Tach Needle Dies then Comes back to Life

[Marccus]

its possible that the new cam sensor is bad, but relatively unlikely.

tracing the wiring is pretty easy, since there are only 4 wires. one goes to the pcm via one of the 8 position connectors that lay behind the rear valve cover. the other 3 go to the dis module.

What's a "position connector"?

 

[Rockledge]

You can't rule out the DIS module as the cause of code 19 and flaky tach. If you can borrow a unit that is known to be good, you can easily swap it in to see if clears up the problem.

 

[sperold]

Good point, especially if, in your removal of things to get to the cam position sensor, you removed the ground to the firewall, or disturbed the cross-over tube.

But, unlikely or not, I would go with the code, and fix the problem it highlights. And that would be the cam sensor..... again.

Does your paperwork mention the T-series component from Standard Motor Products? I am not a proponent of letting price dictate the level of quality (cause you can be fooled by that one too easily), but in this case, it has me thinking. Who knows where the T-series is manufactured, and what quality control program is in place... but they had to do something to cut their own price by 33%.

Have the characteristics of the problem changed at all with the new cam sensor.... like is the time between tach fails longer, or does it start better more often, or does it run better than before when the tach is down?
If it behaves exactly like it did before.... then boy is my face red.
If it has different characteristics, then it is this cam position sensors failure signature.

 

[rubydist]

What's a "position connector"?

its an "8-position connector" - a connector that has 8 positions for wires in and out of it. iirc, these do not have 8 wires - they are not fully populated.

as usual, Rockledge is on to something. I meant to mention that in my last post but forgot. if the wiring is good, and the new cam sensor is good, then the pcm and/or the dis are suspect.

 

[Marccus]

You can't rule out the DIS module as the cause of code 19 and flaky tach. If you can borrow a unit that is known to be good, you can easily swap it in to see if clears up the problem.

Thanks for the suggestion. I haven't had the problem for a couple of days. If it returns, I'll try a DIS switchout.

 

[Marccus]

Good point, especially if, in your removal of things to get to the cam position sensor, you removed the ground to the firewall, or disturbed the cross-over tube.

But, unlikely or not, I would go with the code, and fix the problem it highlights. And that would be the cam sensor..... again.

Does your paperwork mention the T-series component from Standard Motor Products? I am not a proponent of letting price dictate the level of quality (cause you can be fooled by that one too easily), but in this case, it has me thinking. Who knows where the T-series is manufactured, and what quality control program is in place... but they had to do something to cut their own price by 33%.

Have the characteristics of the problem changed at all with the new cam sensor.... like is the time between tach fails longer, or does it start better more often, or does it run better than before when the tach is down?
If it behaves exactly like it did before.... then boy is my face red.
If it has different characteristics, then it is this cam position sensors failure signature.

After it appeared that one time after I installed the new cam sensor, the problem has not reappeared and I have no codes. But I haven't really driven the car much, so I'll see how it does this weekend. I'll look at the paperwork or box .... if I can find them. My life is in utter turmoil right now. Thanks for the suggestion.

 

[Marccus]

I am out of ideas.
What I will comment on is Standard Motor Products have their main products, and then they have a T-series product.
The regular series cam position sensor is LX228 and is priced at $37.00.
The T-Series cps is LX228T and is priced at $24.00.
The Motorcraft cps is DU47 and is priced at $46.00.
Even if you paid a lot of money, chances are you got the T-series cps.

I would use the T-Series unit myself, but I would be wary if I started having problems. There is a small chance that you are getting a bad run of CPSs.
I would take your latest one out and return it.... you have the code data to back up the story.

Look on Rockauto for an easy to read list of parts for your car. Other great sources are Shosource and RCMautomotive as well as others like Advance etc.

I was desperate to get a CAM sensor ASAP so I went to the parts store and paid almost $50 for the Standard Motor Products sensor. Looks like I got taken to the cleaners!! The problem has disappeared for now, but if it reappears, I'll try to return the unit in exchange for another one. Thanks.

 

[sperold]

Everyone loves a happy ending.
I hope the problem stays away, and it sounds like it may.
But you really did not get taken so bad, if it the regular series cps and not the t-series. By the time you add in the shipping, the internet purchased ones are close to the same. When dealing on the internet, it is nice to get a number of parts from the same place, then the shipping makes sense.
Keep us informed on the status of the part (T-series, or not) if you can determine it, as eventually I will need one, and it would be nice to know if one can be ruled out.
Good Luck.

 

[SHOspazz92]

If the problem re appears because of this remaned or whatever Cam sensor, Just get a good working used one from the Forum.

-Sam

 

[Marccus]

Everyone loves a happy ending.
I hope the problem stays away, and it sounds like it may.
But you really did not get taken so bad, if it the regular series cps and not the t-series. By the time you add in the shipping, the internet purchased ones are close to the same. When dealing on the internet, it is nice to get a number of parts from the same place, then the shipping makes sense.
Keep us informed on the status of the part (T-series, or not) if you can determine it, as eventually I will need one, and it would be nice to know if one can be ruled out.
Good Luck.

The product number for the CID on the receipt is "STD LX-228"

Is this the T series?

 

[sperold]

No, this is not the T-series, you got the more expensive one. The T series number is LX 228T.
Did the code or the symptoms (like tach needle dropping and running poorly) ever come back?
I still can't figure why you had the symptom one time with the new unit.
It makes me think that by disturbing the wiring, that you may have reconnected a stretched fitting, and that is what really brought it back to life.
But I don't know enough about how they really work to comment, maybe it is like the check engine light... the key has to be on and off a few cycles for the light to disappear when you fix something.
Don't throw away the old one just yet, there may be a day that they can be checked or repaired.
Thanks for the feedback, I appreciate it.

 

[Marccus]

So far the code and symptoms have not returned.

 

[sperold]

Great.
Happy Motoring.

 

[Frisbeeguy]

So far the code and symptoms have not returned.

I had the exact same proplem intermittently. The car would buck & "jack-rabbit" when releasing the clutch... the tach would go crazy or drop to zero but the engine would continue to run... a bit rougher then normal. An hour later - no problem. It would happen out of the blue - no warning - then be ok for a week or month.

The problem was (is) a wire leading to the cam sensor. While it was idling, I wriggled wires and while doing so - the idle suddenly smoothed out and problem solved. I just taped the bundle of wires tighter and the problem has not returned in over a year.