spark "blow out" under boost?

[gears351]

Can anyone tell me what it'd feel like if my spark was too weak under boost?

Would the motor stop revving almost like it hit a rev limiter (but not as smooth or consistent)?

So long as I keep the boost below 5 I'm fine, I can rev all day. But the minute I hit 6 the motor falls on it's face and won't rev - it surges, coughs & hiccups. let off the gas a little and it's fine. BTW this is around 1/4 throttle.

Diagnosing yesterday I disconnected the MAP while it was running and now I've got a code 13, I also pulled the IAC motor plug while it was running... AND #4 injector. How many start cycles to get rid of these codes?

[86seeS]

Itll fallon its face, backfire, ect.... Set plugs a .030 should fix it

---------- Post added at 06:59 PM ---------- Previous post was at 06:58 PM ----------

Also unplug battery for 30sec to reset codes

[CNH320]

Just disconnect your battery for few seconds to clear the codes then try tightening up the gap on your plugs, if that doesnt work check your wires.

[roachjuice]

Try changing the plugs. I had ngk plugs and it did spark blow out randomly. Went to champion never had another problem.

[Force Fed Mopar]

Sometime it feels like a skip or miss under boost, almost like a rich miss. I gapped mine down to .028 I think, no more blowout.

[gears351]

Thanks, I'm running the stock .035 gap to worsen matters. I'm going to put the Champions back in, if that doesn't do it I'll try the old wires too. After that it's a Blaster II coil!

[Force Fed Mopar]

BTW I'm running stock coil, parts store wires and NGK GR5 plugs. Coils don't seem to make much difference on most of these cars, unless the stock one is weak of course. I have tested a stocker and got 40,000 volts out of it.

[4 l-bodies]

I once had a similar issue on a 87 Shelby Z. It got progressively worse starting to break up around 16 PSI then lower and lower over the course of several months. I threw everything including the kitchen sink at it. I've been around these cars since they were new and this one had me stumped? The ultimate cure was I had horribly weak valve springs! After 20+ years, they can easily get really soft. So after checking everything else, suspect that (lol)!
Todd

[Force Fed Mopar]

I once had a similar issue on a 87 Shelby Z. It got progressively worse starting to break up around 16 PSI then lower and lower over the course of several months. I threw everything including the kitchen sink at it. I've been around these cars since they were new and this one had me stumped? The ultimate cure was I had horribly weak valve springs! After 20+ years, they can easily get really soft. So after checking everything else, suspect that (lol)!
Todd

That's crazy lol, good to know though.

[gears351]

ACK! When I did the HG I replaced the exhaust valves & springs - wouldn't springs float regardless of boost though?

.030 gapped Champions made no difference, I'm swapping the plugwires now..... I'd figured it'd be the coil next but now Todd's got me questioning the integrity of my valve springs. Is there a way to measure the springs in the truck/car?

[4 l-bodies]

ACK! When I did the HG I replaced the exhaust valves & springs - wouldn't springs float regardless of boost though?

.030 gapped Champions made no difference, I'm swapping the plugwires now..... I'd figured it'd be the coil next but now Todd's got me questioning the integrity of my valve springs. Is there a way to measure the springs in the truck/car?

Well in a forced induction vehicle it's possible to blow the intake valve open, and because of backpressure the exhaust valve is going to try to open during intake stroke. Rarely happens on our motors, but can happen more frequently on cars that were N/A that were then changed to forced induction. The bigger the valve and the more backpressure the more spring you need to control the pressures that are being applied to it. Then of course there is the weight of the bigger valve to take into consideration too. I have ran into this problem twice over the years. The first time was when some brainiac installed conical springs on a 8 valve car I just bought. Obviously never checked or corrected seat pressure. When taken apart the springs were like 45lbs on the seat! Yeah that car wouldn't rev past 4K without floating. Surprised it never blew up. Like I said probably not your problem, but just in case nothing else works, some food for thought.
Todd

[gears351]

the old plug wires run marginally better, now I can go a little past 5 psi and it still breaks up but it does it much smoother - fewer coughs. I'm headed to Summit to buy a 60kv coil to see what happens. After that it's a new MAP.

[turbovanman²]

Check your coil, its really easy. Grind the ground electrode off an old plug, now ground out the body and start it up, if it wont' fire, the coil is too weak or keep reducing the plug gap, if it stops with a very small gap, then your call is bunk.

