Knocking on a new 3.4 (Page 2/2)
Notorio FEB 12, 11:52 PM

quote
Originally posted by Patrick:

Seriously guys, spring for a whole five bucks and get a proper mechanic's stethoscope.




LOL, I didn't know there even was such a thing
Patrick FEB 13, 12:30 AM

quote
Originally posted by Notorio:

LOL, I didn't know there even was such a thing



This is why I'm here.

theogre FEB 13, 06:27 AM
⚠️ Warning: Running any GM engine w/ DIS w/ spark plug or there wires pulled even for seconds is often bad and easily blow coils and ICM.

Coils can flash HighV to LowV inside for many HighV problems and once done the coil is destroyed even if seems to work later.
Why? Watch Wells/Airtex @ Parts Plus YT https://www.youtube.com/watch?v=zKYTl6sC-qk
And No Test is available to general public or most parts stores for this problem.
You need a High $ "meger" unit used by some building electricians that test for bad insulation.

Can't tell for sure what sound it.
Careful feel around (don't touch) or use tube trick above often feel/hear exhaust leaks fast.

------------------
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

eti engineer FEB 13, 09:00 AM

quote
Originally posted by theogre:

⚠️ Warning: Running any GM engine w/ DIS w/ spark plug or there wires pulled even for seconds is often bad and easily blow coils and ICM.

Coils can flash HighV to LowV inside for many HighV problems and once done the coil is destroyed even if seems to work later.
Why? Watch Wells/Airtex @ Parts Plus YT https://www.youtube.com/watch?v=zKYTl6sC-qk
And No Test is available to general public or most parts stores for this problem.
You need a High $ "meger" unit used by some building electricians that test for bad insulation.

Can't tell for sure what sound it.
Careful feel around (don't touch) or use tube trick above often feel/hear exhaust leaks fast.




I used meggers for several years in my work as a high-voltage systems test engineer. The bottom end meggers which electricians use only go to 1000 volts. The next step up is 5000 volts and the more expensive ones go to 10 kv. Not sure this would help. There is a unit we used called a DC Hi-Pot that would go from zero to 100,000 VDC, but this would be overkill and is not available to the general public, although I have seen them on eBay and other such sites. We tested 12,000 volt cable at 63,000 VDC. It took that much of a differential to tell if anything was bad, so I don't know if a megger would work that well on an automotive coil, since the secondary voltage is tens of thousands of volts.

[This message has been edited by eti engineer (edited 02-13-2022).]

theogre FEB 13, 11:48 AM

quote
Originally posted by eti engineer:
I used meggers for several years in my work as a high-voltage systems test engineer. The bottom end meggers which electricians use only go to 1000 volts. The next step up is 5000 volts and the more expensive ones go to 10 kv. Not sure this would help. There is a unit we used called a DC Hi-Pot that would go from zero to 100,000 VDC, but this would be overkill and is not available to the general public, although I have seen them on eBay and other such sites. We tested 12,000 volt cable at 63,000 VDC. It took that much of a differential to tell if anything was bad, so I don't know if a megger would work that well on an automotive coil, since the secondary voltage is tens of thousands of volts.

Once a flash over happens, often have carbon track might pass normal Ω meter power by and tested @ 1.5 - 9V and fail 500 - 1000v output megers. But yes, may not be a guaranty for a good/fried DIS coil.
(You often see carbon tracks on Distributor Caps etc but many times read open tested w/ normal Ω meters too.)

I can't justify meger or Hi-Pot to use 1 to a few times. Many sold in 2nd hand markets often have major problems and need high dollar $ repair & calibration services to use them safe.

DIS used more power and volts vs HEI.
Secondary side:
DIS 37kV 80mA 65mJ for 14v 9A in
HEI 32kV 45mA 62mJ for 14v 6A in
Source Delphi datasheets.
Either can hurt or kill depending how they shocks you.
Dennis LaGrua FEB 13, 08:41 PM
As for the noise finder. I've tried the basic auto stethoscopes and have had better results with my hose and funnel. The way I see it the stethoscope detects noises in a solid while the hose can detect noises both in air and in solids. Put the stethoscope in a room with people talking and you'll hear nothing. Now try it with the hose and you will hear the voices. Just my experience.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

Patrick FEB 13, 09:51 PM

quote
Originally posted by Dennis LaGrua:

As for the noise finder. I've tried the basic auto stethoscopes and have had better results with my hose and funnel. The way I see it the stethoscope detects noises in a solid while the hose can detect noises both in air and in solids.



My inexpensive Harbor Freight mechanic's stethoscope, which I bought years ago, came with a "horn". Unscrew the metal rod, install the horn... voilà... the ability to pick up air-borne sounds. I've gotta say though, it's been my experience that the metal rod has been way more useful than the horn when diagnosing engine sounds.
theogre FEB 13, 10:38 PM
Exhaust leaks are often easy to find w/ a "tube trick" because is louder and often some exhaust hit the end as well.
spare heater hose and other big heavy hose can work and could save you burning hitting exhaust trying to feel in tight places. Like Fiero V6 E-manifolds.
⚠️ Don't hold the tube tight to your ear!

Loud noises like above can hurt or damage your ear w/ a stethoscope too.
Cartoons etc w/ yelling into doctor stethoscope isn't so funny when morons actually try that.