I bought another Q

[goody90q45]

I have been afflicted by the Q-bug - spending too much time reading posts on NICO and caught up by the Q45 hype. It's had such a negative effect on me that I went out and bought another Q, a 1990 base model.

This car became available from Ardvarkus (Adam) and was less than 30 miles away. I read his posts for about 6 months and when it looked like it might be going to the junkyard I spoke up and bought the car.

The details- 1990 base model, 221,000 miles, one owner with all reciepts. Adam spent a lot of $$$ four years ago on repairs and has driven only 20000 miles since- factory reman transmission, under-plenum hoses, KS and 2 injectors, fuel pump, all radiator hoses, all engine hoses, AC replacement and yes, a complete chain guide replacement. About $6K in repairs in a 2 month period. And to top it off he installed Yokohama 245-50-16R tires on 350Z rims over 2 years ago and has only driven about 4000 miles since.

The car runs near perfect, color is beige sand with zero body damage, and the burgandy interior is flawless- as clean as the day it came off the showroom floor. My daughter borrowed my digital camera and when I get it back I will post pics. My compliments to Adam for maintaining the car in such great condition. We should all be so diligent in maintaining our vehicles.

There's a couple of fixable issues that I will not have a problem dealing with- cracked windshield, speakers not working, parking brake pedal to the floor, searching for idle for 30 seconds before settling down at 650 rpm. The only real issue, and Adam warned me of this, is the CEL code 45- leaking injectors. Can't register the car until I get it smogged. Can't get it smogged until I can permanently clear the CEL. I can reset the code but it comes on about 10 miles later.

I've read all the posts on code 45 and here is my plan of action and where I need your advice:1) Add BG injector cleaner to a tank of gas and hope it cleans the injectors enough to clear up the CEL. ($13, in progress)2) Take the Q to a shop and have a BG injector flush done. Some of the posts said that this solved the problem. ($120, the price of one new injector)3) Have a test run done at the smog station to check emissions levels. Can't do the real thing since the results tie into the state database and labels the car as a gross polluter if it fails. ($30, part way to buying the second injector)4) Bite the bullet and replace the 6 injectors that have never been replaced. (two were done 20000 miles ago)3) If the test run passes then try and get the real smog check after resetting the codes and hope the CEL does not come on during the test.

I don't have any raw gas odors so I don't think I have a leaky injector o-ring. She has excellent acceleration and idles at 650 rpm so smoothly you can't tell the engine is really on.

I am taking all advice while I use up the first tank of fuel with BG additive. What exactly is the 45 code telling me? Should I spend money on a flush or bite the bullet and buy injectors. Thanks in advance for your help.

[Rex]

Have you ohm'ed the injectors to see if just a couple are WAY out of spec?If (hoping here) the worse ones can be replaced without pulling the plenum, how long does the car have to run (w/out CEL) to pass smog?

If time allows, maybe you could pull a couple injectors and have them re-conditioned by Deatschwerks (NICO Sponsor )?

Glad to see this car isn't just getting "tossed".

[Q45tech]

California Code 45 usually doesn't really mean leaking injectors just running rich or sluggish weak O2..............the ecu cannot correct by leaning bank so it throw a code saying beyond 20% error.

Doesn't the car have to pass a dyno emissions, [plus of course a visual inspection CATS] isn't it illegal to sell a car without a working valid emission certificate to a California resident?

[goody90q45]

I ohmed the injectors and all are 12.5-13.0 except #1 which is 15.5, not that far out of spec.

Update- I was mistaken about the state of CA labelling the Q as a gross polluter if I failed the smog check, so I went and had it done during lunch. HC and CO are at twice the allowable level. It could be a pinched or bad o-ring but I doubt it since I don't have any gas odor and the car runs fine. I suspect I have bad injectors and will end up replacing them. I think I will start with replacing # 1,2 and 8 and see what that does for me. Adam already replaced two others so I figure I've got a 5 out of 8 chance of replacing the bad ones. Any thoughts on this strategy?

[Rex]

You and Q45tech posetd at the same time, I think he's got a good suggestion ... check o2's?

