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Engine backfiring
https://www.smwebhead.com/phpBB3/viewtopic.php?f=6&t=10917		 Page 1 of 2
Author:  gulls@play [ Wed Feb 06, 2013 3:17 pm ]
Post subject:  Engine backfiring
We have a 288 Vista. This engine has been running fine. It fired right up on Sunday and we started out of the marina. We got about 200 yards and the engine started backfiring as i accelerated. It cut off. I was able to fire it back up after giving it a lot of gas only for it to start backfiring and cutting off again. We just had to replace the high pressure pump on the other engine :cry: so i would like to try to fix this myself if possible. Any ideas on what the problem could be or where i should start?
Author:  billcruise [ Wed Feb 06, 2013 9:33 pm ]
Post subject:  Re: Engine backfiring
I would check the distributor cap and rotor for corrosion and/or condensation. Even if you don't find much, there can be hairline cracks that develop and cause similar conditions. If the engine starts fine and runs decent at lower power settings and then starts backfiring under load, that would be a typical symptom.
Author:  noexcuses [ Thu Feb 07, 2013 3:37 pm ]
Post subject:  Re: Engine backfiring
Since you've already replaced a fuel pump as well, I might assume that you are having the same types of problems I had last year. What are your engines, Volvo, Merc, MPI? I'll assume that you have multiport fuel injection, my theory is that you have paint coming off of your fuel pump assembly that is getting trapped in various part of your fuel injection system causing a restriction / fuel starvation. You can check fuel pressure on the fuel rail to start with, check the screen on the high pressure fuel pump, check for debris in the fuel pressure regulator and if all that fails have your injectors tested and cleaned. Cleaning the fuel injectors fixed my backfiring problem.

If you have Volvos, there is a service bulletin for the fuel pressure regulator that tells you to remove the screen and replace it with an e-clip, I personally think you need just clean the screen.
Author:  Jafo4U [ Sat Feb 09, 2013 12:30 am ]
Post subject:  Re: Engine backfiring
Today we finally diagnosed the backfiring situation on my volvo penta 5.7. It all started last week when we removed the water separator and emptied it out and replaced without filling it with gas. So we turn the boat on and it does exactly what yours did, idles great but when you give it some throttle it would start backfiring like it had bad gas but that was impossible since I filled it with Rec 90 non-ethanol fuel. Turns out the fix was very easy in my case maybe some of what I did might help you.

First make sure the engine is cold if you're going to do this and you turn the blower on to air out the engine compartment. All we did was without the engine turning over we kept turning the key until the pump kicked on and on the pump itself there is a schrader valve like the one on your tire. We pushed it in and it bled some gas and air a couple of times but after a couple of times clicking the key on and off it started shooting straight gas. Then we took the plastic cover on top of the engine off and toward the back of the throttle body there is another schrader valve and we did exactly the same procedure and it shot some air and some gas and finally only gas. We took the boat to the lake today and it ran like a bat out of hell! :lol: I hope this will help you out since I know exactly how annoying that engine backfiring can be. Good luck getting your situation taken care of. Keep us posted 8)
Author:  gulls@play [ Thu Feb 28, 2013 8:47 am ]
Post subject:  Re: Engine backfiring
Thank you for all of the suggestions. We are planning to go to the boat this weekend and we will try these different applications and hopefully will resolve this issue.
Author:  Jafo4U [ Thu Feb 28, 2013 3:08 pm ]
Post subject:  Re: Engine backfiring
Wish you luck on beating the gremlin!! Keep us posted
Author:  298VISTA2000 [ Thu Feb 28, 2013 6:38 pm ]
Post subject:  Re: Engine backfiring
gulls@play wrote:
Any ideas on what the problem could be or where i should start?


