I've got a 1995 Honda Accord V6 that began to hesitate (buck) on a 30 mile trip a couple of weeks ago. I was coming off a 3-lane highway and going slow when this happened, toward the end of the journey. On the way back, less than 10 miles into the journey, the car began to buck when I had to slow down and then accelerate to stay with local traffic. At this point, the CEL came on.

Took it to my mechanic who used the old OBDC I diagnostic tool, and he got a code 8 for the TDC sensor (the dual sensor that also has the CYP as well), and he and another mechanic dove down into the timing cover to replace the old sensor. I picked up the car and it was just dandy on the short 5 mile drive home. The V6 engine has plenty of power and pickup, far, far better than the 5 cylinder 2005 GMC Canyon I borrow from friends.

Next day I went to a meeting about 40 miles away and got the bucking back again about 30 minutes into the drive, CEL came back on, and while there was no stalling, I started to watch when the bucking happened before returning to the repair shop.

1. I can rev the cold engine upwards of 3200-4000 RPMs with no problem, but if engine runs 25 - 30 minutes (including just sitting idling), the bucking and rough idle starts up at 3200 RPMs. The more the engine runs, the bucking begins to occur at lower RPMs (down to 3k, then 2500, etc....) Suggests something in the system degrades with increased engine heat.

2. Car recently had new radiator (year ago), water pump, rotor and cap, PCV, valve covers refitted for oil seepage, ignition switch (in April this year), spark plugs cleaned and gapped. Timing belt replaced ca. 35k miles ago (along with all the other belts). So a lot of time spent going over this thing. I have used more than one place for repairs and all are saying the car is terrific for the most part, just starting to feel her age a bit.

3. Mechanic is presently trying to chase down problem in wiring, which seems logical if a hot engine is what causes the bucking to start. ECM is testing fine, distrib. cap is testing fine, sparks are fine, new TDC/CYP is fine (the old one was pretty fried when they took it out). Thought they had it nailed the other day, but when engine heated up, CEL came back on, code 8, and the hiccups began again. The tachometer hasn't been wildly jumping up and down but might be a little off.

Some of the other thoughts they have is maybe bad distributor however it seems that would be idling rough ALL the time, not just when warm. No sign of any leaks or such.

Anyone ever see something like this before, and preferably can suggest a solution to try that is as inexpensive as possible? I have a great shop I use and they consider it their job to ensure that they didn't break something else while replacing the TDC (even offered to give me a free oil change because of all the trouble I've been through and having to wait while the senior mechanic was on vacation).

Thanks for any ideas that can help solve this.

 

Okay, update here: My mechanic put a different distributor in today and the problem seems to have gone away, although another guy was spending a good part of Saturday with the wiring harness and testing wires. But, the new (well, used) distributor appears to have solved the problem (and my guy says "no charge, you put up with a lot of frustration but didn't get nasty mad"). Hopefully this will put an end to this saga.

 

If the tachometer ever intermittently starts to go crazy and the car bucks while that is happening, check the ignition coil. That was happening to me a few years back on my old 95 V6 and it took me MONTHS to figure out it was the coil. I did a long thread about it years ago. I just saw your post and thought about it

 

So far, so good with the replacement distributor (the original had metal filings inside of it so that wasn't good). I will keep the ignition coil in mind in case anything else goes funny as you described in your post. Had a new ignition switch put in last spring when the thing just died completely (mercifully I was on a very quiet country road with no other traffic, and just happened to be a short 100 yard walk to a friend's house.)

 

On my way to a business event, the tachometer (which had been a little bouncy--I just thought it was the lower gears on the tranny being a bit rough in shifting) went a bit crazy and the CEL came on for the third time in a month. I soldiered on and on the way home in the dark, the tach jumped around, the engine sputtered and glided to a stop. I got it started again (I was 30 miles from home) and went a bit and then the thing stalled again. I willed the stupid beast to start again and I got home. It started yesterday, though the tach needle jumped and it started to stall, but it smoothed out. Today, it turned over but runs rough and stalls.

