Engine/Transmission (1994 - 1998) hand held tach hookup?

[PModern]

Hi, Kind of a basic question I realize but I'm not the swiftest when it comes to things mechanical. I'm trying to adjust my idle with a regular old dwell/tachometer. Asides from the obvious ground cable where do I hook up the positive lead? Its a '96CTD, 4X4, 140K.

Thanks,

Paul

 

[kenny61]

cant do it with a dwell meter. there is no ignition pulse for it to sense

 

[PModern]

So what is it, basicaly speaking, that I need?

 

[rattle trap]

So what is it, basicaly speaking, that I need?

I can see 2 basic choices.



Either a photo-laser tach and white out/reflective tape, or a good multimeter and calculator.



Multimeter should be capable of hertz.



Theoretically speaking, the CPS makes 2 ac waveforms per crank revolution IIRC (***might be wrong there***) Should be able to count the frequency in hertz (per second) This number divided by 2 pulses would be the rps (revs per second) of course multiplying by 60 would = rpm. Figuring out a base desired hertz would make life a lot easier. For example 750rpm x 2 pulse per rev = 1500pulse per minute. divided by 60 seconds = 25Hz.



I have never used my frequency function, so I have no clue if it would work in reality. I have used oscilloscopes to measure crank frequency on gassers though.



Another hypothetical would be using the dwell tach inductive clamp around 1 of the 2 cps sig wires. The results would be off, but not sure by what magnitude. Likely would read 4x as high since the cps fires 4x per 2 revolutions as opposed to only once.



The laser tach takes a lot of guess work out of the equation, although possibly too pricey for a 1 time user unless you like to collect unique tools.

 

[PModern]

Thanks rattle trap: is this what you had in mind?

Digital Laser Handheld Tachometer for Motor Rev Measurement: 001480-003 VirtualVillage.com

 

[rattle trap]

Thanks rattle trap: is this what you had in mind?

Digital Laser Handheld Tachometer for Motor Rev Measurement: 001480-003 VirtualVillage.com

Thanks so much!!!



I run an account with matco. They cut me a pretty good "discount" for one of those and the grand total was still ~$75.



Glad I hesitated on the purchase... . that looks identical.



If I were you, I'd get it. I certainly plan to...

 

[PToombs]

They have those on E-bay too, for about the same price.

 

[PModern]

Ok. So I've got a laser tach. I'm still not too clear as to where I put the "reflective tape". Any help?

Thanks,

paul

 

[PToombs]

Clean a spot on the harmonic balancer, and put it on there.

 

[PModern]

As mentioned in my original post, I'm a newbie so bear with me. I've got the Chrysler shop manual for the appropriate year. No mention of harmonic balancer. Would vibration damper be the same? That I can find both in the book and on the vehicle. I'm trying to learn all this as I go along and all I want to do at this point is check and adjust my idle due to rough starts when cold. I'm in northern New Hampshire ,so I mean COLD!. Should be a piece o' cake, right?

paul

 

[kenny61]

same thing its the big round thingie behind the bottom pulley that attaches to the front of the crank shaft

 

[kenny61]

do you plug it in? they all run a little rough for a little bit. on mine the unplugged in roughness starts at around freezing at 20 it may stall the first time it starts but will keep running after the second time

 

[cojhl2]

PModem, I apologize first cause I'm sure to ofend you, but I dont't know how else to say it. .



Based on yor questions i would be very reluctant to screw with that engine until I had a better understanding of it.



Again I dont mean to sharpshoot, I'm just trying to be sensible.

 

[PModern]

PModem, I apologize first cause I'm sure to ofend you, but I dont't know how else to say it. .



Based on yor questions i would be very reluctant to screw with that engine until I had a better understanding of it.



Again I dont mean to sharpshoot, I'm just trying to be sensible.

cojhl2, No offense taken! Its just that it seems like adjusting the idle is simple enough and no need to take things apart. I'm not totally incompetant but wouldn't mess with things that seem to involved. I've never had an issue adjusting the idle or timing on a gasser with a tach/dwell meter.

 

[PModern]

do you plug it in? they all run a little rough for a little bit. on mine the unplugged in roughness starts at around freezing at 20 it may stall the first time it starts but will keep running after the second time

kenny61, no but its garaged (unheated). It'll start ok if I gently let up on the pedal and let it idle. however the idle seems low. When I back out and stop it will stall two or three times when I brake unlessw I slip it into neutal before stopping. All I want to do is check the idle! How hard can that be?

paul

 

[cojhl2]

cojhl2, No offense taken! Its just that it seems like adjusting the idle is simple enough and no need to take things apart. I'm not totally incompetant but wouldn't mess with things that seem to involved. I've never had an issue adjusting the idle or timing on a gasser with a tach/dwell meter.

Thank you PModern you are an understanding gentleman. .

 

[cojhl2]

Thanks so much!!!



I run an account with matco. They cut me a pretty good "discount" for one of those and the grand total was still ~$75.



Glad I hesitated on the purchase... . that looks identical.



If I were you, I'd get it. I certainly plan to...

You can say that again,, I bought a laser tach a few years back it cost me about 200$ as I recall.



Of course I got a genuine plastic carrying case with it!!!!!!LOL

 

[KB0OU]

PModern,

Don't you have a tachometer in the dash, it should be pretty close.

 

[kenny61]

kenny61, no but its garaged (unheated). It'll start ok if I gently let up on the pedal and let it idle. however the idle seems low. When I back out and stop it will stall two or three times when I brake unlessw I slip it into neutal before stopping. All I want to do is check the idle! How hard can that be?

paul

Never did it but if you need to adjust it go ahead its only adjusting a bolt. Do you have the service manual?

 

[PModern]

Never did it but if you need to adjust it go ahead its only adjusting a bolt. Do you have the service manual?

Yep. And there's plenty of real good info. here. Thanks

paul