single issue left No Spark. ( boat cranking now, remote solenoid replaced)

JohnEGraham

JohnEGraham

Active Member
Aug 5, 2008
1,013
Long Island, NY.
Boat Info
250 Sundancer 1998 5.7.
Engines
350 Merc / Bravo 3
No spark issue still is a problem
!Hi, 5.7 Efi Gm regular ignition ( Not Tunderbolt)
(Well, I replaced the remote solenoid and got the engine turning over.)
so I separated from the previous post...
*Bought spark tested and checked with 2nd one to be sure it wasn't faulty
*I replaced the Coil
*Changed the ignition coil sensor - taking the distributor out ( which was only a couple of years old after rebuild)
* Checked all the fuses including the larger 50 amp main
*Cleaned all the terminals /grounds
* Had a mechanic run a computer diagnostic for Faults which checked out
* The larger red wire to the coil does get the 13.7 volts ( when I plug the connector in I hear the Electric fuel pump
* Disconnected the Gray send wire on the Tech *
* Disconnected and cleaned the larger Main Plug / Socket with like 10 connectors
* There are two plug-type relays above which are good
I have an acquaintance who has been helping me who works for a certified Mercruiser shop...
He is going to give me a known good Distributor to try...
After that, he has thought it might be the computer?
I am now starting to research that possible computer issue and what does it do in the firing of the coil
NEW THINGS CHECKED TODAY:
Tried known good computer ECM I think it called?.. I was a little different model, plugged right in but the mechanic said basic functions should work. at 2K. was glad it wasn't that...
*Cleaned the large #10 or #8 grounds that go into the large harness to the two bolts..
* pulled the dashboard to get to the back of the key switch and Checked that that all worked with a test light. ( The purple wire got hot.. which apparently was a good thing)
* the red/white wire feeding the coil got its proper 14. volts
So now we Tried a different Distributor, Another Coil. All known good.
Well, that's where are now.. still no spark.
 
So where is the spark getting lost ? 12 volts to the coil... do you have high voltage leaving the coil ?
 
Hi, thanks for the reply!
No.. I can't get any Spark out of the Coil over to the distributor.. ( i have test Light there)
Thanks..
 
Take the negative wire off the coil and make you up a short jumper wire. And hook it to negative side of the coil. Pull your coil wire out of your distributor and put a plug in it found it on the manifold , now turn your key on and take your jumper that’s coming off the negative side of coil and tap it on a ground , every time you do this you will get spark from the plug out of the coil (if you get spark your problem lies in the distributor and everything else is good if no spark then your problem is not in the distributor)
 
Good Morning, Thanks for the reply on ruling out the distributor but its not like the standard coils I am used to like on my old cars. There is a main red / white ( control wire) with tiny little tabs when you take the connector off there does not seem to be a ground?
oem-quicksilver-mercury-hei-delco-ignition-coil-898253t27
coil.jpg

https://nuwavemarine.com/oem-quicks...wBzsAl-uvZUFRqzK-Xwf8k-aLlX8vNZhoC1LoQAvD_BwE

https://www.marineengine.com/parts/mercury_marine_parts/static/img/COMMON/35346.gif
 
I have that same ignition setup. The high voltage lead coming from the coil will not spark with the distributor disconnected. I will assume the coil gets its ground from the dizzy clamp.
 
I get the impression this engine has not run since you acquired it.

Your Mercruiser friend is most likely right that the distributor is the problem. If it isn't compatible with the ECM...it won't work. If you try to make the distributor independent (old school) of the ECM....the ECM won't fire the injectors.
 
Hi, I have actually owned the boat for 10 years and it was running great before all this..
The thing I don't understand as in most computers (ECM? ) there normally relays that get activated when thing are in their proper sequence. although as you say I can't isolate the distributor and go old school?
isn't there a final controlling relay that the computer activates that I can jump and work back from there? or is it inside the ECM that does the muscle?

Thanks again in advance
John
 
Didn't see your previous post, how did this problem begin? The pickup coil and the primary coil can be tested with a DVM. Maybe you have a broken wire.
 
Below is the Mercruiser diagnostic. It should work on your engine even though you do not have a Thunderbolt V installed. I'm presuming that the wiring is the same. It's a pretty straightforward diagnostic.
 

Attachments

  • Thunderbolt V1.pdf
    28.6 KB · Views: 876
PlayDate said:
Below is the Mercruiser diagnostic. It should work on your engine even though you do not have a Thunderbolt V installed. I'm presuming that the wiring is the same. It's a pretty straightforward diagnostic.
Click to expand...
This is what I was trying to say , process of elimination
 
PlayDate said:
Below is the Mercruiser diagnostic. It should work on your engine even though you do not have a Thunderbolt V installed. I'm presuming that the wiring is the same. It's a pretty straightforward diagnostic.
Click to expand...
Unfortunately, The one thing is different the part where you take the White/Green from the distributor to tap it quickly to ground.. There are no Wht/Grn on a Non- thunderbolt igniton set-up - Thanks anyway...
 
Step by step guide used -- Did all but last one number 8 but still No spark!

