Fuel Injector Replacement
Firstly, this guide is applicable to replacing your injectors with new, second hand or reco'd items, all the steps are pretty much the same. Remember to take care when working around fuel. An estimated time for this procedure is about 4 hours taking it easy. I've got experience and done this a couple of times, so allow some extra time if you're not so familiar tinkering in your engine bay. It's basically a simple remove, replace and refit procedure. It doesn't get too technical.
Please read through the instructions fully before commencing work as you might find helpful hints all along the way that might be of use earlier on rather than later.
How to replace fuel injectors[edit]
Overview[edit]
RB30E injectors by now are getting to the point where a lot of them are developing leaks. The body of the injector leaks petrol out and onto the inlet port runner and you'll see it staining and in worse cases you can see it forming a drip and pool around the injector. It will be purple if you use 91RON fuel and yellow if you use 95/98RON fuel. This is what it looks like:
Okay, so the car in example was just a fairly standard Rb30E Silo, mild exhaust upgrade but other than that no turbo etc. so the injectors I'm using are just off the shelf direct replacement for NA cars. An upgrade with VLT injectors is the same sort of deal.
I bought my injectors from Bursons. They're an ACA brand fuel injector. I did some research and couldn't find anything bad about them. I've used reconditioned injectors via ebay before as well, but had problems with them still leaking and having to remove and replace injectors twice after the initial installation. So I highly recommend replacing injectors with new items, however this is expensive. So it depends on how much you enjoy this little job. I recommend you replace all 6 at the same time and not just one or two for the reason that you want the most similar fuel delivery to each cylinder as possible, so unless you've got a flowsheet for the injectors keep them all the same for the best results.
From Bursons I got 6 injectors at $60.50 each trade price, so $363 total. RRP is $541.00 for a set of 6. at around $90 each.
ACA Part number: FI615
These injectors come complete with new o-rings for the inlet ports and new o-rings for your injector retainers.
Okay, so now you've got your injectors and you're ready to go. Some of the tools you'll need include:
- Phillips head screwdriver size no.1 and 2
- Flat blade screwdriver in a variety of sizes small to large
- Pliers - at the least a set of combination, pointy nose also help
- Socket set - 3/8 is the best. I used a 10mm & 12mm. An extension is also useful.
- Spanner set - 10mm & 12mm, 14mm
- Circlip pliers
- Pick set
- Soldering iron (possibly)
- Degreaser/brake clean
- Rubber grease
- Some rags
- White out
- Optional: Coolant, drain tray, new fuel filter, new fuel hose, new clamps.
Let's begin:[edit]
Looking at your engine bay, you'll need to remove the induction piping up to the throttle body, this includes the PCV hoses & auxiliary air valve hose at the back of the plenum. Depending on your hose clamps, it's basically just undo two of them, one at the throttle body, the other at the elbow just after the air-flow meter. No need to take the airbox lid out or the AFM. If your car's been kept very original then it may still have one bolt (I've seen sizes from 10 - 14mm) holding the induction pipe to the bracket that has your throttle cable held. Undo this and unclip any ignition leads and vacuum hoses.
- Note that series 2 and 3 have slightly different hoses routed over the induction pipe. This is due to the location of the charcoal canister. If you're removing any vacuum lines and fear not putting them back in the right place use the white out to mark them, or some masking tape and write on them. It's fairly hard to do as most of the hoses are different sizes.
Remove the throttle cable:[edit]
Two 14mm nuts secure this at the bracket over the rocker cover. Loosen them, paying careful attention to how much slack you have on the cable and remember to refit it in the same fashion and tension. Once you've undone the adjusting nuts, you'll find it very easy to manoeuvre the cable out of the throttle body, it's just a pin on the end of the cable that slots into a hole at the throttle. Route the cable out of the way along the firewall somewhere.
