2007 VP 5.7L GXI will only reach 3900-4000 RPM

[kdxhx]

I replaced my 5.7L GXI (320 HP) in my 2007 Rinker Captiva 262 with a reman long block due to a potential cracked block with a lot of corrosion--actually caused the starter mount to fail and damage the ring gear. Previous engine ran fine though--47 mph at 4700 RPM on F5 propset.

Ever since the new engine has been installed, I can only reach ~3900-4000 RPM, verified by my Diacom program. Same props and outdrive as before new engine. Outdrive was inspected while engine was out--gimbal, u-joints, etc. all fine. I am suspecting that the reman engine is not producing the claimed 330 HP. It does start and run fine, just doesn't reach proper WOT of 4800-5200 RPM for the GXI engine.

Items checked: Compression is 165 to 175 all cylinders; spark plugs look ok, insulators are white, ground and center electrodes looks normal, little bit of soot on plug ends. Performed cylinder drop test with both injectors and spark plugs under load--checks good.

Cam retard angle is good at 45.5 degrees. Distributor is installed correctly. Firing order checked. Crankshaft position sensor, cam position sensor, ignition coil/module have all been previously replaced within the last 50 hours. Vacuum checks good at 17 psi at idle and gives correct response when engine is revved. Fuel supply is good, fresh 91 octane non-ethanol, and checked for proper vacuum as well as the low pressure and high pressure fuel pumps--also checked under load.

Fuel separator is new, and old separator had no water in it. Fuel pressure regulator checked--clean and it is less than 50 hours old. Oil level is not overfilled. Engine has no exhaust flappers. Hull is clean.Throttle valve opens fully at max throttle. Cleaned the air intake--appears to flow fine. I did raise the outdrive high enough to ventilate the props and the RPM did climb toward 5000...

I tried re-routing the crankshaft position sensor wire and knock sensor wires away from spark plug wires--no change. I also re-routed the #7 spark plug wire to avoid crossfire--no change. Engine appears to run completely normally until 3/4 throttle and 3900 RPM--more throttle does nothing, except a little more engine noise from having the throttle plate wide open. Tachometer reads about 150 RPM high, but I have the Diacom to verify engine speed.

I have to believe the problem is related to the engine install, and not the simultaneous failure of something un-related to the install, like ignition module or spark plug wires, but I am not ruling it out. Boat is on a covered lift, prop and hull issues are not the problem. I installed a F4 propset with no change. I am installing an F3 propset later this week since that is what the boat came with. Boat seems to be using more fuel than before but not positive. Engine now has 23 hours on it and should be broken in.

Only other clue is when watching / recording the engine parameters on the Diacom software, I see the ECU retarding the timing advance back to 18-22 degrees almost continuously above 3200 RPM anywhere from 1 to 10 degrees--apparently due to the knock sensors which are simultaneously being activated. Both knock sensors have been replaced in the last 50 hours and were torqued to 15 ft. lbs. Hate to change something that I don't know is faulty but dang...

I also do not want to approach the engine supplier unless I know I have checked everything thoroughly. I am wondering about cam timing...or wrong cam for the application...At this point I do not know what else to check. Hopefully someone on here has some idea of what might be the problem. Thanks in advance for any assistance. --Jim

 

[Scott Danforth]

22 degrees is the max advance, so not sure that is it.

knock sensors both going off is low quality fuel or crud in the fuel causing knocking

what is your fuel pressure?
when you pour the contents of the fuel filter in a clear plastic bag, what did you find?

when you replaced the motor is the reman a generic SBC, or was the mix of parts the same as the 320? most of the generic crate SBC's only produce about 260-280 hp

 

[tpenfield]

Did you run the recording feature on the Diacom? If so you may be able to email the data file to one of our experts for their analysis.

 

[alldodge]

If your sure the distributor is installed correctly, you can mark the spot then move it 1 or 2 degrees left and right. This changes the timing slightly and can help. If it does not, move it back. Knock sensors going off says you have some preignition

 

[kdxhx]

Hello Scott, et al,
The Diacom software does have a record feature. The symptoms and data listed above were taken from about a 10 minute test-ride recording where I watched the engine parameters change as I varied the rpm: 3000, then 3200, then 3400, etc. up to max that I could attain, approx. 3900.

