Popping/sputtering anything over 15#

[Roc87]

Parked my GN last April, was running perfect, the week before I parked it ran an 11.63 at 118mph. Got it out this past saturday, drove it enough to burn off the old gas/stabil mix & flushed out the mix of water/alky. Fresh 91 octane & pure meth in the alky tank, now it's sputtering & coughing anytime boost gets over 15#. Plus the wideband pegs at 10:1 when this happens. Seems to be worse if the cut-out is open. I'm thinking it's a coilpack/ign module? Plugs are fresh NGK UR5's gapped a tight .032", wires are newer 10mm Magnecors. Last time I had an issue with coilpack/ignition modules, it was suggested to replace both at the same time, this still true? If not, how do I determine which one is bad? Going to borrow a coilpack/module to see if that cures the problem, but the car this one is coming off of is not running correct either. Is it OK to purchase these at Autozone/parts store or should I just wait for the BobBaily ignition module/LS coil pack set up???
TIA!

 

[Roc87]

Come on guys, need some ideas here. My wallet is $330 lighter from the Coil/Ign.Module from NOS4GN & it didn't improve anything. Doesn't seem to happen as bad with DP closed, & doesn't seem to happen at all when the engine is cold. I'm going to replace plugs next, but would like some thoughts

 

[MY T FAST]

just a guess, but i'm leaning towards vac leak. doesn't happen when cold, chip is still in closed loop. under 15lbs, not enough pressure to break the crappily sealed line in question. over 15lbs, pressure/air escaping, engine still fueling for 21lbs but you're only making 15lbs = pig rich. i'm also guessing that it happens exactly the same with the DP closed its just much harder to hear making it seem less severe.

I had a REAL similar problem last summer. turned out my rjc boost controller was leaking, ditched it, plumbed the turbo 'tuner style' and like magic the problem vanished. aside: i'm not bashing the rjc bc, its a great product and i currently have another installed. the first most likely ended up faulty due to OE lol.

 

[turbo nasty]

Could be your maf

 

[GNVYUS 1]

Ya don't buy anything else other than maybe a Boost Leak detector and start looking for those first.

2nd, did you mean you flushed out your gas tank with Water/Alky or was that towards your Alky Kit?

So new items you replaced this year without running the car were Magnacore wires? If this was their Maiden Voyage I'd swap them with a known good set and see if that helps out.

The Caspers Coilpack Module is a good way test it yourself.

UR5's are fine at .032, I'd swap in the old plugs after the Wires test our fine.

Check for grounds, MAF reading at Idle and WOT and what AF/R is the car right BEFORE it pops? This could be the Alky Farts, which happens often with low timing and a fat AF/R in 1st.

 

[DaySleeper]

Chances are good your alky pump is faulty. As it would be fine until it hit 15 lbs. of boost then it starts detonating maybe?

 

[Roc87]

Thanks! Appreciate the ideas. Had never really thought much about a vac. leak, seems to be pulling the same vacuum as it used to, but like you mentioned, it may only leak with pressure applied to it. MAF is reading fine, around 5 at idle and pegs pretty easily by 15# to 255. I did run at the track last year with the magnecors before parking it & it did fine, I don't remember if these were the same plugs or not that were at the track. I'll pull the boost controller & see if that makes a difference. Before the popping starts the wideband is showing between 10.8:1 & 11.2:1. Seems to happen more with a significant load, or maybe I just notice it more in 2nd & 3rd gear, than 1st. Oh & the alky/water was in the alky tank only, haven't done anything to the gas tank aside from driving enough to burn out the old & put in fresh 91. Hope it's not the alky pump, I have the kit from Razor to test it and it puts out around 170# of pressure, it was rebuilt less than 2 years ago, no knock at all while it is coughing/sputtering.

