New / replacement engine losing spark 5.0 v8

[ashley]

Hi, I have just swapped one of the engines over in my 99 regal commodore, the small block chev / volvo penta gi 5.0 motor swapped was in short form ( incl new risers and manifolds )and all the original accessories / cables etc were kept and reattached, the timing has been set and the engines been wired correctly according to the firing order stamped on the engine, however when we crank it over it runs for a few seconds sometimes more, sometimes less and the cuts out, the fuel is clean and getting to the carby however after a few seconds the spark dies and the engine shuts down...

so far to try and resolve the issue we have done the following - checked all switches / remote throttle positions / revving / flooding / unflooding / timing belt / distributor cap / spark plugs / starter engine / battery switches / leads all to avail

The current thought amongst us is that the engines computer is set to the old engine and isnt set up to interface with this one, or if it is interfacing it maybe receiving some kind of error message back like low oil pressure ( as its a new engne etc ) and then shutting down after a few seconds like it currently is ..... therefore meaning we need the volvo diagnostic technician to read the engine with his laptop and reset / retune etc

any further ideas / thoughts most welcome ???


Thanks Ashley

 

[Bondo]

Re: New / replacement engine losing spark 5.0 v8

Ayuh,...

Don,+ the other fellas that Do Volvos are going to have to know Exactly which model you're working on to be of much Help....

All I can say is,...
It sounds like you're loosing Voltage to the primary Igntion circuit....

 

[MikDee]

Re: New / replacement engine losing spark 5.0 v8

Just a wild eyed guess here,if you have 2 small wires, on 2 small terminals on the starter, maybe you have the "start" wire on the "run" terminal, and the "run" wire on the "start terminal"? If it's breaker point ignition, the start wire gives you a full 12volts for cranking only, then when you release the key, and go to "ignition on" the (resistor) "run" wire takes over sending less voltage, so as not to burn up the points. I can imagine the engine running for a second, or so, till you release the key with this scenario.

One more thought, if the engine has an electric fuel pump, then it has a (no oil pressure, no start) fail safe device built in to the oil pressure sender, maybe it's sensing loss of oil pressure, & shutting everythng down, check this out, and make sure you really do have oil pressure.

 

[wannabeamedic]

Re: New / replacement engine losing spark 5.0 v8

if all the gauges work while it is running, oil and voltage then i would look into the distri. as MikDee said the breaker point ignition can give you headaches if it is points double check the gap. good luck

 

[Don S]

Re: New / replacement engine losing spark 5.0 v8

It's a VP Gi, which means it fuel injected. no points.
Really do need to know what the old engine model number or even serial number was. Then we can start troubleshooting. Even a year would help narrow down the field a bit.

 

[ashley]

Re: ( engine number supplied ) New / replacement engine losing spark 5.0 v8

Re: ( engine number supplied ) New / replacement engine losing spark 5.0 v8

Many thanks to all of the members that have posted replies and asked for further info - here is the original engine number and details

volvo penta 5.0gi pbycce - 1999 serial number is 4110168414

and when its running the oil pressure guage doesnt appear to be working either

 

[Don S]

Re: ( engine number supplied ) New / replacement engine losing spark 5.0 v8

Re: ( engine number supplied ) New / replacement engine losing spark 5.0 v8

How sure are you that it is loosing spark? You have a TBI injection system with a high and a low pressure fuel pump. It sounds a lot like the high pressure pump is shutting down once you let off the ignition switch from the start position.
Just to test this theory. Try this.
Remove the fuel pump relay. #1 in the drawing below. Then make a jumper wire and put between terminals 87 and 30. Both fuel pumps should run. IF they do, start the engine and see if it keeps running. If it does shut it off, and remove the jumper.
Report back with your outcome.

 

[ashley]

Re: ( engine number supplied ) New / replacement engine losing spark 5.0 v8

Re: ( engine number supplied ) New / replacement engine losing spark 5.0 v8

Thanks Don, We are going to try this shortly, Ill advise outcome, Cheers Ashley

 

[MikDee]

Re: New / replacement engine losing spark 5.0 v8

Wow! Interesting, I don't think the TBI on my 4.3 Chevy S-10 pickup has anything like that, 2 fuel pumps?

