Gas through rear exhaust

[jmist]

This is a 1998 moomba inboard indmar v8 efi engine and gas is coming out from both of the rear exhaust of the boat. You can see gas on top of the water. <br /><br />I have replaced plugs, recondition the fuel injectors, replaces gas filter, checked fuel pressure regulator (38 psi). Engine is running smooth and there are no visible leaks. I am not sure if it is running too rich causing the excess gas out through the exhaust.

 

[Walt T]

Re: Gas through rear exhaust

Okay, I'll take a stab at it. Two things I can think of, one is the temp sensor thinks the engine is cold and its telling the ecm to run rich, or it IS in fact running cold and running rich. You're positive it is gas? Oil from the drive will make a rainbow on the water.

 

[vinney]

Re: Gas through rear exhaust

The engine is staying in the enrichment mode. TBI You need a scan tool or a thermo gun. Either the engine is not coming up to temp or you have a bad temp sensor. Vinney

 

[vinney]

Re: Gas through rear exhaust

A bad tps will cause this engine to over fuel. You need to get your hands on a scan tool. Rinda makes a scan tool for this engine for about 350 bucks. Dont guess use your tools.

 

[geriksen]

Re: Gas through rear exhaust

I am with both of these guys on this one. Look at your temp guage and see it the engine is warming up, or just put your hand on it. If it is then you will need to put a scan tool on it and check for codes.

 

[jmist]

Re: Gas through rear exhaust

There is gas vapors that you can smell when you are at the aft part of the boat. The engine temperatue guage is operating and shows the proper temperature after the engine is running. I will check the temperature sensor, thanks.

 

[Waterbugtoo]

Re: Gas through rear exhaust

Forgive the giggles, but reading a post about EFI problems, then following, come an array of suggestions on what to check, brings on the chuckles. Like the coming of automotive EFI, so come the marine versions. Do you self fix your auto when the EFI acts up? I doubt it. Not critisizing or blaming for trying to save a buck, but if you purchase an EFI product, your shadetree experience is only going to cost you many dollars toward the still unsolved problem. With EFI, let the pro do the diagnosis/repair, and actually save a buck in the process.<br /><br />

 

[geriksen]

Re: Gas through rear exhaust

Yep, at this point it should go to the dealer.

 

[vinney]

Re: Gas through rear exhaust

If a man looking for advice he will find it. I have learned to help this kind of customer. If you dont help him he will find someone that can. This kind of customer will always get you plent of work from his friends. The last time I look in a Hot Rod magazine it had every fuel injection system known to man. The times have changed and people will figure out how these system work. They dont need to be told to take it to a dealer.They wouldnt have asked how to fix it.

 

[geriksen]

Re: Gas through rear exhaust

My advice is to let a dealer with a scan tool check it for codes. It sounds like he had done a pretty good job of checking the rest.

 

[vinney]

Re: Gas through rear exhaust

If a TBI is running cold there is no code for that. The scan tool will show you what the ecm is getting for a reading from the sensor. It can show you a voltage that is turned in a temperature reading. This forum is to help people not to tell them to take it to a dealer. There would be no forum if everyone took there boat to a dealer. I respect a man who tries to repair his own boat they usally stay boating longer.I want to be there for the big jobs not the small ones. The more a customer knows about his boat the more confidence he has with it.

 

[geriksen]

Re: Gas through rear exhaust

It's not running cold. He says the temp comes up normally. The next step is to scan it whether that means borrowing the tool or having a dealer do it.

 

[vinney]

Re: Gas through rear exhaust

The guage cant tell you the difference between 149*and 150*. The scan tool can tell you if is out of inrichment mode.

 

[jmist]

Re: Gas through rear exhaust

Replaced the Temperature sensor and it still have the gas fumes and gas out of the exhaust. Its going to the dealer, they think that the ECM needs to be reprogrammed.