Volvo 5.7Gi No Spark

[epic mariner]

Engine started on the hose last week. Started hard and ran hard at the ramp this morning. Tach was showing 4000 rpm at idle and fluctuated wildly. Tach finally settled down to 1000 rpm, where it should and the boat ran fine at idle for probably 10-15 minutes. Tried to accelerate to get up on plane and the engine stalled and died. Wouldn't start.

Engine still won't start and there seems to be no spark. Pulled a plug and used a spark tester (for lack of a better word). Had what looked like a weak, inconsistent spark at first. Now none.

Things I know: It's not the fuel cell. Just installed a new one and have pressure at the rail.

Not a fuse or relay. Installed new ones.

Not the tach. Installed a new one today (after getting off the water) and it works fine.

I ordered a new coil. My current one shows signs of wear and tear (only 2 years old though).

Had a previous problem with what I think was a bad ground connected to the coil.

I read Don S.'s post on the tests for ignition systems. I'm kind of at a loss for how to test the coil with a voltmeter to see whether it's getting power. I have already searched several times, just can't find something that seems to address my situation.

Is there any test I can run that would tell me definitively whether the coil is bad or if there is something else bad?

Thanks in advance for any help and I apologize if this has previously been run into the ground.

[Don S]

What is the FULL modle number of this 5.7Gi? Need all the letters after the Gi.

[epic mariner]

Searched volvo's site and all over the engine, still can't find any more info. It's a 2007 saltwater duoprop. Closed water cooled, EFI. Could be a GXi. That's about all I know. I just can't tell. I apologize for not being able to provide more info.

[coastalcruiser]

look for the sn on the plastic air cleaner cover, beside the rams sn is stamped on th drive

[Don S]

You better go look at the engine again. There is a printed tag (Silver) that has the model and serial number on it. Also there is a metal tag on the port side of the block on the very back of the block. Also has the Model and SN.
While you may have a 2007 boat, Volvo doesn't go by years, only model and SN.
If you have the SN that would help, but not today, the site where I can use that number is having problems.

http://www.volvopentastore.com/mall/...enta/help.html

[epic mariner]

Finally found it at the rear port side. 5.7GXI-HF.

[Don S]

Do the fuel pumps run for 2 seconds when you turn the ign. switch to run?

Do you have a kill switch to hook a lanyard too? Is it in?

One other thing. The batteries have to be fully charged before it will get spark. If the ECM sees too much voltage drop and the engine cranks over slow, it will not have spark.

[epic mariner]

Fuel pumps run. Lanyard is good. I will throw the batteries on a charger, but I think they should be good. Might be a little low from me trying to crank it all day.

[Don S]

Also see if you can find the SN of the engine, with that I can find the proper manual. Right now I don't have a manual that even shows an H model.
You are also going to need to stop replacing parts and hopeing it cures the problem.
If you want to buy something, you really NEED one of the TechMate diagnostic tools.
http://www.rinda.com/acro/prodlist.pdf

[epic mariner]

I will look for the SN # today. After charging the batteries over night Sat, I tried to start Sunday morning and got one backfire, but no start and nothing on subsequent tries. The tach still jumps around (up to 4000 or so) while trying to start. I am thinking that it's a problem with a ground or the module itself. I have cleaned and tightened all grounds about as much as humanly possible.

[Don S]

It could also be the tach. Try disconnecting the gray wire off the tach and see if it will start.

[epic mariner]

OK, installed a new coil and it started right up. Still getting erroneous readings on the brand new tach. Disconnected the gray wire like you suggested, didn't seem to make any difference. Old tach was corroded looking. I think there is still a bad ground somewhere that is causing the messed up tach readings, so my next step is to sort those out and fix what's needed. At least it's running.

[epic mariner]

Update: the engine still starts and runs a little rough with the new coil. Cleaned the ground contacts which were pretty corroded. Replaced battery cables. I disconnected the gray wire on the tach from the "Send" post. Somehow, my tach still shows slowly increasing rpm. The gas in the engine is pretty old, but treated with Sta-bil. I'm going to continue to run the engine on the hose until I get the old gas out. I suspect that it might be contributing to the rough idle. Any thoughts on the crazy tach?