Good call on the valve springs Todd. :nod:

[gears351]

Thanks for the tip on the homebrew coil tester - I didn't do that yet, I just decided it was time for a new coil as the old one is original. (I'm still going to "build" one) After lunch I'll bundle up, shovel off the hood and swap coils.

[gears351]

Todd nailed it - bad exhaust valvesprings.

New springs knocked the book out of my daughter's hands (she was reading when I got on it).

[turbovanman²]

Very cool, thanks for the update.

[PunKid]

Wow, weirdo solution. will have to try to remember this for future use.

[Force Fed Mopar]

That is very interesting. One more reason why you should have everything checked out every time you have one built, even if it costs extra. Never assume anything used is good :)

[4 l-bodies]

Todd nailed it - bad exhaust valvesprings.

New springs knocked the book out of my daughter's hands (she was reading when I got on it).

Well good to hear that you got it fixed. Glad I didn't send you on a wild goose chase. Springs should be good for another 20+ years now (lol)!
Todd

[boost geek]

OK, spark blowout at .022, .020 made a pass at 119mph. I need to upgrade the ignition. I'm running Comp conicals, so springs are not an issue. Does no one on this board other than Bakes run a non Mopar coil?

[Ondonti]

I run a Ford 5.0 coil. should be 48000 volts.

I am probably going to end up running a Keene Bell Boost a Spark in the future because I want to stick with 1 coil.

[85glht]

OK, spark blowout at .022, .020 made a pass at 119mph. I need to upgrade the ignition. I'm running Comp conicals, so springs are not an issue. Does no one on this board other than Bakes run a non Mopar coil?

I'm running a Jacobs coil. Had an MSD also but disconnected it for trouble shooting purposes.

[contraption22]

OK, spark blowout at .022, .020 made a pass at 119mph. I need to upgrade the ignition. I'm running Comp conicals, so springs are not an issue. Does no one on this board other than Bakes run a non Mopar coil?

I'm running a Crane Hi-6 Ignition box on my Horizon. No spark blowout at 30+psi plus nitrous. It's an awesome ignition system. I have an extra complete kit with a coil if you are interested. PM me. It also has a built-in two-step.

[bakes]

I'm running a Crane Hi-6 Ignition box on my Horizon. No spark blowout at 30+psi plus nitrous. It's an awesome ignition system. I have an extra complete kit with a coil if you are interested. PM me. It also has a built-in two-step.

I love HI 6. with my accel super coil. thing is tig welder

[bakes]

Here Dick is some good reading.
http://www.hotrod.com/techarticles/ignition_coil_tech/index.html

[boost geek]

I got an MSD 6200 from a friend, hooked it up yesterday, car fired up. I opened the plug gap to .035, but I haven't tried it on the street yet. Maybe on friday I'll put a 1 day permit on it and play around.
How much was that Hi-6 anyways?

[boost geek]

Well, my friend came over and we took the car out for a few freeway on ramp beatings. My first pass I didn't have my alky turned on, hit 17.0 on the wideband in 4th gear. We did the run again with alky, ran 10.8 to 11.2, so alky works great, car was low on power at 17.0. (duh). Tha plugs are gapped at .035 with the MSD, and no misfires, so it works great. I can only get 28 psi boost spikes, my rev limiter is just too low at 7200 rpm. When I see the shift light flash at 7000, I already hit the rev limiter.Weather permiting, track next friday. :D

[zin]

As usual, late to the party!...

But as to how "spark blow-out" feels. I can almost guarantee if you feel like you are hitting a rev-limiter, but you know you are not, it is in the ignition. The fix can be as cheap and easy as the aforementioned closing of the gap.

I recommend going at least .010" if possible to provide a noticeable difference. Sometimes it means new wires/cap & rotor, other times it means a new ignition box/coil...

In any case, the tighter gap will either make the problem go away, or not come on till a higher RPM, where the coil doesn't have as much "charge time" and essentially gets weaker, and so finds an easier place to go, instead of that mean nasty chamber with all that pressure!

Hope this was helpful to someone!

