mushing_madness

99 Accord (4 cyl) that is nearing 300,000. Was hoping for it to go beyond 300k, but I said that outloud and now (2k later) it has an issue. Suddenly one morning it started running rough and the CEL illuminated and started blinking as I drove away from my home.

Pulled back in the driveway, parked it and took the truck -- now I need to figure out what is the issue. When I pull codes I have a misfire on cylinder #1 and #2.

I have replaced the plugs only -- can't recall mileage for cap/rotor/wire replacement...might need doing, unsure. I did a compression test and both #4 and #3 were at 170. Cylinder #2 was at 160 and #1 was at 150.

Was thinking head gasket, but right now -- no symptoms: oil looks fine. coolant looks fine...just the lower compression in #1 and #2. It hasn't overheated, but then again, I have not driven it since the rough running and blinking cel came on.

THoughts on how to proceed/diagnose actual problem?

-- UPDATE --
Ran it until it warmed up -- rechecked compression: 170 in all cylinders.
Not happy at idle -- runs rough
If I rev it up to 2k or above - smooths out
If I attempt to drive it (stick - so clutching with 2k+ revs) - no power under load -- rpms drop instantly and runs rough
It is not overheating at this point...I did notice some white exhaust but cleared up after it warmed up (the car hasn't run in 3 weeks).
Since CEL was blinking again, I pulled codes: Cylinder Misfire on all 4 (p0301, p0302, p0303, p0304).

ICM???

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Thanks for the help!
MM

HonBeer

Clean your EGR ports.

surffog

Change cap an rotor,or at least clean with sand paper an knife. Surffog

holmesnmanny

egr ports probably wouldn't cause it to drive that bad imo...start with cap and rotor replacement

mushing_madness

Picked up a new cap/rotor. Before going to put it on, went to start one more time (simply a wish it would run right). Turns out, it has become a no start...going the wrong direction here.

I put on the new cap/rotor anyhow -- still have a no start. Will have to see if I have spark tomorrow...go to many errand tonight.

Does anyone know if there is a way to test the ICM with a MM?

Thanks!

mushing_madness

Pulled my daughter outside and we tested spark -- good solid snap on all four wires...guess its not the ignition system.

With the compression being adequate, I'm moving onto the fuel system. Never diagnosed fuel injection before, but will be following a few articles. If anyone has advice - please share.

Thanks,
MM

mushing_madness

Ohm'd out the fuel injectors -- all read 10...moving on. Fuel pump/relay/etc..

To recap:
Tested Ignition System using HEI Spark Tester -- good spark, so am assuming ICM, Coil are good. Has new plugs, cap, rotor, and am assuming they good. Ohm'd the wires -- all were between 6.0 and 7.1.

Compression Tested Engine -- good compression across all cylinders. Did not leak-down test.

Ohm'd the injectors -- all were the same; they were cold (won't start) but hope the results are valid still.
Put a noid light on the injectors -- pulsed while cranking.

Getting down to the fuel pump? Don't have a fuel pressure guage...any easy way to test?

Thanks, MM

holmesnmanny

Just turn the ignition to on, listen for the fuel pump to prime....then take the key out and undo the main fuel rail bolt(17mm size head) and see if there's pressure. Use a rag to keep fuel from spraying. If it doesn't spray at all, then it's your fuel pump.