one cylinder no compression AND no leak down
#21
Those leakages should be good. I looked online and saw that 8-12% is typical leakage.
Accords w/ obd2 compensate for a lean cylinder by adding long term fuel trim (LTFT). This may produce a rich condition on the remaining cylinders. If excessive, this sets a lean code. It will also produce misfire codes.
Do you have access to a scanner that can capture LTFT and STFT? This may identify which cylinder is lean.
On the other hand, if you don't have access to a good scanner, you might consider pulling and cleaning FI3. See youtube for diy procedures for cleaning injectors.
good luck
Accords w/ obd2 compensate for a lean cylinder by adding long term fuel trim (LTFT). This may produce a rich condition on the remaining cylinders. If excessive, this sets a lean code. It will also produce misfire codes.
Do you have access to a scanner that can capture LTFT and STFT? This may identify which cylinder is lean.
On the other hand, if you don't have access to a good scanner, you might consider pulling and cleaning FI3. See youtube for diy procedures for cleaning injectors.
good luck
Last edited by TexasHonda; 11-03-2013 at 04:32 PM.
#22
Keeping in mind I haven't followed this entire thread and don't know what you've tried so far, I'd be more inclined to think you were getting no spark as opposed to no fuel.
#23
Maybe I'm confused so I'll try to recap:
- #3 had no compression and 100% leakdown loss with the cam follower assembly attached
- the cam follower assembly was removed
- the tests repeated, and #3 comes back from the dead, both compression and leakdown are normal
#24
Sorry Roader, some (most) of my intitial diagnosis was actually MIS-diagnosis. I think we can ignore the whole zero compression thing and chalk it up to not knowing what I was doing. With your all's help though I think we've narrowed it down to no fuel in #3. For shipo, way, way earlier I'd replaced all plugs, plug wires, cap and rotor with no positive results. I don't blame you for not reading this whole thread, and it would've messed you up anyway (thanks to me!). Thanks y'all for all your help, and TH I think my friend has a true, high quality reader I can borrow for those readings. I'll keep y'all posted. Thanks again, everyone!!
#25
Most recent work, Sunday the 10th (of November). Cleared DTC's with decent scan tool. Started engine and still running rough. After a few minutes of warm up, in Park she surges from about 1000 ("idle" seems high) to 2500-ish, up-n-down, up-n-down. In gear, she'll run, but rough, and "idle" about 800. Once Engine light comes on, I stop engine, read codes, and she has the "manufacturer specific" P1399 code in the Pending area of the DTC codes and P0303 Cylinder 3 misfire code in the Codes list. Just that one code. Earlier in this string I was guessing cylinder 3 was not getting fuel based on the other three plugs being "sooty" and TH talked about fuel trim maybe enriching the other cylinders to make up for 3 being lean (or no fuel at all). I removed the fuel rail and examined the manifold end of all 4 injectors. Nothing apparent. I removed #3 injector from the rail and carefully removed the screen hoping it'd be full of crud. Clean as can be. I rigged 12 volts to where I could quickly energize and release that injector and it seems to "click" just fine. "Clicks" sound exactly as the other three injectors, laying on my bench. So I swapped injetor 3 and injector 1 for the heck of it, re-assembled, ran it, still get P0303 (#3 misfire). Swapped the plug from a different cylinder. Same P0303. (I cleared codes each time before re-starting, warming up, and getting light flashing back on). A lo-o-ong time ago I replaced the cap, rotor, plugs, and plug wires (this was my first step when it began this). What do y'all suggest next? Stethiscope at #3 injector while running to be sure it's "clicking" while getting current through harness (or not)? If it does not click, does that mean it's not getting current to injector (open or shorted circuit to that injector or bad PCM??). If it is clicking (is getting signal) then bad PCM or ??? If you answer "check the PCM" or "swap with known good PCM" I'm up the creek because I do not have a "known good PCM" and from what I read you need a key from that same vehicle (the donor known-good PCM vehicle) anyway. Is all this accurate? As always, thank you all for all your time and effort. "George is gettin' frustrated!!" - George Castanza (Seinfeld reference).
#26
ECM sends a ground signal which causes the fuel injector to open briefly (open time is also determined by ECM). Power should be always available. W/ keyswitch On, you should be able to measure 12V at the fuel injector.
If voltage missing there is damage to the power delivery circuit to the fuel injector. This may not set a code. I looked in 98 Honda shop manual and found no code for fault in the injector power supply or ground circuit, however in 1994 Accord Manual the obd1 code for Fuel Injector circuit fault is 16. I looked at other sources and could not find an OBD2 code for Fuel Injector circuit fault.
You can feel the injector fire or listen w/ a crude stethoscope (small flexible tube) and confirm injector is firing.
Do you have a timing light to check whether #3 is firing? Fire could be shorting to ground at rotor, cap, or wire. Attach spark plug induction pickup to #3 and turn engine over. Flash or absence of flash indicates spark condition.
good luck
If voltage missing there is damage to the power delivery circuit to the fuel injector. This may not set a code. I looked in 98 Honda shop manual and found no code for fault in the injector power supply or ground circuit, however in 1994 Accord Manual the obd1 code for Fuel Injector circuit fault is 16. I looked at other sources and could not find an OBD2 code for Fuel Injector circuit fault.
You can feel the injector fire or listen w/ a crude stethoscope (small flexible tube) and confirm injector is firing.
Do you have a timing light to check whether #3 is firing? Fire could be shorting to ground at rotor, cap, or wire. Attach spark plug induction pickup to #3 and turn engine over. Flash or absence of flash indicates spark condition.
good luck
#27
Good call on the timing light. I couldn't find a specific "fuel injector" DTC either for this OBD2 '02 Accord. I got that manual you recommended, well worth $20. Thanks TH. I'll look for 12V at the injector connector and "induce" the plug wires (#3 especially). I have an ancient timing light that is not inductive. That'd work, too, wouldn't it? It has a 6" plug/plug wire with a metal sleeve in the middle that you push onto the spark plug then the plug wire goes on the other end, and the clamp from the light grabs the metal sleeve. Any reason that shouldn't be used? Thanks again!
#28
Older timing light should work. I've only used the inductive pickup type for this test. It is very easy to create a short to ground w/ this type of arrangement which might give a false positive test.
good luck
good luck
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