Engine Bogs Down

[tman]

I have a '97 2150 and it has been "bogging down" when throddling. I can only get it a little past idle. It is running fuel rich from the smell and you can hear the intake wanting to suck more air while in idle. It almost feels like my old Supra Comp with a fuel rich carburator. Just from getting close to each injector, they seem to be pumping fuel just fine. I blew out the air intake last year with chemtool to clean it and am wondering if I messed up one of the sensors next to the intake because of fumes. I am thinking either an injector is stuck open, clogged injector, or one of the sensors is blown. I am at a loss.

BTW, this is my first post and find the discussions very helpful!

Thanks in advance,

Tman
Lake Austin
Austin, Texas

[Tige M.D.]

you might have a bad e.t.c. (eng temp sensor) telling the e.c.m. that the engine is cold causing it to dump fuel. have someone scan the ecm and check for trouble codes.

[tman]

Thanks! Is the sensor next to the intake? I have a 350 Scorpion multiport EFI.

Thanks,

Todd

[Jeff LaHaye]

Todd,

Have you checked the water-separating fuel filter?

I had similar performance symptoms (but don't recall the gas smell) and found my fuel filter was full of water.

Jeff

[TeamAllen]

I also have a 97 2150, but have the 350 TBI. Our first time out last weekend I had taken the distributor cap off to check the cap and rotor condition. After putting it back on The engine would start and run for about 10 seconds and shut itself down. I checked the cap, rotor and plug wires again and the problem was fixed and we had a great weekend. I have heard engines have a limp mode to get you home (in some cases) if there is a mechanical problem.

My question is about the trouble codes Tige M.D. mentioned. Can you access them from a scanner like the OBDII for an automobile engine?

[tman]

That is a good point. I will check the plugs and cap. I went down to the boat last night and checked the engine temp sensor with a voltage meter and it is in good working condition. So I don't believe it is that. The two channels at the air intake are sucking air big time every few minutes which dumps a lot fuel and stalls it out. I have also heard the filter under the fuel coolant mech. can get clogged and rather than pass the unused gas back to the tank, it re-circulates and bogs it down. The next item to check is the fuel pressure which should be at 30psi. If it is higher than that, I am going to pull the coolant mechanism off and see if the line is clogged. I thought the same thing about the engine scanner on wether it is compatible on a Merc. engine. The lowest cost I have found is $500. If I find out I will let you know.

T

[tman]

Jeff, I will check the fuel seperator, too. Thanks for the info. It would be wierd if that is it because I just replaced it before I winterized. You never know!

Thanks,

Todd

[Tige M.D.]

did you check the sender with the water proof plug or the one that is secured with a nut?
the sucking sound you here is the iac (idle air control valve) closing, letting less air into the intake. this is just like a choke on a carburator. this happens when the engine is cold or when the ecm thinks it's cold.
as long as the OBDII can read a mefi I, II, III, or IV ecm then you should be able to read it.

[tman]

I checked the sensor at the manifold close to the fuel rails. I think the one your talking about is to the right of the fuel coolant mech. with a blue plug and sensor above, right? I will check that as well. Also, I was told by the Austin Tige dealer that they have seen problems with boats kept on the water with condensation in the tank and water in the seperator. He said to check the distrib. cap for moisture, fuel seperator, and plug wires and run chemtool through the tank to eat the moisture. My description was very similar to problems he has seen. Seems simple but I'll try anything. Do you know if you can rent scanners? The cheapest one I have seen is around $500.

Thanks,
T

[TeamAllen]

I have an inexpensive code scanner I use on cars made by INNOVA/EQUUS. They sell for $115.00 from partsamerica.com (part #3100). I'm sure they sell them at Pep Boys too. I just don't know if it will work on the boat. I've never thought about it until now. Where do you plug it in? Are the code numbers the same as a vehicle?

[Tige M.D.]

if your going to spend the money for a scanner then spend a little more and order a service manual for your engine from your dealer. about $40. in the manual it will show a list trouble codes and trouble shooting trees. good luck.

[TeamAllen]

I already have the manuals from Mercruiser. I'll look for the info. Thanks! I'll try my cheapo scanner that I have. What other scanner do you recommend?

[Tige M.D.]

one of the scanners we use is a rinda techmate. it will read any mefi ecm. mercruiser 95'- 01' marine power and volvo penta. $399
for late model mercruiser with the 555 (triple nickle) ecm you will need a ddt scanner from mercury marine approx. $900 or a diacom program for your laptop $1000 and up.
www.rinda.com check it out