Plenum/knock sensor job on '98 Q45 in-process. Need some help.

[duck3986]

I had hoped I'd be able to remove the plenum only and not the runners to replace my knock sensors but ended up having to remove the runners too.

It was more complex than I expected.

So everything's off the car. I'm not sure if this was the right procedure, but I cut the two fuel hoses (to be replaced later) which connect the fuel rails so that I could remove the runners. In doing so, i damaged some of my fuel injectors, but I'm not sure how serious the damage is.

On the bottom of eache injector, where the tiny holes are that shoot out the gas, there are four plastic "fingers" or "clips" that seem to hold the metal injector tip. There seem to be two or three of these "fingers" missing on the left injectors. They broke off when I was wiggling the runners out.

How serious is this?

I was thinking about bringing the injectors to a shop to have them bench tested since I have everything apart and the car has 94k miles.

Is this a good idea? Do I just disconnect the fuel rail and bring it as an assembly or do I remove each individual injector?

What should I request the shop to do? Flow rate? Have them pressure cleaned?

Anyone know what I should expect to be charged to do this?

Thanks,Don

[Q45tech]

Very few shops in the US have the complex equipment to measure the accuracy of fuel injectors, don't confuse whether they dribble or squirt with accuracy.http://www.lindertech.comhttp://www.rce ... oning.html

You can learn alot from Linders newslettershttp://www.lindertech.com/newsletters/nwk6~04. ... chives.htm

As I remember changing the knock sensors on a 97-01 is much easier and faster than on a 90-96 just a little more than half the time.

[duck3986]

I haven't worked on any other Q45 so I can't compare. Where I found it tough was getting the runners out. The fuel lines and rails got in the way.

Maybe the correct procedure is to remove the fuel rails completely. I have an Infiniti repair manual, but couldn't find any details about what needs to be removed and when.

Also, there are just a heck of a lot of vacum lines and connectors and routing to keep track of. Far more than my old '86 Vette and my wife's '00 V6 Toyota minivan. As a matter of fact, the toyota's plenum and runners are all one piece.

What about the injector damage? Loveless just recently posted "Can I clean my injectors myself" and has a perfect picture of the injectors with the plastic fingers on the end. That's what I broke on several of my injectors. I hope I'm not going to have to replace them all.

How would an Infiniti dealer know if an injector needed to be replaced? Is that something that a Consult would show?


Modified by duck3986 at 1:44 AM 9/27/2004

[911/Q45]

I didn't have to remove any lower runners to change the KS in my 90. Much easier to remove the rails with the injectors in them, then remove individual injectors as required. I'm thinking the plastic fingers are there for a reason and any injectors missing them should be replaced. You'd hate to put it back together and then pull it apart again.

[elwesso]

Yeah and it could lead to leaks, so it could start spraying all over the palce... Could be VERY bad.....

[Q451990]

There was some discussion about if those injector tips on later models are available separately... but I don't remember if they are or not. It would be worth calling Joe to check.

1-888-216-5328

Heath

[duck3986]

Last night I attempted pulling one of the injectors out of the fuel rail and it was really stuck in there.

I pulled w/ pliers and fairly hard and it didn't budge. Is there some kind of trick?

[911/Q45]

Twist and pull with the pliers while carefully pushing from the tip end. It helps to have the rail in a vise.