D15, D16, D17 and Mini-Me swaps
By 94hatch
#339021 Would appreciate your ideas, questions to help me solve this fueling issue. I've got a D15B8 (CX motor) that recently began pinging consistently. 170K miles, compression ok on all cylinders, all (new) plugs show white tips, replaced fuel filter, idles fine but any partial throttle/load and pinging starts. Replaced MAP sensor after testing. No CEL or codes. Have used two gas tanks with Techron (and pinging less when Techron is in gas) but pinging returns with just gas (using Chevron premium 91 octane). Set timing at the spec 12 BTDC at idle, still pinging so I've retarded it a few degrees but I can still hear slight pinging. Don't hear or see any obvious vacuum leaks. No surging, just pinging. Accelerates ok. Am I overlooking something basic?
By 94hatch
#339027 Yeah, I'm using the correct pulley mark. In this case the B8 motor is spec'd at 12 degrees +- 2 degrees. The challenge is that the Honda service manual doesn't really offer troubleshooting flow charts, etc. apart from the CEL codes (except to check loose sensor wiring). I considered at first that it might be rod knock or piston slap but the white spark plugs confirm the lean fuel mixture. There is the EACV (which is essentially an idle air control) and I thought that it might be stuck open allowing more air into the intake manifold but this seems to cause idle surging which I don't have. I think my next test will be the fuel pressure. Maybe a restriction somewhere upstream or a weak fuel pump may be causing less fuel to flow through the injectors. Anyone ever experience this?
By 94hatch
#339029 one more point that I forgot to mention... the pinging happens even at cold start (when I believe the ECU is in open loop EFI). I mention this because I have not seen a reason to change the O2 sensor (no CEL). I did forcibly disconnect the O2 sensor just to prove my CEL light was working.
By 94hatch
#339216 Tested the fuel pressure at the service port above the fuel filter. The results: 45 psi without vacuum attachment on the fuel pressure regulator, 35 with the vac attached. The only odd thing I noticed was at larger than idle throttle openings the fuel pressure momentarily rose but then dropped back to 35 psi. I've since blocked off the intake manifold vacuum line to the FPR and driving shows a slight improvement but the pinging is still there. How unusual would it be to have all four fuel injectors go bad at once? (with even one of the four replaced at it also exhibiting the same lean spark plug pattern). At this point I more suspicious of my timing belt having jumped a cog on the cam gear... but, I don't how rare or unusual is this?
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By teal_dx
#339217 I highly doubt all 4 injectors are bad. For a piece of mind, I'd pull the timing cover back off and double check the mechanical timing to be sure the cam gear and crank are both at TDC. I don't think there's enough adjustment in the distributor holes to compensate timing being off a whole tooth, but I could be wrong.

I don't know what the fuel pressure should be but 35 sounds correct. You already changed the filter and if the diaphram in the regulator was damaged, I think you would have smelled fuel. :?

This is a tough one :???:
By 94hatch
#339220 Thanks Teal. I did pull the timing belt cover (top part) when I recently verified the valve clearances. TDC looked reasonably right but I really didn't verify looking for some reference mark not he head relative to the timing belt wheel. I'll check the manual to look for the reference mark and check this. I agree that there isn't enough adjustment in the distributor to compensate for this problem I have. I at about 6 degrees BTDC at this point but pinging persists (and I can feel the loss of power on acceleration). I keep going back to the possibility of a out-of-spec sensor (coolant temp, air intake temp, throttle position, etc.) but again see no CEL light or codes to indicate this. I'm not sure but I think that the pinging happens at high manifold vacuum and slight off idle transition. I think I'll borrow a technique used years ago by carb-jet tuners and test the injector flows by holding the throttle open above idle and then killing the ignition and then looking for the color on the plugs. This should at least tell me if the problem is a sensor input issue at idle/high vacuum. Seem like a reasonable test or any reason why this test wouldn't work in a fuel injected motor?

The other possibility would be somehow the ECU timing table or drive circuitry is bad? But, again, no CEL or codes would point to this...
By 94hatch
#339231 Yup. Using my paper clip.
I did the open throttle-kill-the-ignition test. The spark plugs showed richer burning (actual dark carbon near base as well as some of the earlier white deposits gone). So, at some point the ECU is able to drive the injectors to deliver more fuel... Has there been others reporting faulty sensors that did not trip the CEL?
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By teal_dx
#339240 One time, my car running very rough, fouling up an o2 sensor repeatedly but no cel unless i unplugged it. Turns out the o2 was the problem, causing the motor to run rich- no more troubles after replacing it. I think there's a point where it is starting to fail, but not bad enough to trip the cel. Not sure if other sensors can behave that way or not though.
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By suspendedHatch
#339288 It's uncommon for all four injectors to go bad but very common for all four to be dirty. Send your injectors to injector-rehab (they're the best and cheapest of all the places I've tried). The injectors could be restricted or have a bad spray pattern (pissing out fuel instead of misting it). In fact, I guarantee this is true of all injectors over 100k although the ECU is pretty good at compensating until it becomes an extreme case like yours.

I automatically send mine out every time I change cars or engines because it makes the car run and idle noticeably smoother. You pick up about 3 mpg. Most of the time I'll go to the junkyard and get 6-8 and have them all cleaned, then use the four most closely matched based on the flow specs they send you. Using junkyard injectors means no down time.

Check this out, I had before/after videos done when they did mine: http://www.civic-eg.com/causeforalarm/i ... /index.php
By 94hatch
#339327 Suspend, thanks for the suggestion. I may end up sending out the injectors for cleaning. I did run the two bottles of Techron through the system. With this and the other stuff changed (fuel filter, plugs, map sensor) the motor feels like its breathing very well, no stumbles anywhere across rpms, just the consistent pinging. Not sure if I mentioned in the first post that I had changed one fuel injector (I had thought early the problem was with one cylinder) but even this injector shows its spark plug also lean burning. Yesterday I pulled the O2 sensor (forcing the CEL) to see if the system would fall back into a limp mode or richer fueling, but no go, still pinging. I pulled the throttle position sensor thinking it might also force a limp mode/rich fueling, again, no diff. So, my plan at this point is to (1) confirm the timing belt hasn't slipped a tooth and (2) to check the crankshaft position sensor. I kinda doubt the timing belt slip I would think I could compensate for this via the distributor rotation setting (if the the timing wheel is something like a 36-1 wheel that would give 10 degrees per tooth and I can set the timing from 0 TDC and retard to 12 BTDC and even a little more). Maybe its the crankshaft position sensor, so I'm digging up info on how to test this. Any other ideas welcome.
By 94hatch
#339428 Suspend, you win/rock/da bomb/da man! I had taken out my injectors about a month ago and cleaned the injector filters (which really didn't have any visible crud in them) but didn't have the time to send them out to be cleaned. This time I thought I would give them a quick flush myself. I used some tubing, carb cleaner, tire pump, and a spare motorcycle battery to intermittently pulse the injectors. Had my doubts because nothing dark and ugly spewed out of the injectors. Put things back together and, quick run around the block, and 90% of the pinging is gone. Let's hear it for carb cleaner (tough stuff), woot! I'll keep my eye out for a spare set of injectors and have them sent out to injector rehab. Just for the search engines and anyone having the same symptoms, I first noticed the pinging at light load, light throttle, off idle.