Replacing Fuel Injectors (1 Viewer)

[davisfj62]

Of course things always happen on holiday weekends when it's pouring down rain. Long day of chasing codes on my '98 LC. The fun started with my rig loosing power and running rough followed by the check engine light.

Ran diagnostics and I got the dreaded P0301 code—thanks to IH8mud threads/FAQs to help me understand the problem. I have now ruled out fouled plugs or a bad coil pack. The next step is to pull and check the fuel injector for cylinder No. 1. Since this rig is 22-yo it's probably time to replace no just the no.1 injector but replace all of the fuel injectors with OEM/Denso.

My questions:
1.) Does anyone know of a good how-to video and instructions on replacing the fuel injectors?
2.) From what I've read it looks like I need to pull the intake manifold to get to the fuel rails — is that so?
3.) If I have to pull the intake manifold, what other parts are needed (o'rings, gaskets, etc)?
4.) Any insights/recommendations on sourcing re-manufactured OEM/Densu injectors—I can't afford brand new?

Much thanks,
JD

 

[JunkCrzr89]

You can pull them without removing the intake manifold. I recommend removing the fuel rails from the manifold, though, which makes getting the injectors out/in the fuel rails easier.

Disconnect the injector connectorsEach fuel rail is connected to the manifold with 2 nuts on studs - remove all 4 of those nuts. There are two crossover pipes between the rails, one in the front of the manifold and one in the rear. Two bolts hold the rear pipe to the manifold - remove those. One bolt holds the front pipe to the manifold below the throttle body, remove that bolt. Remove one or both banjo bolts with washers that connect said front crossover piper to the fuel rails. Disconnect the fuel send line from the fuel filter (the 90* plastic elbow with green clip) but leave that line connected to the fuel rail. Disconnect the rubber fuel return line from the back of the intake manifold. Then lift the fuel rails off the manifold with the injectors still attached to the rails.

Cheapest to send your fuel injectors off to have them cleaned, tested, and serviced than it is to buy new injectors. IIRC, I payed $130-150 to have mine done at FIS in CO. Definitely replace all 8 vibration insulators in the injector holes on the intake manifold before you reinstall injectors and fuel rails.

 

[suprarx7nut]

Are you sure it's not a coil? Failed coils are extremely common. Failed injectors are a pretty rare failure.

Have you installed a new coil? Moved coils around?

 

[davisfj62]

Are you sure it's not a coil? Failed coils are extremely common. Failed injectors are a pretty rare failure.

Have you installed a new coil? Moved coils around?

Yes, I moved coil packs around and pulled and checked the plugs. The plugs all looked great and even replaced the no. 1 Coil pack. Still running rough and throwing p0301 code. year I replaced all the plugs and coil pack with OEM/Densu parts. After reading several threads I’m now focused on the injectors.

 

[davisfj62]

You can pull them without removing the intake manifold. I recommend removing the fuel rails from the manifold, though, which makes getting the injectors out/in the fuel rails easier.

Disconnect the injector connectorsEach fuel rail is connected to the manifold with 2 nuts on studs - remove all 4 of those nuts. There are two crossover pipes between the rails, one in the front of the manifold and one in the rear. Two bolts hold the rear pipe to the manifold - remove those. One bolt holds the front pipe to the manifold below the throttle body, remove that bolt. Remove one or both banjo bolts with washers that connect said front crossover piper to the fuel rails. Disconnect the fuel send line from the fuel filter (the 90* plastic elbow with green clip) but leave that line connected to the fuel rail. Disconnect the rubber fuel return line from the back of the intake manifold. Then lift the fuel rails off the manifold with the injectors still attached to the rails.

Cheapest to send your fuel injectors off to have them cleaned, tested, and serviced than it is to buy new injectors. IIRC, I payed $130-150 to have mine done at FIS in CO. Definitely replace all 8 vibration insulators in the injector holes on the intake manifold before you reinstall injectors and fuel rails.

Really appreciate the detailed response. Super happy I don’t have to remove the intake manifold. Had to do that last year when I replaced my starter. I’m going to pull the injectors and send them off to FIS. Thanks again for the help.

 

[suprarx7nut]

Ok. You can check out my Cypress video on the coolant leak. I think it's chapter 1. That shows rail removal on a vvti with intake manifold removal. Maybe not 1:1 exactly what you need, but should cover most things pretty well.

