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Discussion Starter · #921 ·
Now that I got in, spent a little while trying to diagnose the backfiring.

Didn't get too far, other than I was confidently able to reproduce the issue in the driveway. The backfires weren't anywhere near as bad as the drive back from the restaurant, which makes me believe the exhaust simply wasnt hot enough on the unloaded warm up in the driveway, to get fuel/air to violently ignite.

I did notice an interesting characteristic, it idles great, and revs fine till about 3500-4000rpm. Holding it at that speed under no load, the engine is misfiring very steady and consistently, not harsh or anything, but definitely noticible with popping back in the exhaust.

Letting it come back to idle, its fine and will idle all day.

I'm going to try swapping the dist from the green car over, and see what happens. I have a low level feeling though, that this may be a hard mechanical issue, like I broke a valve spring or something. I've diagnosed engines before with very similar symptoms, and a broken spring was the culprit.

But I'll start easy with the dist swap, then pull the valve cover for inspection if it doesn't outright solve it.

One detail I left out, was before the rip to the restaurant I upped RPM by 1k, from 7500 to 8500. Let that little detail soak in :)

After knowing that, what do you guys think will be the end issue? The dist or a spring?
 

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Discussion Starter · #923 ·
Back to VIR weekend at Hyperfest.

I realized I provided some screenshots, a few pictures, and some details, but two things:
  1. I am a terrible picture/video taker at high attention taking events like this lol
  2. I never really described my full experience.

So as mentioned previously a few posts back, I had to pit early on my second run due to overheating fears. It was hard to know which sensor to trust, the one saying 216°F? Or the one pegged to H lol.

This caused my overall confidence to drop on all successive runs, since I didn't have any other way of confirming which was lying or telling the truth. I tried to use an infrared gun to confirm which, but it is also hard to trust an infrared gun in a seriously hot engine bay. The gun generally agreed with what the ECU temp sensor was saying, so I opted to believe that the rest of the weekend.

This being said, I did see ECTs reported as high as 228-230°F, which is toasty and usually considered "overheating", but I don't really have a frame of reference to compare. I opted to push hard out of pits until I saw these temps, then a cool down lap, then back to pushing hard, then cool down. I'm using a 1.4bar rad cap, so these temps didn't allowed boiling over, and the coolant reservoir confirmed this, it never went high or anything.

Another gotcha was the oil catch can. My instructor was dying with all the vapor entering the car lol, since the firewall had holes and cowl HVAC port was open allowing all of it to enter the cabin. This was an area my instructor pinged me on. He introduced me to his buddies in a honda specific class, and all of them had nice carbon fiber panels with silicone around each firewall hole riveted to the firewall from the inside of the car to keep engine bay stuff inside on the correct side of the firewall :) This will be another mod to tackle.

Also high speed sketchiness. This was a big one that made me constantly keep my foot out of the go pedal. The speed shown in the videos I managed to record with the Tunerview overlay were actually 10 mph slower than real/GPS confirmed, and watch the TPS position, hardly never at 100%. Double edged sword, acceleration out of corners needed a light foot to prevent loss of traction, and it would get to speed really REALLY quickly if I matted it down a straight. Also, trying to keep ECTs manageable meant I couldn't really let it rip to its full potential. It was an unfortunate balance act just trying to keep the car out on the track without having any one thing bring it down, meaning I had to keep much of its potential leashed.

Once tires were hot, and speeds went over 120, the rear of the car was really sketchy, especially during high speed straights into braking zones or esses.

Again, experienced Honda track guys to the rescue. They thought I was running too big of a rear sway bar with no wing, and try dropping a link to see how that helped things. Dropping that link did help a lot, but it was still sketchy. Following back up with them after another session, they just felt the rear is just too light at speed with the front having all the leverage when turning in being able to pull the rear out of line too easily, and the rear bumper cover not helping by acting like a parachute to pull the rear around at speed.

They said the next best things to do would be to 1) add a rear wing to push the car down during high speed, 2) add rear spherical toe and camber links so that alignment can't change with high side loading, 3) vent the rear bumper then 4) reattach the sway bar. They said to definitely go rear wing if I planned on keeping the car turbo, since power is on tap and the downforce can be cranked up to make the car heavier at speed, also suggesting getting a real front splitter, one that mounts to the front tow hook mounting points and is strong enough to stand on.

