4.3 Gi ? Sporadic starting, black soot, rough idle

[robershaw]

I have a 1996 (I think that?s the year) Regal 176 with a 4.3Gi. Recently I?ve had a couple issues and I?m searching for answers and wondering if the two problems are related, or just a coincindince that they are occuring simultaneously.

Problem #1 ? About 6 weeks ago I launched the boat and couldn?t get it started. I removed the air cleaner, sprayed some starting fluid and got the boat started. We stayed overnight on a houseboat and the next day I couldn?t get the boat started so I tried the starting fluid again but it didn?t work. I removed the fuel filter/water separator, dumped the contents, refilled with fresh fuel and it started up. We tend to boat every weekend and the problem is sporadic. Sometimes the boat starts right up, other times I can simply spray starting fluid but sometimes I have to remove the fuel filter. The problem has been getting worse each weekend and I really wanted to make it to Labor Day before beginning repairs. However, this Labor Day weekend was the worst so far and I had to remove the water separator multiple times. Note: I have gone through many tanks of gas pulling kids on wakeboards and tubes so I don?t think its water in the tank but who knows. I?m thinking more of a fuel pump or sensors. Any thoughts?

Problem #2 ? About 3 weeks ago the boat started running a little rough at idle. Black soot could be seen coming out of the outdrive and it gathered on the transom. Once the boat is put into gear and brought up to speed, it seems to run great but as soon as I bring it back down to idle the black soot can be seen again. Timing belt?

 

[Don S]

Re: 4.3 Gi ? Sporadic starting, black soot, rough idle

the next day I couldn’t get the boat started so I tried the starting fluid again but it didn’t work.

Never do that, any dirt that was kept out by the filter, is now inside because tipping it over lets what's on the bad side on the good side.

Get it hooked up to a diagnostic scan tool and see if there are any codes set.

Have you done a tuneup or anything recently? Oh, and stop using the starting fluid.

 

[robershaw]

Re: 4.3 Gi ? Sporadic starting, black soot, rough idle

Last tuneup was several years ago. I have a scanner coming and will read the codes and hopefully get on the right track for repairs.


Have you done a tuneup or anything recently? Oh, and stop using the starting fluid.[/QUOTE]

 

[Technologic80]

Re: 4.3 Gi ? Sporadic starting, black soot, rough idle

WOW! Im really glad you posted this. Its not all that common to have this problem, but now you, myself and another member here have the SAME engine and the SAME problem. I have twin 1997 4.3Gi's in my Four Winns Vista 278. My stbd engine starts right up, idles up very nicely and returns to idle EVERY time you start it. The port engine, thats the little bastard. Sometimes it starts and stalls right back out. Sometimes you just get crank-crank-crank for 10 seconds+. Then you have to crank the engine again for 10 seconds. Finally on the third try, it will start but the idle is not smooth like the stbd engine. Sometimes the engine will start, stall right back out, then act like its getting no fuel or spark. Ive tested my fuel pressure and Im at 56psi. Target is 55psi. Im good there.

Heres what Ive done to little avail: Replaced IAC valve, replaced temp sensor, full tune up, new fuel filter/water seperator twice, new low pressure fuel pump, and finally I installed a new ignition control module.

After all that, the problem occurs now 1 out of 5 times, instead of every time. I got closer to the remedy but havent nipped it in the butt yet.

The other member I mention, we message privately on here. Hes replaced everything I have except he's also replaced his throttle position sensor and his ignition coil. All that PLUS all the other parts, didnt solve the problem.

Heres my take on it: Its gotta be on the ignition side of the road. Im betting ignition wires with too much resistance (although mine are brand new, I did go with an aftermarket brand) OR its the pickup coil in the distributor, which is also called the "ignition sensor" and is a very well known part to fail.

I scanned my codes - nothing. Just code 12 which is normal. Good luck and let us know IF you solve the problem, or what you do to get closer to the remedy.

OH and btw, we dont have a timing belt. Ignition timing is controlled by the ECU/ignition module and the timing is (im 99% sure) not your problem.

 

[Tail_Gunner]

Re: 4.3 Gi ? Sporadic starting, black soot, rough idle

Assuming these GI's are tbi motor's you both need to check your fuel cells for paint melting and clogging up things
Take a neon light and shine it on the tbi injectors..They should have a nice even conical spary pattern..no drip's
Fuel pressure on the low side is 30psi again assuming its tbi

 

[Technologic80]

Re: 4.3 Gi ? Sporadic starting, black soot, rough idle

Assuming these GI's are tbi motor's you both need to check your fuel cells for paint melting and clogging up things
Take a neon light and shine it on the tbi injectors..They should have a nice even conical spary pattern..no drip's
Fuel pressure on the low side is 30psi again assuming its tbi

Thanks for the reply Tail Gunner! VP Gi designated engines are TBI.

Fortunately for us, the paint peel/fuel cell issue occured later than 1996/1997. It was on the late model 2000+ VP "fuel cells". We dont even have fuel cells per se', rather we have seperate low and high pressure fuel pumps. The low is located on the front of the motor with the fuel filter/water separator and the high pressure is on the rear of the engine.

I replaced my low pressure fuel pump with a Volvo Penta pump because it was humming and running really warm to the touch. Removed my high pressure and checked the screens at that time - they were as clean as brand new. My neighbor performed a fuel pressure test for me, seeing he has a gauge and said it was ok saying I had one PSI more than what VP specifies.

Dont know where to go from here. Thinking of testing the spark plug wires (just installed new May 2012) for resistance. I get a nice conical spray of fuel.

 

[Tail_Gunner]

Re: 4.3 Gi ? Sporadic starting, black soot, rough idle

I should know not to stick my nose in here...But 55 psi with a throttle bottle marine..im intrigued. Are you sure your not looking at a mpi manual...Do you know the ecm type on that boat

 

[Technologic80]

Re: 4.3 Gi ? Sporadic starting, black soot, rough idle

I should know not to stick my nose in here...But 55 psi with a throttle bottle marine..im intrigued. Are you sure your not looking at a mpi manual...Do you know the ecm type on that boat

Ha! Good point. Last time I listen to my neighbor who is an "expert" ((rolls eyes)).

FWIW, my VP manual says for TBI 11psi (+ or -2) psi for the high pressure pump while running and 6psi (+ or -2) psi while cranking.

 

[robershaw]

Re: 4.3 Gi ? Sporadic starting, black soot, rough idle

Tomorrow (Friday) I will have some time to start working on the boat. It doesn't appear my scanner will be here by tomorrow but I can at least start looking at some of the things you guys mentioned. I'll keep posting as I go along and hopefully be able to post the solution. Thanks for the responses.