Volvo 8.1 nightmare

jgerardi

Seaman
Joined
Feb 27, 2019
Messages
61
My 2007 Chaparral 256ssi (8.1) has been a nightmare. Last summer i had to replace the engine due to what i believe was a lean fuel ignition causing a broken piston. I had the entire engine rebuilt and put it back in. I got it all together and running and put the boat in the water. I had it out for 20 minutes and seized up the upper out drive. Some how i lost nearly all of the oil. I know for a fact that i put the correct amount in because i had the container still.
4K later, i have the boat all back together. I replaced the starter as well at this point because the old one had a loose connector on the solenoid and i just figured i would get it all over with at once. When i started the engine with the new out drive and starter, it turned once and then the starter just started to grind. I took the starter out and found that it had chewed up the flywheel. I ran the starter on a bench and found it was not engaging fully causing it to trash the gear on my flywheel. Now the engine has to come out again. I was able to replace just the ring gear on the flywheel. I finally got it all back together and got the boat in the water.
At this point everything seemed ok with one exception. The boat seems to run very rough at 800 - 1200 rpms. Below or above that it seems fine. It almost seems as if it is misfiring. Once i get about 1200, it it fine. I also noticed that once in a great while, when i start the engine, it seems to jump around. Almost as if it is only running on 3 cylinders. If i shut it off and restart it, it is find until the next random time it does it. if it starts normally (99%) of the time, it is fine. That one in a hundred times, it dances until i shut it off which is always immediately. Then i restart it and its good to go.
Here is what i am thinking. Since changed the ring gear on the flywheel, maybe i screwed up the balance? Im wondering if that could be the cause of the dancing and well as the rough run at 8-1200 rpm.

Any thoughts?
 

GA_Boater

Honorary Moderator Emeritus
Joined
May 24, 2011
Messages
49,038
You don't have a balance problem. Out of balance is not intermittent.

How did the motor run before the flooding and piston destruction? Did you find the cause of the lean condition?
 

jgerardi

Seaman
Joined
Feb 27, 2019
Messages
61
it ran fine prior to the blown piston. this started before the flooding problem. I was also thinking an issue with the outdrive even though it is brand new. I had a ***** of a time getting the engine alignment right although i believe i did get it right. The alignment tool slid in and out with very little effort. All in all the boat runs well with that one issue. I just remember when i first bought the boat it was smooth at all rpms.
 

jgerardi

Seaman
Joined
Feb 27, 2019
Messages
61
As far as the balance goes, i would agree that it would not be an intermittent problem. But i also know that when you have a tire out of balance and it causes a shake. Sometimes you dont experience it and sometimes you do.
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
40,582
With it being intermittent, look for electrical connection on Air control valve, crank position sensor, PCM and a loose ground
 

jgerardi

Seaman
Joined
Feb 27, 2019
Messages
61
Well, although the dancing when i start it is intermittent, the roughness at 8-1200 rpms is spot on, every time. I will check all of the electrical connections again i just have it in my mind that is has something to do with the balance.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,304
it has nothing to do with balance. that is a mechanical impossibility. better chance of winning the lottery 10 times in a row, than that happening.

it has to do with either lack of fuel (running lean) or lack or spark or you have wires crossed.

you need to plug in Rinda and see what is going on.
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
40,582
although the dancing when i start it is intermittent, the roughness at 8-1200 rpms is spot on, every time.

This could be idle air control, MAP, fuel pressure, vacuum leak. Scanner would provide some insight
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
40,582
Has no IAC.