 

[RootMeanSqr]

Check my thread, I had same issue, but cylinder 2. Misfire - Not Coil or Plug (SOLVED)
I just had fuel injectors cleaned and one of them started sticking. I tapped on it worth a wrench and applies power/ground to the terminals (very momentary, just tappi g the lead to the battery) in both directions and got it cycling again, no problems since. I still support getting them cleaned, but you may be able to get it working without having to take it out.

 

[2001LC]

Of paramount importance, when removing FI (fuel injectors) or intake manifold. Is cleaning top of engine. The area where intake manifold and heads meet, holds dust, grim, sand, etc. If this grim falls into intake ports, this can cause future compression problem. The 2UZ engine is a great engine that never burns oil. But, not even it's cylinders walls can stand up to contaminants. Personally I prefer doing injector servicing work, while intake manifold off. This way I can clean the FI port really well, without fear of dropping dirt in intake port(s).

A few test simple test of FI, before pulling them:
1) Listen to fuel injectors with a stethoscope. They should all sound the same.
2) With ohmmeter, measure the resistance between terminals of injector(s) at 68F 13.4- 14.2 OHMS.

Before pull injectors:
1) Clean top of engine.
2) Do a compression test, to confirm within spec.

Pull injectors:
1) Pull injectors, send out for testing, cleaning and rebuilding.
2) Clean intake manifold fuel injector ports. Install new grommets: 23291-41010 INSULATOR, INJECTOR VIBRATION 98-07. Failure to do so, may lead to vacuum leak.

Note:
Anytime any seal or gasket is removed from air intake/fuel system, such as intake manifold gasket, replace it. Many just reuse those, but that is a very bad idea. If an air leak at any intake port, due to intake gasket or grommet. It can burn those intake valve(s).

When to Clean or Replace fuel injectors

Please post your experiences and thoughts on the subject. I’ve been considering cleaning or even replacing all 8 fuel injectors, is this wasting time and money. I understand keeping fuel injector clean by adding a can of additive to the gas tank, now & then, is a good practice. This keeps them...

forum.ih8mud.com

 

[davisfj62]

Update: I pulled the injectors and had them tested, cleaned and rebuilt. I replaced them all thanks to JunkCrzr89 for the great instructions. The check engine light is off —no codes — and she is running better than ever. Sure appreciate all the great advice and help from everyone. The entire took about an hour and a half for removal and install.

 

[JunkCrzr89]

Update: I pulled the injectors and had them tested, cleaned and rebuilt. I replaced them all thanks to JunkCrzr89 for the great instructions. The check engine light is off —no codes — and she is running better than ever. Sure appreciate all the great advice and help from everyone. The entire took about an hour and a half for removal and install.

Great to hear!

 

[Bralow]

I'm a visitor here from the GX/120 side, but I found this thread and we're both 2uz-fe, so I thought I would ask.

Problem: I'm getting negative LTFTs (both sides). No codes and just -11 to -13%. MAF and TB clean, Filter is new, Plugs are new. 0 mis-fires logged, so assume coils are good.

As PM, I'm thinking of servicing the Injectors and replacing FPR. Maybe that fixes my issue, maybe it doesn't but it will be done and rule things out.

Yes - I am just throwing parts at it, but I have been wanting to do this for preventative maintenance anyway.

After reading this and some other threads and FSM, my minimally invasive procedure plan for this is:

1. Disconnect Battery. cold engine that sat over night.
2. Clean Manifold / Head trough area as thoroughly as possible before starting
3. Unbolt fuel rail just enough to access Injectors
4. Replace Injectors and their rubber damper grommets
5. Remove FPR (and it's short rubber fuel line) and Replace. Making sure to include new o-ring lubed with gas.


What (if anything) do I need to do to remove pressure from the fuel system before pulling these?

Is this a safe plan?

Thanks!

 

[LXKevin]

Disconnect the power to the fuel pump and crank the engine to relieve fuel pressure before disconnecting the battery.

1) see post #25 for @2001LC 's fuel pressure relief procedure, 2006 LX470 Maintenance/Build thread - https://forum.ih8mud.com/threads/2006-lx470-maintenance-build-thread.1147291/post-13487572

2) disconnect the battery,

3) then follow @JunkCrzr89 's instructions this thread in post #2 for R&R of injectors

Good Luck

 

[Bralow]

Disconnect the power to the fuel pump and crank the engine to relieve fuel pressure before disconnecting the battery.

1) see post #25 for @2001LC 's fuel pressure relief procedure, 2006 LX470 Maintenance/Build thread - https://forum.ih8mud.com/threads/2006-lx470-maintenance-build-thread.1147291/post-13487572

2) disconnect the battery,

3) then follow @JunkCrzr89 's instructions this thread in post #2 for R&R of injectors

Good Luck

Perfect, thank you!

