Volvo 8.1 nightmare

[GA_Boater]

Your new thread has been merged with the original.

Don't start a new thread on the same problem because you think it took on a life of it's own. The prior history is important, even if some is about terminology.

A second thought, don't write so much. Try to be more concise. Many of the those that replied are pros and time is money to them. Your re-post just copied the initial post then added no sensors were replaced, you checked pin 9 for the MIL signal and now asked about a scanner. Get ready for opinions.

Don't want to spend money on a scanner? Have your mechanic scan it, although buying your own may be cheaper in the long run.

 

[alldodge]

The Diacom SW provides the most info at one time, and most find it easiest to use. The Techmate needs to be stepped thru to see different parameters

 

[BRICH1260]

I purchased the handheld Rinda unit when I replaced my engine. It was a little salty in price but the information that it makes available is very comprehensive and beneficial. You should be able to re-sell when done and re coup some of your costs.

 

[muc]

“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.”
Nope, you’re wrong about the IAC. I assume you think one is there due to the parts listing having a part with the name “Valve, idle air control - not sold separately”. Or because other posters, in an effort to be “helpful” have suggested you check it. But if you read the EGC diagnostics manual, you will find that the IAC is a part that’s used on engines without electronic throttle bodies. Your engine has an electronic throttle body so your engine will not have an IAC. Also, if you look at the wiring schematic for your engine you will find there are no wires present to control an IAC. And while I try to avoid blanket statements. I will make this one. All marine engine IAC’s are electrically controlled.
Do you need a scanner? You do need to have the engine scanned by someone who understands what they are looking at. The majority of the time that a scan tool is used to diagnose an unusual symptom (and your symptom is pretty rare for an 8.1 Gi-H) it is used to quickly rule out a bunch of things that could cause this issue. It is pretty rare that it will actually tell you what’s wrong.

Workshop manual, Wiring Schematics p/n 7746659
Workshop Manual; Engine Mechanical, 8.1L p/n 7748095
Workshop manual - EGC Diagnostics p/n 7749393
Workshop manual, EFI Repair p/n 7743614

These are the four manuals that you should have read and understood as part of hooking up a scan tool. I have no idea what your level of expertise is. But these manuals are written for factory trained mechanics. So they assume the reader understands how marine EFI works. They also don’t include some information that could be important.
One of those bits of information has to do with the CKP (crankshaft position sensor). That’s why I asked if any sensors have been replaced. One of the manuals will tell you that the crankshaft position sensor is designed to contact the reluctor wheel of the crankshaft. And that wear may be noticeable on the end of the sensor. What the manuals don’t tell you is that that sensor can only be reinstalled 3 times because a little bit wears away each time it’s reinstalled. When the 8.1 engine first came out we were instructed that when we had certain symptoms (and your symptom is one of them) we should “reseat” the CKP because it was possible there was too much air gap present. At the time most of us didn’t have Diacom yet, so this was a work around because the VP2000, techmate and Vodia scan tools are not capable of adequately diagnosing this. We were also told that during a long block replacement that the CKP might need to be replaced as part of that repair. Now does this mean you should run out and buy a $250 CKP to try? No. I’m using this as an example of how much knowledge might be required to correct your problem.
Another thing that isn’t covered in the manuals that I listed because it was covered in earlier manuals, and they assume the mechanic reading this one already knows. When using a test light like you did to test the MIL circuit. That test light must meet certain specifications so it won’t damage the ECM.

That brings up your findings on the MIL light. I can’t be sure if your results are valid. To the best of my knowledge, no boat builder ever installed a MIL light with this engine. The ECM had this circuit in it because they knew that a MIL light would be required by law in upcoming years. I have worked on boats that have a MIL light. And when that circuit becomes open (which is the same as not being installed) it will set off the warning horn. So I would guess that if that circuit was active, you would have had a warning horn going off before and I’m guessing you didn’t or you would have said something. Now it is possible that your ECM wasn’t programmed to set a horn on this circuit. Or it’s one of a few circuits in the ECM that don’t become active until the ECM senses a connection. So I don’t know if your tests mean anything, maybe someone else does?

Your problem could be something very simple. Like maybe EMI? Is it possible that when you reinstalled the wiring harness on your new engine it got routed in a different place? This can cause electrical interference and create a problem like your experiencing? Or maybe some of the boots on your spark plug wires are going bad and jumping to ground? That can cause EMI and other problems.