Starting at about 3200 is where the knock sensors really becoming active, and could see the timing advance being retarded back to the 18 to 21 range. At idle, spark advance reads 4.5 to 8.0. At max rpm, it is 20.5 to 25.0 mostly, until it is retarded back. Max observed spark advance was 27.5 at 3200 rpm. Maximum observed timing retard was 7.9 degrees. Total advance on a small block chevy should easily go to 34-36 degrees. There is knock sensor activity even at 1000-2000 rpm...

Scott, not sure where the 22 degrees max you refer to comes from--perhaps that is in addition to whatever the base timing is, which is not set on this engine. All Dodge, if I am not mistaken, the distributor can almost be put in any position and the computer will figure out when to fire the spark plugs due to the crankshaft position sensor and cam position sensor. I am pretty sure it is impossible to move a tooth and change timing, or turn the distributor to modify the timing. All you change is the "cam retard angle" and my understanding is that is to allow the cam position sensor to lock on to the correct spark plug "tower" which is then indexed by the computer.

Knock intensity is also recorded, Max recorded knock intensity was 100% at 3500 rpm.

As stated above fuel pressure on the high pressure pump reads normal: 55-60 psi at idle and under a load. The low pressure pump is 6-8 at idle and under a load.

I am pretty sure the fuel is good as I have run approximately 60-80 gallons through the engine--that's 3-4 separate trips filling up my 25 gallon portable tank over a 30+ day period to the local Shell station that sells 91 octane non-ethanol fuel. IMHO there is zero chance it is fuel quality. Which is why I am questioning the high activity of the knock sensors. They should not be active at all--but I know very little about how to troubleshoot that part of the engine management system. The knock sensors that I replaced about 50 hours ago were rusted to heck and I was surprised even functioned. So I replaced them as they looked reallllly bad.

The fuel was clean when I checked it. The fuel / water separator is new. There was no debris in the fuel regulator. The low pressure pump shows proper vacuum so I am not thinking it is fuel delivery. I removed the fuel cap--no change, I checked the vent and it isn't blocked.

Scott, the entity that I bought the engine from is national and has two shipping locations. I got the engine from the one closest to me. I ordered the Vortec engine that was indicated for my year of VP and was rated at 330 HP. They said they do not make a Vortec engine with only 260 HP. Without taking the new engine apart and measuring cam lobes and valves, I can only say the engine had Vortec heads on it. It came with valve covers, front cover and oil pan.

In summary, I agree it looks like bad fuel or contamination, but I cannot fathom how that is possible. Besides the potential "wrong engine/not a GXI-comparable engine" scenario, I am tempted to replace the knock sensors...thanks for inputs.

 

[alldodge]

All Dodge, if I am not mistaken, the distributor can almost be put in any position and the computer will figure out when to fire the spark plugs due to the crankshaft position sensor and cam position sensor. I am pretty sure it is impossible to move a tooth and change timing,

Will just say I disagree and leave it at that. Hope you prove me wrong

 

[tpenfield]

Did you save the data file from the Diacom recording?

 

[kdxhx]

All Dodge, My statement could be incorrect, however it is moot because the distributor is installed correctly, and I do know that you absolutely cannot change the timing on this model of Volvo Penta by turning the distributor. That only changes the retard angle, which can only be set with the Diacom or similar. They only used this EGC (computer) for 2007 and 2008. So finding another computer to swap for troubleshooting is virtually impossible unless you have twins. I will see if I can pull some info from the manual(s)...

Tpenfield, Yes I did save the recording! It is on another laptop, so will have figure out if the format will let go to a jump drive and play/send from this computer and not from within the Diacom program--I have never tried--but I am sure it is possible. Will give it a shot.
Regards,
Jim

 

[icwingman]

since i think you said you have a smaller tank, put in some fresh gas and octane booster from auto parts store and try that. your knock sensors should not kick in, also was your engine a 2 or 4 block main bearing and did you get a four bolt main, your new motor might not have the same hp rating as the old, shame you cant put it on a dyno

 

[kdxhx]

Okay, so far I can't get the recording to work "outside" of the diacom program, even though it appears to be running as a VLC video.

ICWINGMAN, I think I will try some higher octane fuel and record how the knock sensor react. I have never replaced the MAP sensor; I have pretty much replaced all other sensors on the engine. Could it be the culprit? The readings appear normal via the diagnostics... I doubt either my old block or the new were 4-bolt mains, but don't know for sure.

