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PROBLEM NOT SOLVED!! :(
https://www.smwebhead.com/phpBB3/viewtopic.php?f=11&t=10079		 Page 1 of 2
Author:  Technologic80 [ Sun Aug 12, 2012 9:00 pm ]
Post subject:  PROBLEM NOT SOLVED!! :(
Ive been posting of a cold start problem on my TBI 4.3Gi port engine in my 278 Vista.

I had done a lot of things that were probably good maintenance anyways (cleaned the anti-siphon valve, replaced the fuel line, new fuel filter, full tune up, replaced the low pressure fuel pump, etc). All those items STILL didnt solve my very extended cranking times. As of late, the engine would start on a cold start ONLY if I cracked the throttle half way. It would also start, sputter, and stall about 5 times before it would actually catch and stay running. On a fuel injected engine, this was sure sign something was wrong.

So today I tracked down the problem. Ill give a hint - it was fuel related. Any guesses what it was causing my issue? :D
Author:  ric [ Sun Aug 12, 2012 9:51 pm ]
Post subject:  Re: PROBLEM SOLVED!!
Ill take fuel pump for $600
Author:  Ccmblack [ Sun Aug 12, 2012 10:19 pm ]
Post subject:  Re: PROBLEM SOLVED!!
Damn ethanol gas!!!!!!
Author:  298VISTA2000 [ Mon Aug 13, 2012 8:12 am ]
Post subject:  Re: PROBLEM SOLVED!!
Sounds like the anti-siphon valve was too tight but I won't pass up the chance to jump on the bash ethanol bandwagon any day of the week.
Author:  LouC [ Mon Aug 13, 2012 8:23 am ]
Post subject:  Re: PROBLEM SOLVED!!
If it would not start unless you had the throttle half open, that suggests that it was not getting enough air to keep it running with the throttle closed. IAC valve? Leaky fuel injectors (too rich)?
Author:  ric [ Mon Aug 13, 2012 8:56 am ]
Post subject:  Re: PROBLEM SOLVED!!
LouC wrote:
If it would not start unless you had the throttle half open, that suggests that it was not getting enough air to keep it running with the throttle closed. IAC valve? Leaky fuel injectors (too rich)?


My buddy with his 4.3GXi just went through the process of new injectors for that very reason. Cheappppppppppp but pain in the ass to do.
Author:  LouC [ Mon Aug 13, 2012 10:20 am ]
Post subject:  Re: PROBLEM SOLVED!!
Other clue would be a bit black smoke on start up (rich running). Like an old school carb motor when the choke pull off does not open the choke.
Author:  neutron [ Mon Aug 13, 2012 11:14 am ]
Post subject:  Re: PROBLEM SOLVED!!
IAC all the way
Author:  Technologic80 [ Mon Aug 13, 2012 12:16 pm ]
Post subject:  Re: PROBLEM SOLVED!!
Ding ding ding!! We have 2 winners 8)

T'was the IAC valve. $37 later (found the exact identical part at Advance Auto Parts) and it runs and idles amazingly!! :mrgreen:

Im happy to have solved it. The old IAC valve was slightly dirty with soot and carbon. Probably a result of the boat being 15 years old and only having 90 hours on the engines when I bought it and a combination of having t-stats stuck open/in bypass mode for most of its life.

Trust me, after I fixed that yesterday I celebrated with a nice cold one! :mrgreen:
Author:  ric [ Mon Aug 13, 2012 12:18 pm ]
Post subject:  Re: PROBLEM SOLVED!!
If I remember right, the IAC is a ford part (even though it's a chevy engine)
Author:  Technologic80 [ Mon Aug 13, 2012 12:20 pm ]
Post subject:  Re: PROBLEM SOLVED!!
Oh and FWIW, the IAC valve (Sierra brand) at West Marine was $164 :shock:

I took the Volvo Penta OEM part # off the IAC and it cross referenced right over to a BWD Brand #21813 at Advance Auto for $57.99. Bought it online with a $20 discount promo code and walked out of Advance Auto Parts with a huge smile :D

If it matters, the IAC valve in my 97 Volvo Penta 4.3Gi is the SAME IAC in a 1988-1995 Chevy 1 ton pickup with a big block (454), non governed. Hope to save somebody else money/grief that reads this one day!
Author:  Technologic80 [ Mon Aug 13, 2012 12:21 pm ]
Post subject:  Re: PROBLEM SOLVED!!
ric wrote:
If I remember right, the IAC is a ford part (even though it's a chevy engine)


No, not on the 97's at least. The Ford IAC is a large assembly. The one on my Volvo's are the small traditional looking IAC's.

I think at some point (2002+?) they switched to a 2 wire IAC on the Volvos and a Ford part was fitted. However, mine is a 4 wire GM part.
Author:  LouC [ Mon Aug 13, 2012 1:19 pm ]
Post subject:  Re: PROBLEM SOLVED!!
thanks for the feedback, it makes an old timer like me that grew up with points n condensers and Quadra-Jets feel good when we can figure out the new (relatively speaking) stuff.

The principles (new vs old tech) are the same, just the execution is different, the engine needs a certain air/fuel ratio to run right, if there is too much of one or the other then you get issues like that.
Author:  Technologic80 [ Mon Aug 13, 2012 1:23 pm ]
Post subject:  Re: PROBLEM SOLVED!!
LouC wrote:
thanks for the feedback, it makes an old timer like me that grew up with points n condensers and Quadra-Jets feel good when we can figure out the new (relatively speaking) stuff.

The principles (new vs old tech) are the same, just the execution is different, the engine needs a certain air/fuel ratio to run right, if there is too much of one or the other then you get issues like that.


Yeah I can probably see what was happening:
I was having cold start problems and real low idle after cold starts. The IAC wasnt "choking" the engine correctly because it was stuck in one position, thus letting in not enough air or too much, or what have you. Once the engine warmed up and didnt need a rich mixture, I'd never have a problem starting the engine.

Now on cold starts, the port engine behaves the same as the stbd. After it fires, it jumps up to about 1500rpms and slowly settles back down around 600rpms. :)
Author:  JeffLW [ Mon Aug 13, 2012 9:26 pm ]
Post subject:  Re: PROBLEM SOLVED!!
Oh man! I didn't even think about checking an auto parts store for an IAC. I paid $100 for mine from a marine repair shop earlier this year. :x
Just checked online and found the exact same IAC valve for $54.99.

Thanks for posting.
After mine went bad while on the water I'm thinking about picking one up to keep as a spare onboard.
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