No ground in fuel pump relay socket Volvo Penta 4.3 GXI

[teslasun]

Hi, there is no ground in the fuel pump relay socket of my Volvo Penta 4.3 GXI engine so it cranks but doesn't start. There is spark but no fuel. If I connect the ground slot of the relay socket to the ground on the engine then the fuel pump starts working. But normally after switching on the ignition there is no ground in the relay socket. The cable looks yellow/grey (probably) but I don't know where it goes to from the socket. I would appreciate your advice how to solve the problem.

 

[QBhoy]

Hi, there is no ground in the fuel pump relay socket of my Volvo Penta 4.3 GXI engine so it cranks but doesn't start. There is spark but no fuel. If I connect the ground slot of the relay socket to the ground on the engine then the fuel pump starts working. But normally after switching on the ignition there is no ground in the relay socket. The cable looks yellow/grey (probably) but I don't know where it goes to from the socket. I would appreciate your advice how to solve the problem.

Hi. That’s not a gxi. Quite sure of it. What makes you think that ?

 

[dubs283]

Hi. That’s not a gxi. Quite sure of it. What makes you think that ?

I'd say it is a gxi. The i denotes fuel injection on vovlo engine models. Picture clearly shows the tbi unit on the manifold.

To OP, the ground for the relay could possibly be controlled by the ecm. Can't say for sure as I don't have a vast experience with Volvo fuel injection. Best bet would be to get a hold of an oem manual wiring diagram to find and trace the ground side of the relay

 

[QBhoy]

I'd say it is a gxi. The i denotes fuel injection on vovlo engine models. Picture clearly shows the tbi unit on the manifold.

To OP, the ground for the relay could possibly be controlled by the ecm. Can't say for sure as I don't have a vast experience with Volvo fuel injection. Best bet would be to get a hold of an oem manual wiring diagram to find and trace the ground side of the relay

Most or all of the 4.3 gxi I’ve ever seen, aren’t tbi. They also have the flat cap diz cap.
I’ll stand corrected if it is. But it sure looks like an older red coloured tbi:efi gli or similar thing.

 

[saaristo]

Thats's not gxi - there's no fuel rail and injectors on top of the engine. As to the problem - connect a DMM to the socket leads and squeeze and wigggle and "massage" the harness to see if you get a signal on your dmm screen at any point.

 

[teslasun]

Hi. That’s not a gxi. Quite sure of it. What makes you think that ?

Hi, well, according to the manual and the signature on the original cover of the carburetor it is GXi.

 

[teslasun]

Thats's not gxi - there's no fuel rail and injectors on top of the engine. As to the problem - connect a DMM to the socket leads and squeeze and wigggle and "massage" the harness to see if you get a signal on your dmm screen at any point.

Hi, unfortunately no signal there...

 

[QBhoy]

Hi, well, according to the manual and the signature on the original cover of the carburetor it is GXi.

Up to you. But I urge you not to think of it as a gxi. Gxi are multi point injection. In the 4.3 case, it would have 6 injectors and a fuel rail. That engine in the picture is 100% a single point injection model. Like a GLi as an example.

On another note. Neither the gxi or tye tbi you have, have a carb, as you have suggested.

Hopefully the above helps you Witt trouble shooting. All the best.

 

[teslasun]

Up to you. But I urge you not to think of it as a gxi. Gxi are multi point injection. In the 4.3 case, it would have 6 injectors and a fuel rail. That engine in the picture is 100% a single point injection model. Like a GLi as an example.

On another note. Neither the gxi or tye tbi you have, have a carb, as you have suggested.

Hopefully the above helps you Witt trouble shooting. All the best.

Thanks for your suggestion. It's raining here now so I can't check out the engine type again. I'm not a specialist, I bought this boat last year thinking it was a GXi but strange things happen, it could have been a kind of conspiracy like the fake C-19 pandemic or the monkeypox unfolding now, etc. One believes it is true and it turns out that it is not Anyway, the problem still exists, the engine doesn't start.

 

[dubs283]

Up to you. But I urge you not to think of it as a gxi. Gxi are multi point injection. In the 4.3 case, it would have 6 injectors and a fuel rail. That engine in the picture is 100% a single point injection model. Like a GLi as an example

I think the most important part of this is the fact the engine is fuel injected, for semantics it does not matter what specific model designation Volvo happened to use. It DOES matter for tracking down the correct information. The "i" is the most important as it signifies electronic fuel injection, computer controlled fueling system with various electrical sensors, etc....

As long as OP recognizes this and sources the correct information it will aid greatly.

To OP, it is important you find the model/serial number tag on the engine. Possibly located on the rain hat/engine cover but ime I've found Volvo adept at putting the stickers in strange places. It will be gray with dark gray/black lettering and have model, product and serial numbers on it

 

[QBhoy]

Hi, there is no ground in the fuel pump relay socket of my Volvo Penta 4.3 GXI engine so it cranks but doesn't start. There is spark but no fuel. If I connect the ground slot of the relay socket to the ground on the engine then the fuel pump starts working. But normally after switching on the ignition there is no ground in the relay socket. The cable looks yellow/grey (probably) but I don't know where it goes to from the socket. I would appreciate your advice how to solve the problem.