Mike

[mpgmike]

A side note on ignition, I tested many brands and styles of plugs on many cars over the years. The only plugs that surprised me with massive gains in power were the Pulstar plugs on our '91 R/T. Had to gap them at 0.028" for best results. I tried Halo, platinum (several brands), along with the typical varieties. I'm in Michigan getting some ignition systems tested at the Roush Performance Labs. One of the systems that might be of interest to guys running stupid boost levels is Aqua Pulser. You won't find a more potent spark on anything short of the space shuttle.

Mike

[boost geek]

Never heard of them, but looks good.
http://www.aquapulser.com/performance_ignition/

[Force Fed Mopar]

Looks like a welder lol, better be a stout plug or it'll be gone in no time :)

[mpgmike]

As a matter of fact, the Aqua Pulser system is hard on plugs. Their race-only version can go through a set of plugs every pass down the 1320.....but oh my do you get down that strip quickly!

Mike

[mpgmike]

So far we tested our heavily modified 2008 Hyundai Sonata with stock plugs (41.74 mpg hyw, 26.97 city) and Pulstar plugs (41.99 hyw, 26.99 city). Later this week we will test the Aqua Pulser system. As a side note, the Sonata was certified new at 21 city and 30 hwy. The new hybrid Sonata is rated at 35 city and 40 hwy as a point of reference. I'll post the AP numbers probably early next week.

Mike

[RoadWarrior222]

Ever test those E3 plugs Mike?

[mpgmike]

No, never tested the E3 plugs. They are conceptually similar to Halo plugs, but with more sharp edges. I've heard good things about them from people that kinda-sorta know how to test them (fill in the blanks between the lines here). I still like the Pulstars aside from the Roush test results.

Mike

[contraption22]

I wouldn't trust any of those gimmicky plugs in any type of boosted application, especially one with higher boost.

[RoadWarrior222]

Well that's why I asked about the e3, looks robust. More so than a stock champion... and I've got an HC N/A motor eating plugs...

[turbovanman²]

OK, spark blowout at .022, .020 made a pass at 119mph. I need to upgrade the ignition. I'm running Comp conicals, so springs are not an issue. Does no one on this board other than Bakes run a non Mopar coil?

Really? Do I have to tell you again :p

[boost geek]

Simons back!!! :hail:

Off to the dyno on the 15th.:thumb:

[contraption22]

Well that's why I asked about the e3, looks robust. More so than a stock champion... and I've got an HC N/A motor eating plugs...

My advice would be to figure out why its "eating" plugs. Champions work fine for most of us.

[RoadWarrior222]

Well stock plug for the stock unmolested motor is one of the hottest I've seen anything use... so I'll be going down a heat range or two... When I say eating I mean gap erosion is rapidish, and performance drops off in a couple of thousand miles.

[contraption22]

The last thing you want in your combustion chamber is a piece of metal hanging out in the middle of it. It will turn into a glow plug in short order.

[turbovanman²]

Well that's why I asked about the e3, looks robust. More so than a stock champion... and I've got an HC N/A motor eating plugs...

E3 plugs aren't anything special metal wise, a friend used some, didn't last 40 km's.


My advice would be to figure out why its "eating" plugs. Champions work fine for most of us.

My Aurora setup eats copper plugs in 5k, I have to run Iridiums or I spend more time changing plugs than driving, :p



Simons back!!! :hail:

Off to the dyno on the 15th.:thumb:


LOL. What dyno?

[RoadWarrior222]

The last thing you want in your combustion chamber is a piece of metal hanging out in the middle of it. It will turn into a glow plug in short order.
Funny you mention that, you know what model glow plug engines use, to glow when exposed to alcohol vapor, platinum... so I'm kinda leary of what platinum and other catalytic metals like iridium will do with alcohol in the fuel... but the colder the plug the better heat path it should have to the head, and those E3s seem to have a decent heat path... more so than a single ground strap plug.

[mpgmike]

Had to abort the Aqua Pulser test. Sorry, no results.

Mike

[boost geek]

LOL. What dyno?

Miller, they are into BMW big time.

http://www.millerperformancecars.com/about/dyno-rates.html

[turbovanman²]

Funny you mention that, you know what model glow plug engines use, to glow when exposed to alcohol vapor, platinum... so I'm kinda leary of what platinum and other catalytic metals like iridium will do with alcohol in the fuel... but the colder the plug the better heat path it should have to the head, and those E3s seem to have a decent heat path... more so than a single ground strap plug.

Iridium won't glow.