NGK Colder Plugs Installed: LTFT & Boost is wrong..

[ms3brendan]

I got them installed on my car today and drove a good 50+ miles on 'em.. Then I did a datalog with it and it doesn't seem right. It did get a little chillier out tonight, around 41 degrees but my max boost was 12-13psi and my LTFT is at 6.8 when the throttle is at 50% or more.. and if I'm boost at all under light throttle it's about 2.8. I'm running the Stage 1 + SF 93 Octane map. Has anyone else had any issues after installing the colder plugs with the Cobb AP? I know they recommend to do so.. so I'm not sure why this is happening..

I didn't check the gapping though, NGK claims they're correctly gapped for the application you purchase them for.

I'm also getting much better mileage it seems, I filled up shortly after the install and after 55 miles I had JUST hit the full line..

I'll attach my datalog as well.

 

[mr_mazda329]

Yea, never trust them to be properly gapped out of the box. always check them prior to putting them in. Should be @ .30

 

[92 Couper]

I went with the NGK Iridium IX Spark Plug (LTR7IX-11) which I assume is what you have to. These came with like a .044" gap which was way bigger than our cars can handle. I took them done to .030" gap.

From what I read, the Denso's came pregapped correctly but the NGK's had to be regapped.

 

[ms3brendan]

Ah. Gotcha. Yeah and with the AP I need mine to be gapped in between .026 and .028, that could very well be the problem.

 

[MSMS3]

I went with the NGK Iridium IX Spark Plug (LTR7IX-11) which I assume is what you have to. These came with like a .044" gap which was way bigger than our cars can handle. I took them done to .030" gap.

From what I read, the Denso's came pregapped correctly but the NGK's had to be regapped.

+1. I prefer NGK's, but only due to long time favorable experience with them over several different platforms. But yes, the LTR7-IX-11's were intended for a different stock application as originally manufactured and they come gapped to a huge .044 inches. They need to be regapped to .030, or even a bit tighter if OP is running a higher boost map. I'm on stock ECU but with catless dp/rp with a bout two pounds more boost and am gapped at .030. OP might want to try .028.

Be very careful in regapping iridium tipped plugs as the iridium is very fragile and easily damaged. Use a good gapping tool with a wire gauge rather than the flat "feeler gauge" type, you don't want to wipe the iridium off of the tip. You can very slowly close the gap by just lightly tapping the ground electrode part of the plug against a wooden block, checking progress and tapping again until you get there.

 

[ms3brendan]

+1. I prefer NGK's, but only due to long time favorable experience with them over several different platforms. But yes, the LTR7-IX-11's were intended for a different stock application as originally manufactured and they come gapped to a huge .044 inches. They need to be regapped to .030, or even a bit tighter if OP is running a higher boost map. I'm on stock ECU but with catless dp/rp with a bout two pounds more boost and am gapped at .030. OP might want to try .028.

Be very careful in regapping iridium tipped plugs as the iridium is very fragile and easily damaged. Use a good gapping tool with a wire gauge rather than the flat "feeler gauge" type, you don't want to wipe the iridium off of the tip. You can very slowly close the gap by just lightly tapping the ground electrode part of the plug against a wooden block, checking progress and tapping again until you get there.

Yeah. That would explain the sputter at WOT last night during my logs.. Today I'll definitely be doing that. I'm gonna stop by an Autozone to get a gapping tool. So I don't want the coin type, correct? Since those are more of a feeler type?

 

[MSMS3]

Right. You want the one with the round wire gauges, and the different sized slots that will fit the ground strap to move it back out if you tap it in too close with the wood block.

Something like this attachment. They are cheap. You can spend more, but no need. Make sure you get one that covers a range between about .025 to .035 with .030 being one of them. Just go slow and don't rub against the center tip, just check to see that you are just barely able to touch it with the wire and STOP. If .035 fits loose, you are still to big. If .025 does not want to clear the center electode, you are too tight and need to open it up just a little, etc.

 

[ms3brendan]

Right. You want the one with the round wire gauges, and the different sized slots that will fit the ground strap to move it back out if you tap it in too close with the wood block.

Something like this attachment. They are cheap. You can spend more, but no need. Make sure you get one that covers a range between about .025 to .035 with .030 being one of them. Just go slow and don't rub against the center tip, just check to see that you are just barely able to touch it with the wire and STOP. If .035 fits loose, you are still to big. If .025 does not want to clear the center electode, you are too tight and need to open it up just a little, etc.

Well. I found one at a local advanced auto parts with the round wire gauge but the lowest that gauge went was .040 so I had to get the coin. I took out my plugs and I used the coin and it was measured at .030. So they did come pre-gapped to stock. I started to tap on the the ground electrode a little but it didn't move and I was afraid of breaking something.. so since it wasn't at .040 I reinstalled it and unplugged the battery. I'm hoping resetting the ECU does something.. If not, I'll have to regap them to .028.

