CS_AR

REASON FOR TESTING:

Some years ago, a leaking injector o-ring caused a VH45DE owner I know to lose a perfectly good engine. Apparently, when new injectors were installed, one of the o-rings was pinched or did not seat properly with the rail. After a few weeks, the leaking o-ring allowed fuel to fill an empty cylinder during a compression stroke. Engine hydro-lock occurred and a hole was blown through the the side of the block. The owner got to pick up pieces of his VH45DE from the garage floor. It was a catastrophic failure to say the least. To learn from that situation, I decided to always test any new o-rings in the rail before mounting in the intake runners. If a leak occurs, the best time to catch it is before final installation.

MAXIMA SPECIFIC BACKGROUND:

To resolve a broken pintle cap (flooding/misfire on cyls 2 and 5) issue, I decided to use the three injectors that came with the ~75,000 mile replacement engine. All three of those injectors tested at 11.5 Ohms. Those injectors, screens, and o-rings looked much better than the ones I moved from the old engine. I decided not to use the injectors that had been running on the cylinders 2 and 5 and found three injectors that also tested at 11.5 Ohms. The remaining injectors I did not use were testing from 10 to 10.5 Ohms.

INJECTOR REFURBISHMENT:

To refurbish the injectors with new screens, pintle caps, and o-rings, I purchased a kit on eBay for $34.50. After I installed the new screens, caps, and o-rings in the rails, I wanted to run a fuel pressure leak test. The only problem is, the Maxima has most of the wiring harness unplugged, so I couldn't get the fuel pump to run up pressure for testing in the car.

FINAL TESTING APPROACH:

For a "Plan B", I knew my 91 G50 (a.k.a Q45) generally has more fuel pressure than the Maxima to drive the larger 370cc injectors. So I decided to try hooking the Maxima rail to the fuel filter side of the G50 fuel line and block the return line to hold a constant amount of pressure on the rails with new o-rings. Using the G50's fuel pump, I managed to get slightly over 60 psi of fuel pressure on the Maxima rails for the leak test The good news is the new o-rings held up without leaking a drop.

Here are some pictures of the rails being tested on some blue paper shop towels, the gauge, and a picture of the injector seal and filter kit that I purchased for $34.50 as Fuel Injector Seal Kit Filters Viton Orings Nissan 2.0 2.4 3.0 4.1 CSKJE26.

PICTURES:

The Maxima rails were sitting on a box with the blue paper shop towels under the pintle caps. The blue towels will show the slightest amount of fuel leakage. I polished the visible injector caps and cleaned up the caps that will be located under the plenum. Also I replaced the stock Phillips head screws with stainless steel hex head bolts.



You can see my "China Freight" fuel pressure testing gauge is showing signs of wear.



Here a picture of the parts description for items in a rehab kit from http://injector-rehab.com/.



Note the eBay kit did NOT include new insulators.

Here's a picture of the injector refurb kit that I ordered from eBay. Hopefully, the injectors will all work after I get the car back together. I placed the injectors with the highest mileage in rail for the left bank, with the newer injectors in the right bank rail to live under the plenum.



I wanted to use an injector leak testing approach that worked well on the G50 in the picture below. I tried to replicate this with the rails in the Maxima but the fuel pump would not cooperate. Fortunately, the G50 offered to help.

bewrong

What's a pentile?

metalgod3082

Circled in red here

CS_AR

Thanks Metalgod. I updated the OP with the reason I get serious about testing new o-rings "in the rail" before final installation.

The Wizard

iTrader: (43)

I just went through all this on my 98 Max...busted pintle caps and leaking injectors...

BTW, it's pintle, not pentile.

CS_AR

Thanks Wizard for the pintle clarification. Post corrected. If you like, post pics of your injector pintile caps as mine looked almost identical.

stromm

iTrader: (1)

Just for the record (cause some may not know), the pintle is a needle like pin, not the round "cap" like piece.

FatTony22

I currently have the upper intake manifold removed to replace my valve cover gaskets. I've already replaced spark plugs and ignition coils... is there anything I should check or service with the fuel injectors (particularly the ones in the back)? While diagnosing a misfire, I noticed some very erratic numbers for the 'short term fuel trim - bank 2' -- I mean +/- triple digits(!). Can someone tell me if bank 2 is to the front or rear of the car?

CS_AR

Bank 2 faces the radiator.

The right or left is determined from the driver seat looking forward over the rear of the engine.



What year is your Maxima and how many miles do you have on it?

We are seeing the pintle caps crack that accompanies leaking o-rings.

Here's a picture of two injectors I removed from mine back in 2014 below. You can see the broken pintle caps.

Search the 4th gen section for pintle and you see several threads on this topic and the approach used to resolve the flooding issue.

dwapenyi

iTrader: (3)

Bank 1 is cylinders 1,3, and 5. 2,4, and 6 are bank 2.

Just a small correction to your otherwise excellent pictures and documentation.

CS_AR

Thanks. Different picture updated.