I got one 4 you techies

[Distortion 5.0]

I just purchased a 93 lx coupe today. My question reguards the tachometer, it reads irratically, and typically thousands of rpms lower than it's actually pumping. This car is coil pack dual plug. Any one used to this problem?

 

[TMX]

It seems the ICMs around the world on the '93 are going nuts this year. The tach is controlled by the Ignition Control Module, about $110 at Autozone. When the tach starts going off, it usually means the ICM needs to be replaced, and if the car runs fine it's nearly certianly the ICM.

 

[Distortion 5.0]

Car runs great. I'll look into changing that out. This thing was a steal at 150$ It just cracked over it's first 100k.

 

[TylerDurden]

yup

No $hit....on a newly aquired 2.3 change the module, coils, plugs, wires, fuel filter, air filter, o2 sensor, oil, check the vacume tree for loose or missing hoses and clean the valve in the air/idle control. Now....your 2.3 is well on it's way to 200K.

 

[TylerDurden]

wait, wait, wait.........

Damn, what was I thinking. Your tach is jumping? That's drastic. You better sell it to me quick...I'll double your money and save you the pain.

lmao

 

[Distortion 5.0]

Hey guys, that's not the DIS module is it? I changed the DIS today and it made no difference what so ever. Where is this ICM of which you speak located? Anyone?

 

[TMX]

The ICM is a rectangle, thin, grey box that faces towards the front of the car next to the intake, has 2 plugs on it, one on top and one on bottom. If the car basically runs fine, maybe hestitation, that is usually the one problem. Also would you have an MSD DIS-4? The MSD box will throw the tach off alot and requires a tach adapter. If not get the codes checked, 223/224 denote bad Ignition Control Module.

 

[RustBucket]

Hey guys, that's not the DIS module is it? I changed the DIS today and it made no difference what so ever. Where is this ICM of which you speak located? Anyone?

The DIS module and what is being referred to as the ICM are the same thing. Grey module with plugs on top and bottom mounted to the front of the lower intake manifold right behind the power steering pump.

 

[Stinger]

If you changed it and it didn't help, your new one is no good...the ignition module is the only thing that effects the tach readout.

 

[Distortion 5.0]

If you changed it and it didn't help, your new one is no good...the ignition module is the only thing that effects the tach readout.

Thank you stinger, I knew when I saw that you posted my question was answered. It was a j/y part that I traded a hashed lx for.

 

[kiddiccarus]

Nice deal on a LX hatch I am guessing???

 

[TylerDurden]

yup

stinger is right. bad module. take it back to where you got it and make them una$$ a new one.

 

[vristang]

I'm not real familiar with the 2.3 yet, but have the gears been changed?

If the wrong speedo drive gear is still in the trans or the wrong one was installed, the plastic gears can get stripped/damaged and cause fluctuations.

Just a thought.

jason

 

[TMX]

There really isn't gears for the tach readings. The ECU figures out when a coil fires and how often it fires from the output of the ICM which controls the coil firing and selection. It's very easy to find out how many revolutions the engine makes by the coil spark. With the distributor systems, there might have been gears to control it, but in the DIS system when everything is electronically controlled, it all becomes just calculations.

 

[vristang]

There really isn't gears for the tach readings. The ECU figures out when a coil fires and how often it fires from the output of the ICM which controls the coil firing and selection. It's very easy to find out how many revolutions the engine makes by the coil spark. With the distributor systems, there might have been gears to control it, but in the DIS system when everything is electronically controlled, it all becomes just calculations.

Oooops! Didn'ty realize it was a DIS. Thanks for not making fun of the new guy.

What year did the 2.3 switch to DIS?

 

[TMX]

I believe in 1989, but that could be off. Definately sure in 1993 it was DIS, and I believe 1992 was as well.

 

[Distortion 5.0]

The distributed 2.3 used a tfi module to adjust timing and I believe it also controlled the tach. Or was it the coil on those models? I know that's where I connected the after market one in the 88 because the stock circut was shorted.

 

[Stinger]

91-93 cars are DIS...also the 90 california models as well.

TFI and DIS ignition module do the same exhaust function...

 

[glowstang93]

I believe in 1989, but that could be off. Definately sure in 1993 it was DIS, and I believe 1992 was as well.

Definitely in 92 and 93. I started with a 92 that I bought new in 91.

 

[stackz]

couldnt the tach gauge itself being going bad as well?