1997 Q45 with acceleration issue GREMLINS need removal Who is a supertech?

[workkyle]

I have been trying to get my 1996 (my orginal post had 97' but when i found an owners manual online it appears i own a 96) Q45 running properly. When i got the car the fuel pump was not functioning properly and so i had this replaced. Afterwards the car still did not run correct and the mechanic noticed improper flow from the exhaust so he fixed the CATS and replaced the cat O2 sensors and new plugs and now the exhaust is normal. But the car has an acceleration problem.

When your driving at 2000 to 2500 RPM and you try to accelerated (soft or hard) it will go to about 3000 and no more power. If you start at 1000 RPM and floor it it will run up to redline or runs well at 4000 and up. If you are going 2000 RPM and drop it down to second gear it perform with lots of power also. Any ideas??? The mechanic suggested two things. Since no codes are coming up he said the timing chain may be worn (ie he suspects a mechanical issue) and or it may have lots of carbon build up in the intake and internal engine components. When the car was on a auto shack code evaluation unit the only anomoly noticed was at high revs the timing was going to about 30 degrees advance.

There you have it any help will be greatly appreciated.

Modified by workkyle at 12:27 PM 9/18/2009
Modified by workkyle at 12:29 PM 9/18/2009

[qship96]

Push it off a cliff and collect the insurance money.......UNLESS you are willing yo invest a minimum of $3000- 5000 restoring worn and defective parts to bring it back to near new operating condition,then commit to spending 2500-3000 EVERY year maintaining it.....no joke, thats what it takes to drive a shiny new to you 14 year old lux car.............cheaper to just purchase and maintain a off lease 2-3 year old dependable Accord/Altima/Camry.

[workkyle]

How do you test? The RPM is not erratic it just has power issues in the 2500 to 3000RPM range once you get the car to rev up it has plenty of power. If you try to accelerate at 2500 RPM's all it does it bog down and sit at 3000 RPM's

[elwesso]

Cleaned up this thread.. Troy, if you're reading this, you are BANNED (troy3369 and friends)...

Anyway, does the car idle OK? Was the fuel filter replaced? Any other sort of service history? I highly doubt its a mechanical issue like timing chains, the chains on this engine basically never wear out!

We do need to confirm if you have a 96 or a 97.. If your VIN starts with JNKNG01 you have a 90-96 car... IF your VIN starts with JNKBY31, you hjave a 97.. Thats going to be important in diagnosing your problem, because typical causes are different on the 2 generations!!!

Check that and report back!

[workkyle]

The car idles fine, although it does vary a little when cold vs. warm and hot, but not much, idle at operating temp is 680 RPM. I did put a new fuel filter in it prior to new fuel pump. My wife is visiting her dad in the car so i can't check the VIN but looking at the 96 owners manual shows the fuel gauge to be on the right side of the dash while the 97 owners manauls show the fuel gauge on the left side of the dash if this is a distinguishing factor. My fuel gauge is on the right side of the dash.

[loystock]

Wes, Thanks for getting rid of that foul-mouthed pest - troy33xx. The likes of him are ruining this forum.

workkyle, The appearance of the G50 (90-96Q) and Y33 (97-01Q) are totally different. You can go to Yahoo-Autos or Edmunds.com to find out which car you have. As for your problem, before spending more money (which you have to do eventually), make sure the entire air intake is clean - air filter, MAF sensor and throttle body. My hunch is on a dirty MAF sensor and connector. Once the intake is clean, apply a bottle of Red Line SI-1 (or BG44K) Fuel System Cleaner and do several WOTs on a highway (if safe to do so).

Did you use NGK OEM plugs? Bosch and Denso plugs are not compatible with the VH engine. A bad KS usually throws a code. A misfire will also give a code and turn on the CEL.

As always, the gurus in this forum can help you more.

[goody90q45]

Welcome to NICO Kyle. The 96Q is a strange beast. It's the 1st year for OBD2, the VVT (interference engine) is gone and knock sensors really do make a difference in these engines.

A little more diagnosis is in order before we can stop guessing and and give you some educated guesses. Start by ohm testing the KS and fuel injectors. It won't take ten minutes and will tell you a lot.



Next I'd be pulling ECU codes again to verify for myself that there are none stored. The ECU is behind the passenger side kick panel and the Tech Help section at Q45.org has great instructions. If you don't want to pull out the ECU you can buy a code reader or go to an Autozone or equivalent and they'll plug in and read/clear the codes for you.

If the KS and FI ohm within range and there really are no codes then you've got to suspect a faulty FPCU. To check it you'll need to come in through the trunk, unplug the FPCU connentor, and run a jumper from the connector pin shown in the pic to ground. The FP will now run in high speed only and if all's well then it's a bad FPCU.



Try these things and let us know what you find.