They also suggested later to try adding a flat bottom undertray with rear diffuser, saying this will definitely help stability in the rear, but ONLY if I have a good rear wing. To do this on such a light car without a rear wing would be dangerous, since a rear diffuser at speed can act like a rudder in the wind keeping the car straight, but while turning the rear will want to "follow the air" as the diffuser cuts through it, causing stability issues while making small steering adjustments at speed.

They said if I'm serious about keeping the car fun and safe at speed, these things need to be done on such a rear light car on a high speed track like VIR. It makes sense I mean, most race duty cars out there, the Porsche's, BMWs, GTRs, etc, are all damn close to 3000 lbs and are much closer to 50/50 weight distribution which all help to keep stability at life above 130mph, combined with wings and aero.

I think I might do the wing, and some spherical mods to the rear suspension for next track days, to see how much that helps at VIR.

Also, another instructor pet peave, was the fact that I only had the stock passenger seat and seat belt. He said most instructors wouldn't have allowed that, and the appropriate thing to do is provide equal safety and seating equipment between both driver and passenger. I didn't realize this was an issue, no where in the CCR did anything like that mention stuff, but he said it was courtesy to the passenger, like "do you really value my life that much less than yours?", when he said it like that I could see how it would be considered a dick move lol.

So, to cap this summary off, I have the following things I'd like to do to this car over the course of the winter:
  1. Improve radiator airflow, possibly go larger.
  2. Patch the firewall holes
  3. Route the catch can vents out to under the car, maybe even design a draft tube to feed the vapors into the exhaust
  4. Add aftermarket Coolant Temp gauge, and Oil Temp gauges for both Engine and Transmission
  5. Add a rear wing
  6. Add rear spherical links for camber and toe
  7. Give my passenger more safety stuff (harness, seat and seat bracket)

Hopefully doing these things, my next experiences at VIR will be more enjoyable at higher speeds!

Here's the final session on the final day solo out at Hyperfest, you can see how conservative I was minding coolant temp, and trying to better experience and feel out where and when the rear wanted to step out, and at what speeds that happened at. Again, knowing these speeds are 10mph lower than what they actually are, sketchiness begins around 110mph into high speed esses and Turn 18 on the front straight.

First lap out for HPDE is double yellow flags (a warm up lap, no passing) until the green flag.

 

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Now that I got in, spent a little while trying to diagnose the backfiring.

Didn't get too far, other than I was confidently able to reproduce the issue in the driveway. The backfires weren't anywhere near as bad as the drive back from the restaurant, which makes me believe the exhaust simply wasnt hot enough on the unloaded warm up in the driveway, to get fuel/air to violently ignite.

I did notice an interesting characteristic, it idles great, and revs fine till about 3500-4000rpm. Holding it at that speed under no load, the engine is misfiring very steady and consistently, not harsh or anything, but definitely noticible with popping back in the exhaust.

Letting it come back to idle, its fine and will idle all day.

I'm going to try swapping the dist from the green car over, and see what happens. I have a low level feeling though, that this may be a hard mechanical issue, like I broke a valve spring or something. I've diagnosed engines before with very similar symptoms, and a broken spring was the culprit.

But I'll start easy with the dist swap, then pull the valve cover for inspection if it doesn't outright solve it.

One detail I left out, was before the rip to the restaurant I upped RPM by 1k, from 7500 to 8500. Let that little detail soak in :)

After knowing that, what do you guys think will be the end issue? The dist or a spring?
If the rhthym of the missfire is consistent, it sounds like it could be something cylinder specific. I can't say i've heard of a spring snap though, the valves are more likely to float than have a spring go. Perhaps it was floating and just lightly kissed a piston? Are you still on OEM valve springs? Comp test? Leads good? Check nothing funny is going on with your points?
 

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Formerly weebeastie
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Hmm....could be a valve spring. I'd still swap distributors first, but my second look would be to check compression on all cylinders, then pop the valve cover to check for a broken one. Which springs are you running?
 
