aftermarket ignition parts

dthompson

Registered User
My car is experiencing an intermittent loss of tach signal. The tach needle drops a couple hundred RPMs very quickly and bounces back when idling. Sometimes, it stumbles when this happens and then start idling weird, but will clear up. Under power it drives fine (or at least it feels ok).

I have replaced the cam sensor with a spare that I had and no change. I cannot find my spare DIS or crank sensor. My first thought was the crank sensor got damaged when the jackshaft belt broke at the track the other week. It seems to have started after that (the next time I drove it). However, I do not see anything obviously wrong with the sensor or its cable. I kind of suspect the DIS now.

So I was going to buy a DIS, cam sensor, and crank sensor from RockAuto to have a spare set.
-They do sell a motorcraft cam senso
-The DIS is options are AIRTEX/WELLS 6H1100 $79.99, STANDARD MOTOR PRODUCTS LX231 $83.89, or if I search for the Ford PN on the DIS I have, I come up with STANDARD MOTOR PRODUCTS LX242 (F1SF12A297BA) $150.89 why the one that matches the PN is so much more expensive... I dont know.
-The crank sensor only has one option is AIRTEX/WELLS 5S1751 $61.79

I would prefer to buy motorcraft or OEM parts, but I have not been able to find any online. Do you guys know of a place that sells this stuff anymore? If not, which DIS is better or is all the other crap the same?

thanks,
Derek
 
Why buy all three now. The symptom seems like a crank sensor problem. Did you pull any codes?


I did not try to pull any codes, because the light wasn't on. I hate having to count the flashes, lol. But thats a good idea, i will check tonight. I would buy all three because I can afford it, it's nice to have spares, and it saves time in case I guess incorrectly. But mainly, it is nice to have good working spares.
 
I did not try to pull any codes, because the light wasn't on.

Doesn't mean there aren't codes to be sniffed - Ford tends to be stingy with the light so they don't scare the owner for every little thing.

Buying a code reader can save money when the alternative means throwing parts at the issue(s) ;)

In your case, tho, I'd think the wild belt crippled the harness, for starters. What happened after may be better sorted via codes.

Good luck.

Ken
 
Codes for those who care...

67: improper signal from NDS, NGS, NPS, CS, MLP, or ACC... my guess i the acc, air conditioner clutch... wasnt working the last time i tried it (need to fix that).
82: sc bypass solenoid circuit failure (its deleted)
14: the eca has detected an intermentent PIP signal in recent operation
45: DIS problem primary circuit failure in coil 1,2,3,or 4

I went back and looked at the diagram in the service manual and the PIP signal is related to the DIS and crank sensor.

I fixed a dipping tach a few years back by replacing the DIS, but at that time the tach would drop in and out completely but the motor never did stumble. Looking at the codes Id say its 50/50. I guess we will find out when the parts arrive.
 
14: the eca has detected an intermentent PIP signal in recent operation
PIP = Profile Ignition Pickup = Crank Sensor.

Thats saying the crank sensor is dropping out.. when you get a stumble like you described, thats actually your engine shutting off for a brief moment. If I got this code, I'd replace the sensor before it leaves me stranded somewhere.
 
crank sensor

I would definitely check the crank sensor. I had a similar problem for a few years, took it to several different shops. I had one shop replace the cam position sensor, one say it was a bad ground on the DIS, etc. It turns out that the wiring harness for the crank sensor had become pinched over the years. One of the wires was actually separated, and was only being held together by the rest of the harness. Occasionally the wiring would shift due to vibration or heat or what-have-you and the wire would no longer touch, resulting in a no start/no run condition. I finally resorted to the internet (which is what led me to SCCoA) and since the car finally quit running completely, I learned about the "upshift light tell-tale" which led me to replace the crank sensor. When I took it out that is when I discovered the wiring problem; nothing was actually wrong with the sensor itself.

By the way, I have been running that standard motor LX242 for at least ten years, no problems. I think the differense between the 231 and the 242 has to do with the model years.

Horn
 
Just an update... I have replaced crank sensor and the DIS. I still saw a loss of tach signal on my last test drive. So I guess now maybe either the coil or the harness? I have another coil that I could try.

Also, it seems odd to me that I have only seen the signal drop at idle.
 
Sorry if I missed it - did you replace the spare cam sensor you installed with a new one yet?

When you last installed one, did you confirm the red rubber gasket wasn't doubled up? Is the harness there clean and dry...no oil, etc.?
 
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