Volvo Penta 5.0 GXI type BF Hard Start

[evall323]

I went out for a 35 mile trip a month ago and made it fine, the next day after being out for a little while the engine would crank and crank but not stop. The engine has no codes. Every once in a while it sounds like it gets "stuck" when starting. Other than that it just cranks unless I put the accellarator up about 3/4 then it starts very rough and stalls a few times. After a few minutes it will run ok at idle and under load. but then I stop and try to start it again and it cranks and cranks and I go through the same thing again. These are the types of tests and parts I have replaced

Compression - 110, 145, 145, 145 ,160, 160, 160, 160
TPS - .5 - 5 idle to wot flows up and down smooth
cleaned all connections including the computer and all grounds
changed - starter, fuel pump, plugs, wires, cap, rotor, fuel pump, fuel filter, fuel pressure regulator, IACV.
Cleaned injectors and intake

I am about to buy a techmate. Now this is a personal challange as I am sure most of you can understand. I have been diagnosing car motors for 12 years and the only difference with this is that I do not have a scanner. Please help wallet and patience are running thin.

Thanks

Erick

 

[newport dave]

Re: Volvo Penta 5.0 GXI type BF Hard Start

If your having to advance the throttle to start (Clear Flood Mode), that would suggest that you may be flooding out. Any smell of unburned fuel or anything else to support that?

Do you have normal fuel pressure during the hard start condition?

 

[evall323]

Re: Volvo Penta 5.0 GXI type BF Hard Start

The pressure is 55 at the time the ignition is turned to the on position

 

[newport dave]

Re: Volvo Penta 5.0 GXI type BF Hard Start

The pressure is 55 at the time the ignition is turned to the on position

That should be ok. Again, are you smelling gas? Kinda sounds like a low voltage condition. Are you sure the battery is good? Maybe you could elaberate on the starter getting "stuck"?

Hint - If one line answers is all you have time for, your not going to get much help.

 

[evall323]

Re: Volvo Penta 5.0 GXI type BF Hard Start

Sorry about that, the battery has been changed and the crank is strong. But every once in a while the starter seems to try to crank and get stopped in its tracks. It makes a loud clank sound. This may be becuase I have to crank it so many times to get it started that I drain the battery but then again after that the battery seems to crank fine when I re crank the ignition. AS far as the smell there is a strong gas smell when the boat starts and i seems like it is burping when it starts and wants to backfire. Thanks for all the help

Erick

 

[newport dave]

Re: Volvo Penta 5.0 GXI type BF Hard Start

But every once in a while the starter seems to try to crank and get stopped in its tracks. It makes a loud clank sound. AS far as the smell there is a strong gas smell when the boat starts and i seems like it is burping when it starts and wants to backfire. Thanks for all the help

It sounds like the engine is hydrolocking. One or more cylinders may be gettting water in it, or it could even be one cylinder is filling with gas (stuck injector). I would pull the plugs and look for water and/or gas and do an injector balance test.

 

[JustJason]

Re: Volvo Penta 5.0 GXI type BF Hard Start

im with dave on this one... i think your having a slight hydrolock situation.
You also have a compression discrepency, a 50psi difference between the lowest and the highest is way to much. Your problem is probably in that cylinder.
do a leakdown test on that low cylinder, pull the tstat housing or a couple of hoses and see if you hear any bubbleing, that would be a head gasket.
or pull the intake, see if you see water traces between the cooling passages and the intake port.

Or.... put new plugs in, give the boat a hard run around the lake, and at hi rpm pull your stop lanyard. give it a few days and then pull your plugs out, see if there is rust on any of them, especially that low cylinder. If there is then you know your ingesting water.

 

[evall323]

Re: Volvo Penta 5.0 GXI type BF Hard Start

That sounds pretty logical to me.... is this something that a techmate would help to diagnose? I see that it has an injector testing ability. I am too used to cars and having the computer for everything, it is hard to diagnose those without a scanner and this is even harder.

 

[JustJason]

Re: Volvo Penta 5.0 GXI type BF Hard Start

the techmate will help if it's an injector problem

if it's a mechanical problem it won't do a thing.

if you don't own a leakdown tester/air compressor doing a plugchop is probably going to be the most cost effective troubleshooting you can do at the moment.

but you do gotta spring for new plugs.

 

[newport dave]

Re: Volvo Penta 5.0 GXI type BF Hard Start

The Techmate does have an injector pulse function that would allow you to do a balance test, but at this point there is still troubleshooting you can do without a scan tool. As suggested, pull and inspect the plugs. It might not be a bad idea to pull off the exhaust elbows and check for water also.