I also pulled one plug before we headed to dinner and there seems to be a white stripe on the ground strap about halfway between apex & threads (kind of hard to describe, sorry, & I cannot seem to get a good picture of it to post) almost seems like the spark was not arcing to the nearest point of the ground strap. After owning the car for 11 years, I never really understood why some people had such a hard time diagnosing these things Now I have first hand experience:redface:

 

[The Darkside]

My car was cutting out/popping at WOT last week & it turned out to be a dirty the fuel filter....new AC Delco filter & problem is gone...

The Darkside

 

[Roc87]

Fuel filter has maybe 300 miles on it, not delco, but the FP rises roughly 1:1 with boost.

Almost ready to start over with tuning it, back it down to 16psi without alky, start with one nozzle for the alky and get it back up to 24psi (if possible) then adding the 2nd nozzle to get back up to 28psi. It has been discussed many times that a 2nd nozzle isn't needed until mid 10's, but I have talked with Razor about it and we agreed the 2nd was needed for what I was doing at this altitude.

 

[TurboBuRick]

Sounds like ignition related. Check the balancer. Make sure it's tight, tight.

Check the crank sensor too. Make sure it's not loose or scuffing the ring.

 

[Roc87]

Yep, balancer is on good & tight, and the crank sensor doesn't show any wear marks on it. I'm starting to think all 6 of my plugs are shot. All 6 look like this (I know it's not the greatest picture), doesn't look like they are arcing where they should, almost looks like they are sparking further away and that is why they are getting blown out? Wonder what would cause such a thing?Will post what the new plugs do for it tomorrow morning.

 

[GNeric]

I went thru all this for 1 year and 7 months trying to find mine. Traced every single wire. Sealed off engine and pressure tested everything. No leaks. Isolated FMIC and pressurized it. No leaks. Checked crank/cam sensors, all ground wires, found my ignition module had bubbles and dark brown spot in insulation so I replaced that. All the same thing. Checked voltage drops all over the car. Nothing was out of place. Found mine by accident when I reached in to see how hot the negative cable was getting and it was about 3 inches away from exhaust. Bumped the cable and it did it for me in the garage. Installed a 00 cable and problem GONE! It was causing my ECM to get extra hot, the ignition module. I had Steve Yaklin, Bob Bailey, Eric Marshall all trying to help. Offering to burn a different chip, fix the ME-R ECU and finally found it. Back to 25psi after that.

 

[Roc87]

Ah yes! I had forgot you had that issue for a while, may have to go find some 00 ground wire and make a new one, thanks Eric!

 

[GNeric]

I hope that is it. Mine was frustrating me to no end. I really missed driving my car and hated driving it with only 14psi available. Anything above 15 and it did that. I guess it torqued down enough to tweak the negative cable to make it do that. Good luck.

 

[TurboBuRick]

Yep, balancer is on good & tight, and the crank sensor doesn't show any wear marks on it. I'm starting to think all 6 of my plugs are shot. All 6 look like this (I know it's not the greatest picture), doesn't look like they are arcing where they should, almost looks like they are sparking further away and that is why they are getting blown out? Wonder what would cause such a thing?Will post what the new plugs do for it tomorrow morning.

Looks like you may need need a colder plug there Roc. sparkplugreading

 

[Razor]

If you let the car sit with "todays" gasoline that has the ethanol.. the fuel system goes to hell.

Double check your fp rise with boost.

 

[Roc87]

Guess that a water/meth mix can really take a toll on plugs, I never really "got on it" too much with the mix, only had it mixed to store it, and while driving it around I'd press the "test" button, just to burn off that mix, seems as though it fouled out the plugs. So, lesson learned, DO NOT ever actually use water/meth, just use that to store it, Drain it before EVER driving it. I would have never thought that would happen, especially with newer plugs. So, I replaced the plugs with new NGK UR5's, gapped a tight .031 this time, and the car runs Fantastic. I've got to figure out what model number NGK's would be a step colder.

Really appreciate everyones ideas & thoughts!

 

[GNVYUS 1]

http://www.ngksparkplugs.com/images/pdfs/product_list.pdf

 

[Garycar]

I don't know any sure way to check for a bad crank sensor except to replace it. Have had several go bad, none of them were loose or touching the reluctor.