Ive got a 97 accord LX four banger. Tach started jumping while driving on the highway. Would be fine, running 3k and then bounce up to 4k. Didn't notice any change in engine or driveabilty when this happens. About 30 minutes later tach went down instead of up and the car jerked like a bad miss. Now happens about every couple of minutes.

Any ideas? Car runs fine when tach bounces upward. If tach bounces downward, car misses, jerks, stutters, . .. .whatever. Can't recreate when idling or reving car at a stop.

No check engine light. Anyone know whats causing this?

 

Check your electrical and ground connections, there might be a loose connection somewhere.

 

Had this problem on my '92, ended up being the ignitor module, under the distributor cap. Tach was jumping, started to lose power under load. Also, had to replace distributor shortly thereafter....too much play in the shaft, it was frying my cap and rotor contacts from the slop.

 

I had a '90 civic si, and I had the same problem, it was the ignitor coil in the distributer. I had it replaced, and the problem was gone. I haven't had that problem on my 5th gen accord, but I imagine that the design of the ignitor/distributer are roughly the same.... hope this helps.

 

id also give your MAF sensor connection a look too, its been known that if the MAF isnt connected good then the car may sputter and miss, sometimes stalling.

 

It has to be something in the ignition circuit. When it cuts out now, the tach drops to zero and engine completely quits. I'm hoping someone has had this happen before. I'm guessing it could be ignition module, maybe a crank position sensor(if it has one), maybe the computer.

Does anyone know what gives the signal for the tach? Ignition module, crank sensor, etc..

 

Take the ignition module into a parts store. The nicer stores can test them, I know O'Reilly's will. Might also see if you can find a helpful person at a dealorship who'd test it for you. From my limited understanding of them it has separate programs of sorts that is switches between. It doesn't have to completely fail to be bad.

I actually live in Olathe homey...just right up I-35, its a small world.

 

I'm hoping someone can say definitively what sends the signal to the tach.

Most tach's just trigger off the ignition coil. I've got a haynes manual though that says the RPM info is detected from the CKP (crank angle sensor) which is a seperate assembly attached to the oil pump assembly. Its apparently under the timing cover and the "helpfull" manual says a scan tool is needed to check so no more info.

I'll try and see if I can check the ignition module before I go pulling covers looking for the CKP. I would really like a "repair manual" that actually HELPs me do repairs.

 

I'm confused what makes you think its the CKP? Not saying it isn't but it sounds like an ignition problem and you said yourself it runs fine under 3k RPM. Doesn't sound like its a tach related problem either, the engine itself is surging and that sounds like ignition module.

But to answer you question my Helms (for a 94 Accord Coupe) says the tach runs off the ICM. FYI it also says that "the tach should operate normally if the ICM is OK." That's not necessarily what customers have told me, but they might not have had tachs or it ran off another sensor.

I also thought the crank position sensor was behind the balance shaft belt which would make sense. The oil pump runs on a smaller sprocket thus different timing. There's a magnetic pick up on it, at least the sensor I'm thinking of.


Modified by Schmitey at 11:51 PM 12/6/2005

 

i also had the problem in my 92 dx, replaced the ignition module and the problem was fixed.

 

ICM it is then. . . I'm going to heat up the garage tonight take the module out to be tested.

The reason I wanted to make sure it was the ignition module is I've had other vehicles set up differently. I found a section in my manual about adjusting the timing by moving the distributor. Other vehicles I've had couldn't be adjusted. They ran the ignition by referencing the crank position. Had a cummins diesel tach started bouncing and check engine light comes on. It would go into default mode and ran till it was shut off, then no go. It used the crank position sensor to run the injection system. Jeep V-8 I had used a crank position sensor. Adjusting the distributor did nothing to the timing. I dinked the sensor up when I pulled and replaced the tranny. Couldn't get to start until I figured out that the sensor which was at the back of the motor up by the firewall had to be replaced. Ignition module was fine. I looked at the distributor and ingnition 7 different ways for a week trying to figure out why I had no spark. I threw money at it, didn't help.

I'm just being carefull. I've chased my tail before because I thought I knew how things "should" work.

Thanks for the info guys. If someone else has "been there, done that" its a lot easier to know where to start. I appreciate the responses.

 

Yeah from the diagrams (which I can send to you if you need) looks like the ICM is pretty easy to get to under the distro cap. It doesn't do any harm to pop it out and get it tested. I know what you mean though, my old accord didn't even have a distributor and you adjusted timing by the cam position sensor. If it was an EX I'd say its possibly VTEC/timing related but with your LX its not an issue.

 

I have the same problem now after I replaced my igniter with the non hitachi equipped one. Did I get the wrong one? Do I need the hitachi equipped one?

 

Did you replace just the ignitor unit or the entire distributor housing? If you replaced the entire distributor housing, Did you also reset the base ignition timing?

The timing (Adv. & Ret.) on these cars is controlled by the ECU. Therefore you should set the base timing any time that you replace the distributor or it's internal components.