VP 4.3 Gi PEFS no signs of life

[KjetilS]

Hi

I have an old Draco 2100SC with a 2000 Volvo Penta 4.3 Gi PEFS (Dark grey color), with DP-C1 I/O drive.

Yesterday I had no luck starting my engine. The day before it started on the first turn of the key.
When the ignintion key is turnet on, usually the instruments come on, and the fuel pump does its's thing. But yeasterday it was completely dead.
This happended once before (The last time I used the boat) but after pulling all fuses and connectors I could find, it started right up. I did not do this in steps, with an attempt to start in between, so I have no idea what actually caused the error.

Yeasterday I tried the same, but no result. Still dead. Exept for one short sign of life, when the pump started and I could engage the starter for a few seconds. Then it was completely dead again.

Battery voltage is OK.

I will first check the main power switch between battery and starter, althought I tried jumping this with a car jumper cable yesterday with no apparent success.

Does anyone now if the main fuse is known to fail? This is a 50A automatic fuse, with push reset.

Also I was wondering about the relay in the fusebox on top of the motor. Would a failed relay cause similar errors?

All help appreciated!

 

[bruceb58]

What does the voltage of the battery read when you try to crank the engine. Does it drop a lot? I would load test the battery to msake sure it is ok.

Before I did anything else, I would remove all the cables at the battery and down at the starter and engine block and make sure they are clean to shiny metal and reinstall.

 

[Tail_Gunner]

There are two black relay's directly in front of the tbi, pull them and clean the contact's.

 

[KjetilS]

What does the voltage of the battery read when you try to crank the engine. Does it drop a lot? I would load test the battery to msake sure it is ok.

Before I did anything else, I would remove all the cables at the battery and down at the starter and engine block and make sure they are clean to shiny metal and reinstall.

Thanks for the reply. This engine has electronics that control the starter as well as the wiring loom with the voltmeter. When I turn the key to "ignition ON", nothing happens. Although the day before it startet with no problem. The starter span fast, so I do not think it is a bad battery. The only cable from the battery is to the starter, and the electronics is powered from there.
I will however do as you suggest, and try to clean the connectors to eliminate that as a possible cause.

 

[KjetilS]

There are two black relay's directly in front of the tbi, pull them and clean the contact's.

Thanks for the reply.

The two relays under the spark arrestor cover? I had forgotten about those. I tried to remove the large one in the fusebox, but it was stuck, and I was afraid to destroy something.
I'll try the two smaller ones you mentioned. What are these relays for?

 

[bruceb58]

This engine has electronics that control the starter as well as the wiring loom with the voltmeter.

There are no electronics that control the starter. The starter lead of your ignition switch goes through your neutral safety switch on your control to a relay under the cover of the circuit breaker box on the starboard side of the engine. That relay energizes and 12v is sent to your starter solenoid.

You aren't even getting power to your dash instruments. Figure out why you have a huge voltage drop first.

 

[ericga]

Inspect your engine ground stud connections and battery posts. Make sure everything is clean and tight. From there isolate the point where you have no voltage with a multi-meter.

 

[KjetilS]

There are no electronics that control the starter. The starter lead of your ignition switch goes through your neutral safety switch on your control to a relay under the cover of the circuit breaker box on the starboard side of the engine. That relay energizes and 12v is sent to your starter solenoid.

You aren't even getting power to your dash instruments. Figure out why you have a huge voltage drop first.

OK. I figured there was something "electronic" controlling the solenoid, as the fuelpump usually runs before the starter can engage.

If the safety switch was faulty, I guess the power to the instruments would still be present? The switch only keeps the solenoid from engaging?

The reason I am going on about relays,is the fact that it the day before it was just fine. I just think that if the connections were good enough to spin the starter with ease on one day, and the next day so bad that I dont even get power to the voltmeter is a little odd.

That said, I will disconnect and clean both power and ground cables. Hopefully it is something simple like that.. Just did not have time yesterday.

Thanks for taking the time to help!.

 

[ericga]

Hummmm........ could it be your key ignition switch?

 

[KjetilS]

There are two black relay's directly in front of the tbi, pull them and clean the contact's.

Bingo!

Finally got the time to do some work on the boat. Tried to turn the switch, and the motor started right up of course. The usual fun of electrical errors...

Anyway, pulled the relays on top in front of the TBI as suggested, and the right one was pretty corroded.
Tried to turn the ignition on with this relay removed, and got the same error as before. Cleaned and re-installed the relay. Problem gone, engine started. Pulled the relay once again to make sure, and the error was back.

I am pretty sure this was the cause. Will still clean and tighten the power cables, just to eliminate a possible cause for future errors.

Thanks for all help!

 

[bruceb58]

Pulling the relay was preventing the starter from turning? Those relays should have nothing to do with the starter operation.