De-pressurising the fuel system:[edit]
This I say is an optional step, but I'd recommend it to people who don't have experience with this or are more cautious. Remove your fuel pump fuse and crank the engine. Repeat this a couple of times and you're pretty safe. Needless to say, if you undo all fuel lines slowly and carefully, you shouldn't get sprayed.
To disconnect the fuel supply and return lines you just need a Phillips head screwdriver and undo the clamps at the rail. You may need to twist, turn, pull or pry to get the hose off. Any cracking, splitting or fraying hose should be replaced with appropriate high-pressure fuel hose & quality clamps. In case there's any confusion, your supply line has the fuel filter on it and the return nothing. Return is always the lower line at the fuel rail.
Stripping the inlet manifold:[edit]
This guide requires you only splitting the manifold and removing the top section, you don't need to replace the gasket and indeed if you try, you'll spend another 4 hours trying to get it off and cleaned on both sides most likely. Stripping the manifold requires some patience and care to ensure you don't break the very fragile connectors and hoses.
This is where a pick comes in very handy, or a very small flat blade screwdriver. Removing most of these connectors, you need to pry out the U shaped wire and then pull the connector off. Do this slowly so you don't loose or drop the wire, when refitting, put the connector on, then the wire. Don't try and fit the wire to the connector then put the connector on. You'll never win. Disconnecting hoses, be aware that many hoses are stuck on and need to be twisted and maybe pried with a flat blade to lever them off. PCV hoses tear very easily, so beware. Again, mark everything, unless you're confident at putting it back.
It doesn't matter where you start, just try and keep a system. Start at the back of the plenum and move forward. Items you'll need to disconnect include:
- Throttle Position Sensor, maybe 2 if your car is auto
- IAC motor
- A/C fast idle switch
- Another connector that is related to the fuel rail/pressure in some way I can't remember.
- Earth wires
- Engine Coolant Temp Sensor
- Temp Gauge Sensor
- Cold Start Valve
- Coil (maybe)
Vacuum lines to be removed include:
- Purge cannister hoses
- Brake booster
- Cold start valve outlet
- A/C bypass
- PCV hose
Finally you'll also have coolant hoses to disconnect. Some of you may tie this in with a coolant change, if so, drain the coolant from the radiator. Otherwise, just disconnect the coolant hoses at the front of the plenum first and let them drain into a suitable tray. You won't loose much coolant at all. There's also one coolant hose at the rear of the plenum you'll have to undo. Combination pliers are the best too for the spring clamps.
Splitting the inlet manifold:[edit]
Okay so you've disconnected everything from the plenum. There are 7 bolts that hold the top section to the lower. Four from up top, three from underneath. The top ones are short, the bottom ones long. The bottom middle bolt is slightly shorter than the two outer ones, so keep this in mind for refitting everything.
The bolts are 12mm heads so use a socket and ratchet, or if you prefer a spanner. Being an alloy manifold I prefer to undo bolts in an out to in pattern, but this is probably debatable as to the relevance. I say, it can't hurt, do them up inside to outside as well. Underneath you won't get a ratchet in easily, so use the ring spanner and crack the three bolts, then you should be able to wind them out by hand.
With those undone and everything disconnected from the plenum, you should be able to life the top section off with the throttle body and auxiliary valve still attached and place it aside.
This is what you should see:
The gold pipe is the fuel rail, with the fuel pressure regular on the right.
Removing the fuel rail:[edit]
Again take note to mark all hoses and connections as required. My suggestion is to wrap a piece of masking tape around each injector connector wiring and write what number it goes to. Just for your peace of mind when reinstalling and to save hassle trying to diagnose problems once installed. The injector connectors are held in with those U wire clips which can be annoying to remove, so try and take as much care to retain their integrity and not break or damage the connectors and clips, otherwise you may find them vibrating loose over some time and you'll get a misfire.
The rail is held in a number of places by 10mm bolts and at the side closest to the injectors one at either end by 12mm bolts. See the picture below for a guide on whereabouts the bolts are. Note the ones at the front that are hidden to the side and underneath.