 

[ashley]

Re: ( engine number supplied ) New / replacement engine losing spark 5.0 v8

Re: ( engine number supplied ) New / replacement engine losing spark 5.0 v8

Hi Don, We went back to the boat yesterday however due to all the previous strain the boys had done on getting the boat to turn over they had fried the starter motor, so ive got a new one now and we are going to install and try your advice on monday, one thing that we did do was remove the pump relay to have a look at the connection and on the terminals of the relay was green corrosion and rust, so we have cleaned that out, fingers crossed once the starter is back in will be closer to doing business, have a good weekend, cheers ashley

 

[ashley]

Re: ( engine number supplied ) New / replacement engine losing spark 5.0 v8

Re: ( engine number supplied ) New / replacement engine losing spark 5.0 v8

Hi Don and other forum members, today we spent another frustrating day working on the engine, we checked /cleaned out the oil sender unit, " hot wired " it like Don said thru the relay and also double checked all the starter motor connections etc, after puitting the bypass thru the relay as in the above diagram it did raise the oil pressure and we now have that, and it did run a little better, it sounded better and it ran longer, however it still conked out after several seconds, it is hard to say whether its been shut down by the computer or if its dying on its own accord!!

Any further ideas / things to check would be much appreciated


cheers ashley

 

[ashley]

Re: ( engine number supplied ) New / replacement engine losing spark 5.0 v8

Re: ( engine number supplied ) New / replacement engine losing spark 5.0 v8

How sure are you that it is loosing spark? You have a TBI injection system with a high and a low pressure fuel pump. It sounds a lot like the high pressure pump is shutting down once you let off the ignition switch from the start position.
Just to test this theory. Try this.
Remove the fuel pump relay. #1 in the drawing below. Then make a jumper wire and put between terminals 87 and 30. Both fuel pumps should run. IF they do, start the engine and see if it keeps running. If it does shut it off, and remove the jumper.
Report back with your outcome.

Hi Don and other forum members, today we spent another frustrating day working on the engine, we checked /cleaned out the oil sender unit, " hot wired " it like Don said thru the relay and also double checked all the starter motor connections etc, after puitting the bypass thru the relay as in the above diagram it did raise the oil pressure and we now have that, and it did run a little better, it sounded better and it ran longer, however it still conked out after several seconds, it is hard to say whether its been shut down by the computer or if its dying on its own accord!!

Any further ideas / things to check would be much appreciated

 

[MikDee]

Re: New / replacement engine losing spark 5.0 v8

If you have TBI (throttle body injection), take the flame arrestor off and watch to see if you're injectors are continuing to pulse fuel, at start up, and then while running. If they are, then your problems elsewhere.

 

[ashley]

Re: New / replacement engine losing spark 5.0 v8

Hello Mikddee, Thanks for your response, Yes there is fuel coming thru and we have been adjusting it to avoid flooding and make sure enough is coming thru etc !!

 

[Don S]

Re: New / replacement engine losing spark 5.0 v8

Yes there is fuel coming thru and we have been adjusting it to avoid flooding and make sure enough is coming thru etc !!

YOU, can't adjust it. Whatever you are doing, you probably shouldn't be.

Do you have any experience with EFI systems, do you have a service manual?

Have you actually checked to see if you have spark when the engine dies?

 

[ashley]

Re: New / replacement engine losing spark 5.0 v8

Hi Mike, When I say adjusting I mean having having the air filter / top panel removed so you can see straight down the carby and see that the fuel is spraying thru, and then manually revving it after the engine is started ( we tried to rev and also to do nothing several times )

yes there has been a petrol mechanic with us with experience in petrol efi systems and he assures us that the carby etc are functioning correctly and the fuel and spark is reaching us, (I will advise you if the spark is being lost as the engine dies shortly )

No service manual except we have the section of it thats got all the wiring diagrams showing the where the cables go to locations such as the starter motor / dizzy etc

Thanks

ashley

 

[ashley]

Re: New / replacement engine losing spark 5.0 v8

Hello all, we have finally solved the problem !! it was the secondary / boost fuel pump that was faulty and for some weird reason it was causing the other one ( located near the belts ) to also shutdown, Pretty much as DON S said !!! We changed the pump from the other engine and tried it out and it ran !! so ive ordered a new pump that will arrive tomorrow and we will be set.

thanks and seasons greetings !!