My HPDI is idling very rough.

[HAWKHPDI]

Hey guys my 06 HPDI is idling very rough at first start up. I let it warm up after the first start up for the day while I am parking my truck. Then I will put it in gear and it will chug very hard like it is still hitting on 3 cylinders. Anything off idle it runs fine. It does the same thing if I run 15 miles.. shut it off and fish for 45 min. When I go to start it up, it idles very very rough in gear and shakes the whole boat. It kind of clears out after idling in gear for 2 min or more, but still doesn't idle as smooth as it used to. It was doing this before I changed the plugs 2 months ago, so I changed the plugs and it stayed about the same. But it seems to be progressively getting worse. Any ideas? It is going to the dealer next thurs, they were thinking maybe an injector sticking at idle.

[Kyle35]

That's what mine did too. I changed the plugs and it seemed to run better, but about a month ago it blew one of the cylinders.

[HAWKHPDI]

Oh don't say that. Motor had 72 hrs on it when I bought it, if it goes pop under 100 hrs I am going to go ballistic.

[Grant2]

02 censor may need to be cleaned or changed. Check your filters mine is in them shop now for the same thing.

[HAWKHPDI]

Mine will be in the shop Thursday, I gotta have my boat because tournament season is in full swing. I am hoping it is not too costly. After doing some reading it looks like 3.3 liter VZ's do not have a o2 sensor so we can rule that out.


Modified by HAWKHPDI at 4:12 PM 3/17/2012

[Charlie206]

If a diaphragm starts leaking in a lift pump it will idle poorly.

[HAWKHPDI]

Would this cause the motor to not hold prime as well as it should?

[Charlie206]

It isn't necessary for the HPDI to hold a tight bulb. The lift pumps only fill the VST, where another pump takes over and steps up the pressure to the high pressure pump. But a leaking diaphragm can cause flooding at idle and therefore a very poor idle.
If you are running out of fuel in the VST, and having to pump the bulb to get fuel, then it is a bad lift pump.

[brokejeep]

Mine was doing it and the mechanic had to adjust some linkage and it fixed the problem.

[HAWKHPDI]

They hooked a comp up to it and ran it, performed a injector cut out test all of them are hitting perfectly. Ran compression on all cylinders all of em at 110-112. Checked for spark all around, the sum bitch is just carboned up and I run the recommended dose of Ring Free in EVERY tank. So I am going to shock treat the next 2 tanks. I bought the boat last June and it had 72 hrs, and its at 102 now so I have put 30 on it.

[Charlie206]

Did they check the lift pumps for a leak? It's easy to do, but you don't mention that they checked that. It's a common problem on these engines.

[Bassin Bob71]

<table width="90%" cellspacing=0 cellpadding=0 align=center><tr><td>Quote, originally posted by HAWKHPDI &raquo;</td></tr><tr><td class="quote">They hooked a comp up to it and ran it, performed a injector cut out test all of them are hitting perfectly. Ran compression on all cylinders all of em at 110-112. Checked for spark all around, the sum bitch is just carboned up and I run the recommended dose of Ring Free in EVERY tank. So I am going to shock treat the next 2 tanks. I bought the boat last June and it had 72 hrs, and its at 102 now so I have put 30 on it.</td></tr></table>

Just curious....what kind of oil do you run? Glad to hear its only carbon that's the problem.

[HAWKHPDI]

Yamalube.. thats probably whats carboning it up. They did not check the lift pump, however I ran it pretty good this weekend with double the amount of ring free I normally run and it ran like a champ. I am going to run 2 tanks of that amount of ring free then probably check/change the plugs.