Misfire Problem.... - CEG Archives

Cool, thanks for replies guys

Rick, I'll agree a set of plugs are cheaper than a new engine.

I'll pick up a set that's one step colder to be on the safe side.

Tom, TH sent me an email saying FI should run .32". I appreciate he'd respond via email, but I'll go with what you advise in this situation seeing that you have more (to my knowledge atleast) hands on tinkering with turbo duratec V6's.
Honestly, everything I've read here on CEG has said to start out at .35, and the people I've asked have said the same. Though since you're able to run upwards of 14 psi, I somehow think my candy assed 3.5psi won't blow out the spark

I'd go cheapy plug wires again, but the Ford Racing turds and now these Bosch wires have got me spooked.

Well, 30-35 thousandths is very old school tech about turbos.

I won't say NOT to do what Terry says....but I will say that you should take a look and see what the '03 cobra runs in plug gap, or the late model lightning pickups.

Then decide from my hands on, from Terry's advice, and what the Factory says. Remember, the supercharged Fords are around 10psi.

Originally posted by Swazo:
Cool, thanks for replies guys

Rick, I'll agree a set of plugs are cheaper than a new engine. I'll pick up a set that's one step colder to be on the safe side.

Tom, TH sent me an email saying FI should run .32". I appreciate he'd respond via email, but I'll go with what you advise in this situation seeing that you have more (to my knowledge atleast) hands on tinkering with turbo duratec V6's.
Honestly, everything I've read here on CEG has said to start out at .35, and the people I've asked have said the same. Though since you're able to run upwards of 14 psi, I somehow think my candy assed 3.5psi won't blow out the spark

I'd go cheapy plug wires again, but the Ford Racing turds and now these Bosch wires have got me spooked.

I hate to cause dissension, but I really should reiterate that unless you are misfiring under boost then gap the plug as close to the factory spec as possible! Why would you want to reduce the power of the spark? It is also an easy thing to test, you can gap the plugs close to stock and see how it runs. If it performs worse tighten up until there are no further improvements. Then keep it a bit under where you last experienced misfiring due to wide plug gaps.

I don't understand why people keep going back to the old school stuff that was figured out back in the day with weak stock ignition systems. As I stated earlier, the shorter the air gap the lower the spark energy. You want a bigger gap for a higher energy spark. This is PHYSICS of electromagnetism is taught in basic course curriculum when going to school for engineering.

Here is some interesting reading from the web though I can't guarantee the accuracy of anything posted on the web, I think it is valid. Just remember, the stock contour ignition is VERY good and is better than the stock 4.6 mustang ignition from back in the day.

From the Dodge Stealth Forums:

Stock plug gap on Dodge Stealth/3000GT turbo V6: The stock gap is 1.0-1.1 mm (0.039-0.043"). The proper spark plugs are platinum NGK PFR6J-11 (or Denso PK20PR-P11 or equivalent) for the DOHC engine
The only reason for reducing spark gap is to eliminate misfires. Misfires are usually occuring because the ignition energy produced by the coils and wires is less than what is needed to produce a good spark. Smaller gaps, or smaller electrode tips (like found on platinum- and iridium-tipped plugs), require less energy to spark. So reducing gap to elminate misfires is OK up to a point. After that either the ignition must be made better (more energy) or the cause for increased spark voltage requirements must be dealt with (lower the boost).

For our engines, too large a gap, say over 0.045", should offer no performance advantage. Medium gaps, say 0.034" to 0.043", should be fairly equivalent powerwise. Use the largest gap that also produces the least amount of misfires for your setup. Small gaps, say less than 0.030", may start to hurt combustion a little and lead to poor idle (popping in the exhaust for example) and poor emissions (the spark kernel may now be too small for good initiation of combustion). Use small gaps only in extreme situations (such as the ignition system is maxed out and boost is very high).
Remember, this is a factory turbo setup going on 15 years ago!!