I did get the following info from my included manuals regarding the distributor and ignition system:

"This ignition system consists of a single ignition coil and ignition control module (ICM). Spark energy is delivered via a distributor cap, rotor, and secondary spark plug wires. The driver module within the ICM is commanded to operate the coil by the engine control module (ECM), that has complete control over spark timing. The DI system consists of the following components:

The crankshaft position (CKP) sensor-- is a magneto resistive type sensor. The CKP sensor works in conjunction with a 24X reluctor wheel.

The reluctor wheel-- is mounted on the rear of the crankshaft. The 24X reluctor wheel uses 2 different width notches that are 15 degrees apart. This pulse width encoded pattern allows cylinder position identification within 90 degrees of crankshaft rotation. In some cases, this can be achieved within 45 degrees of crankshaft rotation. The reluctor wheel also has dual track notches that are 180 degrees out of phase.

This design allows for quicker starts and accuracy. The CKP sensor also outputs a 4X signal for spark control, tachometer output and fuel control. All CKP signals are output as a digital waveform.

The camshaft position (CMP) sensor-- (1) works in conjunction with a 1X reluctor wheel (2) mounted in the distributor. The CMP is used to determine the top dead center position of cylinder #1, and will synchronize with the 24X CKP sensor signal for quicker starting. The CMP signals are output as a digital waveform.

The ICM-- is connected to the ECM by an ignition control (IC) circuit. The ICM also has a ground circuit and shares an ignition voltage supply with the ignition coil. The coil driver in the ICM controls current through the ignition coil based on signal pulse from the ECM. There is no back-up or by-pass function in the ICM.

The distributor-- is only used as a means to operate the CMP sensor and to distribute spark in the correct sequence. The distributor position is adjustable but has no influence on base timing. If the distributor is rotated, there is a chance of crossfire between terminals due to the proximity of the terminals in the distributor cap.

Circuits Affecting Ignition Control To properly control ignition timing, the ECM relies on the following
information:
• The engine load, manifold pressure or vacuum
• The atmospheric, barometric pressure
• The engine temperature
• The manifold air temperature
• The crankshaft position
• The engine speed (RPM)

The ignition control (IC) system consists of the following components:
• The ignition coil
• The 24X crankshaft position sensor
• The engine control module (ECM)
• All connecting wires

The ignition control utilizes the following to control spark timing functions:
• The 24X signal - The 24X crankshaft position sensor sends a
signal to the ECM. The ECM uses this signal to determine
crankshaft position.
• The ignition control (IC) circuits - The ECM uses these circuits
to trigger the ignition coils."

Regards,
Jim

 

[tpenfield]

The recording file should be able to be viewed by any one with the Diacom. Several of the members here have the software.


Humor us a bit here . . . rotate the engine to TDC #1 cylinder on the compression stroke. Remove the distributor cap and take a picture of the distributor base and rotor from above. Post the picture.

 

[Scott Danforth]

I go back to my question, was the motor that you installed, the same mix of parts as the 320 or did you simply grab a base model 350, as in from a truck?

volvo's 320hp is a custom order assortment of parts that turns out 370hp at the crank (320 at the prop)


you are correct, total advance is about 32-34 degrees. advance curve is still about 22-24 degrees over base timing.
dizzy does need to be installed correctly. its not a drop in anywhere sort of thing. its a line up the rotor with the notch on dizzy body with the motor at TDC on #1 sort of thing

the CPS is a reluctor wheel that is installed between the crank timing gear and the damper
the distributor is the cam sensor. and it does need to be dropped in correctly on TDC of cylinder #1

 

[kdxhx]

Scott,
First, some background on me: I was a Dodge mechanic back in the 70's, I have owned 7 boats. I have rebuilt everything from PWC's, motorcycles, a European-spec Jaguar, 2 GTO's, many motorcycles, etc. I do know my way around most gasoline powered machines that the average human might encounter. None of us are infallible, and simple mistakes are the easiest to make and overlook. We often go for the obtuse, vice the easy stuff...hence my posts here. I have solved multiple problems with my boat by reading up on these posts (lots of smart folks here!) and elsewhere. But there ain't a whole lot of applicable info for this particular scenario.

I had mucho problems with the original engine. I have gotten pretty experienced working on this version of VP engine/EGC/ECM system. Had the cylinder heads off the original engine twice. Probably pulled and reinstalled the distributor 1/2 dozen times. Got to be pretty good at it after a while.

The current engine was ordered online after phone conversations and research. It was touted to be the correct replacement engine for my 5.7L GXI 320 HP. I did not receive nor inspect the reman engine on its arrival. It went straight to the shop doing the install. I discussed the particulars of the install of the engine and items like the timing with the technician and he was familiar with the process. I did drop by and view the engine just before install, but the only thing of note was that it did appear to have the Vortec heads. What the components are is unknown as it came with valve covers, timing cover and oil pan installed. The tech that did the install has no idea what else to check either.