One of the things I look at with this symptom is to watch the butterfly in the throttle body while the problem is happening. How much it’s “fluttering” can sometimes provide some insight. But be careful, that butterfly is electrically controlled and has enough force to cut your finger off. And of course all the other safety warnings that apply when running an engine with the flame arrestor off.

Or you might have a complicated problem that would take an experienced tech 4-5 hours. I have had to spend that much time more than a few times.

 

[cptbill]

Is it the GM based engine? If it is all GM based TBI units use the IAC ( call it a valve or a motor what ever makes you happy) to control Idle speed, If your ADJ the idle by moving the throttle stop that could be a part of the problem

 

[jgerardi]

@cptbill....I think there are a couple of typos in your post. In the last line you say "if your adjust the idle....." Do you mean If you adjust the idle, or do you mean if you adjusted the idle? In any event, i have never attempted to adjust the idle. if i were to, the ECM would simply re-adjust it.

@MUC...Thank you very much for taking the time to write that response. It was quite clear and easy to get your point. FYI, my meter falls within a rating of 10Megohms resistance, and my light, although an inexpensive one has less than .3 amps of current flow.

As far as my capability, I am an amateur for sure. I am quite capable or reading and understanding what i am reading from a service manual. I have had some experience with OBD in cars and i do realize that scanners give you a whole boat load of information, however knowing what to do with it is the trick.

If push comes to shove, i will bring the boat to someone however finding someone who has all of the necessary knowledge to diagnose something like this might be tough to find. I have the time to spend (as many hours as it may take) to try and figure this out for myself and since the boat is quite usable, short of damaging something, i dont see a down side.

As far as wire routing causing some sort of interference, when i reassembled everything, i did my best to replace any damaged or missing loom and electrical tape covering on the harness. I also did my best to route the wires as they were making sure none were looped or wrapped around others.

Regarding the crank sensor, im not sure i understand how removing it and reinstalling it causes wear however i suspect it has been removed and reinstalled more than 3 times. This is the third engine that has been in this boat.

When i get the scanner software and hardware, hopefully it will give me some insight and point me in a little bit of a more definitive direction.

The seloc manual gives some pretty good instruction on how to used the scanner and steps to take prior as well as when using the software. Additionally Rinda gives some good tutorials via youtube.

Once again, thanks for taking the time to write all of that information and wish me luck. Any other thoughts you might have are much appreciated.

 

[muc]

It sounds like you will have a good chance at fixing this.I understand about finding a good tech, I have worked at some places that I was the only one with enough training for something like this and at other places where there were 4 of us. Even some of the Volvo schools had a few people there that would really struggle with this issue.

Tape and loom don't have any effect on EMI, it's all about routing. The crank and cam sensors along with the knock sensors are most vulnerable.

Both Volvo and MerCruiser (they both used this block) really pushed the 3 times on the CKP. But I know of at least one engine that has had it out at least 4 times. So I think it has more to do with how hard you push it in.

I highly recommend the Diacom software, it is the best out there short of Vodia and Vodia is a Volvo dealer system only. A added benefit is you can record the engine running with it and email or post those files and people who have knowledge can run them on a PC and maybe help you out. The Diacom software is pretty much free, it's the cables and interface that cost.

I haven't looked at a Seloc manual for decades but I think they do a good job of giving a person an overview of the engine. They are written with a non-professional in mind. But I do think you will need those Volvo manuals before you are done.

I'm happy to help when I can.

 

[jgerardi]

I understand the whole EMI issue from working with electronics. The point i was trying to make is that i really made an effort to put the whole wiring harness back in the way it came out and make sure everything was properly protected from rub-thru damage and heat.
I was out last night on the boat and one thing i also noticed is that the rough running seems to be much more pronounced when throttling down from a cruising speed to a slow/no wake speed.
The software should be here tomorrow and we'll see what happens next.

 

[Lou C]

Given what you just posted, is it possible that it’s pulling water from the exhaust causing misfiring under those operational conditions? I know some Volvo engines used vacuum break valves on the exhaust elbows to prevent that (when they went to the Vortec design). Do the spark plugs look slightly rusty?