Additionally, each injector is held into it's respective inlet port with a 10mm bolt that goes through a black plastic retainer & into the manifold. You'll have to undo all 6 of these as well to get the injectors and rail out. Remove the rail with injectors attached to it. The bolts are located as follows:
Now I took the fuel pressure regulator out with the rail, you can disconnect it at the hose if you want to and just take out the rail, but I found it easier to just remove lot. You will have to wiggle and turn the rail to get it out with the injectors in and the reg on a bit, but it's not much of a task.
The result should be this:
and this
- Note - clean the hole in the inlet ports where the injectors will sit. There'll be dirt and grease in there, just use some brake clean or degreaser and with a rag and a screwdriver get in and wipe the surface clean so your new injectors seal well.
Removing injectors from the rail:[edit]
All the injectors are held to the rail by a rubber hose and a clamp. Simply undo the clamp and pull / twist the injector off. Some force may be required, depending on the age and condition of hose etc.
- In the event that you are removing your injectors, having them cleaned and flowed, my suggestion (as I've been taught and told) would be to replace the fuel hose. To get the hose off the injector end, you can use a soldering iron rather than a blade to pierce the hose and cut it in order to get it over the barb fitting. Pulling, you're unlikely to have much success.
Removing the retainer:[edit]
Each of the injectors has a black plastic retainer to hold it to the inlet port. The retainer is fitted to the injector over an o-ring and held in by a circlip.
Use your circlip pliers and get the circlip off, then using a pick or flat blade pry the old o-ring off the old injector. The retainer will just slide off. You may break the o-ring, don't stress unless you really have to use it again. But the new injectors come with a replacement.
These are the parts you'll get off the old injector:
This is the fuel pressure regulator disconnected from the rail.
- I'll note here that I found the short piece of hose from the reg to the rail very cracked and brittle. I replaced it with high-pressure fuel hose which I just bought at my local parts store. I'd suggest going to somewhere like Pirtek or Bursons and ensure you use proper fuel hose. Vacuum hose or heater hose won't do. It'll perish being exposed to petrol after awhile.
Now begins the fitment and reinstallation. Some of these steps can be disregarded if using reco'd or second hand injectors.
Fitting new injectors:[edit]
Unpack your new injectors, and fit the retainers you took off earlier to the injectors. Locate an o-ring under the retainer, if you want use some rubber grease to help ease the o-ring on. Then fit the circlip and ensure it's retained in the groove correctly to make sure the injectors bolt up okay.
Slide the injector hose over the barb on the fuel rail with a new hose clamp or one from the old injectors. I chose to salvage the ones from the old injectors, but the ones without the little grooves in the worm drive clamp. This is because those grooves in the clamp cut into the hose and don't apply as even a pressure on the hose. It's all preference in the end.
Leave the injectors a bit loose so you can turn them on the fittings at the rail. Wait until they are in the ports before tightening the clamps to ensure that you tighten them up the right way around and so you can get the connector on the injector.
This is the old injector next to the new:
This is how the new injector should look when ready to go on the rail:
New high-pressure hose on the fuel regulator:
Refitting the fuel rail & manifold:[edit]
From here you should have your injectors on the fuel rail, the regulator fitted back to the rail and all the small o-rings should be on the end of the injector on the side that goes into the port. In the case of the new injectors there were little red caps on all the injectors at the fuel delivery end, remove these and the small sealing o-ring is already fitted. Using reco'd or second hand injectors, make sure you replace the o-rings, otherwise you're taking the risk of a fuel leak. It's a good idea to smear a little rubber grease on the outside of the o-ring to ease it into the inlet port.
I'll stress here that using rubber grease is important and not Vaseline or petroleum jelly as such because rubber grease won't perish the o-ring. Petroleum based greases can ruin the seal faster and dry them up easier.
Bolt the rail and injectors in, making sure to start all bolts before tightening any of them, otherwise you'll find injectors don't seat properly and the rail is awkwardly lined up. Start everything by hand first. Tighten all bolts up. You can now also fit the supply and return fuel hoses & tighten the clamps.
