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View Full Version : 1994 Prostar 5.0L TBI Too Rich floding


William
07-02-2009, 04:03 PM
After sitting all winter my boat is running too rich, Idles about 1200 RPM, runs rough and smokes out the exaust.
I put a computer on it and it said the MAP sensor was bad so i replaced it with NO change.

So Here is what I have done to try to fix:
Replaced the fuel filter.
Replaced all the spark plugs.
Replaced Throttel Pos. Sensor.
Replaced the air fuel Motor.
Rebuilt the Fuel Pressure Regulator.
I swapped out the computer from a working boat.
Checked the voltage to the Injectors.
Every thing I have done has made no changes.

Any help will be greatly appreciated.

flipper
07-02-2009, 04:05 PM
Clean the spark arrestor?

Chicago190
07-02-2009, 08:22 PM
Have the injectors cleaned and flowed?

JimN
07-02-2009, 08:42 PM
After sitting all winter my boat is running too rich, Idles about 1200 RPM, runs rough and smokes out the exaust.
I put a computer on it and it said the MAP sensor was bad so i replaced it with NO change.

So Here is what I have done to try to fix:
Replaced the fuel filter.
Replaced all the spark plugs.
Replaced Throttel Pos. Sensor.
Replaced the air fuel Motor.
Rebuilt the Fuel Pressure Regulator.
I swapped out the computer from a working boat.
Checked the voltage to the Injectors.
Every thing I have done has made no changes.

Any help will be greatly appreciated.

If it's idling at 1200 RPM, you have a vacuum leak. Make sure the PCV valve hose isn't cracked or loose and do the same for the MAP sensor hose. Sorry, but unless you have codes, replacing the TPS and MAP sensors was a waste of money. If by 'air fuel motor' you mean the Idle Air Control, you can check that by reading the voltages on the blue and green pairs, depending on whether you turned the key on or off. Then, watch the pintel for movement at key ON and OFF. If it opens and closes partially with key ON and closes completely and reopens on key OFF, it's probably good.

What you did wasn't diagnostics, it was just throwing parts at it. Do some research here and online to find out what you need to look for objectively, instead of guessing. The answers for your problem are probably on this site, including how to read any codes you may have stored in the ECM.

Have you done a vacuum or compression test? How about verifying base timing (I posted instructions for that and how to access codes in the last week)? Did you check your fuel pressure and take a sample?

What diagnostic software did you use? Which code was shown- 33 or 34?

William
07-05-2009, 05:31 PM
The first thing I checked is for a vacume leak, I sprayed Ether arround Intake manifold and
TBI, The engine will typicaly speed up if there is a leak. I replaced the PCV valve and hose,
I replaced the hose to the MAP sensor I don't believe it is a vacume leak.

I do not have a computer to check codes, I have had 2 boat mechanics work on this boat
with different computers, Not sure what software they used or what the codes were they just told me what to replace. And yes I may be throwing parts at it to fix it but remember this boat is 15 Yrs old sits in my backyard on a hydrohoist all year long so throwing a couple of 25-30 dollar parts at it now may save me problems down the road. And thats why I am throwing new hoses belts and thermostat, plugs wires etc... at it I Can't afford a new boat?

I was not able to check the timing accuratly, Acording to the service manual you need to put the engine in service mode by jumping across the connector when I do that the engine races to about 2000 RPM and the timing advances greatly...The service manual said that this is the first generation computers and may react that way. The engine wont idle down so timing is ??? at the current 1200 RPM idle the timing is advanced about 20 Deg....

I am new to this site and will look for your post about verifying base timing and give it a try.

The last mechanic who worked on this boat has been a boat mechanic for 30 years and said he has never seen anything like this.

The only thing that has no been replaced is the injectors and they both spray the same..so what is the chances the would both go bad at the same time?????? Although when I unplug one of the injectors the engine idles down and runs smoothe of course its dumping half as much fuel but does one injector affect the other electronicaly ???

THX

JimN
07-05-2009, 07:11 PM
The first thing I checked is for a vacume leak, I sprayed Ether arround Intake manifold and
TBI, The engine will typicaly speed up if there is a leak. I replaced the PCV valve and hose,
I replaced the hose to the MAP sensor I don't believe it is a vacume leak.

I do not have a computer to check codes, I have had 2 boat mechanics work on this boat
with different computers, Not sure what software they used or what the codes were they just told me what to replace. And yes I may be throwing parts at it to fix it but remember this boat is 15 Yrs old sits in my backyard on a hydrohoist all year long so throwing a couple of 25-30 dollar parts at it now may save me problems down the road. And thats why I am throwing new hoses belts and thermostat, plugs wires etc... at it I Can't afford a new boat?

I was not able to check the timing accuratly, Acording to the service manual you need to put the engine in service mode by jumping across the connector when I do that the engine races to about 2000 RPM and the timing advances greatly...The service manual said that this is the first generation computers and may react that way. The engine wont idle down so timing is ??? at the current 1200 RPM idle the timing is advanced about 20 Deg....

I am new to this site and will look for your post about verifying base timing and give it a try.

The last mechanic who worked on this boat has been a boat mechanic for 30 years and said he has never seen anything like this.

The only thing that has no been replaced is the injectors and they both spray the same..so what is the chances the would both go bad at the same time?????? Although when I unplug one of the injectors the engine idles down and runs smoothe of course its dumping half as much fuel but does one injector affect the other electronicaly ???

