Bad coils delco hei voyager ignition

[dnemeth]

Purchased new GM marine engine from Michigan motors last year. From the first day it had an issue that was causing miss-firing at around 4300rpms. After checking everything, fuel, ignition modual I changed out the coil and it would then run up to WOT. The ignition system is the GM Delco HEI (voyager). Very simple system distributed with a small modual and an external coil, has electronic advance. Mallory sells a version of this as they must make the ignition system for GM. I am now having a similar mis-firing issue and have ordered a new coil. Started out like it was starving for fuel and would randomly quit or loose power then come back in the same breath and run fine. Not it seems to run ok up to around 4000rpms and breaks up. My question is what could damage a coil, it's attaches at the back left corner on the bracket used to lift the motor and not in contact with anything else. I disconnect the battery while it's in the garage.. I hear good things about this ignition system but don't want to keep buying new coils or at least understand what might cause them to go bad.

 

[Don S]

Re: Bad coils delco hei voyager ignition

Mallory sells a version of this as they must make the ignition system for GM.

No, Mallory cloned the Delco Voyager (EST) distributor from GM.

My question is what could damage a coil, it's attaches at the back left corner on the bracket used to lift the motor and not in contact with anything else.

Only ones I have seen fail was due to rust or heat from an overheated engine.

 

[dnemeth]

Re: Bad coils delco hei voyager ignition

Well it was not a coil, went to a Mercruser dealer to get a coil, first mistake ended up paying 3 times what the same thing goes for online. I also replaced the cap, rotor and the modual and it still breaks up at high RPM. Here we go , any sugestions much appreciated.

 

[Don S]

Re: Bad coils delco hei voyager ignition

You wouldn't happen to be running Champion spark plugs would you? If so, put the right AC or NGK plugs in it and see what happens.
It would also help to know what engine and it's vintage.

 

[dnemeth]

Re: Bad coils delco hei voyager ignition

The engine is a GM marine 5.7L from michigan Motorz. It was new last august, it came with the Delco EST ignition, a Edelbrock 600cfm carb #1409 and the fuel pump is a carter electric 6-9 psi 72 gph. It wouldnt run up to WOT when I first got it, replaced the fuel pump because I felt 2lbs was low and the new pump was around 4psi, far from the specked 6-9 psi. the fix last time was a new coil. I will have to check the plugs. Will get back with that information. Thanks

 

[Jlawsen]

Re: Bad coils delco hei voyager ignition

Two common problems with the HEI ignition systems is module failure and cross fire. Typically it 5 and 7 that cross fire. The solution for the crossfire is to not run your plug wires parallel. Cross them over at least once and this will break up the flux lines that radiate off the wire and induct into the other wires.

Make sure you are using at least 8mm plug wires. Use the best you can find that are rated for HEI ignition systems. As a side note, it's rare to find the smaller wire diameter these days since most vehicles use a high energy ignition system of some sort.

The modules are a different story. Mallory makes a high temp module that will out last the Delcos. The killer is heat. The coils in the cap rarely ever fail but you can mod that with an aftermarket standalone coil also.

One other failure point is in the electrical plug/connector to the cap. Check it to make sure it was made up properly. A loose or poor connection there will cause the problems you're experiencing.

 

[dnemeth]

Re: Bad coils delco hei voyager ignition

Decided to get out my voltmeter now that I am home from a vacation with a boat the wouldnt run right. Checked the voltage at the coil and it was 10 volts. Started to run down tha wiring and found a loose feed wire on the ignition switch. Fixed this and also noticed that the wire that feeds the coil was paired with another on the amp meter, stupid way to make a splice and this same wire feed the gauages before making its way to the back of the boat for the coil. Removed the coil wire from the amp meter and attached it directly to the ignition switch making it a clean shot to the back of the boat. 12.1 volts at the coil seems to run smoothly up to wot. Thanks for the help. Good idea to always carry a volt meter in the boat along with some simple hand tools. Properly trouble shooting this issue would have saved me $200 for the parts I unnessarly replaced.