90 Q45t - Time to give up??

[JohnN]

126,000 miles, but it now has gremlins. After fixing the electrical grounds and installing a Nissan rebuilt alternator, I took the car to my college for an AirCon conversion. After 6 weeks, they gave up (long story). When i took the car home I noticed the following problems:

1. No power steering
2. ABS light is on
3. Brake pads worn light is on
4. Fuel filler door doesn't work
5. Gas gauge doesn't work
6. Passenger power seat doesn't work

I don't want to give up on this car. I have owned it 7 years and 34,000 miles, and replaced many, many items, mostly with new Infiniti parts. For example, shocks, timing chain, fuel injectors, knock sensors, fuel pump, driveline, Stillen slotted brake rotors and related pads, water pump, radiator, suspension links and bushings, etc.

If anyone has any ideas, please let me know. Otherwise, I guess it's time for the wrecking yard.

Many thanks in advance - John -

[elwesso]

IF its in good shape body and interior wise, the stuff you listed isn't worth giving up on in my opinon. If its trashed in the inside and out, then maybe it might be time to say good riddance.

No power steering could be a simple issue. Can you give a little background on this? When did it start, has it always been like this, are there any funny noises coming from the front of the engine, etc.. I've not seen PS pumps go out too often, so chances are its something electrical. There is a pressure switch on the pump itself that I've heard of going out (rare), and there's also a solenoid on the steering rack that sometimes can be finicky. Also the PS will not work if something is screwed up in the instrument cluster on the speedo.

ABS light chances are your ABS actuator is done for. You can do the self diagnosis on the ABS system to see what the issue might be.

Brake pad worn light is an easy fix, just bypass the sensors on the passenger side front and passenger side rear calipers. Sensor is a 2-wire plug, and all you have to do is clip the wires and splice them together.

Never heard of the fuel filler door not working, again that is probably an easy fix I would think.

Gas gauge.. Let me guess the gauge stopped working after the fuel pump replacement? Chances are the sending unit on the gauge got messed up in the install, its pretty easy to do if you don't replace the fuel pump properly (IE through the trunk and not through the back seat)..

Passenger seat could probably be from the switch on the door, most of the time the motors and stuff on the seat don't go bad.

[maxnix]

Yeah, it seems you just have to get after it a little more. It is a 22 year old car.

No maintenance history nor condition of fluids report (white paper towel test), so tough for us to comment beyond what Wes has said..

Have you never changed the PS, or ATF fluids? LPFP? Did you hit the sensor or damage it on the ABS?

[Skibane]

Hey, John - welcome to the forum!

Most folks get rid of their Q when something major happens - blown engine or transmission, getting totaled in a crash, catches on fire, etc. You don't have major problems.

Only a couple of the problems you've described need immediate fixing - Everything else you can set aside for a while.

You definitely need power steering to drive the car. Since your college buds worked on the AC, it's possible that the culprit is something as simple as a missing belt or loose idler pulley for the PS pump. Get in there and poke around a little bit!

The car will still drive and stop OK without the ABS working, but will be more prone to sliding when braking on wet pavement.

The brake pads aren't particularly difficult or expensive to replace yourself.

The fuel filler door is released by a little electrically-operated plunger that retracts whenever you push the release button. The plunger can get sticky with age - You can fix it by applying a little bit of oil (I use automatic transmission fluid) on it. If it's stuck in the retracted position, use a pair of tweezers to pull it out before oiling it. If you can't open the door to gain access it, try pulling the emergency fuel release cable (located in the trunk).

Hope this gets you started - Don't give up!

[JohnN]

Elwesso - Maniz - Skibane

I'm honored that all three of you, really involved NICO members, responded to my dilemna so quickly. This week was mid-term exams, so I haven't had much time to reply. A few more details about the problems may help.

The car was inoperable for quite a while while I tried to figure out what blew out my headlights, radio head unit, and boiled over a brand new closed-cell, gel-type battery. Turns out that the rebuilt alternator I sourced from a local auto parts store wasn't functioning properly, AND I had a grounding problem. Fixed the grounds and installed a rebuilt alternator from Infiniti of Scottsdale, traded out the headlights and radio unit for some used ones, and everything was A-OK. During the process I found a loose connection at the fuel pump controller unit, fixed it, and the car has never run stronger. While I was at it, I replaced all of the belts. So, I decided to put some more time and money into it.

I next installed new front upper suspension links, new front rotors and related brake pads sourced from Stillen, and broke them in over the next 100 miles. The car was running so well that I decided to 'bite the bullet' and convert the AirCon system before my very noisy compressor gave out, so I took it to the local Community College for the work. Well, it didn't, work out that is, so I got the car back with no charge except for the conversion kit and rebuilt compressor ($$$), and drove it home - about 10 miles. That is when I noticed all of the problems I listed in my original post. Everything was working before, so your suggestions probably won't have any effect, because it all happened at the same time.

