[Fogman1941]

Hello,
I have a 1980 Trans Am Turbo 301. I drove it into the shop , rebuilt the motor, reinstalled it and now it won’t start. I’m not getting spark to the plugs. I have power going to the Batt side of the coil (checked with test light). The light comes on when the key is on and it dims when cranking- so I know we’re getting juice to the coil. But nothing to the plugs. The coil and ignition module have been replaced. I’ve been told to simply replace the distributor, but I’d prefer to know what the issue is before I replace more parts. Any help would be greatly appreciated. Many thanks

[steve25]

Are you seeing power to the distributor when cranking , and not just when the key is on?

If you do then the pickup coil in the distributor sounds like it’s gone open .

[Goatracer1]

Two things I have found over the years that cause HEI problems. 1) the wires break where they connect to the magnetic pickup. 2) The rotor will arc through right in the center and ground out on the distributor shaft.

[Formulas]

Light dims while cranking ??? I would think that is suspect that means power to the distributor is dimming as well.. hot wire it temporary straight to the battery see if its a go.. also make sure battery is charged sufficiently

And i hope paint and body people didn't replace the coil most are not mechanics

BTW When i put HEI in my points car i still used the coil connection on the starter for a more direct path to battery spliced in near dist. that can still be done in a original HEI car

[M91196]

I have also had numerous issues with the plug/connector being jacked up at the distributor over the years……………

[johnta1]

Make sure the distributor housing is grounded to the engine. (no paint on block where it bolts down)
Ground wire from battery to engine, frame to engine, engine to cowl/body, etc.

Check under cap that there's nothing wrong. (cap button not screwed up, rotor tip ok, wires broke, frayed, etc)

Sparkplug threads on head not painted. (plugs need to be grounded)

[Formulas]

Outside chance,, But any welding on car body with dist. in car?

[Dragncar]

Headlights dimming while cranking is a sign of issues at the connectors on the battery itself. If your test light is dimming maybe more of a issue.
Clean those things and go from there.

[78w72]

Originally Posted by Fogman1941

Hello,
I have a 1980 Trans Am Turbo 301. I drove it into the shop , rebuilt the motor, reinstalled it and now it won’t start. I’m not getting spark to the plugs. I have power going to the Batt side of the coil (checked with test light). The light comes on when the key is on and it dims when cranking- so I know we’re getting juice to the coil. But nothing to the plugs. The coil and ignition module have been replaced. I’ve been told to simply replace the distributor, but I’d prefer to know what the issue is before I replace more parts. Any help would be greatly appreciated. Many thanks

After all the above basic suggestions... check the ESC, known to go bad on these 301 turbos. Service manual has steps to check it... or contact TTA performance online, they sell a board to bypass the ESC.

[bbnotop]

I have experienced a bad wire harness issue at an HEI distributor. Wire was damaged right where it went into the distributor and grounding out. Visually couldn't see the damage as it was underneath the grommet. And once I had the center copper tang on the rotor break off. Didn't notice the rotor issue until I saw the tang sitting in the bottom of the distributor.

[george kujanski]

"I have power going to the Batt side of the coil (checked with test light)"

I'm confused. If this is an HEI, are you measuring the BAT wire plug on the side of the distributor? If not where are you measuring?

George

[Schurkey]

FIRST, verify that the rotor turns when the starter motor is cranking the engine. If the roll-pin on the distributor gear shears, the distributor may not be turning, or not turning smoothly/steadily.

If the distributor rotor turns...

Get a spark-tester CALIBRATED FOR HEI, a spark plug boot from the Treasure Yard, and a jumper wire. Cut the boot as shown. (Photo 1.)
There are many styles and brand-names of spark testers. My favorite--and the GM-Recommended type--is this. There are other brand names of the same sort of tester. NOTE: A "spark tester" that make a light-bulb glow is WORTHLESS. You want one that forces the spark to jump a calibrated gap.
http://www.amazon.com/dp/B003WZXAWK/...=2VLYZKC3HBBDO
https://www.amazon.com/dp/B003WZXAWK...=2VLYZKC3HBBDO

Flip the distributor cap upside down, secure it away from the distributor rotor. (DO NOT disconnect the wire harness from the cap.) Install spark tester as shown, ground the jumper wire. Turn ignition "on". (Photo 2.) Crank engine. You should get consistent sparks at the spark-tester. If you do, suspect a failed rotor, failed plug wires, or maybe a failed distributor cap. If you do not get sparks...

...Connect the lead of a 12-volt INCANDESCENT test-light to BATTERY POSITIVE (or the alternator output stud, if that's more convenient.) Touch the pointy-part to a good ground, assure that the test light lights up. Remove the pickup coil connector from the ignition module. Touch the pointy part of the test light to the "G" (Green wire, small) terminal of the ignition module. The test light won't light-up. That's OK. Remove test light probe from "G" terminal. (Photo 3)

GM has many "HEI" modules. Perhaps you have something other than the usual "4-pin" module. If so, you'll have to identify which pickup-coil terminal on the module to probe. (Photo 4--Not a complete listing of every HEI module.)


Every time you REMOVE the test light from the terminal, you should get a spark across the spark-tester. If you do...the pickup coil has failed. If you don't, it's the ignition module, the ignition coil, the wiring connecting them, or some combination.

[Gary H]

My bet is on the ESC being bad. I worked on a customer's 80' TA turbo 301 car years ago that had the exact same issue, no spark. I tried all the normal checks and replacements with a HEI with no success. Bypassed the ESC and it fired off immediately.

[jamaca85]

have you connected the timing light to the spark plug wires and turned the motor over to see if the timing light flashes?