fuel delivery problems

[Evanarc]

Alright guys i need some more advice..I previously posted about a sputtering and bucking problem, along with a fuel smell in the cabin.sometimes theres a weird clunk but idk if its relative.

I cleaned the MAF sensor and that helped but it still drives like s---I also did a bunch of standard maintenance I thought might help

My friends dad, the mercedes guy, up the street took a good short look at it and said fuel injectors.

Im prayin its not the fuel injectors nor does it feel like thats my problem. I did a jiffy lube fuel rail flush. BG44k etc

Heres some more symptoms,

-Its rattles alot when you crank it for the first time of the day

-then 9/10 times will stall immediately, or 10/10 the idle is droppin like crazy

-once you get it in drive it usually fine besides the heavy bucking andbouncy idles.

-It will rarely stall at this point.

I think it might be the fuel pump and/or a leak in the plenum hose.

I dont believe the prior owner ever changed the hoses among other things, I curse him for in my sleep..

has anyone ever been to this sad point before?what gets replaced first on the road to fixing this issue?

[Haitian_King]

Alright guys i need some more advice..I previously posted about a sputtering and bucking problem, along with a fuel smell in the cabin.sometimes theres a weird clunk but idk if its relative.

I cleaned the MAF sensor and that helped but it still drives like s---I also did a bunch of standard maintenance I thought might help

My friends dad, the mercedes guy, up the street took a good short look at it and said fuel injectors.

Im prayin its not the fuel injectors nor does it feel like thats my problem. I did a jiffy lube fuel rail flush. BG44k etc

Heres some more symptoms,

-Its rattles alot when you crank it for the first time of the day

-then 9/10 times will stall immediately, or 10/10 the idle is droppin like crazy

-once you get it in drive it usually fine besides the heavy bucking andbouncy idles.

-It will rarely stall at this point.

I think it might be the fuel pump and/or a leak in the plenum hose.

I dont believe the prior owner ever changed the hoses among other things, I curse him for in my sleep..

has anyone ever been to this sad point before?what gets replaced first on the road to fixing this issue?

What's the fuel pump sounding like? Do you hear a sort of buzzing sound? Like a swarm of bees in the trunk. I totally recommend ohming the injectors. If it is the injectors, at least you know what the problem is. If it isn't, then at least you can rule it out.

Go to the car and turn the key. Don't start it. Just turn the key to "ON" and listen for the fuel pump priming. If it's really loud, or you can hear it while driving, that may be the culprit.

The fuel smell in the cabin could be a leaky hose. It's usually the one in the rear of the engine, close to the firewall. It's really noticeable in the cold. Especially right after starting the car. The hose will begin to swell as it warms up and it seals the leak. (If the hoses are old, it'll be like small holes that close easily after warming) Tightening the clamp on it helps, but replacing it is the best solution.

Now that's assuming it's coming from the front. If you have a heavy fuel smell in the cabin and it's strong in the trunk, it could be the o-ring seal around the fuel pump.

[ddrumman]

It sounds like a MAF and Fuel Injectors.

You're saying your MAF is fine. When my (Air Flow Meter) was bad, she would want to drop rpm like crazy as I was coming to a complete stop, and then she'd die when the wheels would stop rolling. So what I'd do was, put it in neutral and step on the gas. Maybe it's not your maf.

The bucking though, I think it's your injectors. I've had all 8 changed over the last 3/4 years, and every time she shook like a belly dancer in competition with Shakira to see who would do a better shimmy.

The Fuel Pump, If you can hear a hum from the rear that's an indicator.

[jmorasch]

I HAVE THE EXACT SYMTOMS IN MY 91Q WITH THE BUCKING IDLE AND SUCH.AT FIRST I HAD THE SMELL OF GAS IN THE CABIN,BUT THATS NOT THERE NOW.I OPENED THE TRUNK WITH THE CAR RUNNING AND THERES THE NOISE OF MAD BEES BEHIND THE DIVIDER IN THE TRUNK.IM PROCRASTINATING THIS ISSUE DUE TO THE COLD WEATHER HERE IN K.C. ILL BE CHANGING THE FUEL PUMP HERE TODAY IF I CAN GET MOTIVATED AND ILL LET YOU KNOW THE RESULTS.