Before you put the manifold back on, clip all the injector connectors back on and fit the U clips and ensure they're all tight and sequenced correct.
Fit the top half of the manifold and start all the 7 bolts that hold it together. Remember on the underside the shorter bolt of the three goes in the middle. Once all started and seated, tighten them up, remember its alloy so start inside and work out, and don't over tighten them. Again, a new gasket is unnecessary, just make sure no large bits of dirt or grime as on the sealing surfaces.
Connect all the electrical connectors, vacuum and cooling hoses removed before hand. Making sure you get all the small vacuum lines on. One under the throttle butterfly, one on the front of the manifold towards the PCV valve, another at the rear of the plenum. Make sure you don't leave any coolant hose clamps off or stuck half way down a hose.
Once everything is connected that you previously removed finish fitting the throttle cable and induction piping.
Prime the fuel system by turning the key to IGN and listen for the fuel pump.
Bleeding the cooling system:[edit]
Since you had to remove the manifold where coolant runs through, you'll need to bleed the cooling system to ensure no air is the system. This is just a quick bleed and does not outline a complete cooling system flush. Open the heater all the way by turning it to full hot in the car. Fit a bottle like a coke or brake fluid bottle with insulation tape around the neck to create a seal to the radiator filler neck. Like this:
You can bleed the system at both of the bleed holes which I've circled here:
However, I saw it fit to only bleed through the topmost hole as no coolant lower than that was lost. So crack the bleed bolt and fill up the bottle at your filler neck. Watch until green coolant or water comes through the hole then fit the bolt. Tighten it and start the engine.
You will likely find it takes a bit longer than usual to crank as the injectors will need to fill up with fuel and start working, and there may be some debris in the cylinder from cleaning the injector holes in the runners. Once running listen to the engine and make sure there is no misfiring or unusual sounds, like vacuum leaks.
Continue running the engine if all is okay and bring up to temperature with the radiator cap still off. Once up to temperature you know the thermostat is open and coolant throughout the system, it's safe to remove the bleed bottle and fit the radiator cap.
Road-test and troubleshooting:[edit]
Now take the car for a road-test and see how it feels on the road under load. Make sure power delivery is smooth and no misfiring occurring. Bring the car back, and inspect the injectors for leaks at the o-ring and the injector itself. Double check all connections and hoses for vacuum and coolant leaks. Make sure your throttle cable is adjusted and tight.
You're now complete.
If you encounter misfiring problems, think about what you've removed and changed and try and eliminate items. I did a set of injectors once, and whilst I seated all 7 manifold bolts, I hadn't tightened them. The car ran like crap and barely idled. Tightened the bolts up and it was fine. If you didn't label the injectors and you have a miss, consider you maybe put them on wrong.
Misfires can also be caused by bumping or pulling on spark plug leads whilst working on the injectors.
Comments:
- This may be a good opportunity to tie in a few other service items on your car such as a new fuel filter. Spark plugs, as you will have easier access to them with the manifold split. A cooling system flush & refill / bleed. Repairing connectors or replacing broken ones with new push clip style connectors.
- Always use rubber grease instead of petroleum jelly like Vaseline.
- Use high quality fuel hose in repairs and don't take a cheap way out on this.
- Take the time to be clean and neat. Keep wiring tidy and use cable ties where you can to neaten wiring.
- Look out for loose nuts and bolts related to your work or otherwise and tighten everything accordingly
- Whilst you have the throttle body off with the top manifold, give it a clean out with throttle body clean or degreaser to freshen it up a bit and improve your idle.
- Check your sensors such as Engine Coolant Temp for corrosion on the pins in the connections. Corrosion can affect readings and signals from sensors and impact on engine running and economy. Use contact cleaner and remove corrosion where you can.
- Check for rusting cooling pipes like this:
Repair and monitor these conditions where you can.
Hopefully this guide is helpful to you.
- Trustpower