THX

When I referred to throwing parts at it, it was more about the IAC, TPS and MAP sensors, which I know were more than $25-$30 but what I was really trying to do is get you to look at it objectively, using measurement and observation. I consider the plugs, wires, cap/rotor and thermostat to be maintenance items but the sensors aren't and unless you see a code, they shouldn't need replacement.

Have you tried removing the PCV hose and covering it with your thumb? I'd like to know what that does.

I mentioned looking at the IAC for movement when the motor is started. You should see it open and then close a bit, to set the idle speed. If it doesn't move, measure the voltage on the green pair and the blue pair, as I recommended. If you don't see any voltage at all, do a continuity test on the wires, going back to the ECM plug. If there's no more than about .1 Ohms of resistance, leave them alone unless wiggling them causes a drastically higher resistance. If this doesn't reveal anything, without removing the IAC from the throttle body, look at how the blue and green pairs are installed and put 12VDC on the wire that your manual shows to receive voltage and ground the other. Repeat this for the blue pair. One pair will make it move in and the other will make it move out. If you see no voltage on the pair that closes the IAC, it's a good bet that the ECM may have lost IAC function and this isn't repairable, since the ECM is completely sealed. Indmar should be able to help you with this.

If you want to check your idle advance, remove the harness clip from one injector. It should settle down and make it idle at about 1K RPM. You usually won't see 20 of advance until about 3000RPM so I would back it down to 10BTDC. Did the idle mark stop wavering when you put it in diagnostic mode? It should be rock steady unless you go back to normal mode. Unplugging one injector won't have any affect on the other. The ECM has a driver for each one and as far as them being bad, you would be more likely to see voids in the spray cone than for them to cause high idle. Since you aren't going to be taking the boat out with only one injector firing, it won't damage anything.

The Vetronics Tech 1 was the only diagnostic computer with a cartridge for the Indmar programs when your boat was new. If the other guys have Diacom and it specifically indicates that your program is included, you should be OK but it may not show all of the data- I haven't used anything other than the Tech 1. I have seen one ECM lose IAC function but I don't remember exactly what the symptom was. If the other techs can repark the IAC, have them try that and see what affect it has. If it can't be reparked, my guess is that the ECM is bad, unfortunately. In that case, I would send it to Indmar for diagnostics.

FYI- if you do need to replace the ECM, you probably won't find a MEFI 1 controller and after MEFI 3, the outputs changed from positive to negative, so some wiring changes will be needed but they're pretty simple. Programming a new ECM will require pulling the original from the old ECM and downloading it to the new and if you get one from Indmar, they'll do it for you.

You may want to see if EngineNut is around- he works for Indmar.

Delta Demon
10-09-2009, 08:10 PM
Hello, 1st time and Newbie here - remarkably, I have the same boat ('94 205) with almost the same issue - if you found the problem, please post. Mine does not idle too high, rather, after initial morning runs, stop for lunch, and problems begin...may run very rough, hard to keep runing, black smoke, etc. If I can keep it running, it eventually clears out and runs, but if I stop for too long, like at the end of the day to get the truck to pull out, it happens again.

1st a simple question...PVC valve...does it come off the port valve cover to a tube to the spark arestor? What is there is a plastic L-tube that is just that, a straight open tube to the hose to the spark arestor, where there is a fair amount of oil residue...is that correct?? I thought the PVC valve had a spring mechanism in there...am I looking in the worng place for it?
Thank you,
Delta Demon

JimN
10-09-2009, 09:10 PM
Hello, 1st time and Newbie here - remarkably, I have the same boat ('94 205) with almost the same issue - if you found the problem, please post. Mine does not idle too high, rather, after initial morning runs, stop for lunch, and problems begin...may run very rough, hard to keep runing, black smoke, etc. If I can keep it running, it eventually clears out and runs, but if I stop for too long, like at the end of the day to get the truck to pull out, it happens again.

1st a simple question...PVC valve...does it come off the port valve cover to a tube to the spark arestor? What is there is a plastic L-tube that is just that, a straight open tube to the hose to the spark arestor, where there is a fair amount of oil residue...is that correct?? I thought the PVC valve had a spring mechanism in there...am I looking in the worng place for it?
Thank you,
Delta Demon

Temperature sensor, most likely. When you let it sit, the average temperature in the motor increases because there's nothing going through the motor to cool it and because it's under the motor cover. Then, if the coolant temperature sensor is reading high resistance (low temperature), the ECM delivers too much fuel and you end up running like crap with black smoke. It's the two-wire sensor with a yellow wire & a black wire.

As far as the PVC, one side is the valve and the other side is a breather. The breather goes to the flame arrestor and the PVC goes to the base of the throttle body or the runner in the intake manifold for cylinder #8. If it goes to the runner, Remove it, plug the hole and find a way to use the vacuum under the throttle body to ventilate the crankcase.

Tony_225VRS
10-10-2009, 10:46 AM
I have a '94 225 VRS with a 5.7 L TBI. I had an intermittetent problem all summer. When it was running bad it would backfire through the throttle body. Mine was setting code 42 some of the time. I learned I could unplug the primary wires on the coil and plug them back in and it would run fine for a while. I changed the engine wiring harness but still had issues. I then noticed that the rotating magnet in the distributor was loose on the shaft. This results in timing issues. I replaced the distributor and all is well now. I learned that these distributors often have loose magnets. You will not discover a wiring harness or distributor proble like mine by reading the codes. To check your distributor, pull your cap and rotor and try to rotate the magnet with a screwdriver. Mine moved 180 deg. I have a freshwater boat but there was some corrosion between the magnet assy and the shaft.