How test Timing Mark & Impulse senders on 84' 3.2L

[911 tweaks]

I am guessing it is a resistance test like on the cylinder head temp sender...
**I read from another thread that to test the head temp sensors 2 wires, 1 wire is grounded & the other wire should read btwn 1-2k ohms...is this correct...??

Does anyone know the procedure & value ranges to test these other 2 sensors that are sensing the rotation of the engine flywheel...??

I've attached a pic of the fun to get at sensors as I removed them & cleaned off all of the metal filings on their ends & I want to make sure they are working...I know...I should of tested them BEFORE I spent 5 hrs removing them & cleaning them to hopefully have NOT reinstalled 1 or possibly 2 bad sensors...

Thx in advance for your help...

Bob

[911 tweaks]

Found the info in the bentley...all set...

[ischmitz]

Just be aware there are cases when a static test (Ohm-meter) indicates a working sensor and you still can have issues that ultimately can be traced back to one of the sensors:

Heat and vibration over time lead to performance deterioration and intermittent working conditions. The better test would be an oscilloscope across the sensor while the engine is running or cranking. The output of the sensor is a sine wave (speed) and a pulse (reference)

What is the reason you are looking into the sensors?

Ingo

[911 tweaks]

Thx Ingo...reason for checking is a poor idle on an 84' Carrera w/ 50k original miles...
I have completed many items that needed to be check into and still rough idle...car is also sluggish unless you floor it but still then seems off...
Car starts up fine & initially will idle fine but as it warms up it drops down to a rough idle @ ~ 600rpms per dash tach...

I have done the following:
1. checked for vacuum leaks & tightened up all clamps
2. removed & cleaned both crank sensors...now need to electrically check & keep your good point in mind...:-)
3. fuel pressure in spec...
4. just rec'd all fuel injs back from cleaning, testing & flow matching & they were not bad but needed the servicing as also original on car...injectors were a BI^CH to remove & I suspect that 1 of the injectors may of had a leaking o-ring...
5. fuel filter kind of dirty so replaced...
6. just bought lm2 so going to test exhaust...plug already removed by PO on metal air box so I can tweek setting if needed...
7. I am going to pull all spark plugs & inspect...I replaced them last spring so they only have a couple of k miles on them...but, good to see what state they are in...
8. plan on checking aux air idle control unit...need to see what the specs for good ~ bad status & how to test the unit...
9. last spring new cap & rotor also...
10. spark plug wires are original I believe...I did a nite test of spraying water must on wires while engine running & I did not see any arcing...

Any other items I cannot pull off of the top of my head at this moment...Plan for the weekend is to install injectors, re install all air filter & air flow sensor parts & start engine & see where i am at...then check & adjust idle speed & fuel mixture & items listed above...

Hopefully then I don't have to tear out my remaining hairs on my head... :-)

Any & all input welcome...

Thx, Bob

[ischmitz]

I can't believe I am saying this but here is goes anyway:

I filled up the car last week at one of the cheapo gas stations on my way to work. I was running on fumes.

Ever since it runs like sh|t. Idle is hunting, it is spotty and hesitant on pickup, and when I floor it I can hear the onset of pinging. Overall it feels like the engine has aged 20 years. Idle is so rough I feel I am in a V8 muscle car of the sixties.......

My first thought was that one of the dual-ignition circuits has failed (rather comon with earlier 3.6) but both work fined. Tested that when I pulled into work. So in conclusion it must be related to the crappy gas.

[911 tweaks]

you are absolutely right about gas these days...I will double check on the gas condition but is was fine in Jan when I filled it up as we had a very mild winter here in New England...I did stabilize the fuel too if that helps w/ the new stuff for boats that specifically says it works great w/ the 10% alcohol gas (crap gas I call it) & boat environments...
I'll [post up what I find...if you have any other input let me know...

oh, I almost forgot, I also did check the exhaust gaskets @ the heads & muffler...as a last ditch effort I will pull the entire exhaust, dis assemble & reassemble w/ new gaskets to eliminate that as I believe age of the car, NOT miles, is what I am fighting now on this car...

[Tippy]

Originally Posted by ischmitz

I can't believe I am saying this but here is goes anyway:

I filled up the car last week at one of the cheapo gas stations on my way to work. I was running on fumes.

Ever since it runs like sh|t. Idle is hunting, it is spotty and hesitant on pickup, and when I floor it I can hear the onset of pinging. Overall it feels like the engine has aged 20 years. Idle is so rough I feel I am in a V8 muscle car of the sixties.......

My first thought was that one of the dual-ignition circuits has failed (rather comon with earlier 3.6) but both work fined. Tested that when I pulled into work. So in conclusion it must be related to the crappy gas.

With your vast knowledge Ingo, it isn't hard to think of the worst first.......I'm the same way. I think of the worst thing that can go wrong and work back finding it was the easiest.