Chrysler PT Cruiser Turbo forums report 0.045" for Turbo and 0.050" for Naturally aspirated.
Exactly the same as what I decided to run. Factory contour is what, .050-.053". It's nice to be validated over and over again.

More light reading for you.

Sparkplug 101

Wires testing...cool stuff here

Good reading material, thanks Tom

Also, I wanted to point out that I have my IMRC turned off in my tune all together. AFR is a pinch leaner than what my dyno shows. I also have another tune that has less timing. I get misfires with all 3 tunes, so that's why I think it's a mechanical issue (plug wires, gap, grounding issue, etc)

Now I'm coming away from this armed with some good knowledge to improve upon my currant setup

Originally posted by Swazo:
...I have my IMRC turned off in my tune all together. ...

That damned IMRC. I went 3.0L with oval ports and no IMRC to speak of. I still got a wierd A/F bump where the IMRC would have opened... Damn thing was haunted.

Tom- Good to see that some things do not change. You are still the reference material king!

Originally posted by Rev. Po-Jay:

Originally posted by Swazo:
...I have my IMRC turned off in my tune all together. ...

That damned IMRC. I went 3.0L with oval ports and no IMRC to speak of. I still got a wierd A/F bump where the IMRC would have opened... Damn thing was haunted.

Tom- Good to see that some things do not change. You are still the reference material king!

I am hoping to smooth that bump out with my tuning/

Originally posted by MapOfTaziFoShoâ�??¢:

Originally posted by Rev. Po-Jay:

Originally posted by Swazo:
...I have my IMRC turned off in my tune all together. ...

That damned IMRC. I went 3.0L with oval ports and no IMRC to speak of. I still got a wierd A/F bump where the IMRC would have opened... Damn thing was haunted.

Tom- Good to see that some things do not change. You are still the reference material king!

I am hoping to smooth that bump out with my tuning/

Yeah, that will be the best bet. You'll have to tune and check, then repeat it until it's all gone.

Thoughts about this process? Horse found this on a Volvo/Turbo brick forum. Interesting to say the least... side gapped spark plugs

That is the only way you should cut plugs for use with nitrous or high boost. That trick is about as old as spark plugs are. It's actually a good idea for any engine.

Matter of fact some new plugs already come cut like that. NipponDensos are one. They do it one step better by making the electrode come to an edged point.

However not gapping like that is not going to be the cause of spark blow out at very low boost. Yes do this to your plugs. No it's not the problem.

I know the plugs aren't causing my misfire, it's likely the plug wires or the coil itself (it only happens when it gets hot).

[censored] plug wires could be causing it, but more likely it is a combination between your plug wires and your tune.
Only when warm is when the mixture will be at its leanest.

It's not the tune, I've got some decent datalogging in and dyno time to know it's not. The AFR is fine, even after it warms up. I simply get a random misfire after 10+ minutes of street driving. Chris is who pointed out that it's most likely my coil, so good ol' Bill J will have one on my door step tomorrow.
My SVT has just shy of 75K on the car, and I reused some of the items with my basicly new drivetrain. I've gone this far, what's a new stock coil and great Magnacor plug wires?

::dumps more money into the SVT fire to keep it going::

Originally posted by Swazo:
It's not the tune, I've got some decent datalogging in and dyno time to know it's not. The AFR is fine, even after it warms up. I simply get a random misfire after 10+ minutes of street driving. Chris is who pointed out that it's most likely my coil, so good ol' Bill J will have one on my door step tomorrow.
My SVT has just shy of 75K on the car, and I reused some of the items with my basicly new drivetrain. I've gone this far, what's a new stock coil and great Magnacor plug wires?

::dumps more money into the SVT fire to keep it going::

But its almost NEVER the coil!!!!!! I can't remember when the last time somone installed a coil by itself that it fixed the problem.