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Discussion Starter · #927 ·
If the rhthym of the missfire is consistent, it sounds like it could be something cylinder specific. I can't say i've heard of a spring snap though, the valves are more likely to float than have a spring go. Perhaps it was floating and just lightly kissed a piston? Are you still on OEM valve springs? Comp test? Leads good? Check nothing funny is going on with your points?
BC 1070 springs, BC retainers. Comp was relatively even across all cylinders. To kiss a piston, that valve spring would have to have bottomed out AND pistons would have had to grow like 1/2" taller. With everything in time, I have like 1/2" clearance from valve to piston :) my static comp ratio with the piston dish is pretty low, maybe 8.5:1, but there is lots of piston to valve clearance while in time.
 

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Discussion Starter · #930 ·
So I bought this on Xenocron today, they upped their discount level to 20% off:


Figured this was a good spend, since even though coil packs will be different between the two engines, the system will work for both the B and D series, and go away from the reliance on the factory igniter modules, and get the benefits of COP.

Will be heading outside in about an hour to begin diagnosing the issue on the race car civic, see what I can find!
 

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Just bought/installed the same COP board. I didn’t buy the whole kit since I’ll be trying to integrate the coil harness into the engine harness I’m making. I wish I would have waited and gotten it for 20% off!
 

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So I bought this on Xenocron today, they upped their discount level to 20% off:


Figured this was a good spend, since even though coil packs will be different between the two engines, the system will work for both the B and D series, and go away from the reliance on the factory igniter modules, and get the benefits of COP.

Will be heading outside in about an hour to begin diagnosing the issue on the race car civic, see what I can find!
does the cop circuit board go in the engine bay?


did you find any resolve outside?
 

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Discussion Starter · #934 ·
did you find any resolve outside?
Tstat install on green car took more out of me than I planned (i posted on that thread, see why :) so I didnt get a chance to get the scope on it and take before measurements, then swapping the green car dist over to it and re-testing.

I am looking forward to the COP kit, board goes inside the ECU, and external harness routes out to the COPs

B Series supposedly takes K series packs, and D will take the D17 packs. I guess they share the same connector style? Leave it to Honda and Denso to not re-engineer what isnt broken haha.

I'll have more time tomorrow to get on it and test.
 

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Have you gotten coil packs yet? I got Densos from RockAuto for $30/ea. Interested to see how it goes for you as I’m going COP as well. Have you figured out how to mount them yet?
 

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Discussion Starter · #936 ·
Have you gotten coil packs yet? I got Densos from RockAuto for $30/ea. Interested to see how it goes for you as I’m going COP as well. Have you figured out how to mount them yet?
No coil packs yet. I'll definitely see Rockauto and elsewhere for the best deal on some Denso's, not going with anything else lol.

Haven't figured out how to mount them, but from a previous discussion I think we all had on your build thread a while ago, Slo said the D17 valve cover works? Still haven't verified if this is true or he was just pulling my leg lmao, but if this is actually a thing then I'll just go grab one of those VCs, and modify it for new breather ports and remedy any other issues that might come up with using it.

If not, I'll fab up something :)
 

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BATSLOMAN GIVES NO FUCKS.
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Discussion Starter · #938 ·
Finally got a scope on this car tonight. Youtube videos coming as soon as they upload (fuckin takes forever for some reason...)

I'll still swap over the distributor from the green car just to satisfy the process of elimination and using all resources I have available, but I'm telling you guys, I'm 99% sure this issue is not related to the distributor or any of my ignition components. Almost positive I hurt the top end somehow when I upped the redline by 1k.

Outputs from the current distributor look rock solid, all three AC signal generators are clean as could be during the problem (breaking up/backfiring at not loaded around 3-4k rpm). Same this when inspecting the primary driven side of the coil from the ICM, coil was being driven cleanly by the ICM during all the unloaded rough running/misfiring events, no drop outs at all, and coil saturation and burn time/event looks unbelievably drama free, suggesting the distributor signals are making their way to the ECU, are being cleanly interpreted, and the coil and ICM are doing their job.

The fact that I have all these rock solid looking events, suggests that my "loaded/violent_non loaded/light" mis/backfires are being caused by some mechanical problem.

It just runs too damn good up till about 3k, until it reaches about 3500-4000 and "something" occurs that allows backfiring to take place. Then of course it returns to idle and idles like a damn champ.

Almost positive this will end up being mechanical, but like I said, I will still swap distributors to see what happens. Videos of scope night coming soon.
 
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