hey woundering what would cause my f 250 with 302 not to have any spark.. it happened the other day went out to start it and it started breifly and stoped.. I turned it over and over and nothing but a dead bat.. i charged the bat took out all the plugs and they were all soaked with gas. dried all of them with torch put back in.. tried it nothing took out all the plugs again soaked.. put an old plug in a wire layed it aganst a ground nothing.. is there anything but the coil that i could try that could be gone...???? before the truck would start and at times it would sputer and kick out some black smoke.. and then stop and run fine again.. Also i put a test light on the two wire goning into the coil and had one with power in it

 

What year of truck?

 

I'm dealing with a similar situation on a '95 Mustang right now. You can check the resistance on the coil and see if it's good or not. You check the primary resistance by connecting a DVOM (Digital Volt Ohm Meter) to the coil. The terminals are marked plus and minus. Connect the neg. lead to neg. and the pos. lead to pos. and you should see between 0.3 - 1.0 ohms. This is on the electrical plug connected to the coil. Less than 2 anyway. Leave the neg. lead connected and remove the coil wire. Move the pos. lead to the output terminal of the coil. It should read somewhere between 5000 and 8000 ohms. This is the secondary resistance, the higher of the two. The one I checked read - primary = .7 and the secondary = 7.28 k. This should indicate o.k. if its within spec. Resistance is checked with the key off also.



guzzler96

 

its 89 f250 4x4 I tried the tests they came out good but im going to replace the coil anyway the metal all around the coil is expanding and cuming apartso bad that the screw in one corner broke of... but what about this modual its on the rotor asembley what does it do???? im thinking this may be my problem

 

From his other posts his truck appears to be an 88.

If you test between ground and the coil, with the key in "on" but the engine not running, you should see 12 volts on BOTH sides of the coil. Unlike a system with points, I don't believe it is possible for the TFI system to leave the negative side of the coil grounded with the engine not turning. But just in case, try rotating the engine a bit and test again. If the coil still shows 12 volts on one side and no volts on the other, remove the connector to the lead that shows no voltage. Test the coil again. NOW does it have 12 volts on both sides? If it does not, the coil is bad. If it does, the wiring or TFI module is bad.

The fact that the plugs keep getting wet suggests that the computer is seeing the "PIP" signal from the distributor. This would tend to rule out the usual catastrophic failure of the TFI module. You can confirm this by listening for the whine of the fuel pump. As you turn the key from off to run, you should hear the fuel pump start, run for two seconds and stop. Crank the engine for 15 seconds. Just as you release the key from "start", you should hear the whine of the fuel pump continue for about one second and again stop.

Let's say that you confirm the computer sees PIP and you confirm that the coil negative side is constantly grounded. As a test, remove the 5 bin gray rectangular connector from the TFI module bolted to the side of the distributor body. Check the negative side of the coil again. If it now has 12 volts, the TFI is bad. If it does not have 12 volts, there is likely a short in the wiring.

Run through these tests and report back...

 

I ll check all of this in the morning im at work right now but if any one else wants to add their 2 cents ill listen thanks for all the info

 

hey every one got a coil at the local scrap yard today charged up the battery and away she went,, running a gain just in time for the snow the coil must hav been going for a while becouse the engine light was on before and now it gone out...

 

Glad you got it running.



guzzler96

 

BTW I failed to mention that it turned out to be the distributor on the Mustang. The magnet on the PIP had disintegrated. Distributor had 175k on it, so just replaced it. Cranked and runs now.



guzzler96

 

some times the smallest things stump us??????