Sale ends todayGet 30% off any course (excluding packages)

Ends in --- --- ---

Detonation Help

General Tuning Discussion

Forum Posts



Tech Articles

Discuss all things tuning in this section. News, products, problems and results. 

= Resolved threads


I was on the dyno last night and blew a spark plug/valve.. We were tuning the fuel map and were up to 6k rpms. I had two experienced tuners working the car. We kept running into an overheating issue, but had several reasons to think it was strictly a coolant issue and pressed with cool down between pulls as needed. While working the 6k portion of the map, the tuner had to cut the car off. I didn't hear anything, but something was wrong. They pulled the plugs and #4 had melted leads and a chunk of ceramic missing (see pics).

If anyone can take a look at the hondata (current cal & datalog) info I posted and see if they notice anything that may help, I would be greatly appreciative. I've already lost at minimum a plug and a supertech valve, so before I crank up again, I'd like to see if anyone else has any input.

Attached Files

What engine you got? What power you aiming for?

I cant get data log to come up but looking at the photo of the plug if your b-series and boosted id say you might want to try a different heat range of plug. I think we was using ngk br9eix I think it was in a 500hp civic

Thanks for the response. My full build is in the build thread, but it's a CRX with a lightly bored b16a1. As for power, I'm not looking for over 400whp, closer to 350. I ran br7's based on what I found online. Would that have an impact on just one cylinder? I'm not sure why the datalog won't play for you, I just re-played it on my end. Did you do the latest firmware update? Thanks again!

I'd say you'd probably still want a better plug you might just be unlucky that one melted? Can't see any other reason for it unless it was extremely lean. I can't see the log so just a suggestion but can't see any other reason a plug would melt like that. Will try and open the log again in a few days

I{'e never seen one melt like that before, that' taken some serious heat. I'd say more heat than det. do a compression and leak down test then test the injector. if it's only one plug that's damaged it's likely mechanical issues

Hey sorry to hear about your issue but one problem is you plug!! I NEVER use those because of issues like these, for some reason they tend to do that. My recommendation is to only use NGK plugs and like JF84 said for 400hp 8 heat range would be a better choice.

How are you measuring the AF because in the log its just 10to1 and then to 19to1 not much in between. The way this map looks , you might wanna look for another tuner. I have a question as to not use one of the basemaps in th s300 and modify to suit instead of trying to start from scratch?

Is it just me, or are there no real boost cells past .5? Am i perhaps reading this wrong? Noticed you had around 14 psi into it around the end of the log. Duty cycle looks good and on track (only around 40% injector duty cycle peak?) Not sure what the hell your afr meter is doing there..... if that is a lambda reading, theres your problem. Maybe im just reading this all wrong? lets work it out

Ok figured out how to show boost maps, not familiar with the software much yet.

This is an edit: I had originally posted that you had a massive drop in the numbers at around 15 psi of boost, but i did learn that that was a secondary map, and that you had that disabled, so, pointless. I guess it would be pertinant to ask, what were the afrs when the engine failed? the numbers suggest that it should transition into boost fairly rich, so i dont see that as being an issue, but again that is hard to tell without an AFR reading. Your afr on the log does not seem correct, not sure what its representing. Im assuming by your wideband settings in the configuration (0v=10 and 5v=20) that you were running an AEM uego? I do see a nice gradual increase in injector duty cycle as boost comes up, but as mentioned above, it could be as simple as an injector failure. is there anywhere you can have them tested? I have not ever had any ID injectors fail on me, but that being said, all it takes is for a bit of sediment to get caught up in the screen, to seriously decrease an injector's flow. It could even be, that even if you were seeing a nice 11.8:1 afr on boost at the wideband, you may have had one injector lagging behind the rest. Even 5% would be a 12.3:1 ratio, putting it in the danger zone.

Was your wideband set up and functioning? It looks to me like its saying full lean (4.9volts) but during the log, i see very little fluctuation so im assuming the wideband was not working.

I guess the last things that stand out, is your lambda target map. All of the values in the boosted areas are 12.5:1. In my opinion, that is way too lean to be comfortable at that boost level. That being said, maybe they werent targeting those, and hadnt set up the target table yet? Answer the questions about fuel ratio at the time, etc. Maybe we can isolate it.

One more thing, it would be interesting to read the other spark plugs and see what they look like.

Attached Files

I've melted a plug like that, it comes done to running too hot a heat range for the load that the engine is seeing, go one to two ranges cooler. The issue that occurs when you have a plug that is getting hot enough to melt the ground strap, then the plug is acting like a glow plug in the combustion chamber, and preigniting the fuel. This leads to a lot of damage to the bearings as a minimum, with the possibility of bore damage, melted valves/pistons (see attached image) and headgasket failure.

Attached Files

+1, Chris250.

You should perform a flow test of your injector set before continuing.

We usually reply within 12hrs (often sooner)

Need Help?

Need help choosing a course?

Experiencing website difficulties?

Or need to contact us for any other reason?