The IAC is term used by Merc
The Air Control Valve is term used by VP

All fuel injected motors have either a IAC or ACV. They are either part of the TB or the intake manifold. The issue we run into with VP is they delete items no long available many times. Since the Merc uses the same intake as VP it could very well use the same IAC/ACV. See item 38 which connects to the TB

https://www.mercruiserparts.com/bam/subassembly/31816/11414/70
 

muc

"Retired" Association of Marine Technicians...
Joined
Jul 7, 2004
Messages
2,064
The IAC is term used by Merc
The Air Control Valve is term used by VP

IAC is a term used by both MerCruiser and Volvo when the engine has one.
The 8.1Gi-H doesn't have one. It has an electronic throttle body and uses the butterfly to control idle speed.
Not sure where your getting Air Control Valve from as Iv'e never seen Volvo use that term. Volvo will sometimes use the term sensor in their parts list when referring to the IAC, why I don't know.

jgerardi
Volvo had a service bulletin about vibration caused by a bad coupler and it only showed up at a certain RPM. So an out of balance issue can and will sometimes only show up at a specific RPM. But based on your symptoms I think it's only a remote possibility.
When your engine block was replaced, was a new crank position sensor installed?
I agree that a good scan tool may speed up the troubleshooting and maybe pay for itself. But be aware that the scan tool is only 1/2 of it. If the scan tool operator doesn't have enough knowledge it can be worthless.
 

muc

"Retired" Association of Marine Technicians...
Joined
Jul 7, 2004
Messages
2,064
AllDodge Thank you for correcting me. I’ve never seen Volvo use that term before. What engine did you find that on? I’m pretty sure that if you look at the service manual for that engine, you will find that they call it an IAC. I have found that it’s best to take Volvo’s part descriptions carefully. As I posted earlier they will quite often call this component a sensor in the parts catalog. I find this very strange because a IAC is an actuator and provides no electrical feedback to the ECM. My guess is that some of these strange descriptions are the result of a Swedish to English translation.

But I do stand by my statement that the O.P.s engine doesn’t have a IAC, Air Control Valve or a Idle speed air valve. And yes I’m aware that if you look up the 8.1Gi-H engine in the parts catalog, Volvo will list a Valve, idle air control. But my guess is that they are referring to the butterfly, because that’s what controls idle speed on this engine.
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
40,582
I don't look at the VP manuals much (my very short comings), just try to assist and mess up not rechecking, glad your here.

Been looking at that term for a long time and find it on most (will not say all, sure I missed some) parts listing found at marine parts europe. That was on a 5.7 Gxi, Gi and others. Found also on some 4.3's. My bad issue as before I just keep finding the term so it started to stick.

Glad you pointed out the IAC, because I look at a few VP manuals at boatinfo and did find IAC, so I will try to stop using the other term
 

muc

"Retired" Association of Marine Technicians...
Joined
Jul 7, 2004
Messages
2,064
I don't look at the VP manuals much (my very short comings), just try to assist and mess up not rechecking, glad your here.

Been looking at that term for a long time and find it on most (will not say all, sure I missed some) parts listing found at marine parts europe. That was on a 5.7 Gxi, Gi and others. Found also on some 4.3's. My bad issue as before I just keep finding the term so it started to stick.

Glad you pointed out the IAC, because I look at a few VP manuals at boatinfo and did find IAC, so I will try to stop using the other term

Marine parts Europe, hadn’t seen that one before. Appears to be based in Sweden. A different format, I can see how some would like it.

For people in the the U.S. our host iBOATS has a pretty good lookup, only problem I have with it is that it doesn’t cover the newest engines. The other official Volvo.US parts lookup is volvopentashop and is very close to what dealers use. It would be nice if iBOATS could use it.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,304
the volvopentashop.com is the US version of Marine Parts Europe.
 