This is largely what I based my decision to purchase on from their website:

"This is a completely remanufactured 5.7L/350 c.i. Vortec marine base engine. This engine will replace those 5.7L marine engines used in Mercruiser, Volvo Penta, Crusader, Indmar, Marine Power, and other applications between the years 1997-present. This engine has the composite (plastic) timing cover, 8 intake manifold bolts, and accepts only an electric fuel pump.

Our Remanufactured engines are totally remanufactured to the original blueprints and exact OEM specifications, and are tested to original equipment standards. Note that ALL of our remanufactured marine engines are bored, decked, and blueprinted on a CNC machine making these units some of the best in the industry.

This "Base Engine" Package includes:

• remanufactured engine block, heads, crankshaft, all new internal engine components
• valve covers
• timing cover
• oil pan
• harmonic balancer
• 1 year parts & labor warranty
• NO core charge!

Specifications:

• 1 Piece Rear Main Seal
• Standard rotation
• Intake Manifold: 8 bolt
• Cylinders: 90 Degree V8 Cylinder
• Hydralic Roller Camshaft
• Composition Ratio: 9:4:1
• Bore: Standard
• Firing Order: 1-8-4-3-6-5-7-2
• Oil Pan Capacity: 5.5 quarts
• Oil Type: SAE 15W40 Pennzoil Marine
• Horsepower: 330 hp @ 4800 RPM (4bbl carbureted)
• Torque: 355 lb-ft @ 3600 RPM"

Because I also had concerns about the distributor being installed incorrectly, about 2 weeks ago I had my wife crank the engine over while I checked for compression stroke on the number one cylinder while watching the distributor rotor. It passed the number one position on the distributor housing whilst the number one piston was quite obviously on the compression stroke. I was mainly checking that the distributor was not installed on the exhaust stroke, commonly called "180 out", and did not check that the rotor lined up exactly with the mark on the housing, because my experience is that it doesn't matter. I don't think I can hit actual TDC with a remote starter. I usually do that by hand using the bolt on the crank damper, but on this engine gotta remove the impeller housing.

The distributor mark is there so that if you line it up correctly on reinstallation, it will be very close to where it needs to be for cam retard, and the engine will start. You can then adjust the distributor to 45 degrees cam retard angle using the software. Although I have seen 42 degrees in some pubs... maybe I will try 42... I will also check to see if it actually lines up to humor youse guys.

The only other things I can think to try is test the knock sensors, or verify the correct reluctor wheel for the CKPS is the correct one and/or installed correctly--not something easy to do AFAIK.

Thanks again for the inputs.
Regards,
Jim

 

[kdxhx]

Update: I resolved the problem, but only after trying some of the recommendations above. As predicted-- it was something simple, almost embarrassingly so.

I checked the distributor alignment/install, it was correct. I took pics but no need to upload now. I tried moving 1 to 2 teeth on the dizzy gear advance and retard--made no difference. I bought 93 octane ethanol fuel and added octane booster--made no difference.

Got to thinking about the spark plugs; why was the insulator so white, yet a buildup of carbon soot on the end of the spark plug...remembered a post, I think it was "Bondo" that mentioned the Vortec engines did not take a regular GM 5.7L plug. Plugs installed by mechanic-- AC Delco MR43T. Numbers sounded correct (I had been running iridiums). Plugs that SHOULD have been installed: MR43LTS-- which are extended reach plugs by almost 1/2 inch, and the electrode/insulator protrudes more.

Completely explains the odd look of the plugs, and I am guessing I was not experiencing "detonation" per se, but at least partly pre-ignition from the carbon build up all around the spark plug due to the shielded location of the shorter plug, not to mention a terrific impediment to a proper combustion event. At any rate, I now have a properly running 5.7L engine for $20.

Thanks much for all the assistance!

 

[tpenfield]

Wow. Who would have thunk that was the issue. Thanks for posting the update, they are always helpful to other going forward :thumb:

 

[Lou C]

Yep that is great information, since people being creatures of habit, may continue installing AC/Delco MR43s in every Chevy small block in a boat that comes their way...and the Vortecs came out so long ago, some have forgotten that there was actually a pre Vortec (different heads, 12 bolt intake vs 8 on the vortec).