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Havoch

Proven Member
48
5
Apr 15, 2019
Mission, BC_Canada
Hey ya'll, I may have an issue with engine management rather than anything else but could use some help narrowing it down.

Running a 6 bolt block with black top CAS in 1998 spyder. Tuning with ECUFlash and EvoScan. Currently the turbo is upgraded to a big 16g (or is it an Evo3) cant remember haha. Front mount FMIC, 3" exhaust with no CAT. AEM FUel pump with Aeromotive AFPR. Just added FIC 650cc. Running with stock boost and no boost controller, puts me right at 10 PSI. I think that is all the relavent info.

So without fail the engine missfires after 5000-5200 RPM.
I have done the usual

- boost leak check and repair, (still a small leak at TB shaft seals)

- coil pack was suspect so i swapped that.

- Plugs and wires, check! (NGK wires, NGK BPR6EK)

- Connections and vacuum lines, all good there.

- Power transistor, swapped with good one, no results so swapped back

- swapped in the 650 injectors and retuned, same F'n problem

- tried raising timing, lowering timing, leaning out as well as enrichening fuel, no noticeable effect.

Going to do a compression test but don't expect anything out of the ordinary there.

-AFR's are aprox. 10.2 right before the misfire, injector duty cycle is around 50%

and yes.... I have done a search and read old threads. Lots of ideas but not many results.

Thanks.

This is not fuel cut.
 
I've been having a similar problem. I'm still fixing a small boost leak or two but I will be watching this thread closely if my issue isn't resolved after fixing the leaks. I did change my throttle body with remanufactured one and swapped to BPR6ES with a gap of .28 and it helped.
 
You shouldn't have that at 10 PSI. Not familiar with the ECUFlash/Evoscan. But if they have the ability to adjust dwell, or set it up for different coils, make sure the correct coil is selected. Does it happen at 5200 RPM even if you aren't at 10 PSI boost? Is the AFR calculated? Or is it measured with a wideband?
 
NGK spark plugs are great, NGK wires are junk! borrow a set of oem ones is you can and just try them to rule those out, I have seen this same thing happen first hand with brand new NGK wires, a swap fixed the problem.
 
True about the ngk wires I was having the same problem getting a miss fire at that rpm range turns out the spark plug wire wasn't going into the coil far enough on cylinder #3 it drove fine until I got into boost for some reason the connector on that wire to the coil was a little shorter than the rest and I could not pull it out /push the boot back any more so I was trying to push it in more and the very top of my coil broke now it goes in all the way LOL no more miss fires check to see if your spark plug wires are all pushed into the coils the same amount you can tell if the boots are all even also check that the connectors all look the same inside the boots all should be round and not out of shape so they are making good contact hope this helps
 
You don't have a limiter set in that tuning set up or a 2 step at that point, if that is possible with ECUFlash, do you?
I have to agree with the plug wire deal, same thing here. Even a cheap set of Red Ebay wires worked when my NGK's started giving me troubles too.
 
I'd check plug gap, for reference I have mine at .025 at around 17-18psi, 10.5-10.8 afr.
get a set of magnecor or Taylor wires, hell even my cheap Napa wires are still running strong.
 
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Never had any issues with NGK wires... if you suspect a problem, spray them with water while the engine is running. ANY arcing or spark jumping is a sign they are bad. If they run wet without spark jump, they are doing their job.

When you said it misfires 5000-5200 rpm - Does it always start missing at the same RPM? Does it continue to misfire through the listed RPM range? Is this a single cylinder miss or multiple holes (read the plugs?)? What cam/crank sensors are used on your setup?
 
Sheeeeeeeitt! gonna take me a minute here. All good ideas, let me think.......
Essentially, this happens on WOT or near to it at same RPM each time, I have only let it misfire briefly and then let off.

It's like this..... VVVVROOOOOOOOOOOOOOOOOOOOOMMMMMMMMMM..pop-pop-pop-pop PSSSSSSSSSSSSH!!!
If not under boost it will go through the RPM range smoothly.

Sadly, I tried three sets of plugs (including the originals) and two more sets of wires that were good but not new.

Desired AFR is set by me and ECU calculates needed fuel to acheive my settings. AFR is monitored by gauge/wideband.

I am thinking of upping the AFR's in that region, i did actually try it already but just made a minor alteration, perhaps a more drastic change is in order.... 10.2->12.4?

hmmmm... hold on a second...
 
Perfect! I have a pic of my AFR map from when i was setting up the injectors..
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Carrying on with my thoughts...... I was thinking about the 2 step settings and set my RPM limits to 7500 just to be sure that it wasn't activating for some reason. I wonder if there is a factory setting that i need to turn off somewhere in the ECU. Not sure also if I need any other ROMs or not. MAYBE it;s a MAF scaling/reading issue. I am monitoring Load and 1Byte Load which are very similar, as i enter into the realm of the 5000's the load is increased and rises past ten psi up into the 15 psi range. EvoScan shows load differently so I would have to convert to Psi but I am tired so f*** it. As I pass approximately 5200RPM load begins to read 160 and stay there as that is as high as it will read, however; by reading 1Byte load i can see that load continues into170->180->190. etc... So I need to figure out which information the ECU is utilizing and blah, blah, blah...
 
You are at least following a path and maybe need to do some temporary altering of the load scale to blend with the 160,170,180 etc....but I am not an expert on Evoscan. Just trying to think outside of the box!
 
I tune my car with the same software setup. Your AFR is way too rich and you need to pull fuel. Also gap your plugs to around 0.25. You also need to check the fuel cut limiter and see if your using the 318% or the 632% load. Either or you shouldnt be hitting it at 10 psi.
 
Do you log knock and are you getting high knock readings going into boost? Knock or phantom knock will cause these same problems. Especially with a 1g cas into a 2g ecu. Just a thought.... In ecmlink you can ignore knock below your set rpm to deal with this issue. I don't know how it is dealt with using ecuflash and Evo scan. I thought there was a sensitivity adjustment you could modify.
 
Do you log knock and are you getting high knock readings going into boost? Knock or phantom knock will cause these same problems. Especially with a 1g cas into a 2g ecu. Just a thought.... In ecmlink you can ignore knock below your set rpm to deal with this issue. I don't know how it is dealt with using ecuflash and Evo scan. I thought there was a sensitivity adjustment you could modify.
Same thing, you can ignore knock based on load or rpm. You can also change the knock sensitivity as well. 1g cas should be fine, the problem is when you run the evo 8 ecu with a 1g/2g knock sensor.
 
Your the exception then, definitely not the norm.
I’ve ran multiple sets in different cars with no issues. I also use ngk non projected plugs gapped to .018” in high boost applications. This setup works fine up to 40psi with copper plugs in every car I’ve put it in.

If you nick the wires, if they rub, or if the boots are damaged you’ll have issues with any wire set.
 
NGK wires are completely fine. Accel wires are my go to though. Before i went accel i was running NGK, i switched due to accel having less resistance and they seem to help my car run a little smoother. Spark plug type and the gap plays a bigger role. Once you get away from the common (BPR?es. BR?es) style plug you'll be able to tell the difference. A plug with no resistor (B?es) or a reach plug like BR8cs or Br9cs.
 
Just a couple weeks ago I saw a post by motomatt about the ngk wires. I walked out the door and put in the some old Taylor (?) wires and the car ran noticeably smoother. NGKs only had 3k on them. It was exactly as described in his post. Not saying they're all bad but I won't be running them again.
 
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