Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue... Left works right not))

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skywidget

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I've read many posts that seem close to my issue. Learned alot from them for sure.
I just couldn't stumble on one that had my odd condition.

Idles fine...WOT starts to gen up and then boggs down. If you sneak up on ~2700 RPM it will run for a time.
As soon as you touch the throttle to go to WOT it boggs down again. Those are the 2 most obvious behaviors.

I changed the fuel filter...no joy.
I took off the air cleaner cover to observe the injectors...here's what I saw.
Two nice cones of fuel on both sides until it boggs. At that point the left sides sputters and then no spray at all.

Suggestions? On my next steps?

Seems like a lot of experience/knowledge here. (I'm a work smart not hard kinda guy.)

BTW, I'm a car/motorcycle guy with very little boat time. :)

Thanks,
j
 

skywidget

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Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

(Tried to edit...it would take my change) So repeat of above.

I've read many posts that seem close to my issue. Learned alot from them for sure.
I just couldn't stumble on one that had my observation.

Idles fine...WOT starts to gen up and then boggs down. If you sneak up on ~2700 RPM it will run for a time.
As soon as you touch the throttle to go to WOT it boggs down again. Those are the 2 most obvious behaviors.

I changed the fuel filter...no joy.
I took off the air cleaner cover to observe the injectors...here's what I saw.
Two nice cones of fuel on both sides until it boggs. At that point the left sides sputters and then no spray at all.
Right side (appears) to continue to provide right amount of fuel.

Suggestions? On my next steps?

Seems like a lot of experience/knowledge here. (I'm a work smart not hard kinda guy.)

BTW, I'm a car/motorcycle guy with very little boat time.

Thanks,
j
 

Tail_Gunner

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Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Now that's...funky one injector runs and the other cuts off....ALmost has to be and bad connection clean the bad injector tip's both male and female with a some abrasive...Switch injectors it take's a sec..its a short or a bad connectiorn or maybe a bad injector...can you measure the voltage to the connection and see what happen's at 2700
 

skywidget

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Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Ok...Cleaned connection/connector. Looked pretty good actually.
Swapped the connectors to their opposite.
This caused the injector on the right side behave like the left one had done earlier.
So the problem followed the connector.

I don't know how I would measure the voltage at 2700 on the water without riggin' up some leads. Plus it backfires sometimes and don't particularly want to be near the TB with a meter don't cha know. LOL

Next? I'm thinking...What drives the injector? Is it variable dc off the ECM or what?

Thanks,
j
 

Tail_Gunner

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Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Ok...Cleaned connection/connector. Looked pretty good actually.
Swapped the connectors to their opposite.
This caused the injector on the right side behave like the left one had done earlier.
So the problem followed the connector.

I don't know how I would measure the voltage at 2700 on the water without riggin' up some leads. Plus it backfires sometimes and don't particularly want to be near the TB with a meter don't cha know. LOL

Next? I'm thinking...What drives the injector? Is it variable dc off the ECM or what?

Thanks,
j

Without looking at my setup its pretty safe to assume you have a hard wiring problem you just have check the continuity of that side of the circut....I cannot see a ecu firing one side and not the other. It looks like a dead short..and at 2700 the vibrations are allow the wiring to dead short
 

lcmains1

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Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Sounds t me like your high pressure fuel pump is bad.
 

skywidget

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Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

I managed to find (half) of a schematic online that shows the Injectors having two separate control lines. One for each injector coming from what I think is the ECM/ECU though that half of the schematic wasn't shown. Looks like one pin on each injector is 12VDC (power) and the other is (guessing) routed to the ECM where the control grounds the second pin to control when the injector is open and for how long. I shot some cleaner on all the connectors at the ECM and the injectors. Will test again a little later this morning. Grand kids are all over the house. :) Would like to get this going before they are gone.
 

Don S

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Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

What is the full model number of your engine. Need all those letters following the 5.7
 

skywidget

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Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

photo.jpg
Will this work? 5.7 GSI PWTR?

