94Q Fuel Injector and Knock Sensor

[ponytrekker]

Yesterday I had my dealer diagnosed my check engine light as being triggered by a bad (open) #6 Injector and a knock sensor code.

I am looking for advice on their quotes and recommended additional work if they have to remove the plenum.

Their qutoes for the repair are:

210 for the injector400+ for the labor189 for the knock sensor 37 for the harness?

Are these reasonable qutoes?

and/or Should I also

1) have the TB and Plenum cleaned2) replace the Plenum hoses3) replace the other injectors 4) Perform any other work

I live in Oceanside Calif. My 94Q has 122k, has an excellent mechanical history. Always drinks Techron with consistent 3k oil changes. The engine has been good to me over the years.

Finally, I think someone once recommended on this site a good Q shop in the San diego area but I have been unable to find that thread, If anycan know the shop name that would help also.

Regards,

Jay

[DAEDALUS]

You gotta check with Scottsdale for the parts. The injector, for instance, is just south of $150. Otherwise, labor is reasonable since they have to remove the plenum. The "harness" is the KS harness? Scottsdale's at 1-888-216-5328.

Did they do anything besides get the codes to determine you need a new knock sensor? Why only 1 KS and not both? There is a good chance that the knock sensor does not need to be replaced. Based on experience, the bad injector probably set off the knock sensor code. I would bet that if you replace the injector and clear the codes, things would be fine. It was the rough running that probably set off the KS code...make it smooth and it goes away. The KS should be ohmed to get a better idea of its health (550k-ohm nominal), and visually inspected for cracks.If you remove the plenum, replace the hoses. Maybe they'll soak the plenum in cleaner for free--not really much labor in that. If you replace any other injectors, only do the 4 under the plenum (#3-#6) since the others can be done with the plenum on.

Jerry Tucker's All Import Service is the shop to go to in SD.

[maxnix]

http://www.jerrytucker.net/

[forecast]

I agree with Daedalus. Do the hoses. There are water 6 hoses and a few PCV hoses down there. The water hoses are relatively cheap from Scottsdale ($7-$10 each) the PCV hoses are much more - $35 each. Scottsdale sells a complete kit of both sets of hoses.

Note that changing the head outlet hoses will involve another hour of labour since that involves sealant. The 4 small hoses just clamp on and shouldn't involve more than 15 min total.

If a single water hose breaks in the next 60K, you'll have saved money by doing them now.

Also the hoes *may* be good for lots more miles, but they may be brittle and be cracked by the techs getting at the knock sensor.

On my '90Q, there is just one knock sensor harness - it's shaped like a long Y

The labor seems fair. Pulling the Plenum is difficult and a major pain in the lower back! Its tough to get it out under 1.5 hours.

Re the knock sensor, I would have ohmed it on the car (very easy under the hood - 5 min or less) so I kind of assume the shop would have too.

Was the car running rough? missing? (shaking at idle?)

dan

[natsoundup]

How long do you think it would take to pull the plenum and change out the hoses....

Never done it before on a Q, however, I have some mechanical ability...

My Q is driven 99% in town... never changed any hoses (my bad) 90Q 153k miles...

[forecast]

If you've never pulled the plenum, it will take about 4 - 5 hours. Make a Saturday of it and don't plan any heavy lifting later on that day.

To pull the plenum:

- Disconnect brake booster vacum- Disconnect accelerator and cruise cables- Pull airduct- Disconnect vacum lines of fuel pulse modulator and fuel pressure modulator- Disconnect TB water hoses- Disconnect Cannister vacum line- Disconnect TPS harnsesses- Disconnect PCV valve- Disconnect PCV hoses to plenum- Disconnect IAC air well hose (tricky)- Disconnect all eight runners (16 bolts) - don't drop one!- Very gently lift the plenum off - there is trick to angles.

All in all - I need 1.5 hours to do just that!

[ponytrekker]

Thanks Daedalus and Dan. The car was running rough at idle and higher RPMS, prior to that it ran like the proverbial top. I am ordering 4 injectors, 2 KS's and 1 harness, and full hose kit form Scottsdale. It makes sense as I will be keeping this Q for at least 3-5 years. Also contacted Jerry Tucker and got a good quote for pulling the plenum and replacing said parts, and clean the TB and plenum as well. I can't say with certainty if the Infiniti tech ohmed the KS, or if he was just recommending the inherent advantages, the service writer was new and that didn't help matters any.

Jay

p.s. If I hadn't ruptured a disc in my lower back last year I'd be game to DIY.

thanks again.

[forecast]

Scottsdale sells two different hose kits... one for water (absolute must) and one for the PCV hoses. Makes sure you get at least the water if not both.

dan

[landtodd]

Forecast said: "Also the hoes *may* be good for lots more miles, but they may be . . . (clipped) . . . cracked by the techs getting at the knock sensor."

Exactly what happened to my car. KSs had just been replaced when I bought it. Coolant leaks were terrible.

[natsoundup]

Thanks on the play by play for removing the plenum....

If I have days off left towards the end of the year, I will do it then... I would like to have a three day weekend so I can do it over two days...and rest on the third.