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Idle problem and gas smell


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Hello Guys!!

I have a problem with my malibu response 2002 with a mercury 350 magnum mpi 2011 as a engine.

It runs more or less good but :

- when I cruise and then go back to idle quickly it stalls. I have to come back to idle very slowly to stay in idle.

- it's sometimes hard to start, I need to put the throttle ON to make it start and it finally start with a huge smoke like on this video Video

- it smells gasoline a lot when its idling and a little when it is cruising.

what could it be ?? What should I check ? Or change ?

thanks a million times guys !!!

mickey from tahiti

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13 hours ago, Mickeypowa said:

Hello Guys!!

I have a problem with my malibu response 2002 with a mercury 350 magnum mpi 2011 as a engine.

It runs more or less good but :

- when I cruise and then go back to idle quickly it stalls. I have to come back to idle very slowly to stay in idle.

- it's sometimes hard to start, I need to put the throttle ON to make it start and it finally start with a huge smoke like on this video Video

- it smells gasoline a lot when its idling and a little when it is cruising.

what could it be ?? What should I check ? Or change ?

thanks a million times guys !!!

mickey from tahiti

Mickey -

'Ia ora na!

I would clean the throttle body with a can of spray carb cleaner.  Try to make sure that the edge of the butterfly is clean along with the throat where the butterfly touches.  Then make sure that the idle air control passages are clean as well.  It is possible that your idle air control valve is sticking, so if the basic cleaning doesn't do it, pull the IAC and clean it and the cavity with the spray.  Even if you have a bad part, you want to make sure the throttle body is clean before you start throwing parts at it.

If it still won't run right, check the fuel rail pressure to make sure it is within specifications.  If it still won't run right, come back and we can try to help some more.

‘Ia mānuia.

- Just Gary

P.S.  What island are you on?  We went to Tahiti in September of 2017, and I tried really hard to find someone who would pull me barefoot.  The only place I found for skiing was on Bora Bora, and he said that I needed to buy a few hours from him, and absolutely no barefooting.  I really only needed 30 minutes, so I passed.

We stayed a few days on a small island northwest of Taha'a, and a few more days on a small island south of Bora Bora.  What a great place!

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Ia orana Gary !!! Thanks for your help!! 

I cleaned the throttle body today, it was so dirty !! Thanks for the advice.

Screenshot-20200105-224304-Gallery.jpg

I already changed the IAC few months ago. But I was thinking of changing the 2 parts between IAC and throttle body ? What are the names of it ??

I think of changing the air filter which is covered by grease..

There is now less smoke and gas smell, but I ran the engine only few minutes. But the engine still stalls if I go suddenly from 1500rpm to idle.

What could I change to prevent that ? I never dit a tune up yet ...

I was thinking of changing :

maf sensor, rotor and distributor cap, electronic control module, maybe the wires, the plugs

what else you would recommand?

Where can I get the reference number for all that and a good website to order ?

 

Ps : I live on the main island of tahiti ! Should be hard to barefoot here as I haven't seen anybody doing that here !!  Only wakeboards and foils ! you should be talking of the island of maupiti ! Glad you liked these islands, it's almost paradise. But the are not a lot of malibus here so it's hard to repare them !!

 

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@Mickeypowa -

If you have the inside of the throttle body really clean (including the two side passages to the right in your photo, definitely do the rest of the tune up that you mentioned: plugs, rotor, distributor cap, and maybe wires.  Those are by far the low-hanging fruit that you can easily change to see if they fix the problem.  When you get a cap, try to get one with brass contacts instead of aluminum since they will last a lot longer in your marine environment.

You can just clean the air filter with your carb spray.  It's mostly just a flame arrestor instead of a cleaner.  Another fun thing to try just for kicks before you change the cap (and especially if you have to order one and wait for it) is to clean the inside of your old one.  Flip it over and chip the white growth off of each contact, then clean all of the dust and crud out.  Do the rotor too.  Then pull the plugs and clean and regap them.  Wipe a little grease on the external part of each plug before you reinstall it, and put a dab on the tip before you put the wire boot back on.

I boat in salt water, but I keep my boat in a garage the rest of the time.  Looking at your photo, I see typical salt air corrosion.  Start the engine and spray it with a fresh water hose while it is still cold to try to flush as much salt off as you can.  Don't spray into the throttle body (do it with the air filter in place), and don't soak the alternator.  When you are done, let the engine warm up to help bake the water away.  After it is dry, touch up any severely rusty places with a can of spray paint, then let it dry again.  Next, spray the whole thing with a light spray oil; it really doesn't matter what brand.  Do everything except the belts and pulley grooves.  Wipe some on the pulley faces and inside the throttle body horn.  Don't forget to get under the oil pan as well as you can.  It also helps to remove the ECM cover and clean under it, then spray the ECM and harness with light oil.  Once you have the corrosion under control, you can just spray it with oil a few times a year and it will stay nice.  I repeat the wash job every few years just to knock the grime off and start over.

Regards,

- Just Gary

P.S.  I'm not sure why I said northwest of Taha'a.  We were northeast, on Vahine Island.  They have a tiny little resort with a French chef that could hold his own anywhere in the world.  I hope to visit them again some day.  The thing that keeps Tahiti wonderful is its extreme remote location.  It is hard to get to you and expensive to stay, so it isn't trampled as badly as other easy-to-reach places. 

Next up on my list of places to visit is Palau (between Guam and the Philippines).  I hear that the snorkeling is even better than yours, if you can imagine that!

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Change the fuel pressure regulator. If they go bad they supply full fuel rail pressure at idle and over-fuel the engine. 

