Thunderbolt IV ignition question

ussoldier_1984 · Mar 16, 2011

Been having a strange issue with my boat ignition system for about a year. I used the thunderbolt IV diagnosis flow chart and I am to the step where it says disconnect the red white lead from dist and test to see if there is 12 volts. there was only 9 volts present, battery is charged to 12 volts. its then says if 12 volts is present replace ignition sensor. My question is why the drop in voltage and should I go ahead and replace the igniton sensor?

Update put the battery on charge it gives me 11.8 volts when the red and white wire from dist is connected. when disconnected I get 12.8 volts help please!!!! i really want to get the boat ready for spring im in tx and warm weather is just around the corner

ussoldier_1984 · Mar 17, 2011

Re: Thunderbolt IV ignition question

anyone?

Don S · Mar 17, 2011

Re: Thunderbolt IV ignition question

I think you are reading your chart wrong. Below is the diagnostic chart and I lettered it so we don't get mixed up.

In step C, if you have between 1 and 12 volts with the red/white wire hooked up, you should move to step D, not C1.

In step C If you have 0 V, then you move to step C1 not before.

ussoldier_1984 · Mar 17, 2011

Re: Thunderbolt IV ignition question

Yea I followed the flow chart as stated first time I did It I had 0 voltage at red white wire took it off had 12 volts second time I tested I had 11.8 volts when my battery was at 12.8 volts I think. I then tested my spark coming from coil and had really good spark from coil both signs point to ignition sensor in distrubutor but last aug I put a brand new ignition sensor in the dist.

Update why do I have spark from coil when I crank engine but no spark from coil when I ground out white green lead from dist like the flow chart says?

Don S · Mar 17, 2011

Re: Thunderbolt IV ignition question

Yea I followed the flow chart as stated first time I did It I had 0 voltage at red white wire took it off had 12 volts second time I tested I had 11.8 volts when my battery was at 12.8 volts I think.

That's confusing. and the "I think" doesn't help.

Do this, hook all your wires back up as if you were ready to go boating and nothing was wrong.

Follow these steps exactly. Do these tests new, DO NOT reuse old numbers. Make sure you have the same good clean ground on your meter for all the tests.

1. Check battery voltage.. What do you have ?
2. Turn the ign. key to the run position, check the voltage at the + terminal on your coil. What do you have?
3. Check the voltage at the red/white. What do you have?

Post the answers to all 3 questions.

ussoldier_1984 · Mar 17, 2011

Re: Thunderbolt IV ignition question

Werid I have spark now wtf. but wont start letting the battery charge for a bit then take new readings get back to you soon

Bondo · Mar 17, 2011

Re: Thunderbolt IV ignition question

Werid I have spark now wtf.

Ayuh,... Check all the various Grounding straps/ wires...

ussoldier_1984 · Mar 17, 2011

Re: Thunderbolt IV ignition question

Battery voltage- 12.6
+ terminal of coil-12.31
Red/white- 11.55

Gonna go through all wires and see if I find any bad grounds or corroded contacts

Don S · Mar 17, 2011

Re: Thunderbolt IV ignition question

Gonna go through all wires and see if I find any bad grounds or corroded contacts

Ahhh, Step A in the troubleshooting chart.

Battery voltage- 12.6
+ terminal of coil-12.31
Red/white- 11.55

Ok, then you have no reason to be removing the white/red or using any of the steps in the C1-C4 section.
You should now move on to step D.

ussoldier_1984 · Mar 17, 2011

Re: Thunderbolt IV ignition question

I already have gone through it once checking for bad connections it was the first thing I did Im gonna do it again is all im saying I followed the flow chart to a tee. I have spark at coil but if i have spark at coil doesnt that mean the ignition sensor is working correctly and telling the coil to release the charge?

Don S · Mar 17, 2011

Re: Thunderbolt IV ignition question

I have spark at coil but if i have spark at coil doesnt that mean the ignition sensor is working correctly

No, you're looking at it wrong. When you remove the white/green wire, you disconnected the sensor in the distributor from the system. Striking the wire on a ground, is now doing what the sensor does, and it causes spark.

Since you have spark at the coil when striking the wire to ground, your next step is D1.

ussoldier_1984 · Mar 17, 2011

Re: Thunderbolt IV ignition question

Ops I explained it wrong sorry I am horrible at explaining myself ill try again haha. When i crank engine I have nice spark from coil. when I disconnect green white wire and tap on ground I dont have spark from coil. make sense? what does that mean?

Don S · Mar 17, 2011

Re: Thunderbolt IV ignition question

when I disconnect green white wire and tap on ground I dont have spark from coil.

Did you have the ignition switch on?

Don S · Mar 17, 2011

Re: Thunderbolt IV ignition question

When i crank engine I have nice spark from coil

Now, I'm really confused. If you have spark when cranking, why are you doing all this to begin with??????

ussoldier_1984 · Mar 17, 2011

Re: Thunderbolt IV ignition question

ignition on First i did the steps because last season I lost spark so i kinda started as if I dont have spark. and If I do have spark I loose spark after about 15 mins of running boat. why would I not have spark from coil when tapping green white wire on ground but have spark when cranking? I know my thoughts are all over the wall Im sorry tramatic brain injury lol yea I got it to pop for a second but I lose spark completly after that pop off. something is intermittently working then dying on me soon as the motor spins a bit faster then the starter turns

Don S · Mar 17, 2011

Re: Thunderbolt IV ignition question

What you are going to need to do is get it running, then do your tests when it stops running.
Why it didn't work when you tapped the green wire, I don't know. Could have been a bad place you tapped, (painted, rusty) or maybe you picked the wrong wire of the 2 white/green wires. Might try the wiggle test while tapping the wire. Things like the connector on the ignition module.

ussoldier_1984 · Mar 17, 2011

Re: Thunderbolt IV ignition question

it will not run but will pop one or two cylinders then lose all spark. wait 10 mins or so and it will get spark back but soon as it pops off it dies and loses spark again.

Don S · Mar 17, 2011

Re: Thunderbolt IV ignition question

Then you need to do your tests quickly after you loose all spark.

When you check it and there is no spark, immediately check to see if you have power on the + terminal of the coil.

ussoldier_1984 · Mar 17, 2011

Re: Thunderbolt IV ignition question

Yep I have 12.4 volts to the + terminal on coil 11.8 volts at red white wire. what else should I check after it loses spark?

On the ignition module is there a way to test it to see if it works besides the flow chart? Ohms between the pins on it or some way to test the curcuits on it

Don S · Mar 17, 2011

Re: Thunderbolt IV ignition question

ussoldier_1984 said:
Yep I have 12.4 volts to the + terminal on coil 11.8 volts at red white wire. what else should I check after it loses spark?

On the ignition module is there a way to test it to see if it works besides the flow chart? Ohms between the pins on it or some way to test the curcuits on it

Then you go to step D and check for spark with the white green wire. But it has to be done when you don't have spark.

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