[Q45tech]

For some reason people don't want to believe that 14 year old V8 lux cars need $3,000 [at least] in rehabilitation when you purchase them used.The paint and body and interior creates some dazzling hypnotic spells.

After 18 years of dealing with my Q and hundreds of others the defects and wear items are very very very well known...............in fact after 2000 nothing new has occurred even on 1996 models that cannot be traced back to similiar faults on 90-93 or 94-96.

After all we had MTBE and water in gasoline in early 90's:"Beginning on November 1, 1992, 39 areas of the county were required to participate in the oxygenated gasoline program".

Nissan reported [to CARB and US] shortly thereafter as soon as problems began occuring from oxygenates. They tried to redesign injectors for 1994 models to tolerate MTBE oxygenates but no consideration for ETHANOL was given since it was never planned to be used during the 10 year legal life nor 7 year warranty from.

Then things changed with oil prices and weird fuels were allowed to be sold and WORSE PROMOTED to public.

You must understand that neither manufacturers nor the various governments want old cars on the road ---- they sell new cars and the government get tax revenue and JOBS from new cars.

[Evanarc]

I would spend 3000$ to make this car right..add it up what ivce spent already im probably almost there.They just dont make theQ45 the way they use 2.

[Haitian_King]

I would spend 3000$ to make this car right..add it up what ivce spent already im probably almost there.They just dont make theQ45 the way they use 2.

Isn't that the truth? Matter of fact, they don't even make them anymore. A damn shame really. Who'd-a-thunk it?

[Evanarc]

so drumman,when you first started up your Q it would shake like crazy and seem like it was gonna die or somethin but then it would rev up it would be fine until the bucking at acceleration? AND you smelled gas in the cabin?

[sdkhalsa]

A couple of simple things that you can do to get the ball rolling:

1. Connect a fuel pressure gage with a t-fitting to get a reading. This will give you a quick readout on the pump circuit.2. Connect a vacuum gage with a t-fitting. This will give you a quick check for gross vacuum leaks. 3. Clean the IAC, making sure that it does not stick. Put in a new IAC gasket while you are at it. This is standard maintenance, so the effort will be well worth it even if not the direct problem.4. Take resistance readings on the injectors at the harness(described in earlier postings). There is a good chance that if you are having to replace the injectors, the o-rings are due also.5. Snoop around the fuel lines to see whether the fuel is leaking around the fuel pressure regulator and dampener. You have the question of whether the leak is internal(probably a bad o-ring) or external(leaking fuel lines). It is possible that the fuel odor is an independent problem that is not causing the performance problem.6. Take a resistance reading on the knock sensors at the harness(described in earlier postings).

Very often you have a few problems going on at once, although your attention needs to be on the primary ones.

[Evanarc]

aight im gona try all this. ill post what happens soon as i can

[Haitian_King]

aight im gona try all this. ill post what happens soon as i can

Good luck!

[goody90q45]

aight im gona try all this. ill post what happens soon as i can

Good luck Evan. You're going to find that what you're taking on will take but a few hours, cost only a few $$, and as you look back on it you'll see that it was very easy.

5. Snoop around the fuel lines to see whether the fuel is leaking around the fuel pressure regulator and dampener.

From the passenger side look really close with a flashlight at the under plenum fuel hoses towards the rear. Look for obvious leaks (drips) but also look for wetness near the hose ends since the drips may be few and far between. The cold weather brings out the fuel leaks and most of the time it just takes a tightening of a clamp or 2 to put an end to it. All the clamps are accessible you just have to be creative in the tools you use and the angle you approach it from.