Yes, BPR6EIX. Love 'em. Ran the first set for two full driving seasons of MFI tuning, 7 or 8 thousand KM's with some really RICH mixtures.

BUT!!! Not suitable for waste spark since you need iridium or platinum on both electrodes. Look for DOUBLE iridium.

Ah. Probably one of the BPR6E-something plugs, like a BPR6EY I bet. Nothing wrong with those but you'll get better spark (and plug life) with iridiums or platinum imo. Of course people have whole belief systems built up around spark plugs (same way they do with oils) so you'll get varying suggestions, some of them downright crazy, even from normally sane and intelligent people.

Thanks!

I just replaced the plugs on my M3. 3 years and 40,000kms and they were worn out. More power and fuel economy improved by 15%.

I got a timing light, and had my son crank over the car.

I confirmed all plugs wires are going to the right spot, but all I can do is get the car to stumble.

Starting fluid did not help.


I'm assuming that when the timing light flashes the mark before TDC should line up with the parting line?

After continually trying to start this thing I did notice fuel leaking out of the headers.

At this point I'm ready to either tow it to a shop, switch to EFI or burn the thing to the ground.

Is it possible to put the original distributor back in, maybe isolate the problem between the carbs vs ignition?

There's a mark at 10 degrees BTDC I think - which should be about 11mm from tdc. That's where you want to see a flash. You'll see it every time the crank goes to that position if you are on either the 1 or 4 plug wire. It's worthwhile putting some makeshift marks on the pulley at 120 from there and 240 from there to make sure the proper cylinders in the firing order are getting the fire at the right time. I know you've double checked but if you're double checking using some wrong information or assumption it won't get you anywhere else than where you already are.

PS - just confirming you got a fully non-computerized timing light, correct? And have you confirmed what plugs you've got in there?

Fully non computerized, correct. When I aim the light, it flashes at the timing mark that is pretty close to the Z1 mark.

Plugs are NGK BPR6ES

Part Number: NGKW0133-1641844
Part Name: NGK Spark Plug Standard BPR6ES NGK

I've reached out to Jeff Alton at Turn 3 (Jeff's a member here). If it isn't running by the end of the weekend, I'm towing it to his shop to get sorted.

Nothing wrong with getting a set of fresh eyes on the problem. We all get clouded by our past experience and sometimes can’t see the obvious.

You’ll get it sorted eventually and can direct all this frustration toward 6000 RPMs

You'll be in good hands with Jeff.

Those plugs are the standard copper plug. It would be worth trying a BRP6EIX which is the iridium version and has a fine tip electrode and will fire more easily.

Long term, you'll want to get a Double Platinum or Double Iridium plug to suit the waste spark setup.

6000rpm?

I thought this was a 911, not a John Deere.

Lol!

I’m in the farm league with my 2.7 so I’ll humbly exit stage left and leave the 7000 club to play ball.

If the spark timing is close enough (say 10* ATDC to 20* BTDC), it should fire if you have compression and fuel.

Firing order is 100% correct?

Pics and video might help.

I'll take a video tomorrow. Good chance I f*cked up the carb setup

Took a short video trying to start the car.

Ignition box was set at 10 degrees advanced, I rolled it back to 5 degrees advanced towards the end of the video.

I'm going to install a seat and some axles then send it over to Jeff to get it running.

Fuel pressure is 3.5 psi

https://youtu.be/jkfnvgq7Knc

Well that was a spectacular flame show! I assume you have a fire extinguisher handy.... I had 3 at the ready when I was first firing up Project Heavy Metal.

I was expecting to see you hop in and pump the accelerator 4 or 5 times to prime the intakes with a bunch of fuel. Not sure at any point in the video you pumped the carbs enough to give it a good starting shot. Not having a choke is really going to make it tough to get started without doing that.

The few times it did fire it sounds like its running like it should - although without those few instances to go on I would still swear there are at least two cylinders swapped in the firing order - my cue on that one is the odd pause in cranking that seems to occur rhythmically as you crank it over.

Also, the flame show out the cylinders.... oh my. I know you've checked the timing of #1 and 4, but have you checked the spark timing with the light against the pully 120 degrees from TDC to confirm those two cylinders are firing at the right time (and again at 240 for the last set?) just in case the XDI is doing something you don't realize swapping pairs on you in software? It's possible that the next two pairs in order have to be swapped at the coil pack (or a setting changed in software).

Also, that odd pause in cranking could indicate a poorly performing battery (or simply one low on juice) - the starter could be drawing so many amps at that very short moment it could be causing the XDI to reboot, in which case it might take a short time to come to life, and if it's like other systems it may need to see a few valid pulses before it will allow the spark to fire. Do you have a backup battery or one you could steal from another car and add to yours with jumper cables?

Last but not least, I'd make sure your timing curve is set to absolutely flat at first or at least quite conservative for the are between 0 and 2000 rpm, just in case the unsteady cranking is causing the XDI to advance the timing as it's cranking because it momentarily sees the engine speed spike up to a point on the curve where it's calling for advance. That might see the cranking smooth out a bit since the spark advance won't be fighting the cranking.

Sure behaves like a firing order issue.

Very interesting. The pauses in the cranking is me not wanting to crank it for 3 straight minutes.

I did pump it a few times each time.

I think I'm going to pull out the xdi and double check the pin out and dip switch setting.

Fire extinguisher was definitely at the ready.

Really glad I took a video.

By pauses I meant how the motor seems to come to almost a complete stop WHILE you are cranking. Like it's fighting an out of time spark.

I did see that you were pumping, but one or two pumps while cranking get "used up" and shoved out the exhaust right away.

It's worth trying to pump is 4 or 5 times before you even turn the key to create a nice slug of super-rich mixture that gets pulled into the intake port all at once during the first rotation.