 

Pat

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2 hours ago, patsproule said:

Change the fuel pressure regulator. If they go bad they supply full fuel rail pressure at idle and over-fuel the engine. 

 

Pat

So will a stuck injector.

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The gas smell should be a huge concern.

Gas is extremely explosive.  The is LEL and UEL, lower and upper explosive limits while the sweet spot is the GBZ, GO BOOM ZONE.

Just a suggestion, but I would trace all the gas lines, connections, etc. looking for any leaks, and fix that problem first.

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  • 2 weeks later...

Hi guys! 

As you adviced I cleaned the throttle body, and the grill between idle air valve and the tube that go to the TB (with carb cleaner).

I cleaned the flame arrestor with carb cleaner and then put it in gasoline... and the plastic melted a bit !!! so I will buy a new one soon.

But since I did all that, my idle is arround 900 rpm whereas It was at 600 rpm before !!! I only tested it on the rack, not on water yet...

What is the usual idle rpm for a mercruiser mag mpi 2011 ?

What could have changed that ?? What could I do ??

 

Thanks a lot !!

Mickey

Edited by Mickeypowa
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Hi guys !!

 

I still have 950 rpm idle.

so i did little tests :

- I tried to disconnect the IAC when the engine is ON and it changes nothing the idle stays exactly the same.

- I tried to disconnect the TPS and the idle drop to 750 rpm and is a bit rough.

Any ideas ?

Should I change both ?

Thanks!

Mickey

Edited by Mickeypowa
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  • 2 weeks later...
  • 8 months later...

Hello guys !!!

I give you some news, my IAC wasnt working properly. I got a new one, and now I can hear it working, my idle is back at 600 rpm.

I also changed :

- the throtle position sensor

- the flame arrestor

- the rotor and distributor cap

- the plugs

- oil filter, fuel-water separator, line fuel filter

the boat work now a lot better, but there is still smoke and gas smell when the engine is hot ! Less than before but it is still annoying!

it stalls less than before, but it still stalls if I cut throttle very quickly!

and the other problem is that I have a check engine fault blinking and the bell blinking on the screen of the smartcraft ! and impossible to go over 3500 RPM !!!

 

So what can I do next ? Check the fuel pressure ? Put an additive for cleaning the injectors ?

I also think my fuel pump is maybe a bit old because sometime, when the boat hasnt worked for a while, I need the hit the pump to make it work properly ahah ^^ and then it work great !

I just ordered the rinda tool to see what my check engine logo means.

 

Thanks !!!

 

Mickeypowa

Edited by Mickeypowa
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5 hours ago, Mickeypowa said:

Hello guys !!!

I give you some news, my IAC wasnt working properly. I got a new one, and now I can hear it working, my idle is back at 600 rpm.

I also changed :

- the throtle position sensor

- the flame arrestor

- the rotor and distributor cap

- the plugs

- oil filter, fuel-water separator, line fuel filter

the boat work now a lot better, but there is still smoke and gas smell when the engine is hot ! Less than before but it is still annoying!

it stalls less than before, but it still stalls if I cut throttle very quickly!

and the other problem is that I have a check engine fault blinking and the bell blinking on the screen of the smartcraft ! and impossible to go over 3500 RPM !!!

 

So what can I do next ? Check the fuel pressure ? Put an additive for cleaning the injectors ?

I also think my fuel pump is maybe a bit old because sometime, when the boat hasnt worked for a while, I need the hit the pump to make it work properly ahah ^^ and then it work great !

I just ordered the rinda tool to see what my check engine logo means.

 

Thanks !!!

 

Mickeypowa

Definitely check your fuel pressure.  It wouldn't hurt to clean the injectors, but it sounds like you have a pump or regulator problem.  Having to hit the pump is usually a bad sign.

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  • 1 month later...

Hello guys!!

Thanks for the help, you were right.

So for the check engine sign : I did a scan with a rinda tool, finally it was the horn output disconnected, I reconnected it and no more check engine !

I put an injector cleaner in gas, and now no more need to hit the low pressure pump, maybe it had some gum inside and now its ok!

And I finally did a fuel pressure test

 

So I have only 30 PSI whereas I should have 43 PSI.

We can see that the pressure decrease quite quickly after the pump activation.

If I start I have 30 PSI, if I rev I have between 28 and 30 PSI!

If I disconnect the vacuum line from the regulator, it doesnt change anything!

Do you think it is the regulator, or the high pressure pump, or both ??

Thanks a lot !

Mickeypowa

Edited by Mickeypowa
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6 hours ago, Mickeypowa said:

Do you think it is the regulator, or the high pressure pump, or both ??

Mickey -

Pressure too high would indicate a likely regulator failure.

Pressure too low would indicate a likely pump failure.

The problem is going to be finding a suitable pump to replace yours.  I have read several threads here about replacements and correct fittings.  As I recall, the pump that fits is not marine rated, and the marine rated pump has funky fuel connections.  With a little work we can help you find the parts to buy.  Since you are in Tahiti and it is close to Christmas, you probably don't want to order the wrong part and have to wait for shipping more than once.  Read up on it (at least for a 1999 engine) in this thread:

Before you buy anything, verify whether you have a Monsoon (Multiport injected) or a Throttle Body injected engine.  I am pretty sure that Malibu only used the Multiport engine, but you should make sure.  Can you read the part number on your fuel pump?

Somebody has done the leg work and parts fitting and made a replacement kit that is probably twice what you would pay for just the pump, but here it is if you would prefer to just hit the "Easy" button.

https://skiboatpartsonline.com/Indmar-High-Pressure-fuel-pump-kit

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