yet another rough-idle-after-timing-belt thread, but with a twist

[ttcheung97]

I changed the timing belt on my 1994 Accord Wagon EX 5-speed with 180k miles. After putting everything back togehter, I started the car and it cold idled fine ~1800rpm. Upon the engine has warmed up a bit the engine started to put along at THREE cylinders! I had a friend listen to the engine and he said that I had probably missed a crank sprocket tooth. We then redid the timing belt and made absolutely sure everything was correctly aligned.

After that second time around we started the engine. The cold idle sounded fine, and so I proceeded to back it off the driveway. I then notice, with the engine warmed up now and the idle having dropped a bit, the engine was again putting with only THREE pistons.

The distributor works fine, the wires are all clicking, and I'm pretty sure I didn't bend a valve during both procedures. I decided to disconnect the fuel injector connectors one-by-one and pulling cylinder 1's did nothing to the rough idle. The same could be said for cylinder 2. When I pulled the connector off cylinder 3, the engine stuttered til it died. When I pulled the connector off cylinder 4, the engine stuttered til it died.

I decided to repeat the same procedure, but at a higher idle. Again, disconnecting cylinder 1's injector did nothing. However, disconnecting cylinder 2's injector yielded an audible drop in RPM. Pulling out connector's 3 and 4 resulted in further rough engine operation.

I am going to check the compression across the cylinders, but until I do that, has ANYBODY come across something remotely similar to this problem? My distributor is good, my NGK wires are good, the spark plugs are fairly new, and I don't see any signs of oil in the spark plug chambers. There's current on all four fuel injector connectors as well.

Thanks in advance.

[jdmcertified909]

Originally Posted by ttcheung97

I changed the timing belt on my 1994 Accord Wagon EX 5-speed with 180k miles. After putting everything back togehter, I started the car and it cold idled fine ~1800rpm. Upon the engine has warmed up a bit the engine started to put along at THREE cylinders! I had a friend listen to the engine and he said that I had probably missed a crank sprocket tooth. We then redid the timing belt and made absolutely sure everything was correctly aligned.

After that second time around we started the engine. The cold idle sounded fine, and so I proceeded to back it off the driveway. I then notice, with the engine warmed up now and the idle having dropped a bit, the engine was again putting with only THREE pistons.

The distributor works fine, the wires are all clicking, and I'm pretty sure I didn't bend a valve during both procedures. I decided to disconnect the fuel injector connectors one-by-one and pulling cylinder 1's did nothing to the rough idle. The same could be said for cylinder 2. When I pulled the connector off cylinder 3, the engine stuttered til it died. When I pulled the connector off cylinder 4, the engine stuttered til it died.

I decided to repeat the same procedure, but at a higher idle. Again, disconnecting cylinder 1's injector did nothing. However, disconnecting cylinder 2's injector yielded an audible drop in RPM. Pulling out connector's 3 and 4 resulted in further rough engine operation.

I am going to check the compression across the cylinders, but until I do that, has ANYBODY come across something remotely similar to this problem? My distributor is good, my NGK wires are good, the spark plugs are fairly new, and I don't see any signs of oil in the spark plug chambers. There's current on all four fuel injector connectors as well.

Thanks in advance.

Do you have a compressor? If you do I can give you a diy on making a cheap leak down tester from a compression tester hose.

[redbull-1]

This may give a little insight to your problem:

http://www.justanswer.com/honda/29ws...-cylinder.html

[ttcheung97]

Thanks; that is a pretty good thread. Shows how the guy's process of elimination worked, something I haven't exactly applied to my situation. ONe thing I haven't checked are the spark plugs, but I'll check them once I take them out for the compression test. If i have current to all four injector connectors, that doesn't necessarily mean the injectors themselves are working, correct? I'm just not a big fan of fluid connections, ie taking apart the fuel system.

will update when i get more progress in....

[ttcheung97]

update: So the engine has sat for a few days, and today i decided to start it up. The engine cranked over and started right up. 2000rpm cold idle and all four cylinders running smoothly. I throttled the engine lightly and the response was smooth. i decided to disconnect each fuel injector connector: as predicted the engine got progressively rougher until it died running on one cylinder.

