Fuel Injector Removal & More

[My_Q45]

Hey All,

I have a 94 Q45 with 2 bad fuel injectors, dead knock sensors & I don't know what's goin' on with the temp sensor.

I have the plenum off & I'm trying to get the 2 bad injectors out. I have never done it before on any car & searching didn't reveal anything so I thought I would ask. I'm gonna switch the bad ones with injectors # 1 & 2 so I can replace them later with the intake manifold on. What's the trick to getting them out without damaging them. I know the metal cap comes off and that's it.

Is there any chemicals you guys suggest to clean the plenum? My hand doesn't fit inside of it. This car was not made to be worked on unless you can dislocate your wrist to fit in some of the spots! I'm thinking of investing in Band-Aid stock!

I also wanted to replace the temp sensor(s). How many are there? I think I read there are 2, but I only see the one next to the water pump. Any suggestions about how I get it out without removing the fuel rail & lower intake manifold?

Finally the knock sensors. Besides going to Infiniti of Scottsdale, can I get them cheaper anywhere else? I saw Bosch KS for $110 online. If that's the best I can do I might as well go with oem. Any suggestions.

I know I sound cheap (well I am), but I already put a lot of money into this car & I have more repairs after all this is over. But first I'm gonna enjoy the car for a while!

As always, thanks for the help.

[forecast]

for the plenum cleaning - carb cleaner or accetone will work. For $30 any shop that rebuilds engine will have a hot tank they can soak it in.

If you've got the plenum off, I'll suggest you pull the entire fuel rail and scrub the runners out too - JUST BE CAREFUL no to drop anything into the engine!

there are two temp sensors. A singe wire on runs the dash and a more accurate two wire one runs the ECU. Really not much point in changing the dash one if it appears resonable correct. Engine performance is tied to the two wire ECU one.

You didn't mention the age or model of your Q, but a quick suggestion - replace all the water hoses down there. Swallow hard and spend the $60 to get all new from Joe at scottsdale. If even one gets cracked while you're messing with the knock sensors and starts leaking a week after you get it back together ... , well, no chiropractor in the world might be able to fix the discs in your back!

I'll let someone else talk you through pulling an injector out of the fuel rail.

[DAEDALUS]

No hot tank! There are several types of cleaning devices, including hot tanks, jet washers, and parts washers. A hot tank will probably discolor the aluminum. A parts washer uses a much more gentle solvent at a lower temp and is fine for aluminum. Plug the small holes in the plenum, turn it upside down, and then just set it in the washer and fill it with warm solvent. A jet washer is not damaging either, but probably not too effective on such a cavernous part.

No way to remove the injector without damage that I can figure out, unless you remove the rail. Then you can just push them out (carefully) from the bottom-side. But a few scratches in the plastic body probably won't hurt much. Just don't pull up on the metal stem! To remove from above, grab the outer body with some grips, rotate to break the seal set, and just turn it back and forth while pulling up. Empty out the fuel rail first, or you will fill the cylinder with fuel when you remove the injector.

The temp sensor near the water pump can be replaced with a short 19mm (or 17mm?) socket and a wobble ratchet extension. I've done it, yet I don't know if that's the ECU or the dash sensor. I just figured I'd replace all sensors at once.

[My_Q45]

Thanks for the help!

I thought a wobble ratchet extension might do the trick! I thought that about lots of bolts in this car. It's a shame someone stole a tool box of mine that had a bunch of socket's & attachments. I guess I will buy one tomorrow.

[szh]

for the plenum cleaning - carb cleaner or accetone will work. For $30 any shop that rebuilds engine will have a hot tank they can soak it in.

I'd recommend against acetone - please stick with the carb cleaner! Acetone can be dangerous to your skin - you have to wear gloves when playing with it and it is apparently difficult enough getting inside the plenum with bare hands!

Plus, acetone can damage rubber and plastics. If you drop some on the hoses, or elsewhere, ... you know what you are in for!

Z

[Highway Q45]

I did my plenum about 3 weeks ago. I took the TB off and sprayed "GreaseEater" all over the inside and runner areas, then hosed it off with water. I followed that with "Easy-Off" oven cleaner with a 5 minute sit time, another thorough hosing and it looked near to perfect. You can hand wipe the lower runners with a good solvent and rag, just don't let much run down the walls. I also shot a little PB Blaster around each injector after the cap was pulled. A slight twist with pliers and they pulled out very easily. Be sure and use a little dielectric grease on the new o-rings if you swap them. As everyone here will tell you replace all the air/water hoses unless you know they have been done before. Good luck it's a lot of "Fun".

Steve

[AZhitman]

Get the KS from Joe, as well as the hose kit... You're halfway there!

[DAEDALUS]

Yeah, almost as "fun" as eye surgery.

[cdiver]

I used a new toilet brush and lots of carb cleaner to clean the inside of the plenum. For the outside, I used Simple Green, let it soak in a bit and used the high pressure hose at the carwash to wash and rinse the plenum. The outside didn't look perfrect, but it did look pretty good. I have also heard of people simply painting the outside of the plenum (silver high temp paint i guess).

Good luck,

Stephen

[90Q45blue]

So it looks like the KS from Joe are about 120-130 each. I will spend this much if I must but don't really want to. If anyone has anywhere else where you can get them significantly cheaper let me know. The 110-dollar Bosch wouldn't be worth it. Better to go OEM with such a little price difference.

Nick

[cdiver]

I know you R short on $$, but since you have the plenum off, you might also want to consider replacing the 02 senors. I did mine when the P was off, and it was a piece of cake.....comparted to the amount of time I spent cleaning the oil and grime off the top of the block and the other fun parts of the P job.

Stephen

[My_Q45]

Thanks for all the suggestions!

I haven't gotten time to work on the Q since I took off the manifold. The toilet brush sounds like a great idea! I don't know when the hoses were replaced, but they looked good inside & out. I think they must have been changed at some point since I have 4 newer injectors in there. I'm still going to replace the coolant hoses & I think that's about it. Truthfully I didn't think taking the plenum off was that bad:rolleyes . If an air hose goes, the engine's not gonna overheat. I already experienced an overheat last year when a heater hose went! I was driving up in the mountains to go hiking & suddenly there was a hell of a lot of smoke. Good thing it was the heater hose so it spilled over the exhaust manifold so it all turned to steam & let me know before it was really too late. I thought for sure I just bought myself a new engine. That was a bad day! I was lucky that there were no major adverse engine issues after that.

Anyway, at least the Jeep is doing good. It's not a Q though!