I have tried a couple of things. I swapped out the combined HICAS/power steering control unit and also the relay above the steering column under the dash with used items, but to no avail. I also noticed that the 120 amp main fuse looked corroded, so I replaced it with a new Nissan unit, but nothing changed. I even pulled the instrument panel and replaced the fuel gauge with a used one, but of course it didn't work either.

I can't think of anything the college students might have done to cause the problem, but they did have the car for 6 weeks. I really think that I may not have fixed all of the grounding problems and maybe that is the problem. I love this car, and have always maintained it to NICO standards, so I'm at a loss. Is there a chqance that any one electrical component could be at fault?

Again, I appreciate your input ............... John

[maxnix]

I can't think of anything the college students might have done to cause the problem, but they did have the car for 6 weeks.

Really? This reminds me of Q45tech's quote that more harm is done to these cars by ignorant techs and uncaring owners than even outright abuse.

Oh well. Live and learn.

[Infinitiguy19]

Why do so many people say they have a Q45t when they don't!? Like three people so far recently have said it at least.

What automotive courses were the college students taking?

[maxnix]

What automotive courses were the college students taking?

Chop Shop 101, evidently.

[JohnN]

Mr. Infinitiguy19,

I was told my 90 Q45 was a "t" model because it has HICAS steering, the special 15" lightweight forged alloys supposedly found only on "t" models, and it also has the factory rear deck spoiler. Doesn't matter, the car looks great.

As for the students, they were studying air conditioning systems for the first half of this quarter. I think the car's problems may be related to more grounding gremlins - any ideas about grounding points that may be hidden around the car. I fixed the obvious ones in the engine compartment, and also checked out the battery cables before installing the Infiniti rebuilt alternator. Worked fine for about 100 miles before I took it in for the AirCon conversion. My Bad!

[Skibane]

The factory service manual should have wire harness diagrams, including all the ground points.

Do you have a factory service manual?

[maxnix]

Grounding the MAF separately was a common modification in the early cars.

You need to go back and compare to another car or FSM what they Effed Up and correct it.

Presume you know a conversion from R12 to R134a requires an entire retrofit of all AC components for it to work well?

[JohnNordling]

The factory service manual should have wire harness diagrams, including all the ground points.

Do you have a factory service manual?

Actually, I do. I'm going to go over the electrical schmatics in much more detail to see if there are any grounds for each of the symptoms I am experiencing. Thanks for the idea. I just worked on the obvious ones under the hood. Can't get to it until next week - I'll let you know if anything works out.

John

[JohnNordling]

Grounding the MAF separately was a common modification in the early cars.

You need to go back and compare to another car or FSM what they Effed Up and correct it.

Presume you know a conversion from R12 to R134a requires an entire retrofit of all AC components for it to work well?

Based on what I could gather from earlier posts on the subject I didn't, but I probably missed some. What I did learn is that PAG oil used with R134 refrigerant is not compatible with the early Q45 variable displacement AirCon compressors. However, I want to resolve the electrical gremlins before tackling the AirCon problem.

Now, about this grounding of the MAF idea, could you shedd any more light about why or how, or refer me to a post about it? Many thanks, Manix. - This time I spelled your name right!

John

[maxnix]

Try this thread with the FSM.

1993-mass-air-flow-sensor-wires-t406387.html

Check your ground with DVM before wasting time to install another one if it isn't needed.

Another:

post4824600.html?hilit=MAF%20ground#p4824600

[DrewQ45]

Grounding the MAF separately was a common modification in the early cars.

You need to go back and compare to another car or FSM what they Effed Up and correct it.

Presume you know a conversion from R12 to R134a requires an entire retrofit of all AC components for it to work well?

Based on what I could gather from earlier posts on the subject I didn't, but I probably missed some. What I did learn is that PAG oil used with R134 refrigerant is not compatible with the early Q45 variable displacement AirCon compressors. However, I want to resolve the electrical gremlins before tackling the AirCon problem.

Now, about this grounding of the MAF idea, could you shedd any more light about why or how, or refer me to a post about it? Many thanks, Manix. - This time I spelled your name right!

John

John, I successfully converted a 90Q to R134. You can read about it here...

ac-converting-90q-to-r-134-t235199.html?hilit=R%20134

...Drew...

[JohnNordling]

Hi Folks!

I found the problem. When taking the passenger side lower dash out to have access to the AirCon evaporator items, the student(s) removed the 'main harness RH' just below the main dash. They plugged it back in, but forgot to tighten the bolt that keeps the contacts secure. This is similiar to the connections for the ECU and TCU. While looking for grounds in the service manual I noticed it was not tightened, so I simply wrenched it up snug. On a hunch, because of the number of electrical item affected by that connection, I started the car and viola! - all of the problems disappeared! I have hours of work to put the car back together, but you're looking at one happy camper.

Thanks for the tip an checking out the service manual for the grounding points. I might easily have overlooked the solution without your advice. Anyone interested can find the electrical elements affected on page EL-186 of the 1991 Q45 Field Service Manual.

It ain't time to give up on the Q yet after all - John:)

[maxnix]

Good! Onto the power steering.

[Q451990]