Problem after new injectors

Discussion of Infiniti's amazing (and underrated) sport-luxury crossovers, the EX35 and EX37. For 2014, the EX series will be renamed QX50, in line with Ininfiit's new naming conventions.
Avalanche325
Posts: 67
Joined: Wed Jun 03, 2009 3:44 pm
Car: 2008 EX35
1965 427 SC Cobra (Factory Five Racing)

Problem after new injectors

Postby Avalanche325 » Sat Jul 09, 2022 2:36 pm

2008 EX35 128,000 miles.

I have been getting a stutter for quite some time when cruising around town 35 - 40 mph. I occasionally got a P0420 Catalyst code. I decided to do a DIY injector clean and and it all went south from there. Some of the fuel line I used didn't hold up well with the carb cleaner. When I started up it was missing pretty bad. CE light flashing. So I decided to just replace the injectors. Beck Arnley OEM style. New intake gasket also. Followed the torque pattern, etc.

After the new injectors, the car was very hard to start. It took 4 tries, which was way more than after the injector clean. It is still stuttering at 40mph and the idle is rough, but no CE light flashing. I drove around for a little while. It is still doing the stutter. I got a multi-cylinder misfire code. It is very hard to start. It takes 3 or 4 tries. Even if I turn it off and try to start right back up. I eased the line off at the tank, after attempting a start with power disconnected, and it still had a lot of pressure. I clicked it back on.

Any ideas? The only other thing that got touched was jostling the pressure damper around enough to get the fuel rails out. I wish I just had my stutter back.


Avalanche325
Posts: 67
Joined: Wed Jun 03, 2009 3:44 pm
Car: 2008 EX35
1965 427 SC Cobra (Factory Five Racing)

Re: Problem after new injectors

Postby Avalanche325 » Sun Jul 10, 2022 9:06 am

I tested fuel pressure at the pump. 50psi at idle. I also tested just before the fuel rail. 50 psi.
I am going to pull the intake and then pressurize the fuel system to see if I have any leaks at the injectors.

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VStar650CL
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Car: 2013 Nissan Altima 2.5 SL
2004 Nissan Altima 2.5 S

Re: Problem after new injectors

Postby VStar650CL » Sun Jul 10, 2022 9:42 am

For pumps from about 2001-up the nominal pressure is 51, so it sounds like that's okay. Did you lube the o-rings on the new injectors when you installed them? If not, there's a pretty good chance you'll find a couple of rolled or nicked rings when you pull them out. The rings should always be coated thinly with a neutral lube like vaseline or white grease before you push them in, otherwise some bad seals are almost inevitable.

Dzionassi
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Joined: Fri Apr 13, 2018 8:50 pm
Car: 2017 Infiniti QX50

Re: Problem after new injectors

Postby Dzionassi » Sun Jul 10, 2022 10:29 am

I suggest you out back OEM injectors back, because it is not your issue.
Inspect cat on bank one. It sounds like you have clogged/damaged cat. Inspection has to be done from engine side.

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VStar650CL
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Car: 2013 Nissan Altima 2.5 SL
2004 Nissan Altima 2.5 S

Re: Problem after new injectors

Postby VStar650CL » Sun Jul 10, 2022 11:24 am

Dzionassi wrote:
Sun Jul 10, 2022 10:29 am
I suggest you out back OEM injectors back, because it is not your issue.
Inspect cat on bank one. It sounds like you have clogged/damaged cat. Inspection has to be done from engine side.
That might well be too, given the previous P0420. But the problems getting worse immediately after new injectors means something got bollixed-up with those as well. When that kind of thing happens, it's always something you touched. I'm afraid the OP will be doing a lot of tearing-down.

For the OP, be very afraid of running it much until you resolve the injector issue. @Dzionassi is right, and if that bad cat happens to melt from the leaky injectors, your engine will be headed to the JY.

Dzionassi
Posts: 67
Joined: Fri Apr 13, 2018 8:50 pm
Car: 2017 Infiniti QX50

Re: Problem after new injectors

Postby Dzionassi » Sun Jul 10, 2022 11:28 am

inspection can be done through the oxygen sensor hole with the camera (done it many times)

Avalanche325
Posts: 67
Joined: Wed Jun 03, 2009 3:44 pm
Car: 2008 EX35
1965 427 SC Cobra (Factory Five Racing)

Re: Problem after new injectors

Postby Avalanche325 » Sun Jul 10, 2022 12:36 pm

Putting this here is case it helps someone.

I started thinking that I must have a leak causing my starting issue. I pulled the upper intake, pressurized the system and looked at the injectors and connections to see if any o-rings were leaking. They all looked good. Then I pulled the injectors up out of the intake and one was dripping pretty bad. I put an old one in that hole and the car is running perfectly.

Ironic, since my whole problem was that one of the old injectors was leaking.

Avalanche325
Posts: 67
Joined: Wed Jun 03, 2009 3:44 pm
Car: 2008 EX35
1965 427 SC Cobra (Factory Five Racing)

Re: Problem after new injectors

Postby Avalanche325 » Sun Jul 10, 2022 12:39 pm

VStar650CL wrote:
Sun Jul 10, 2022 9:42 am
Did you lube the o-rings on the new injectors when you installed them?
I agree that dry o-rings are risky.
The Infiniti manual specifically states not to lube them. I did put some spit on them, though.
Last edited by Avalanche325 on Sun Jul 10, 2022 12:42 pm, edited 1 time in total.

Dzionassi
Posts: 67
Joined: Fri Apr 13, 2018 8:50 pm
Car: 2017 Infiniti QX50

Re: Problem after new injectors

Postby Dzionassi » Sun Jul 10, 2022 12:41 pm

Did you ever had hard starts before? If not put old injectors in.
Also you always have to go with oem injectors unless you getting custom tune.

Avalanche325
Posts: 67
Joined: Wed Jun 03, 2009 3:44 pm
Car: 2008 EX35
1965 427 SC Cobra (Factory Five Racing)

Re: Problem after new injectors

Postby Avalanche325 » Sun Jul 10, 2022 12:48 pm

It was just some stuttering before. So the new problem lead me to check everything that I had done and lead me to find the bad part. They are OEM replacement injectors, so no tuning needed. Beck Arnley is usually a good OEM level brand.

I am going to give the oil a good sniff and if it smells like fuel, do an oil change.

Dzionassi
Posts: 67
Joined: Fri Apr 13, 2018 8:50 pm
Car: 2017 Infiniti QX50

Re: Problem after new injectors

Postby Dzionassi » Sun Jul 10, 2022 12:56 pm

you are not listening, when there is leaky injector you always have harder cold start, because there is no fuel pressure in fuel line. I takes time for fuel pump to build pressure.
Misfires or sputtering at idle usually shows issue with bad cat, exhaust gases are getting sucked in back to combustion chamber. Also fuel trims will be messed up.

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VStar650CL
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Car: 2013 Nissan Altima 2.5 SL
2004 Nissan Altima 2.5 S

Re: Problem after new injectors

Postby VStar650CL » Sun Jul 10, 2022 1:02 pm

You just drowned one of the cats, too. If the leaker was on bank1 where you already have a P0420, you should probably give the cat a tap-tap with a deadblow hammer and then an IR temperature scan to make sure it isn't fixing to disintegrate. Like I said, a melted cat is the quickest way I know to completely destroy an engine.


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