Yea, replace the other fuel pump and quit running that government mandated piss water (ethanol) in her. Been there.
Author:  gulls@play [ Mon Mar 18, 2013 12:50 pm ]
Post subject:  Re: Engine backfiring
Update: This weekend we removed the fuel filter, dumped the gas from it and inspected it. There was a small flake of paint in the container. We filled the filter with fresh gas and replaced it. The engine still didn't start. We removed the fuel pressure regulator to check the screen. The screen was a little dirty. Our shop manual said not to reuse the o-rings and we cracked the plastic on the screen so we couldn't see if it started after the screen was cleaned. So we're ordering new o-rings and a new pressure regulator since it doesn't look like you can order the screen separately. We also checked the ignition fuses. Fuel pump is working.
We've had the boat about 3 years and we only fill up at our marina so we've always put ethanol-free gas in it.
Any suggestions are appreciated.
Author:  Winter Sux [ Mon Mar 18, 2013 1:51 pm ]
Post subject:  Re: Engine backfiring
If you went from a backfire condition to a no-start condition, it's an ignition failure. I'd say if you have a distributor as opposed to distributorless ignition, time for a coil.

We all could help you better if you told us what you have for engines.

John :mrgreen:
Author:  Cap'n Morgan [ Mon Mar 18, 2013 2:18 pm ]
Post subject:  Re: Engine backfiring
Winter Sux wrote:
We all could help you better if you told us what you have for engines.



WS, I believe the ladies have the V8's in their Vista...

gulls@play wrote:
We have a 2004 Four Winns 288 and the boat is in excellent condition with only 99 hours on the twin 5.0 gas Volvo Pentas .
Author:  Winter Sux [ Mon Mar 18, 2013 3:01 pm ]
Post subject:  Re: Engine backfiring
Thanks Cap'n.

I'd start with a coil. Bill Cruise had some good tips also.

John :mrgreen:
Author:  noexcuses [ Tue Mar 19, 2013 9:17 am ]
Post subject:  Re: Engine backfiring
Do you have 5.0 GXi-E engines? I'm assuming they are the same as mine since both of our boats are 2004.

According to Volvo, you should replace the screen with an e-clip:

http://www.marinepartsexpress.com/VP_Se ... ulator.pdf

Is your engine cranking? Have you checked the ignition relay? There is another service bulletin that says to replace the fuse/relay box since it can fail due to vibration. I believe this is one problem that I had at the end of last year. The engine will start intermittenly, and sometimes just quits at cruising speeds. I swapped the boxes from the other engine and that seemed to fix the problem. I will be replacing both of them this spring.

http://www.marinepartsexpress.com/VP_Se ... placed.pdf
Author:  gulls@play [ Tue Mar 19, 2013 10:26 am ]
Post subject:  Re: Engine backfiring
Yes we do have 5.0 GXi-E engines. It is cranking but not starting. We checked the fuses but not the relay. Not sure how to go about checking the relay. But the relay should be good if its cranking right?
Thanks for the information on the parts changes. We'll check into that.
The ignition coil and fuel cell were changed last season.
Could it be bad spark plugs?
Author:  noexcuses [ Tue Mar 19, 2013 1:04 pm ]
Post subject:  Re: Engine backfiring
You should have spare relays within the fuse/relay box, try swapping them, if the spares are gone pull them from the other engine. Also, make sure you are in neutral, I've made this mistake more than once. Does the alarm sound when you turn the key?

Also, I don't know that there is a definitive root cause for the paint peeling situation. I asked this question on the Volvo forums and no one gave any good leads.

http://forums.iboats.com/volvo-penta-i- ... ost4049162
Author:  Cap'n Morgan [ Tue Mar 19, 2013 1:39 pm ]
Post subject:  Re: Engine backfiring
noexcuses wrote:
Also, I don't know that there is a definitive root cause for the paint peeling situation. I asked this question on the Volvo forums and no one gave any good leads.

http://forums.iboats.com/volvo-penta-i- ... ost4049162


Cause. Painted fuel pumps. It was mentioned in your iboat link. Also here is a link from this forum.
viewtopic.php?f=11&t=6109

I'm not sure if this is the problem the ladies are experiencing, but she did mention paint in the fuel filter. I know at least a half dozen people that have had this problem related to the painted surfaces. I also know dozens of people that have not had a problem with it. But, it is a possibility worth looking into.
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