 

[ms3brendan]

I took it out for a drive and I'm getting some pretty violent sputtering if I give it anything more than light throttle and/or it hits 9..10PSI.. I checked the hoses and everything seems like they're on tight. I'm wondering if I may have damaged one of the plugs measuring it? *shrug* would that cause a violent sputter/bucking?

 

[hugador]

I took it out for a drive and I'm getting some pretty violent sputtering if I give it anything more than light throttle and/or it hits 9..10PSI.. I checked the hoses and everything seems like they're on tight. I'm wondering if I may have damaged one of the plugs measuring it? *shrug* would that cause a violent sputter/bucking?

Then you'll have to regap them to .028 . What plugs did you had running before the NGK upgrade?

 

[ms3brendan]

Then you'll have to regap them to .028 . What plugs did you had running before the NGK upgrade?

But the strange thing is that the day prior when I had these on the car was driving fine minus the lack of target boost, which makes me wonder if they were damaged yesterday checking gapping. I don't think so though.. Today I'm going to pickup a set of stock spark plugs and a proper gapping tool. I don't know if I want try regapping the NGKs to .028 or the new stock set first..

I was running the original plugs that came with the car prior to the NGKs.

 

[ms3brendan]

My local Autozone only has some Bosch platinums which I don't imagine are a good idea and a set of Autolite XP Iridiums...

http://www.autozone.com/autozone/ca...yDisplayName=RoutineMaintenance&parentId=42-0

which I think would be my best option there? And if they fix the issue, that means I most likely would have messed up one of my NGKs when measuring gap yesterday and I could probably order 2 more from SU since I had only touched 2 of 'em and just replace those? *shrug*

This sucks because I have a short road trip next weekend and the car the way it is, is hardly drivable.. If all else fails I guess I can take it to a local shop to see what they say the middle of next week.. I wish at least it were throwing a CEL or something..so I can read in a code..

 

[MSMS3]

Something is not right. Check the part number on those NGK's. For one step colder it should be NGK Iridium IX LTR7IX-11. And they definitely, absolutely and beyond doubt come from the factory gapped at .044, unless a vendor regapped them before selling them to you. If so, vendor may have damaged them when regapping.

If you used the coin type to gap them you may have swiped the iridium off of the surface of the tip. I hope not.

Try regapping them with the proper tool before buying any more plugs.

 

[ms3brendan]

Something is not right. Check the part number on those NGK's. For one step colder it should be NGK Iridium IX LTR7IX-11. And they definitely, absolutely and beyond doubt come from the factory gapped at .044, unless a vendor regapped them before selling them to you. If so, vendor may have damaged them when regapping.

If you used the coin type to gap them you may have swiped the iridium off of the surface of the tip. I hope not.

Try regapping them with the proper tool before buying any more plugs.

I bought them from Protege Garage. And yes, that is the model number for it.

I hope I didn't either.. but I can only assume one of 'em could have been damaged seeing as if anything, the car ran prior to me taking 2 of 'em out and measuring them. I think the part number for the NGKs are 6510? I think I found it at my local NAPA if I need to get some replaced right now..

http://www.napaonline.com/Search/Detail.aspx?R=NGK6510_0006500967

Is there any way to tell if the iridium is off of them or not?

 

[ms3brendan]

Maybe I had bad plugs or something.. but I got those Autolites from my local Autozone, gapped them to above .025 and less than .030 and the car seems to be running fine. I let it warm up for a bit and then drove it around, then took it on the highway to do a few WOT pulls and it seems to be alright. The LTFT is at 3.9 though and 2.9 at idle, but it may just need to adjust.

Now the debate is whether I keep these in there or do I attempt replacing the NGKs with another set.. or get the Densos.. I'll have to get more driving in and get some datalogs sometime this weekend to see how things are.

 

[ms3brendan]

The weather got hot and I was getting KR up to 2 at WOT.. I figured I should probably go back to getting some one-step colder plugs so I went with the Densos this time & checked the gap & re-gapped them to .026~.028 and at first the LTFTs were really high even after 50 miles but after 130 miles.. they seem to have settled to +/- 3% and can now go WOT on hot days without any KR

 

[spdjnke]

did anyone ever figure out what was the issue yet?

 

[ms3brendan]

did anyone ever figure out what was the issue yet?

I can only assume the NGKs were bad or I messed them up because the gap was too large.. and then I got the Autolites which aren't too great of plugs to begin with so it was fine when the weather was cool out but once it got hot out I started getting some KR.. and so I got the Denso ITV22s in and they were gapped properly and now everything is running fine.

 

[spdjnke]

good to hear. glad you were able to figure it out.