/1. Visually check the ignition coil for

melted plastic on its outer case. If the case is melted,
the tachometer lead (gray or white) is shorted to ground somewhere. Isolate and repair ( ISOLATED TACH ok)
before replacing the ignition coil. (REPLACED COIL)
2. Make sure that battery voltage is present at the purple power lead (carbureted) or red ( YES)
power lead (EFI) at the ignition coil. If not, isolate and repair the problem in the engine or
boat harness.
3. Isolate the gray (carbureted) or white (EFI) tach lead at the negative side of the ignition
coil as described in the previous section, step 4. If spark is now present, the tach lead is
shorted to ground in the engine harness, boat harness or in the tach itself. (OKAY)
4. Disconnect the 4 pin connector from the ignition module.

EFI models: if spark is now present, ( NO) the ECM is sending bypass voltage to pin “B” of the
ignition module and it is not supposed to. The EFI system will have to be diagnosed at
this time, as there is not a problem with the EST system (NO)
5. Disconnect the 2-pin connector from the ignition module. With the Key ON, check for battery

a voltage at both the pink and brown terminals of the harness. (YES) Good

a. If there is not battery voltage at the pink terminal, replace the 2-wire harness as the

filter is most likely blown open.

b. If there is not battery voltage at the brown terminal, replace the ignition coil as the primary

windings have most likely melted open (because of a shorted tach lead).

c. Reconnect the 2-pin connector to the ignition module when finished.

6. If spark is still not present, remove the distributor cap and check the pickup coil for resistance

and short-to-grounds. Resistance across the green and white leads must be

500-1500 ohms (750-850 preferred) and the reading must be steady. The resistance between ( 847 ohms here )

the green lead and the distributor frame must “infinity” and resistance between ( GOOD)

the white lead and the distributor frame must be “infinity”. If any of these readings differ (GOOD)

from specifications, replace the pickup coil.

7. Verify that the timer core is still magnetic. This is the part that rotates above the pickup (NEW)

coil.

8. ( NOT SURE ABOUT THIS???) If spark is still not present, you will need to “false trigger” the module to determine if it is

opening and closing the primary circuit. Proceed as follows:

a. If still isolated, reconnect the tach lead to the ignition coil. Connect a voltmeter to the

gray tachometer lead bullet connector (near the ignition coil). Set the meter to read

DC volts. Connect an air gap tester from the coil’s secondary terminal to ground. ( WHAT IS AN AIR GAP TESTER? a SCREWDRIVER NEAR GROUND?)

b. Remove one of the ignition module mounting screws and loosen the other. Rotate the

module out from the distributor frame, then retighten the loose screw. Connect the

positive lead from a 1.5 volt AA (or similar) battery to the ignition module’s “P” terminal

(pickup coil terminal).

c. With the key in the ON position, note the voltmeter reading. It must be the battery voltage.

If not, you didn’t verify the coil primary windings are good or you didn’t find the short

to ground in the gray tach lead. If the voltage is OK, proceed.

d. While observing the voltmeter, momentarily connect the negative lead of the 1.5 volt

battery to the distributor frame. The voltage must drop several volts as the module

grounds the negative side of the coil. If not, replace the ignition module.

e. When the negative battery lead is disconnected from the distributor frame, the voltage

must rise back to battery voltage and the ignition coil should fire. If the voltage

changes, but the coil does not fire, replace the ignition coil (the secondary windings

are open or shorted).

f. When finished, reconnect all leads and connectors.
STILL NO SPARK,, LOOKED FOR BROKEN BURNT WIRES.
 
You may get more help if you tell us what happened. Like...my boat was working great and then 1 day ???
 
I would need a drink if I followed that list.... If you have power to the distributor and the pickup has continuity.....it should fire the coil. It's a mechanical system.

On the purple wire.....sometimes the engine connector gets corroded and while it looks okay on a volt meter ....it isn't. One test I do is to run a separate, temporary 12 volt wire to the coil and piggyback the wire. If it fires up.....then it is engine connector or possibly a faulty safety lanyard circuit (if you have one).
 
Okay I skip the last post, have you taken the distributor cap off and turn the motor over to actually make sure that your rotor is rotating, have seen many times fighting a fire problem and see the rotor is not turning
 
PlayDate said:
I would need a drink if I followed that list.... If you have power to the distributor and the pickup has continuity.....it should fire the coil. It's a mechanical system.

On the purple wire.....sometimes the engine connector gets corroded and while it looks okay on a volt meter ....it isn't. One test I do is to run a separate, temporary 12 volt wire to the coil and piggyback the wire. If it fires up.....then it is engine connector or possibly a faulty safety lanyard circuit (if you have one).
Click to expand...

Hi, There there is no Purple wire on the coil? its a 97 - 5.7 Bravo-3 with regular GM ignition ( EC-3 )
I think you're talking about a Thunderbolt ignition?
There is a Red wire with 13.7 volts and white wire

Thanks
 
Now we're talking about replacing the Electrical Harness.
The original two problems where Starter Remote relay fried. maybe it melted some wires in the harness? Hopefully, it didn't mess up the ECU-3. just peachy

2) found an Electrical Harness of another running boat on ebay. Guess its worth a shot...
 
Last edited:
You must log in or register to reply here.

Forum statistics

Threads
113,241
Messages
1,429,113
Members
61,122
Latest member
DddAae
Back
Top