 

[ericga]

Bruce58, On my 5.7Gxi one is the fuel pump relay and the other one is the starter motor relay. KjetilS is referring to the two relays next to the TBI. Not the ones in the fuse box.

I still find it strange that fuel pump and instruments didn't come on originally.

 

[KjetilS]

Pulling the relay was preventing the starter from turning? Those relays should have nothing to do with the starter operation.

As ericga points out, these relays are positioned on top of the engine, in front of the TBI, not the one in the fusebox on the left side.
Pulling the relay definitely prevented the fuel pump from starting. I am not 100% sure the starter would not engage. I just figured that with no fuel pump sound the problem was still there.

​Found a wiring diagram on-line now (http://forums.iboats.com/forum/engi...-penta-4-3gi-cable-wiring-diagram#post6382558) , and this states that the two relays on top is 1. Relay Fuel pumps and 14. Relay Ignition/fuel. Not sure which is left/right though.
It could be that the ignition/fuel relay was corroded and kept the ignition from powering the wiring loom and instruments.

​

 

[bruceb58]

One relay is to energize the fuel pump. The other relay is for the power to the ECM and to the TBI injectors.

The relay that goes to the TBI and ECM is engaged by the ignition switch. The fact that you had no power to your gauges and you could not operate the starter means in addition you were not energizing that relay.

The fuel pump relay gets energized by the ECM.

You haven't fixed your original problem yet which was causing no power to your gauges hence no power to energize the ECM/TBI relay. It may have gone away but it WILL be back.

 

[KjetilS]

One relay is to energize the fuel pump. The other relay is for the power to the ECM and to the TBI injectors.

The relay that goes to the TBI and ECM is engaged by the ignition switch. The fact that you had no power to your gauges and you could not operate the starter means in addition you were not energizing that relay.

The fuel pump relay gets energized by the ECM.

You haven't fixed your original problem yet which was causing no power to your gauges hence no power to energize the ECM/TBI relay. It may have gone away but it WILL be back.

I see your point.
There is also the fact that the motor did work fine before I started fault-finding, and found the corroded relay.

Are volt/temp/trim/rev gauges connected via the large connector/plug on the top/rear of the motor? (Socket between 7 and 8 on the diagram). The wiring loom is origanal VP, and everything is neetly organized in "hoses". I guess the ignition switch is also connected here?
If everything runs through this socket, I guess I could have multiple errors that would give the same symptoms as pulling the ECM/TBI relay..

I'll check the connection between engine and wiring harness.

Thanks again for taking the time to help.

 

[bruceb58]

Basically, your main battery cable goes down to the starter. From there, a smaller gauge wire heads up to a circuit breaker on your starboard manifold. From there, a wire goes through that large connector up to your helm fuse panel. From there, a wire passes through a fuse to your ignition switch. From your ignition switch, the ignition side passes through your man overboard switch to both your gauges and back to that large connector.

Any point along that chain can be the culprit but best odds are your battery cables down at the starter including the negative battery cable that connects to your block.

If your symptom was that your gauges were not on and/or you couldn't get the starter to operate, the TBI relay is not your problem.

 

[KjetilS]

Basically, your main battery cable goes down to the starter. From there, a smaller gauge wire heads up to a circuit breaker on your starboard manifold. From there, a wire goes through that large connector up to your helm fuse panel. From there, a wire passes through a fuse to your ignition switch. From your ignition switch, the ignition side passes through your man overboard switch to both your gauges and back to that large connector.

Any point along that chain can be the culprit but best odds are your battery cables down at the starter including the negative battery cable that connects to your block.

If your symptom was that your gauges were not on and/or you couldn't get the starter to operate, the TBI relay is not your problem.

The original error was back this morning, as you anticipated
Completely dead. Checked the relay, just to make sure it had nothing do do with it. No change.

Measured voltage at the starter, and had a reading of 7-8Volts. 12V on the battery, and cable going to the main switch.
Had to unscrew the main switch from the bulkhead to get to the connectors. Measured 12V on both sides of the switch, and finally I had 12V on the starter.
All connections was clean and tight, except the one on the starter. Don't trust the main switch anymore, and will get a new one.

Anyway, with 12V on the starter, still no life. Measured 12V on both pins of the 50 A fuse. 0V on the ignition switch.
Wiggled the plug to the wiring harness and suddenly power was back.

Had a closer look at the plug, and discovered it was only partially plugged in and held on with a hose clamp.
Inside one of the pins had "split open" and half of the pin was outside the socket, and another pin was slightly corroded.

Bent pin back in position cleaned the connector and re-assembled. Plug went all the way in, and it seems OK.

Just to make sure I had a good connection at the starter I sprayed on some WD40 and was trying to unscrew the nut to clean the connection.

Without using much force, the housing cracked open, and the stud came off.

- Guess I will have to get a new solenoid/starter. Boating is expensive...