Hey folks!

Lately I have the problem that the engine of my 1980 cutlass cuts out at high rpm and is hard to start.
It doesn't matter how much throttle i apply. Even full throttle and kickdown is possible. But only until it shifts down or reaches higher rpms. Then the engine cuts out and needs some time to accept throttle again.
Also its really hard to start. It cranks fine but won't fire.
The exhaust was corroded to straight pipe, so i thought that would be the issue. Now i repaired the exhaust but the problem remains.
Fuel lines and air filter are okay, so i assume a problem with the ignition system.
I measured the ignition coil according haynes repair manual. And had following readings:
BAT-TACH = 0.4 ohms
Ground -Secondary = 12.28 kilo ohms
Secondary -TACH = open loop

So this means the ignition coil is defect, right?
Could there be something else i could check before ordering parts? (I'm from germany and parts need around one week to arrive. And i need the car to be running.)

 

The coil looks good based on your resistance tests.

 

Really? Because haynes says secondary to tach shouldn't be open loop. Or am i wrong?
Any other ideas what could cause this?

Maybe some issues with the HEI system? How can i check this?

 

Test the pick up coil as well. Check the insulation on the wires for bare spots. Anytime pick up coils have gone for me it was suddenly. Doesn't hurt to have spare parts around anyways, especially where you are. Even over here, being my car is nearly 50 years old, I carry a trunk full of parts for just in case.

 

On my phone (I could not enlarge the pic) your secondary ohms check looked to be showing a short, but now that I look on my laptop your correct it clearly shows an open. Sorry, my mistake.

 

Oldcutlass, no problem. So yo agree the ignition coil is faulty?

Olds 307 and 407, thanks. I will check the pickup coil and wiring insulation too.

I think it's a good idea to replace both hence they are already 36 years old...
Thanks guys!

 

I test this way:
TEST 1:Remove and invert the cap, Measure between the "TACH" and "BAT" terminals , using your DVOM, Set to OHMS scale, RX1 and be sure the scale reads zero ( 0.00) It should read less than an ohm, typically around 0.5 to 0.6 ohms. Anything less or more, replace the coil.

TEST 2: Set your DVOM scale to RX10k or higher. Touch the probes between the "BAT" and the carbon pickup for the coil. This reading should read between 6000 and 30,000 OHMS. Outside of that range the coil is bad, replace.

Also using test 2 as a reference, check for shorted to ground connections, by probing the "BAT" connection and the center terminal with your DVOM leads. There should be infinity resistance or OL on your meter. You can also check the "TACH" connection as well. Either way, if the reading is anything less than OL, replace the coil.

 

Id check to make sure the meter is up to the task....Id use a FET front end old swing meter for the real low ohm stuff. very very few meters are stable or accurate below 2 ohms, even the good ones. Because of my radio work I keep around meters most would never buy, but I still have a VTVM and an analog radio shack for just this...