to my original wires (from 2004! and they're not in the best shape) and it has actually slightly improved. Took it for a run, seems to rev a bit nicer with less hesitation at 7k. Timed it using torque and its doing 6.8s (0-100kmh). Not perfect but a definite improvement.

I have ordered some new wires and will update this thread as soon as they're installed. Hopefully they were the issue! Only 0.7s to go!

RX-POP

Oh, and forgot to mention that my OMP seems to no longer work... I've been premixing a lot heavier lately to counteract that but it still worries me. Giving it a lot and oil level hasn't changed in about 5 fill ups.