[goody90q45]

Thanks for the reply Tech. Your post came in while I was responding to Rex.

Normally the seller is required to get it smogged before the sale but I took on that risk in exchange for a very good selling price. I took this on knowing that if something happenned and I couldn't get it smogged (worn out engine) then I could get the $700 tires and $600 rims and part out the rest. Hopefully that will not be the case and I can get it running and pass it on to another NICO member.

If it were the O2 sensor wouldn't I get an ECU code? It does search for a good idle for 20-30 seconds before settling in at 650 rpm. Could this be an IAC valve problem and would an adjustment of the valve cure a fuel rich issue?

[Q45tech]

California ODB1 ecu are all funky - trying to do the impossible before OBD2.

Read/diagnose with Consult to learn the true story.

[elwesso]

Nearly every time code 45 comes up, its the o2 sensors..!!!!!!! especially with more sensitive cali ECU..

Personally what I would do is take the injectors out of the car, send the to detche works and have them sonic cleaned, and they will install new O rings and stuff if you send them the entire rail.. If they ohm good, just clean em.... its only like $6 an injector, and then maintian every90 days with 44k.

[goody90q45]

Wes- You, Rex and Tech have all said the same thing- O2 sensors. The previous owner who is also very knowledgeable suggested either this or injectors.

I think I am going to go with the 4 experts and have the O2 sensors changed out. I ordered 3 injectors from Joe today at $160 each (yikes!) but if I don't use them they can be returned. I'll take a chance on a couple hundred bucks for O2 sensors if it will save me from buying $1000 worth of injectors.

Can you post again and help me understand why am I not getting the O2 sensor code on the ECU.

Now that I've driven a 90Q I can compare it to my 94Q and say that the 90 is much better built and a lot faster. The seats are extremely comfortable and you feel more like your driving a racing machine. It will be a great bargain for someone when I get it to the point of being able to sell it.

[elwesso]

Ill try and make this easy to understand, hopefully without insulting your intelligence.....

As you know, the o2 sensors work by basically switching on and off, much like the IAC does... It doesnt really know what the actually A/F ratio is, it just detects RICH and LEAN... Basically its on for RICH and OFF for lean, or something like that... you get the idea.....

Lets say over the same period of time, bank 1 injector reads LEAN LEAN RICH LEAN RICH RICH and bank 2 reads RICH LEAN RICH RICH RICH LEAN or something like that.. Well if the ECU isnt picking up that the o2 sensor is bad, and bank 2 is richer than bank 1, then it assumes that theres a bad injector...

The point is whenever the computer reads a big difference on either of the o2 sensors, it assumes that the o2 sensor is FINE (since its technically giving an acceptable signal to the ECU, but its not really FOR PERFECTION OEM NEW)... So if one bank is a lot different, what could the problem be?? Its gotta be an injector!!!!!

This probably works great for cars that have brand new o2 sensors,and also for cars that were under factory warranty, since the o2 sensors were good at the time... One time i drove my car with one brand new o2 sensor on the drivers side and an old o2 sensor (with 130k) on the passenger side, and I got hte injector leak code....

Get your o2 sensors from http://www.sparkplugs.com... They sell the OEM ones for $50 each, instead of Joes 100 each..... Theyre made by the same company that makes the OEM nissan ones, so theyre gonna be golden......

IF YOUR INJECTORS ARE OHMING FINE, DONT REPLACE THEM YET!!! Seeriously man, take them off the car and send them to detsche works... Theyre a NICO sponsor and know a Ton about Nissan Fuel injectors... everyone Ive heard of dealing with them loves them, andthey have a quick turnaround time... Their cleaning method is about half price of a rail flush (assuming free labor for taking the plenum off to get the injector rail out)... Plus they flow test and adjust them so each injector flows exactly the same, for a silky smooth idle!

[goody90q45]

Thanks Wes. Good explanation and you've convinced me that replacing the O2 sensors would be a good first step. I'll keep you posted.

[maxnix]

I like Wes' advice. Call Sparkplugs.com (tell Natasha you are from NICO).