I think the most important part of this is the fact the engine is fuel injected, for semantics it does not matter what specific model designation Volvo happened to use. It DOES matter for tracking down the correct information. The "i" is the most important as it signifies electronic fuel injection, computer controlled fueling system with various electrical sensors, etc....

As long as OP recognizes this and sources the correct information it will aid greatly.

To OP, it is important you find the model/serial number tag on the engine. Possibly located on the rain hat/engine cover but ime I've found Volvo adept at putting the stickers in strange places. It will be gray with dark gray/black lettering and have model, product and serial numbers on it

But it’s a totally different type than what is presumed. The engine looks like a hybrid to me. The paint gives it away

 

[teslasun]

But it’s a totally different type than what is presumed. The engine looks like a hybrid to me. The paint gives it away

Perhaps this picture will be of help. Here is the engine with the air filter cover on. It was raining so there is some water on it.

 

[Lou C]

That looks like the throttle body injection system used by GM where there are 2 fuel injectors like a 2 bbl carb. A stopgap system between carbs & port fuel injection.

 

[teslasun]

That looks like the throttle body injection system used by GM where there are 2 fuel injectors like a 2 bbl carb. A stopgap system between carbs & port fuel injection.

I have no Jeep, my boat is 2001, RIO 700 Cruiser, Italian

 

[teslasun]

The problem was there was no ground in the fuel pump relay socket and there was power there no matter ignition was on or off. Today I
connected both grounds from both switches together (black cable) and
both powers from both switches together red/purple. I disconnected two cables from the fuel pump relay socket, one was the power which was on all the time (red/white) and the other was ground which didn't work (grey/yellow). It seems to work well now (on DMM), unfortunately I still can't start the engine because it turned out that the fuel pump did not work. I include the wire diagram, if someone can verify the connections I'd appreciate.

 

[Fun Times]

The Corrosion inside the ground terminal connector in your photo would be concerning… maybe the wire underneath what we see is corroded too not allowing a ground circuit to complete.., Try cleaning and thoroughly testing everything you can and see what happens… or maybe replace the wire running to the ECM I believe it should be without having time look over the wire schematics.

 

[dubs283]

But it’s a totally different type than what is presumed. The engine looks like a hybrid to me. The paint gives it away

Is it possible someone installed a tbi system and ecm from a Volvo 4.3 on a gxi branded Volvo 4.3 by abating the mpi system? Absolutely.

Is it possible before Volvo committed to an mpi system they produced some tbi 4.3 engines, branded them gxi and painted them red? Absolutely.

Quick Google search pulled up this info from Volvos epc...

External redirection

www.volvopentashop.com

Until we have verified information from OP regarding their engine we can presume everything, or nothing. We can use only what we know and can see based on experience and information provided

 

[ripjmk]

You have throttle body fuel injection controlled by a MEFI engine control unit. The fuel pump relay is actuated by the MEFI providing a path to ground when it deems it is ok to do so. You need the VP EFI diagnostics manual (VPA 7742218 03-2003) to guide you to a solution to your problem.
The fuel pumps should turn on for approximately 2 seconds when the ignition key is first turned on to build pressure in the system and then shut down until the engine control unit senses the engine running ok when it turns them on again.
Do you hear them turn on for a brief period when you turn the ignition on but not try to start ?

 

[dubs283]

Agree with funtimes about the corrosion at the female lead(s). Needs to be attended to before fully troubleshooting the issue.

Based on your information and the wiring diagram provided it appears the ground for both relays is the same and tied into the harness ground circuit, not controlled electronically/anything special. The wiring diagram doesn't exactly match wire color(s) you mention however the system in question is not complex. It has constant 12 volts + and constant ground. The relay is energized by the ecm to make contact between the constant 12 volt + and the + lead for the fuel cell assy.

When you say by adding/jumpering a ground the relay works and provides + voltage to the fuel cell it appears you have found the issue, just need to clean/solidify the ground and repair/replace the faulty fuel pump cell/assy

 

[teslasun]

You have throttle body fuel injection controlled by a MEFI engine control unit. The fuel pump relay is actuated by the MEFI providing a path to ground when it deems it is ok to do so. You need the VP EFI diagnostics manual (VPA 7742218 03-2003) to guide you to a solution to your problem.
The fuel pumps should turn on for approximately 2 seconds when the ignition key is first turned on to build pressure in the system and then shut down until the engine control unit senses the engine running ok when it turns them on again.
Do you hear them turn on for a brief period when you turn the ignition on but not try to start ?

Thank you for your help. I'll try to get the manual. I can't check out the fuel pumps with the ignition key now because the high pressure pump apparently have died so I dismounted it yesterday. It doesn't show any sign of life after connection of 12v to the socket, only one click. I'll get the new one on Tuesday-Wednesday.