240T ignition help needed

I have an 84 245Ti that has no spark...

Could you guys post some help tips that I might try?

Things I have tried:

Per Bentley's, I ohmed out the coil, impulse sender (section 280) I also checked the ignition computer, but I think the instructions are bad.

Ignition computer is good in another 240Ti.

I'm at a loss until I can try another dist. on it's way from IL

yeah you probably answered your own question, take off the cap and inspect the points, the rotor and the wires. if they're nasty-looking then you have your problem.

I should have gone into more detail:

I have tried a brand new cap + rotor, new bougicord wires off a running 240T, and the relay that is attached to the ignition computer. None of these made a difference. Still no spark.

good plugs, dripping wet when pulled to check. I'm hearing the fuel pump run and the freq valve turn on. Just no spark!

No spark checked with a known good timing light on ANY lead, coil included! Timing was set to straight up via crank, cam, and the mark on the dist.

wiring harness is shot then would be my guess.

ignition issues

So, what did the impulse coil measure in ohms? I would suggest starting at the ignition coil. Put a test light on both the positive then the negative lead when cranking the engine. The positive should be bright. The negative side should flash as the ignition box triggers sparks. If you don't have flash but have a solid bright light on the negative. And you know the ignition box is good. Then you aren't getting an ignition trigger from the impulse coil. If the negative side is out then you have an open in the primary circuit either the coil or wiring. One of the sneaky problems that can happen is a bad ground for the ignition box. It's a black wire coming from the ignition box connector to the inner left fender where it's grounded with a screw.

Dave-

I back-probed the black wire on the connector and managed to get continuity to ground. Bentley then says to get battery voltage at the green wire with the key on. I don't get voltage, but I don't get voltage on the green wire on my running 240T either!

As for checking the coil, I'm getting 12V at both 1 and 15 with the key on.

IF you are talking about testing the impulse sender, should I get flashing out of either the brown or green wire?

As for the wiring harness, it was the first thing I replaced on the car, using past experience and my running 242 to check against.

If you're getting fuel, then the fuel pump relay is getting ignition pulses; is the coil?

ignition

Do you get a flashing when cranking on the coil negative? Also to check for power to the ignition box it gets 12V on the blue wire on the connector. The blue wire leads to a single connector coming out of the harness. This is usually located underneath the ignition box. A bad connection in that will lose power to the box and no spark. Be sure that fuse 13 is good in the fuse box.

For a basic check of the impulse sender you are doing that when you check the coil negative for flashing when cranking the engine. If you have a solid light when cranking on the coil negative terminal. Then the impulse coil signal isn't being switched by the box or the signal isn't there.

For a voltage check of the impulse sender signal. It's a very low AC voltage that you should read across the brown and green wire when cranking the engine. Something like .1-.2V AC if I recall correctly.

coil neg is ?1? or ?15? It doesn't seem as though I'm getting flashing on either. I do get battery voltage at both.

I do get 12v to the ign. box via the blue wire. Per the bentley, I believe it goes to fuse 11, where I measured voltage and continuity.

I haven't measured voltage at the impulse sender (brown and green wires), just resistance, which seemed to fall within specs comapred to Bentleys and the runnign 240T.

I should have the working dist. in my hands tomorrow or Mon., but would like to get it running without swapping dist if possible.

Thanks-

Kerry

ignition issues

Coil negative is terminal 1, terminal 15 is 12V. If you don't have flashing on terminal 1 during cranking then you need to troubleshoot the impulse sender, it's wiring, and possibly the ignition box. If the sender ohmed out to spec. You need to check it right after trying to start the car. Sometimes they open when being used. Also be sure the wiring isn't breaking where the connectors are on the distributor and the inline connector. Seems like you are missing the trigger signal. Inside the distributor be sure the roll pin for the flywheel isn't gone or worn away letting the star wheel move out of position or spin.

I'll pull the dist. later today.

Thanks for all your help!