Lacking Power

[Cadbury]

Hi all,
My 1999 ST 4500 auto seems to be sluggish at low revs. When I put my foot to the floor she drops down and goes but normally it seems a bit dead. I have only had it for about 3 months and its been like that all the time sinv\ce I have had it. Its done about 260k kms.
The tappets seem a bit noisy too will this affect power at all.
Cheers
Cadbury

[Bob]

Hopefully a fellow Queenslander YNOT will see your post and answer. He is the Guru
I had the same problem with my 4500 and cleaning the MAF sensor fixed the problem but I would wait for Tony to give you some tips.

[Cadbury]

Hi BOB
What and where is the MAF sensor
Cheers Canbury

[Bob]

Hi BOB
What and where is the MAF sensor
Cheers Canbury

TRY THIS LINK
http://www.nissanpatrol.com.au/forums/showthread.php?597

MAKE SURE THAT YOU DISCONNECT THE BATTERY FOR 4 HOURS OR SO AFTER CLEANING

[Bob]

By the way you have more than 25 Posts and are entitled to download the Manual. Refer to EC Section re MAF Sensor

[Cadbury]

Oh right, cheers for that

[Cadbury]

i have got the spray so I will give it a go on the weekend. Why do I need to disconnect the battery and for so long?
How am I going to listern to my country music while under my car?

[Bob]

i have got the spray so I will give it a go on the weekend. Why do I need to disconnect the battery and for so long?
How am I going to listern to my country music while under my car?

Disconnecting the Battery resets the Computer ECU A shorter time would probably be OK but I am conservative. Be carefull and do not touch the MAF Sensor. Whistle Dixy that should help. If you dont know what Dixy is you are too young

By the way I am not an expert in things mechanical but this worked for me so no harm in trying

I would also have it tunded up by a qualified Mechanic

Regards Bob

[Cadbury]

Right, I have cleaned the MAF sensor with the special spray, but no difference.
I changed the fuel filter and still no difference.
Does anyone know how much it costs to get your injectors cheacked and clean.
Cheers
Tim

[YNOT]

Hi all,
My 1999 ST 4500 auto seems to be sluggish at low revs. When I put my foot to the floor she drops down and goes but normally it seems a bit dead. I have only had it for about 3 months and its been like that all the time sinv\ce I have had it. Its done about 260k kms.
The tappets seem a bit noisy too will this affect power at all.
Cheers
Cadbury

Oooops, missed this thread 'till now.

There are a few things that may be causing lack of power. Assuming the engine has been looked after and has good compression etc, a partially blocked exhaust, exhaust gas oxygen sensor, ccolant temp sensor, ignition timing etc could all be contributing. Valve clearances (tappets) and injectors could also be contributing.
Where to start? If you have a timing light and feeler gauges you can check the timing and adjust valve clearences for $0. I have feeler gauges and don't mind buying a timing light (tax deductable in my trade) so could help you with these.
Oxygen and coolant temp. sensors I'm guessing around $150 and easy to install at home.
Injectors I'm not sure of price to overhaul (been out of the trade too long), but you can save some money by removing and refitting them yourself so you only have to pay for overhauling.
The exhaust, if you suspect it (and if it's the original exhaust at 260k then I would) replace it with a full extractor exhaust system (mandrel bent).

Tony

[Cadbury]

Tony,
Thanks for the feedback.
I have set the tappets last night purely cause the ticking was bugging the shit out of me.
I have a timing light so I will check that. I did how ever notice the rotor was a little pitted and burned. I cleaned thr contact, but will be replacing those soon.
As for the sensors I hope they are not the cause as I got a code 55 on the diagnostic test.
Will it help it I just remove my baffle from the eahaust as someone else as done in a previous thread as a full exhuast system is just a bit pricy for me at the moment.
Cheers
Tim

[YNOT]

I hope for your sake it's not a sensor fault either but I know other forum members have had big improvement after replacing those 2 sensors recently-not saying it will fix yours but it is possible.
A sensor can still be faulty even if it does not log a fault code. A coolant sensor for example might have an output range of 0(hot) - 240(cold) ohms resistance, as long as the output is within that range the computer will not register a fault. So the sensor may be telling the computer the engine is cold when it's actually at operating temp which can cause all sorts of issues but not log a code.
Your exhaust has a catalytic converter, main muffler and rear muffler. Any or all of them may be contributing. If you remove all of them it's going to get very noisy.

Tony