BIGJIM13

Guys - 1993
finished changing plugs and wires and optispark and water pump and throttle position sensor....seems to run ok - but have service ASR light and the Tach is not running - is there a tach connection that I might have pulled loose... does the ASR need reset somehow... I did disconnect the wire connection but nothing else....
Thanks for any suggestions

BIGJIM13

Guys
was running the car to make sure I had no water leaks...
I unplugged the ASR unit while the car was running...then turned it off
and then plugged it back in.... Tach came alive and the Service light went out.... = the FIX!...

BIGJIM13

well - service asr light and dead tach are back
any suggestions?
Thanks

0ChandlerMotorsports

Why not look at the ASR related issues? Wheel speed sensors, brakes etc?

littlesk8cracker

icm. check to make sure the ground is good, and if that checks out then consider changing it

BIGJIM13

"Why not look at the ASR related issues? "
Thanks have checked all related issues before posting my question..
that is what is perplexing ...make no sense!

FireRoc

If the '93 is the same as the '94, the IP tach, ASR and ABS all get the engine RPM signal from the tach filter, which connected to the Ignition Coil Module.

I cannot say exactly where it is is, but I believe it is on the right front of the engine and is taped into the wiring harness in that area.

BIGJIM13

Thanks - replacing the icm today....the tach filter is exactly where you say...that will be my next part if the icm does not fix the issue
Thanks

BIGJIM13

Well .. replaced ICM still no tach and service ASR light
is the general conclusion to replace the tach filter???

FireRoc

Before doing that you might want to make sure the ground for the tach filter is okay. Barring that, my guess would be tach filter.

BIGJIM13

Thanks
any idea where that ground might be?

FireRoc

No, and I have no access to the FSMs right now (they are in a different city).

BTW, I've only had to look at this from the perspective of trying to make an LTCC set-up work on my wife's '94. We are still working through some..............issue!!!

Her tach and ASR/ABS all stopped working from a loss of signal from the tach filter when the ICM was disconnected with the LTCC setup. We wound up getting an RPM signal from the ECM, but that probably will not work for you unless the ECM's are the same, which I highly doubt ('94 was the first year for sequential fuel injection).

BIGJIM13

Thanks
was on my way out to look BUT...its actually SNOWING here in Texas
Thanks

BIGJIM13

I was looking in the book and on other posts...so nothing runs the tach except the tach filter...?

FireRoc

That's my understanding. The tach filter is in series with the ground for the ignition coil module, which gets its power from the ignition coil. One of the reasons I suggested checking the ground.

The opti-spark also generates rpm signals (high res and low res) but they are only used by the ECM.

If you have the FSMs check the section that has the wiring diagrams. Ther should be information on where all the grounds are located.......and you can check the wiring diagram to see how the tach filter is connected to ICM.

There is another rpm output signal from the '94 and '95 ECM that comes from terminal 13 on block A. That's how we solved the problem for a tach/ABS/ASR rpm feed when we changed to the LTCC setup.

But I do not think that will help you, as the ECM's are probably different. But it may be something to check out.

BIGJIM13

Thanks

jmgtp

Had same issue with my 94 when installing LTCC. Someone on the forum (maybe it was you FireRoc) suggested using the tach signal right off the ecm (IIRC it was pin A14 on the 94 ECM). Been working great ever since. Could the OP have a fried tach filter?

Thomas Morefield

the ltcc is a real piece of work no dought. however as many folks having tach trouble it seems they would insert some solutions with the unit. after 10 days the retailer finally gave me the email for Bob i still havn't resolved the problem will someone help. painless laptop fuel 383 kiesler simple shift 4l60e sure would like to drive it.

89'Bowtie

i'll look into my notes, i recall something about this popping up before.