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1993 maxima poor acceleration
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tyrex
Novice
Jun 18, 2014, 12:11 PM
Post #1 of 8
(1550 views)
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1993 maxima poor acceleration
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I have a 1993 maxima,3.0L, DOHC 227,000 miles.
When I got the car 3 months ago it wasn`t running at all,I`ve replaced a lot of parts and it now runs but it just doesn`t want to accelerate at low speeds.
At speeds under 45 mph when I press the gas pedal it hesitates and bucks and most of the time it won`t do anything, the rpm`s will stay at idle (700) rpm`s.It acts like the gas pedal i`sn`t even attached to the throttle body.
The only way to accelerate at speeds under 45 mph is to press the gas pedal about 3/4 of the way down and then it reluctantly accelerates with lots of hesitation and bucking.
When the engine warms up the only way it will start is by holding the gas pedal all the way to the floor and crank it for about 15 seconds.It starts fine when it`s cold.
It idles at a steady 700 rpms with no fluctuations at all not even the tiniest bit, and it idles so quite you can`t tell the engine is even running,so I`m sure the Idle air control valve is working.
it gets good gas mileage so I don`t think it`s running rich,but I haven`t pulled the plugs to check them.
I`m thinking there must be a vacuum leak but I haven`t found any although when I stick my head under the hood by the firewall on the passenger side it sounds like there might be something leaking.It`s hard to say though because of the engine noise.There are only 2 vacuum hoses back there and neither one of them is leaking.
as I said the car wasn`t even running when I got it,
some of the parts that I had to replaced are:
fuel pump/and strainer
fuel filter
fuel pressure regulator
all 6 coil packs
valve cover gaskets
intake plenum gasket
MAF
coolant temp sensor
O2 sensor
spark plugs
TPS
I replaced the TPS last week but I`m not sure I have it adjusted right.With the throttle closed the sensor reads at 1.3 ohm.
The fuel pressure stays at a steady 35 psi with the engine running but drops to zero within 3-4 seconds after the engine is shut off.
I have a feeling that it`s something obvious that I`m overlooking but i can`t figure it out.
(This post was edited by tyrex on Jun 18, 2014, 12:28 PM)
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Discretesignals
Ultimate Carjunky
/ Moderator
Jun 18, 2014, 12:24 PM
Post #2 of 8
(1540 views)
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Re: 1993 maxima poor acceleration
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Any trouble codes stored in the ECU?
Vacuum leak won't cause the engine to buck and surge on acceleration.
Adjusting the TPS using ohms isn't accurate enough. You need to measure the voltage coming from the TPS at the signal wire and then adjust to the correct voltage.
Would be nice to see scan tool data stream information, but your not going to get that on this vehicle unless you have the factory scan tool or an enhanced scan tool.
Have you considered taking it to a shop that specializes in drive-ability problems on Asian vehicles? Might be cheaper than replacing a bunch of parts it doesn't need.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
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tyrex
Novice
Jun 18, 2014, 12:32 PM
Post #3 of 8
(1533 views)
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Re: 1993 maxima poor acceleration
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I only replaced the parts that it definitely needed.
nope, no codes the check engine light has never come on.The bulb isn`t burned out because it does light up when you turn the key.
When the car is in park the throttle works smooth and the engine revs up and down smoothly as the the throttle moves.
I don`t know if this relevant but the neutral safety switch makes a loud clicking noise and you can feel the vibration in the shift handle from it, also it won`t shift from reverse to neutral it will only shift from drive into neutral.
(This post was edited by tyrex on Jun 18, 2014, 12:40 PM)
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Discretesignals
Ultimate Carjunky
/ Moderator
Jun 18, 2014, 12:48 PM
Post #4 of 8
(1522 views)
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Re: 1993 maxima poor acceleration
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Bucking on acceleration or when the engine is under load is usually caused by ignition system problems.
Surging or lack of power on acceleration is usually fuel related. Anything that affects how much fuel is allowed into the engine is a suspect until testing proves otherwise. Lack of power on acceleration can also be cause from incorrect valve timing or excessive exhaust restriction problems.
The problem with your situation is there is no silver bullet approach. It takes many years for a technician to become proficient in diagnosing drive-ability issues. There are things that you can test yourself, but you need the right equipment and service information. You don't have any data gathered up for anyone to sit down and review to point you in the right direction. Just saying you replaced a bunch of parts because it needed it doesn't help figuring out the solution to your issue. Even telling us over and over it does this and that won't help because we understand your symptoms, but there are many things that can cause those symptoms. Each one would have to be eliminated to find the culprit.
We need more data which you can't get unless you have the equipment.
Just a few of the many tests that would be needed for gathering data to give you direction.
Fuel pressure during bucking
TPS voltage sweep test results
ECT voltage
MAF sensor voltage
Cam and crank sensor signals
Alternator ripple data
Power balance test results
Relative compression test results
Computer and sensor ground voltage drops
Computer and sensor power voltage drops
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
(This post was edited by Discretesignals on Jun 18, 2014, 12:52 PM)
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tyrex
Novice
Jun 19, 2014, 2:23 AM
Post #5 of 8
(1495 views)
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Re: 1993 maxima poor acceleration
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I have all that info around here somewhere, see,
when i first got the car i took it to one of those highly trained mechanics with their half a million dollar diagnostic machines and they told me the car would never run again,said it had MASSIVE internal engine damage,but for $3,800 they could replace the engine for me.
well, for a car that has been officially declared dead by a "highly" trained mechanic and his diagnostic machine, I think it`s running pretty good for less than $500 in parts so far.I got the car free.
You`re obviously lost without your diagnostic machine to do your thinking,so I`ll seek advice elsewhere.
Thanks for your time.
(This post was edited by tyrex on Jun 19, 2014, 2:25 AM)
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Hammer Time
Ultimate Carjunky
/ Moderator
Jun 19, 2014, 3:00 AM
Post #6 of 8
(1490 views)
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Re: 1993 maxima poor acceleration
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well, for a car that has been officially declared dead by a "highly" trained mechanic and his diagnostic machine, I think it`s running pretty good for less than $500 in parts so far.I got the car free.
You`re obviously lost without your diagnostic machine to do your thinking,so I`ll seek advice elsewhere.
Thanks for your time.
At speeds under 45 mph when I press the gas pedal it hesitates and bucks and most of the time it won`t do anything, the rpm`s will stay at idle (700) rpm`s.It acts like the gas pedal i`sn`t even attached to the throttle body.
The only way to accelerate at speeds under 45 mph is to press the gas pedal about 3/4 of the way down and then it reluctantly accelerates with lots of hesitation and bucking.
When the engine warms up the only way it will start is by holding the gas pedal all the way to the floor and crank it for about 15 seconds.It starts fine when it`s cold.
OH yeah, that was a well spent $500
PLEASE go elsewhere for you free advice.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
(This post was edited by Hammer Time on Jun 19, 2014, 3:02 AM)
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