Their website often lists the wrong part number for Q45.

Adam took great care of his Q, and I am sure he would post more if he weren't enjoying his M5 so much.

[ddrumman]

The 02 sensors on the 94 Q are part #wise 24521(front left) and 24615(front right) right?

Can any of you guys tell me if the KNOCK sensors are the same thing as the 02 sensors? Forgive my ignorance.

I called sparkplugs.com and spoke to Linda and she was real nice. She gave me those part #s.

Their website often lists the wrong part number for Q45.

I hope those 02 sensors part #s are correct.

[Rex]

... Can any of you guys tell me if the KNOCK sensors are the same thing as the 02 sensors? Forgive my ignorance.

Nope, knocks are up on top of the motor "listening", the o2's are down in the exhaust "sniffing" to use crude terms.

[ddrumman]

Thanx Rex!

[miata007]

goody,I am about 30 miles from where you are. Where do you bring your Q for service? I haven't been able to find a good mechanic with experience on the Q. It's been a while that I try to fix/maintian my own cars. It's time for a change. Thanks!

007

[goody90q45]

Where do you live?

So far I've only had her to the shop twice in the last 14 months (strut install, starter install) and have managed to do all of the other work myself. I've used Kenely Auto Care at Greenback and Hazel in Orangevale for the past 15 years and they've done a good job on all my cars. Both times I've brought her in I also supplied step-by-step instructions printed from the NICO site just in case they hit a snag. I've seen a few Infinitis in their lot over the years and they are great about getting me in and out on short notice, usually the same day (open until 8pm).

Shoot me an email and we can talk.

[elwesso]

The 02 sensors on the 94 Q are part #wise 24521(front left) and 24615(front right) right?

Can any of you guys tell me if the KNOCK sensors are the same thing as the 02 sensors? Forgive my ignorance.

I called sparkplugs.com and spoke to Linda and she was real nice. She gave me those part #s.

I hope those 02 sensors part #s are correct.

The difference between those part numbers is the lead length... One is like 12 inches, the other is like 60 inches.... you only need the 12 inch lead for BOTH sides... Yes, thats right BOTH sides use the same part number (short lead).

[ardvarkus]

Only if you sell it as an operational vehicle... I suppose maybe I could have junked it to avoid any potential violation...

My trade off was selling it for less than half the cost of the tires and wheelsorjunking it for the 40% tax write off that the private party blue book would give.

I perferred to sell it to someone willing to invest the time and keep an exceptionally clean car for someone to enjoy-

I even gave Mike the little tag that the Infiniti test technician signed when he did the road test- to explain why the 'new' car had 20 miles on it.

Mike emailed me a few questions, and I realized I was remiss in not checking in... so I will.

Adam

PS Maxnix- you're right. Had a 300C V8(maybe an SRT8) challenge me yesterday -two lane road. I walked on him from 2nd gear on out. 6 lenghts at 120 then a light. Next time 8 lengths to 130, another light. THird time he finally gave up I looked down and it was 152 or so- he was a good 1/4mile back. Mike will know the road- grantline behind security park on the back side of AJ...wild

[goody90q45]

Nearly every time code 45 comes up, its the o2 sensors..!!!!!!! especially with more sensitive cali ECU.

As usual your advice was right on. I'm not sure how the average owner or mechanic would know that a code 45 (leaky injectors) would mean bad O2 sensors unless they had read it here first. Most people would have spent $166 X 8 for new injectors, plus labor changing them out, and still not fixed the problem. Another great reason to belong to NICO. Looks like I'll have to send Greg (Hitman) another donation to the NICO cause.

Got her smogged and registered today after changing out the O2 sensors. I gave my word to the previous owner that I would offer her up for sale to NICO members first so be looking for her to show up in the Infiniti classifieds very soon, as soon as I can get my daughter to return my digital camera. This is an excellent running car in superb condition inside and out. Someone from NICO is going to get a great car at a great price. More to come.

Thanks again to all for the spot-on advice.

[goody90q45]

This Q is now for sale in the Infiniti Cars classifieds forum.