jgerardi

Seaman
Joined
Feb 27, 2019
Messages
61
From what i have found, the IAC is a part of the throttle body. (see attached picture) . None of the sensors were replaced when the engine was redone. The engine ran great right up until i lost the cylinder so i did not feel it was necessary.
I came across something in the sealoc manual. My boat does not have an MIL light. But the ECM does have an output for it. According to the manual, it is pin 80 on the ECM and it runs through pin 9 on the engine harness. According to them the light is powered by the ignition switch and when the light should come on (either when the ignition is on and engine is not running, or when there is a code, the ECM throws pin 80 (pin9) to ground.
I started the boat and connected my test light clip to + on my battery and checked the pin 9 and the engine harness. The test light did light up with the engine running.
Am i interpreting this correctly to say that the is a malfunction that would be throwing a code on the scanner?
If i have to shoot the lock off my wallet and buy a scanner i will. Does anyone have any suggestions? It seems the one that keeps coming up on google search is the techmate pro. I also found a used techmate (2014 edition) on ebay that has never been used. My other option is the rinda software connected to my PC.
Anyone have any thoughts on this?

JG
 

Attachments

  • photo324637.png
    photo324637.png
    144.1 KB · Views: 2

jgerardi

Seaman
Joined
Feb 27, 2019
Messages
61
Engine running rough.

I am reposting this because the thread where i originally posted it seems to have taken on a life of its own.
My 2007 Chaparral 256ssi (8.1 Gi-H) has been a nightmare. Last summer i had to replace the engine due to what i believe was a lean fuel ignition causing a broken piston. I had the entire engine rebuilt and put it back in. I got it all together and running and put the boat in the water. I had it out for 20 minutes and seized up the upper out drive. Some how i lost nearly all of the oil. I know for a fact that i put the correct amount in because i had the container still.
4K later, i have the boat all back together. I replaced the starter as well at this point because the old one had a loose connector on the solenoid and i just figured i would get it all over with at once. When i started the engine with the new out drive and starter, it turned once and then the starter just started to grind. I took the starter out and found that it had chewed up the flywheel. I ran the starter on a bench and found it was not engaging fully causing it to trash the gear on my flywheel. Now the engine has to come out again. I was able to replace just the ring gear on the flywheel. I finally got it all back together and got the boat in the water.
At this point everything seemed ok with one exception. The boat seems to run very rough at 800 - 1200 rpms. Below or above that it seems fine. It almost seems as if it is misfiring. Once i get about 1200, it it fine. I also noticed that once in a great while, when i start the engine, it seems to jump around. Almost as if it is only running on 3 cylinders. If i shut it off and restart it, it is find until the next random time it does it. if it starts normally (99%) of the time, it is fine. That one in a hundred times, it dances until i shut it off which is always immediately. Then i restart it and its good to go.
Here is what i am thinking. Since changed the ring gear on the flywheel, maybe i screwed up the balance? Im wondering if that could be the cause of the dancing and well as the rough run at 8-1200 rpm.

In my first post on this, the consensus seems to be possibly a bad IAC. Now there were many responses to this theory because of terminology, where it would be, etc. I have determined with certainty that it is a part of the throttle body and can only be replaced with the throttle body itself. (700.00). There is also a consensus that i need to get a scanner.

None of the sensors were replaced when the engine was redone. The engine ran great right up until i lost the cylinder so i did not feel it was necessary.
I came across something in the sealoc manual. My boat does not have an MIL light. But the ECM does have an output for it. According to the manual, it is pin 80 on the ECM and it runs through pin 9 on the engine harness. According to seloc, the light is powered by the ignition switch and when the light should come on (either when the ignition is on and engine is not running, or when there is a code, the ECM throws pin 80 (pin9 on the engine harness) to ground.
I started the boat and connected my test light clip to + on my battery and checked the pin 9 on the engine harness. The test light did light up with the engine running.
Am i interpreting this correctly to say that this is a malfunction that would be throwing a code on the scanner?
If i have to shoot the lock off my wallet and buy a scanner i will. Does anyone have any suggestions? It seems the one that keeps coming up on google search is the techmate pro. I also found a used techmate (2014 edition) on ebay that has never been used. My other option is the rinda software connected to my PC.
Anyone have any thoughts on this? Either the mentioned scanners or an alternative.

Any thoughts?
 
Top