 

[cptbill]

My meaning was if you try to adj. the Idle at the stop for the throttle plate( the screw at the linkage were the throttle cable mounts) all that will do is hold the butterfly open if moved in thus bypassing the IAC

 

[jgerardi]

A
lthough i have not pulled all of the plugs, i did pull two of them and swapped them. The number 3 cylinder when pulling the wire while the engine is running seems to have less of an effect than when i pull the other 7. I tried sapping the wires, then the coils and then the plugs. Nothing seemed to matter. I guess it could be nothing at all since none of the cylinders when shut down have a very significant effect on the engine when at idle. In any event there was no rust on the plugs.
Im still waiting on the software so while im waiting im going to check the fuel pressure. I just noticed today a bit of a whine coming from the fuel pump. I pulled the wire off it and it had quite a bit of oxidation on it. I tried to clean it up and if i hold it on and move it around a bit the whine comes and goes. Im thinking im not getting enough current to the pump. Cleaning it isn't too easy because the contacts are quite small and inaccessible. I also ordered a new connector for it today because the old one had a broken clip and i had it held in place (obviously not as tight as i thought) with a wire tie. Maybe I will get lucky and that will solve my problem? (YEAH RIGHT, Imagine that)
Its a 13yo boat so i guess this is all par for the course. And the roughness isnt really all that bad. Im just a bit neurotic when it comes to things like this
I any event, im still working at it and appreciate all the input.

PS..Does anyone know of any good solutions for cleaning the oxidation? Baking soda, vinegar, some sort of acidic solution?

JG

 

[alldodge]

While oxidation can be an issue, I don't see that as being the problem with the pump

Those small contacts are rough to clean, CRC or vinegar, and brushes

This is an expensive kit but can see about what is needed to get at the contacts
https://www.zoro.com/ipa-electrical-terminal-maintenance-kit-8048/i/G5385782/

 

[muc]

cptbill this engine has an electronic throttle body ---- no throttle cable, no screw, no IAC.

Lou C brings up a good point. This family of engines did have some reversion issues in some hulls. The 07 256ssi wasn't one of them. But who knows what cam is in there now. The 8.1 Gi-A and up do have an exhaust balance tube between the two cylinder banks that did work to stop water reversion. When you pulled the exhaust manifolds to replace the block, was there ANY rust stains in the ports of the manifold or head?

jgerardi Your last post makes it sound like you haven't done any basic troubleshooting yet. Only 2 plugs pulled? Kind of hard to have done a compression test. Found a bad electrical connection at one of the fuel pumps? Sure makes it sound like you haven't done a visual inspection.Haven't checked fuel pressure yet? All of this basic troubleshooting must be done before connecting a scan tool. None of these things will show up during a scan, other then weird information that could lead you down a wrong troubleshooting path. Please stop and reassess how your going about finding this issue.

For cleaning electrical connections? Electric Contact Cleaner (not brake or carb cleaner), auto parts store carry it. What works best for me is to, open the connector, spray it with the cleaner, shake out the excess (you don't want to hydro-lock the connector and compromise the seals), plug and unplug a few times, cleaner again, let dry completely and paint a THIN film of dielectric grease on both sides after a close visual inspection. ​​

You commented on pulling spark plug wires when the engine was running. This is called a cylinder drop/canceling test and is a good test when done correctly. It is almost impossible to do this test correctly on this engine by pulling spark plug wires. The spark needs to be redirected to ground almost instantly or you run the risk of damaging the coil or ECM. This test is best preformed with a scan tool and will be found in the tests section and called Volvo Penta EGC Spark Kill Test and Volvo Penta EGC Injector Kill Test. These tests must be done at about 1500 RPM with a load on the engine to be valid.

I'm not trying to be a jerk, but as a dealer tech. Over the years I have worked on a lot of engines that other people tried to fix first. And many times, the original problem would have cheap to repair. But because of bad troubleshooting and parts swapping there are now multiple problems that need to be worked thru one at a time and it gets expensive. I'm not saying that you shouldn't attempt this yourself, I'm saying that you need to read the manuals I posted earlier and you will need to read between the lines in them because you haven't had factory training. Case in point --- do you think the scan tool designer added the spark and injector kill tests for fun? No they had a very good reason, because on this engine there is only one safe way to do this necessary test.