 

[OwnerCS]

I'm a visitor here from the GX/120 side, but I found this thread and we're both 2uz-fe, so I thought I would ask.

Problem: I'm getting negative LTFTs (both sides). No codes and just -11 to -13%. MAF and TB clean, Filter is new, Plugs are new. 0 mis-fires logged, so assume coils are good.

As PM, I'm thinking of servicing the Injectors and replacing FPR. Maybe that fixes my issue, maybe it doesn't but it will be done and rule things out.

Yes - I am just throwing parts at it, but I have been wanting to do this for preventative maintenance anyway.

After reading this and some other threads and FSM, my minimally invasive procedure plan for this is:

1. Disconnect Battery. cold engine that sat over night.
2. Clean Manifold / Head trough area as thoroughly as possible before starting
3. Unbolt fuel rail just enough to access Injectors
4. Replace Injectors and their rubber damper grommets
5. Remove FPR (and it's short rubber fuel line) and Replace. Making sure to include new o-ring lubed with gas.


What (if anything) do I need to do to remove pressure from the fuel system before pulling these?

Is this a safe plan?

Thanks!

A good plan to replace the FPR on older engines along with injector service. I see people skipping that step on 20+-year-old vehicles and have issues with it later on.

 

[crtx]

Just want to share some info about different set of injectors I have pulled from 2UZs. All sets have been sent off to be flow tested and cleaned, with interesting findings.

I have had 3 sets sent off so far, all part number 23250-50040

• Set 1 (7 injectors total, 1 injector damaged) from a 1998 UZJ100
• Set 2: 8 injectors from a Sequoia, exact motor year unknown
• Set 3: 8 injectors from a Sequoia, exact motor year unknown

The injector set from the 98 UZJ100 flowed nearly twice the amount of the other 2 sets from a sequoia.

• Set 1: Flowed 41.84 LB/HR
• Set 2: Flowed 24.73 LB/HR
• Set 3: Flowed 25.11 LB/HR

So, obviously there is a massive flow difference between set 1 (from UZJ100), and set 2 and 3. There is also a slight visual difference between the 2 sets of UZJ100 injectors that I have (1998 and 1999). Toyota specs the same injector part number across all non VVTI 2UZ motors.

Is it possible toyota changed injector specs across the different years of the UZJ100, even though part number remained the same?

Here are the reports:

Set 1 from a 1998 UZJ100, Flowed 41.84 LB/HR

Set 2:

Set 3:

 

[2001LC]

Visual difference would indicate different PN # and so different FI.

If you've access to BK 2 heads of the Sequoia FI's. You should see the VIN # plates. If not throttle body will help identify year range.

 

[crtx]

Visual difference would indicate different PN # and so different FI.

If you've access to BK 2 heads of the Sequoia FI's. You should see the VIN # plates. If not throttle body will help identify year range.

All injector part numbers are labeled 23250-50040. Here is photo comparing 99 UZJ100 injectors, to 98 UZJ100 injectors.

Top right injector is 99UZJ injector. Has more of a straight sleeve at the opening. With 2 indentions sticking out. I have yet to flow test these. Just pulled them.

Botom left: 98UZJ. Has more of a conical sleeve at the opening. No indentions.

 

[hoser]

Flow rate spec is 23.8 lb/hr... so your 1st set is the outlier.

 

[JunkCrzr89]

There is also a slight visual difference between the 2. Toyota specs the same injector part number across all non VVTI 2UZ motors.

Is is possible toyota changed injector specs across the different years of the UZJ100, even though part number remained the same?

Unlikely to have changed specs or part number. Certainly possible that the Jap-made 2UZ in the UZJ100 uses Jap-made Denso injectors whereas the NA-made 2UZ in Sequoias and Tundras uses NA-made Denso injectors, resulting in slight variations between injectors from the different Denso manufacturing facilities.

 

[crtx]

Unlikely to have changed specs or part number. Certainly possible that the Jap-made 2UZ in the UZJ100 uses Jap-made Denso injectors whereas the NA-made 2UZ in Sequoias and Tundras uses NA-made Denso injectors, resulting in slight variations between injectors from the different Denso manufacturing facilities.

I may have worded initial post poorly - The visual difference is present between both Japenese made 2UZs. For example, my 98 UZJ injectors are slightly different then the 99 UZJ injectors. Those are the ones photographed above.