I hope it is in your case, but my plug wires did exactly what you are talking about only more so on my 3L swap (you know, runs great cold for first five minutes then starts to stutter or misfire getting quickly worse, drive easy on the throttle and at certain rpms to minimize the misfiring, misfires begin to clear up as you go full throttle at higher rpms, etc when I first put it in. Air fuel had changed and I was using an eManage to help improve the problem, but it was fuggin plug wires @$^T!Q@%!#$@^#$^&$&*%&$%$#@!

I'd have never bought the emanage in the first place if it weren't for the wires going bad and me being STUPID. I even swapped in a different coil, the one from the 3L.

Later on I got tired of thinking that wires could be bad at 40K miles and Voila, problem gone....Several hundred dollars in mods later!! It was a combination of running leaner A/F from swap, though still right where it should be according to the wideband at the dyno, and the plug wires.

Get the Magnecores that DemonSVT recommends if the problem recurrs.

Remember, since every coil is different, it may alter the problem but unless the coil is really failing, it will come back.

You forget, when I was building the timing control device for the eMAange back in 2002. I went into great depth on how the PCM controls the coil packs in this car. Most people are part-changers, I ran every part of that circuit on an oscilloscope so I even know what he spark vs. time graphs look like, what the voltage spikes on the primary look like, etc. I know the part numbers on the chips in the PCM, the wiring schematic by heart, how the coils work, and how the wires and plugs work.

If you test the resistance on your coil across the primaries and across the secondaries you will know whether to replace it or not.

There are some cars where anytime you have an ignition problem, you go and change the coils. The old late 80's Potiac Grand Am is a primary example.
THere are some where you go and change the ignition module, GM V6's in the early 90s are another.
Fords wastespark duratecs eat up plug wires. Yes other problems occur, but by far, probably 99% of the time it is just plug wires.

If anyone happens to be looking for magnecore's I got a great price on them at SPMotorsports. They've got them for just under $100 where everyone else is around $125.

Rick

Tom,

Like I've said, I have my LM1 to know that I am not running lean at all. I have 3 tunes that I am using. I have 4 hours of dyno time to boot, and know it's not my tune.

1) The one that I used on my dyno run that you thought was a little rich.
2) The same tune, but with 15%-10% less fuel (LM1 still shows good AFR, Raptor shows the PCM is still pulling up to 5% fuel in spots, but otherwise all bouncing around 1)
3) The same tune as 2, but with less timing.

I had a few misfires on my 2.5L and thought it was probably the crappy Ford racing wires. The Bosch wires were on just before I spun a bearing, so I can't say for sure if the misfire stopped.
With 75K on the coil, I'm willing to drop $80 to have a new one under the circumstances.

I should be getting the coil from Bill Jenkins today, along with the Magnacor wires and NGK copper TR6's that I'm going to 'un-shroud'/sidegap.

Originally posted by Buckshot77:
If anyone happens to be looking for magnecore's I got a great price on them at SPMotorsports. They've got them for just under $100 where everyone else is around $125.

Rick

That's good to know!

Yup, it made my day for sure. I searched a good number of sites and he was cheapest by far plus I got them in a few days after the order. I can't imagine with other places selling them for $125 that dealer cost is much below $70 or so, so good for Joe by selling them at that cost.

Rick

Originally posted by todras:

Originally posted by Buckshot77:
If anyone happens to be looking for magnecore's I got a great price on them at SPMotorsports. They've got them for just under $100 where everyone else is around $125.

Rick

That's good to know!

Wow, I should have looked there. I checked with CTA and they were $155 and a week out on being able to get them to me. I ended up finding a set for $85 off of Ebay, and that was with 2nd day shipping

Popped the new coil in along with the new Magnacor wires (still waiting on the new plugs to get here....

), and I've put 100 misfire free miles on 'er

The new wires/coil have cleared up many other very small issues, like a small amount of surging when holding a specfic RPM. Throttle response is WAY more lively, and the over all feel is GOBS of more power!

This car is very fun to drive!