1994 Q45 KS & Injectors

[CalQ45]

Now 88000 miles. Two years ago at 80800 miles with intermitend check engine light after consult test dealer recommended replacing all injectors & KS. I did not do anything. Few month later at 83000 miles a fuel pump quit. I replaced it myself and never got check engine light ever since. Recently car started shaking at idle. I cleaned MAF, replaced fuel & air filters. Slight improvement, but it got worst now. Snap-on meter did not show any codes. I went to the dealer for diagnostic and was told to replace injectors & knock sensors. After asking which parts are bad I was told that injector #3 is bad, #4 and #8 are going bad, and KS in bank1 (driver's side is bad). I measured resistance on #3 and indeed it is high, about 50 ohms. Before in 1998 at 49000 miles dealer replaced injectors #8, 6 and 1. In 2001 & 2003 at 72K & 79K miles I replaced injector #2.I see a need to replace injector #3. Since I have to remove plenum I will replace 4, 5, 6, 7 & 8. Will I have access then to check KS? Can I measure their resistance? What is your advice?

[maxnix]

If KS original, plan on replacing them, harness, and under plenum hoses for access and 100K miles of peace without going back in. You will not want to repeat this before it is absolutely necessary again.

Move in-spec but suspect injectors to accessible locations. Replace out of spec injectors.

Use only tier 1 gasolines. It is just not premium grade, but brand/producer.

Use BG44K and ISO-HEET religiously.
Modified by maxnix at 10:38 AM 8/31/2005

[CalQ45]

Thanks for replying. I always use premium gas. What is BG44K and ISO-HEET ? Any advice on removing plenum? Do I have to drain coolant? How to do that?

[AZhitman]

^ Great advice.

One can accomplish many things once the plenum is pulled.

[maxnix]

Start by downloading the FSM and TSB for your car from

http://www.nissan-techinfo.com/infiniti/ for a one day subscription fee.

Then read here (a lot), especially all posts by Q45tech. It will take a while.

Start by searching on plenum.

Get parts from http://www.everythinginfiniti.com

[CalQ45]

Thanks for all the advices.

[DAEDALUS]

You do not need to remove the plenum to measure KS resistance. However, measuring resistance does not necessarily prove anything. You can pull the codes from the ECU in about 15 minutes--it will tell you of the ECU thinks the KS are bad. No question if the plenum comes off you should replace them, but the plenum does not have to be entirely removed to replace the #3 injector, just loosened.

[CalQ45]

Thanks for you reply. Perhaps I should start with replacing injector # 3. Can you please elaborate more on loosening plenum? Which other injector can be replaced by loosening plenum only?

[CalQ45]

Also, how to pull the codes from the ECU?

[DAEDALUS]

zerothread?id=49246

I'm assuming #3 wouldn't be any harder than #6.

zerothread?id=21144