I connected everything back up and started the engine; once again a smooth idle. I shut off the engine and checked the spark plugs; they were all fine and slightly discolored. I started the engine once again and let it warm up. The temperature gauge reached "warm" and still, the four cylinders were running smoothly. i blipped the throttle and the response was smooth.

It's been almost 7 minutes now, and still smooth. I blipped the throttle once more, the needle goes to about 4000rpm and upon coming back to idle, the engine goes to two cylinders.

Now I read on another thread that there's a LIMP mode were the redline is reduced to about 4000rpm when there's a certain fault. The fault I've been getting when I jumped the two-pin plug was CEL16, fuel injector malfunction. Might I have tripped a fault when I revved the engine too high?, causing LIMP to occur?

The thing that really irks me is how the injectors are failing on me when I did something completely unrelated, changing a timing belt. Any feedback?

[Fliptard]

it's possible, stupid thinks happen at stupid/random times.

[jdmcertified909]

Originally Posted by ttcheung97

update: So the engine has sat for a few days, and today i decided to start it up. The engine cranked over and started right up. 2000rpm cold idle and all four cylinders running smoothly. I throttled the engine lightly and the response was smooth. i decided to disconnect each fuel injector connector: as predicted the engine got progressively rougher until it died running on one cylinder.

I connected everything back up and started the engine; once again a smooth idle. I shut off the engine and checked the spark plugs; they were all fine and slightly discolored. I started the engine once again and let it warm up. The temperature gauge reached "warm" and still, the four cylinders were running smoothly. i blipped the throttle and the response was smooth.

It's been almost 7 minutes now, and still smooth. I blipped the throttle once more, the needle goes to about 4000rpm and upon coming back to idle, the engine goes to two cylinders.

Now I read on another thread that there's a LIMP mode were the redline is reduced to about 4000rpm when there's a certain fault. The fault I've been getting when I jumped the two-pin plug was CEL16, fuel injector malfunction. Might I have tripped a fault when I revved the engine too high?, causing LIMP to occur?

The thing that really irks me is how the injectors are failing on me when I did something completely unrelated, changing a timing belt. Any feedback?

yup stupid things happen at random. Could have been that they were going out. My experience is that bad injectors stop working when hot. And dead injectors just dont work cold ir hot. I have 1990 nissan stanza gxe that when the car warmed up it would woek on 3 cylinders ended up being a injector.

[slomofo]

You didn't mix up the #1 and #2 spark plug wires when you put it back together, did you?

[ttcheung97]

no, the plug wires are NGK and their lengths correspond with the cylinder. The other thread I've been following, "My car won't rev past 4000rpm" has many suggestions on checking the myriads of intake gaskets. I had to take apart my intake plenum when I was installing the clutch line during my transmission swap, but it's been well over 20k miles since I touched that.

[Rowdy Rod]

How did you determine that two cylinders stopped firing?

[ttcheung97]

i wouldn't say "firing," but two cylinders were not providing power. pulling the fuel injector connectors didn't yield any changes in engine operation.

When the engine was idling smoothly with all four cylinders, i pulled both injector connectors and the result sounded exactly like the rough idle I've been getting.

[Steve Z]

Check the spark plug on #1 cylinder and maybe 2 also. That's the easiest thing to check and you haven't eliminated a bad plug? Make sure ya have good blue spark. It's the simple things sometimes. Eliminate that first before moving on to a bad injector.

[ttcheung97]

the spark plugs are good condition across the engine; slightly discolored from the heat.

I'm wondering, would fuel injector cleaner clear-up any of the clogged injectors?

[ttcheung97]

Problem solved: I had two vacuum lines swapped when I changed the timing belt. I had removed the power steering pump out of the way, and in doing so I disconnected some vacuum lines so that they could be out of the way. Having them incorrectly connected created pressure issues, causing the fuel system to not be correctly pressurized. Swapping them smoothed out the idle. YEAH!