Yes, fuel pressure could cause this problem.

One other thing. It sounds like you assume that because this problem is only noticeable at certain RPMs, it is OK to continue to use the boat. That could be a expensive assumption and may result in a 4th engine.

Please, please. Read the manuals I listed and ask the questions that come up when you do.

 

[Lou C]

this is all very interesting stuff, I realize that you really have to keep up if you want to be able to properly diagnose these modern engines, I do what I can on my vehicles, but there are some things I have to leave to the dealership techs. On the other hand, this is why in large part I kept my old boat with 1960s technology, it is pretty easy to troubleshoot and repairs are similarly simple. EFI and electronic engine management are great, but when you understand old school points ignition systems and can rebuild Quadrajets and Holleys, that is good too!

 

[jgerardi]

This whole issue began last summer when i replaced the engine. I did do a compression check when this first began. I also checked all of the connections on everything. I believe the recent issue with the fuel pump connector was a result of all of the water i got in the bilge when the cooler drain was off. The water was pretty deep in there and was being slung all over the place by the belt and pully. This connector as i said was not as tight as it should have been because of the broken retainer clip which is on order and hope to have it today.
I have the software now and sealoc gives a good instruction on everything that must be checked prior to using the scanner.
I found 3 of the 4 manuals online. The one i am having the issue getting is 7749393 (EGC Diag.) . The only one i can find is going to take 6 weeks to get. Probably the most important one as well.
I do have some old bad habits as far as things like pulling a wire while it is running. Im learning as go with much of this. Another issue is i am in Fla and although i have some basic tools here, most of my others (compression gauge, fuel pump pressure, meters and the like) are at home in NY.
Make no mistake, i am reading what is being said here and trying to do my best. Unfortunately getting all of this stuff together takes time and money. I NEVER mind spending money on tools or good informative books, of course its always nice when you can find this stuff on ebay.
Thanks once again.

 

[jgerardi]

One other thing. This issue i am having with the roughness, it is nothing that is so bad. In fact most people on the boat think im nuts to even think about it. It bothers me quite a bit here because on the intercostal, i have to keep the boat in that rpm range so as not to get yelled at by everyone for too much wake. When i use the boat at home on the Hudson river, it takes about 3-4 minutes to get out of the marina and i dont even think about it again. Im just one that knows if it isn't supposed to do it, then i want to fix it.

 

[muc]

Please take my advice with “a grain of salt”. I’m not there and can’t see,hear and feel your engine. I only know the history of this engine that’s in this post

 

[jgerardi]

Well, if nothing else I'm learning quite a bit. I did manage to track down all of the manuals you suggested but it is going to take a few days to get them. I did do a compression test today and found some pretty good results. According to the repair manual if the lowest is within 25% of the highest, that is considered normal. My lowest was 160 and highest was 175. They were 175, 175, 175, 175, 170, 170, 165, 165, 160. I did find that the spark plugs were not at the correct gap. When I checked the manual for the gap i found it should be .060. I have never seen a spark plug with that big of a gap before. I suspect that when i installed them after the rebuild, i read the gap for the 5.7 motor which is .045 (i believe).
In any event that seems to have made a very slight difference. At least i think it did. I only had a chance to do a quick run with it.
One thing i did notice is that the tach does not seem to be correct. Is seem to be off by about 100rpm. I also dropped each cylinder out using the test function with the scanner via the injector kill as well as the spark kill. According to the RPM graph at 1200 rpm, the change with each cylinder was the same.
Tomorrow I'm going to take a whirl at the fuel pressure test and the vacuum test and see where that leads me.
I did order new ignition wires even though the ones i have dont appear to be compromised. I just noticed that they have red paint on them. That tells me that these wires were on the motor when it was rebuilt the first time. 6 years and 350hrs. (I have only owned the boat a year.) When the motor was done the second time, they painted the harness, injectors, fuel rail, etc. and got overspray on the hoses, wires, etc. When i did the motor i painted everything black.
To be continued ..........

 

[jgerardi]

Oh another question. I did manage to find some of these manuals online in PDF form. I ordered the paper copies anyway but..... They do make reference to the fuel pump test using the scanner to run the pump. I don't see this test anywhere on the scanner. Am i missing something?

 

[muc]

What scan tool do you have?