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  #21  
Old 02-19-2017, 11:12 PM
Cumminscj Cumminscj is offline
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Originally Posted by JimN View Post
Yours is set too rich or the choke isn't set correctly. Open the choke and if it runs, adjust the choke. If the carb hasn't been rebuilt, I would say that it's time to do that- 31 years with the crappy gas that's being shoved down our throats is a really long time.
Need to update my profile I guess. I still have the Marlin, but the boat with the idle issue is a 2000 Maristar 210vrs with a LTR engine. There is a whole thread here on it.

To the thread author try starting the boat with some throttle. This will eliminate the idle air control and any problems associated with that circuit.
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  #22  
Old 02-19-2017, 11:21 PM
Cumminscj Cumminscj is offline
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Have you checked what vacuum you are getting? That would be useful. Really need to know if it will run with throttle applied. If it will run with throttle applied you know it is reading sensors and the computer is functional. At least most of the computer is functional. There could still be a fault in it, but this will help eliminate a few problems.

Last edited by Cumminscj; 02-19-2017 at 11:22 PM. Reason: Typos
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  #23  
Old 02-20-2017, 09:32 AM
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JimN JimN is offline
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Originally Posted by Cumminscj View Post
Need to update my profile I guess. I still have the Marlin, but the boat with the idle issue is a 2000 Maristar 210vrs with a LTR engine. There is a whole thread here on it.

To the thread author try starting the boat with some throttle. This will eliminate the idle air control and any problems associated with that circuit.
Is that the thread where I asked if the throttle plate has a hole in it?

Is this crank/no fire problem when it's hot, or all of the time? If it's only when hot, check the ECT.
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  #24  
Old 02-20-2017, 02:29 PM
Cumminscj Cumminscj is offline
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Originally Posted by JimN View Post
Is that the thread where I asked if the throttle plate has a hole in it?

Is this crank/no fire problem when it's hot, or all of the time? If it's only when hot, check the ECT.
Yep that thread. Throttle plate has the hole. Happens mostly when it is hot, but sometimes when it is cold. I added some info in that other thread. Currently thinking the vacuum leak is on cylinder 4 due to plug coloration or that injector is partially clogged or leaking. Will update that thread after I do the intake and get the injectors flowed.

***ECT checked good. Replaced it anyway. No change in symptoms.

Last edited by Cumminscj; 02-20-2017 at 03:12 PM. Reason: Additional Info
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  #25  
Old 02-20-2017, 03:19 PM
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Originally Posted by Cumminscj View Post
Yep that thread. Throttle plate has the hole. Happens mostly when it is hot, but sometimes when it is cold. I added some info in that other thread. Currently thinking the vacuum leak is on cylinder 4 due to plug coloration or that injector is partially clogged or leaking. Will update that thread after I do the intake and get the injectors flowed.

***ECT checked good. Replaced it anyway. No change in symptoms.
If the plug is white, the injector isn't leaking. Go to an auto parts store that loans tools and test equipment to get a set of 'Noid lights' for your engine. They'll tell you if the injectors are getting the pulses they need.

If you have fuel, spark and compression, it should run.
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  #26  
Old 02-20-2017, 03:59 PM
Cumminscj Cumminscj is offline
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Originally Posted by JimN View Post
If the plug is white, the injector isn't leaking. Go to an auto parts store that loans tools and test equipment to get a set of 'Noid lights' for your engine. They'll tell you if the injectors are getting the pulses they need.

If you have fuel, spark and compression, it should run.
On my end all 8 cylinders run and the balance is pretty good. There is zero doubt that all injectors on mine are firing. Just smells slightly off at restart like it might be a little rich. After you run it at high idle around 30 seconds the rich smell is gone.

To the original poster since you can't get it to run more than a second this would be a good idea. It would appear your ecm sees that the motor is rotating, and fires the correct injectors and plugs at the right time, but when it tries to control the idle circuit it seems like it has a fault. I realize the engine is a reman, but I would check the compression. Mostly I would try and see if your motor will start at partial throttle. If you can get it to run at partial throttle you may be able to figure out you have a cylinder not firing.
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  #27  
Old 02-20-2017, 06:25 PM
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Originally Posted by Cumminscj View Post
On my end all 8 cylinders run and the balance is pretty good. There is zero doubt that all injectors on mine are firing. Just smells slightly off at restart like it might be a little rich. After you run it at high idle around 30 seconds the rich smell is gone.

To the original poster since you can't get it to run more than a second this would be a good idea. It would appear your ecm sees that the motor is rotating, and fires the correct injectors and plugs at the right time, but when it tries to control the idle circuit it seems like it has a fault. I realize the engine is a reman, but I would check the compression. Mostly I would try and see if your motor will start at partial throttle. If you can get it to run at partial throttle you may be able to figure out you have a cylinder not firing.
One or two injectors won't affect idle to the extent that it won't run- once it starts, the ECM REALLY wants it to keep running, so it will open and close the IAC in order to maintain the correct idle speed. The three most likely culprits when it won't start with the throttle closed are:

Bad IAC
Bad ECT
Faulty wiring that removes 12VDC from the Run wire in the harness.

I still haven't seen comments statingvthat the purple wire has voltage when the key is in the Run position.

If the idle stop on the throttle bosy has been adjusted in any way, it can act like it has other problems. If anyone gets the urge to adjust theirs, just let it pass- this is painted for a reason- leave it alone!

FWIW, the first time I went for MC technical training, we worked with a TBI engine and an LT1. Once we were done with the tests we were supposed to do, the group I was in decided to do a few of our own, so we started removing the plugs to the injectors, one at a time. On 7 cylinders, there was no difference in idle quality and it was only after 3 were off that it was even noticeable. It still idled on three cylinders.
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  #28  
Old 02-21-2017, 02:57 AM
Lukex45
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Great info thanks guys, I have tried the throttle partly open, fully open, all positions. Iv traced 12volt feed on the purple wire to J1-19 ECM input throughout the start process without ever loosing 12volt.

ECT has been tested correct, on the dash and resistance test.

I have ordered MEFIBURN for MEFI 5. Should arrive Thursday so will be interesting to see what going on in there. As said on my original post, the whole boat was subject to 100% humidity, the ECM was covered in white powder from the moisture. I'm really starting to think the ECM has had it !
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  #29  
Old 02-21-2017, 06:41 PM
Cumminscj Cumminscj is offline
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Originally Posted by Lukex45 View Post
Great info thanks guys, I have tried the throttle partly open, fully open, all positions. Iv traced 12volt feed on the purple wire to J1-19 ECM input throughout the start process without ever loosing 12volt.

ECT has been tested correct, on the dash and resistance test.

I have ordered MEFIBURN for MEFI 5. Should arrive Thursday so will be interesting to see what going on in there. As said on my original post, the whole boat was subject to 100% humidity, the ECM was covered in white powder from the moisture. I'm really starting to think the ECM has had it !
I know you checked the positive power to the ecm at key on, starting, and then starting to key on, but what about your ground? If you are loosing ground it can cause a rash of problems.
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  #30  
Old 02-21-2017, 07:13 PM
Lukex45
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Originally Posted by Cumminscj View Post
I know you checked the positive power to the ecm at key on, starting, and then starting to key on, but what about your ground? If you are loosing ground it can cause a rash of problems.
Iv removed the ground terminal from the main harness, wire brushed, removed all paint so i have a metal to metal contacting face. I have even ran a seperate ground direct to battery to the engine. Same issue

Maybe i should open up the loom and check the ground terminals joints within, as i believe these are spliced together ?
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