spark at coil packs 8.1gi-b volvo penta

[tannermullins2994]

I am having trouble with my boat it has no power at take off or under a load. no problems out of the motor last year. i put new plugs and wires. the plugs came in from volvo gaped at 65''. the ones i took out from last year were at 40''. i pulled the wires on each coil pack while at full throttle. on 2 cylinders i got no respose from the motor like i did from the other 6 cyliders. u could tell i unplugged the plug from the coil on the other 6 cylinders. unlike the other 2 but they where sparking just didnt effect the motor running smooth like the 2 cylinders i got no response from the motor when i unplugged the wire. i replaced those 2 coil packs and got the same result. no differance. please help

[rabiddawg]

ECM?

[rabiddawg]

I just called a mechanic buddy.

He said ecm doesnt typically lose individual holes

He suggests checking the wiring harness for damage or corrosion.

He said sensor/sensors could be bad. But I think you have already changed most all of those.

I’m not optimistic about solving my problem by switching around a coil

[rabiddawg]

Tanner and I have been talking on the phone but I want to post what we are finding for others in the same boat. Pun intended

Took boat out to check coils under load. Found three holes that were dead. Took it back to shop and called my buddy (mechanic in oil fields).

He came over. We did a compression test two holes 140+, other 6 were all 150+ So the engine is healthy.

Next we verified all we're firing at idle using a timing light. I had previously done this. Next he started removing fuel injector wires. On the port side there were two holes that didn't make a difference, one made a big difference and one connector we couldn't get off without removing the rail. This was done at about 1200 rpm.

Oh, he also used his fluke meter to verify the injectors are being fired

We also checked fuel rail pressure at 50 psi

This backed up what I saw on the water when removing the plug wires one at a time.

In his professional opinion I have injector problems.

I guess I will order a set Monday

[Big Block Power]

Tanner and I have been talking on the phone but I want to post what we are finding for others in the same boat. Pun intended

Took boat out to check coils under load. Found three holes that were dead. Took it back to shop and called my buddy (mechanic in oil fields).

He came over. We did a compression test two holes 140+, other 6 were all 150+ So the engine is healthy.

Next we verified all we're firing at idle using a timing light. I had previously done this. Next he started removing fuel injector wires. On the port side there were two holes that didn't make a difference, one made a big difference and one connector we couldn't get off without removing the rail. This was done at about 1200 rpm.

Oh, he also used his fluke meter to verify the injectors are being fired

We also checked fuel rail pressure at 50 psi

This backed up what I saw on the water when removing the plug wires one at a time.

In his professional opinion I have injector problems.

I guess I will order a set Monday

You can send them all in to a guy in Texas that another member posted last year. I would have to dig that place up. But there are a bunch on the Internet. Or buy new ones or try to have them cleaned while still in the boat like we do in the automotive world. Or yes just buy new ones. Don't buy cheap ones though. My 2 cents.

[rabiddawg]

The Holley fuel injectors I ordered will not fit so my injectors are going back to the service company I did find some black looking powdery trash out of the fuel rail

I removed all the paint from inside the fuel pump assembly last summer I don’t really know where this contamination could be coming from right now

fuel poured out of the filter was perfectly clean

My buddy has a connection to the injector place. They will have them back to me this afternoon.

We also used his scope to look into the rail best we could. It looked shiney and clean also.

[rabiddawg]

Follow up.

I had my injectors cleaned. The tech said he had to run two of them twice to get them spraying.

I believe the source of the black powder in my rail was the fuel lines from the pump assembly to the rail.

Boat is running good again.

[Big Block Power]

Another reason not to run ethanol has.
Glad it's Running good.