Called my mechanic and plan to have him get me a new ignition coil, though he worried that the replacement distributor might be a problem. However, I think after combing through more posts on this forum, I am pretty sure that since we've put in new platinum sparks, new distributor and new TDC sensor (and has a rotor and distributor cap that is fairly new), and I had a new ignition switch put in last April, we are hopefully down to the last problem. The fuel pump and fuel delivery systems were gone over last spring when the switch was done and no problems there.

This is how a 17 year old car becomes new again (and yeah, the body is in pretty decent condition with little rust so she's worth the effort).

 

I had similar problem w/ Code 9 on my 4-cyl. 94 EX. In the end, the problem was the ECM, which had an internal fault. Check the sensor resistance from the ECM/Harness connector end. If all checks OK at that point, the ECM is likley the fault.

good luck

 

My mechanic went through the wiring harness and tested the ECM, which came back flying colors. The original problem threw out a TDC sensor code (8 on the OBDI, I think). The tach going a bit crazy and the very rough idle with stalling out really seems to point to the ignition coil (or, worse case, the ignitor/ICM).

Anyway, gotta tow the sucker over there later today and get moving on it. Thanks for everyone's help. This is a great place for information.

 

Well, I thought I would post an update since my car is still off the road (my mechanic said he feels like he's married to it by now, it's been there so long). We tried a new ignition coil (despite the fact that the diagnostic tool said there was no problem with the coil) and the problem was still there (stalling out, CEL coming on). Since the replacement distributor was under warranty, a new used dizzy was ordered and has been installed.

Car ran fine immediately after that but acted up first thing the following morning. Mechanic now beginning to take it personally! CEL back on and the old code originally thrown out is back. He pulled the new plugs out (at least three of them) and found the points were black and burned, but not oil-coated, on every single one.

So today, he is putting in a new Crank Sensor (companion part to the TDC/CYP for the engine timing) because the spark plugs' condition suggested too rich fuel mix to his mind. He has declared that this is gonna do the job and I hope he is right because this is almost epic in scale. He admits he probably should have done something with the Crank Sensor when playing with the TDC/CYP. With good karma, I'm hoping that I will have a reliable car once again tomorrow.

Anyway, am posting all this in the hope that it may help some poor bugger someday.

Carol

 

I posted back last August when I had a similar problem (bucking when RPMs go over certain limit). At that time, I had a new ignition switch (April 2012) and in August 2012 my mechanic and I finally replaced all the sensors affecting timing (TDC/CYP plus Crank Sensor) and put in a new distributor.

The new wrinkle is the car is fine when cold but if I ran different errands, each stop and start made it harder for me to start the car up again. Would turnover but then stall out. Now it is just stalling out after a short drive. CEL came on initially (I was low on gas at the time), it went off on its own, but then came back on (was at a quarter tank of gas again); I don't run it often with a low tank, so these circumstances were out of the ordinary. I have never run out of gas (once the engine cooled, I could restart the car and drive it a good distance).

CEL code on the OBDI indicates the same sensors we replaced last August. But it seems like a fuel delivery problem. Car currently has over 10 gallons in its tank so it is NOT out of gas.

Here's what we've done so far: tested fuel pressure (it's 44 which is in the desired range), tried new master fuel relay (car still died after a short test drive), and because there is a sort of occasional electrical burning smell, we're thinking wiring. Fuel pump can be heard running so between that and the pressure test, we've ruled that out. But the warmup time to engine stall is getting shorter and shorter.

The ignition coil was tested last August, as well as the ECM--all were testing fine. Test again?

Anyone have any suggestions of where to look elsewhere? I would assume the fuel pressure regulator is fine if the fuel pressure is fine but that may be a wrong assumption. Other parts of the ignition that I HAVEN'T replaced?

Once I get driving, the old V6 oomph is there and even with this stalling problem I am not having the previous problem of it bucking over 3200 RPMs, and the car isn't rusted out at all for its age. Buying a new car is out of the question at this time.

 

When you replace sensors and same fault codes return, you have to look elsewhere; wiring, connectors, or ECM.

If you check sensor resistance at harness connector, and if OK again at ECM connector and find same result (good), then ECM is faulty.

good luck