ECM.jpg
Is this the ECM/ECU?
Thx,
j
 

gbeltran

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Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Doesn't the engine protection mode cut off one of the injectors? You probably need to get it connected to a scanner to see if that's the case. Is this the first time out this year? Or is it used regularly and this just happened?
 

skywidget

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Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Good question.
Technically, this is out the first time. It was only taken out for a test run to see if there were issues. It was fine for that time but the second time they were out longer and pulling skiers, tubers and that's when it starting acting up. I was not on either of these trips. It was the wife. My first time out was when I had pulled the air cleaner/cover to observe the injectors in action.
 

Don S

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Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

You do have a "SLOW" mode that cuts off one injector to keep the engine under 2500 rpm (or that area) when the sensors indicate either low oil pressure, or high coolant temp. Once you come down below that speed, the other injector should start working again.
Which sounds exactly like what you are seeing

Here is the diagnostic manual for the WT model http://www.4shared.com/office/0Tw4me4b/3850078_WT_EFI_Diagnostic.html?
 

Tail_Gunner

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Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

I assumed mefi used electronic cutoff and after doing some research it look's like they use fuel cut off for both slow protection and the rev limiter. Hmm that could make for a lean burn when running at WOT in a under propped boat. You need to check your alarm it should have reported..I actually blew one of those at one time,,never could understand why it did that.

But that would make a lot more sense than short and a lot less work hopefully
 

skywidget

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Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Been reading the diagnostic manual that Don S sent the link for. (Thanks ALOT Don btw...it's exactly what I had been searching for.)
Says...Slow mode is temp or oil pressure. Both instruments indicate within range. (20@idle/40@highers) and Temperature gauge is indicating below 180. Much cooler actually but I forget the exact indication. Is there any sensor that could be telling the ECM that one of those two are out of range and the instruments still indicate normals?

When you mention "...check your alarm it should have reported." are you meaning to read the codes set in the ECM or the audible alarm?
when you mention "blew one of those at one time" what were you saying was blown? (blown scares me. :))

Thanks for everyone's help...I haven't nailed it yet but I certainly feel momentum as a result of your help.

Thanks,
j
 

bruceb58

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Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

The SLOW mode uses seperate senders than your gauges. You need to check those senders.
 

Don S

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Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

The gauge senders for the oil pressure and water temp are different from the senders feeding info to your ECM, that is why you need to hook up a diagnostic tool to find out which one is causing the problem.
You should have an audible alarm that goes off if you have an overtemp or low oil pressure. The alarm is controlled by the ECM and should have sounded. Of course if your alarm is out of order, you won't hear anything.

Basically, without a diagnostic computer of some sort. Troubleshooting becomes a hunt and peck, and swap parts in hopes of finding and/or fixing the problem type deal.
 

Tail_Gunner

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Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Picture002-5.jpg


Picture003-5.jpg


Blown as blew apart...:confused: Location left bank on the very back..opposite of the dist. So many variations i cant be sure you have one but that looks like a mefi controller dunno why they would leave it out..It a audible alarm reports a high pitched beep..One for a soft alert 3 for a hard alert

http://www.volvopentastore.com/Elec...on_id.088030192--store_id.366--view_id.775937

Audible alarm kit
 

skywidget

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Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

I'm getting the feelin' you done this a time or two Don. I'm gonna take your advice and pause this process until I can read the codes.
I looked online but everything seems fairly high dollar. Any recommendations on a middle of the road computer?

WHOA! just saw pics....I see what you mean. BLOWN! Dang!

Thanks again,
j
 

Don S

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Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Re: Penta 5.7 Throttle body WOT boggs/drops out (Injector Issue)

Tail Gunner has a newer model than you do, his had an obnoxiously loud buzzer mounted on the engine, your WT model doesn't. But, you should have a buzzer under the dash. Just a little guy, about the diameter of a quarter or a little bigger.
 

Don S

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