Z150 TXRB running poorly

[old gold]

I have a 2003 150 HPDI on an 18' Parker CC.
I have replaced all the fuel filters and still only get ~4600 rpm wot.
It also bogs down a few hundred RPM then surges back up on occasion.
All 6 plugs are oily/fouled and it is going through quite a bit of 2 stroke oil.
Any insight?

 

[rodbolt]

Re: Z150 TXRB running poorly

did you replace the VST filter and the medium pressure inline filter?
replace the plugs and try to monitor how much oil is used and compare it to how many gallons of gas.
over oiling wont be the cause of RPM loss.

 

[old gold]

Re: Z150 TXRB running poorly

I bought the engine used out of Florida (~600 hours) and replaced all the fuel filters, thermostats and rebuilt the impeller at the beginning of the season. (It bogged down big time prior to filter replacement!)
The medium pressure filter was extremely clogged. It ran much better but WOT was only 4800 RPM. Just this week I pulled the filters and they checked out OK. My plan is to pull the injectors and send them out for cleaning during the winter. Could clogged injectors be my problem or could I have a setup/adjustment issue?
The engine has used 1 gallon of oil for ~40-50 gallons of fuel

 

[rodbolt]

Re: Z150 TXRB running poorly

come out to about 50/1.
bout right.
have you checked the lift pumps?
only way to really tell if its injector or not is to monitor both medium pressure rail and HP rail at the same time at the problem RPM and load.

 

[old gold]

Re: Z150 TXRB running poorly

I have not checked the lift pumps. I will reference the service manual to figure that out. As far as checking medium and high fuel pressure at the same time would you have to have a laptop plugged in during a sea trial?

 

[rodbolt]

Re: Z150 TXRB running poorly

going to need a fuel pressure test gauge capeable of 70 PSI and a laptop,diagnostic test lamp or a digital multimeter.

 

[old gold]

Re: Z150 TXRB running poorly

Thanks, a pressure gauge and a multimeter it is.
I will report back with findings..

 

[old gold]

Re: Z150 TXRB running poorly

Checking the lift pumps and medium fuel pressure at the shrader valve is straight forward but will I need to purchase test harness YB-06769 called out in the manual to get the 2.8V-3.2V high pressure sensor reading? Any way to sneak test leads onto the back of the connector?

 

[rodbolt]

Re: Z150 TXRB running poorly

paper clips

 

[old gold]

Re: Z150 TXRB running poorly

OK here are the results.
Took the boat out last Saturday.
4.95V steady on the high pressure pump
60 psi down to maybe 55 psi on the medium pressure. (~4600 WOT)
Pulled the boat today and just got the lift pumps off the engine and they both do not hold pressure or vacuum per the manual.
One bleeds down from 7 psi in 5-6 seconds the other one in half that time.
Should I replace or rebuild?
58$ locally per pump...
update: Just bought a couple of pumps and they bleed down the same way..
What's up with the test procedure?
Also I notice the high pressure reading was supposed to be between 2.8 and 3.2 so I must have measured across the wrong pins.....

 

[rodbolt]

Re: Z150 TXRB running poorly

wrong pins, you were testing the 5v reference. at least ya know thats good .
on the pumps, if they are not bolted to the block, or dont have bolts with nuts holding them together if bench testing, they leak.
me I cap one end off and pressure/ vac test the other then reverse, should hold both either way.
I dont like the book method and they dont tell ya about bolting the pump together or place it back on the block.

 

[old gold]

Re: Z150 TXRB running poorly

Half $%# update:
Reinstalled original lift pumps and put back in the water before reading the reply and testing properly (with 2 extra bolts!) Striped bass were biting...
Re-loaned the fuel pressure gauge from Autozone but during 2nd round of sea trials got 0 psi on the gauge (either a problem with the gauge or my VST shrader valve)
I did note the high pressure voltage dropped from 3.1 volts down to 1.6 while the RPM and power dropped...

 

[old gold]

Re: Z150 TXRB running poorly

Got a chance to run tests again yesterday.
Medium pressure stayed at 55-60 psi the whole time.
At ~3800 RPM the high pressure dropped from 3.0 volts down to 1.6 volts.
The harder I pushed the throttle the more the voltage dropped (1.4 volts)
What am I fixing over the winter??

 

[rodbolt]

Re: Z150 TXRB running poorly

if medium pressure held at 50 PSI and High pressure dumped then either the medium pressure inline filter is clogged ,the HP pump regulator is failing or the HP pump filters are clogged.

 

[old gold]

Re: Z150 TXRB running poorly

I plan on sending the hp pump and 6 injectors to Flagship Marine over the winter for rebuild/cleaning. Thanks for all the help!

 

[jeffersondodson561]

Re: Z150 TXRB running poorly

55-60 psi is a tad bit high, might want to pull some vacuum on the fuel pressure regulator (faulty/clogged regulator?)(if you can get your hands on a "mighty vac") rig up some hose that will fit the regualtor hose, to check that fuel pressure drops some. Assuming that your gauge was accurate and just one more test before you send stuff off to be replaced. I have never had to send a single or dual stage high pressure fuel pump off to be replaced have talked to some techs that have but those injectors are under about 750psi of fuel pressure and the fact that gas in a solvent I would think that the injectors would be ok, but just speculating and trying to save you some time and money.

 

[rodbolt]

Re: Z150 TXRB running poorly

55-60 psi is a bit high but wont cause a surging issue. you may still have a clogged medium pressure inline filter.
I would also pull the VST and double check that and pull the regulator and check the regulator screen.
the HP pump has a regulator and 2 non field servicable filters.
55-60 psi may just be your test equipment.
no need for mity vacs and such, while the engine is idling simply unplug the reguator vacum supply and watch for about a 5PSI pressure spike.
each injector has a fuel screen that if debris gets past the HP pump filters they can clog as well.
yes we send HP pumps several times a year to have flagship service them as well as all injectors in the case of a powerhead failure.
the Z motors dont tolerate lean burns as they are already on the ragged edge of lean.
but if the medium pressure rail holds 50 PSI and the HP rail falls below about 550 PSI then either the inline medium pressure filter is clogged,the HP regulator is failing or the HP pump filters are clogged.

 

[old gold]

Re: Z150 TXRB running poorly

One last check. While at idle in the driveway I pulled the regulator hose and the medium pressure did not budge. It stayed at 61 psi...

 

[jeffersondodson561]

Re: Z150 TXRB running poorly

Did you check the regulator screen? If it did not change one of two things is wrong, regulator is bad/clogged or the reference hose is damaged. Did you notice any vacuum at the regulator hose? A kinda gentle "sucking sound" put your finger over the tip to detect vacuum.

 

[rodbolt]

Re: Z150 TXRB running poorly

not enough intake vacum to suck anything on that engine and your simply not fighting a VST medium pressure regulator issue.
either fix the restriction between the VST and and the injectors or continure running it and post about detonated pistons, which is coming soon.