Question about ASCD Cable

[KPotter]

I am having problems with my car accelerating... I replaced the fuel filter and recently put in new NGK Iridium spark plugs. Car runs fine under normal cruising speeds but if I get on the gas, It acts as if its being held back... One person told me that he noticed that the ASCD cable, next to the Accelerator called isn't moving when I rev the engine up, and it should... This cable in connected to a round looking device with what looks like a vacuum hose of some sort plugged into the back of it, and It has an electrical plug at the bottom of the device... When we tried to move the ASCD cable, The cable would not move, as if the device it is attached to is locked up... Can someone let me know what this part is called and what it does.... Oh, Its on a 1994 Infiniti Q45 base..

If you were in front of the car with the hood open, the part would be located in the far right/rear side... (Drivers side, Right below the Windshield).

Thanks

[maxnix]

Why not use the NGK PFRG plugs that were designed for the VH engine?

[KPotter]

Well people were telling me that these were better and so I used them instead... They are actually better... I'm not sure if they will last as long or not, but I did see a performance and a very small but noticeable gas mileage increase... But Ill probably get the original ones next time... But does anyone know what the part is called and what it does, and how it works... I at least need to know what it is to see if it is doing what it is suppose to... Details on what part I am talking about is in the first post of this thread...

Thanks for the reply maxnix...

[goody90q45]

I think you're talking about the cruise control actuator. Could be a problem but you might also take a look at your fuel pump. What psi are you running after the fuel filter? Have you changed either the fuel pump or fuel pump control unit recently?

[KPotter]

Then that would explain a lot.... Its for the cruise control... Thats why the cable doesn't move when the accelerator cable does... So thats not the problem... ok... Thanks... But as far as the Fuel Pump goes, I don't no the pressure i'm running at, and I don't have to tools to test it, And I recently, along with a lot of people, got laid off at work for factory shutdown, I don't have the money to take it to the shop. But I can say this much, Sometimes my fuel pump makes a sizzling noise, and sometimes, it sounds like a 12lb bumblebee in my trunk... lol... It sounds really weird.. But everyone always told me that Either it works or it doesn't, It cant just not work right... Is this true... Id hate to replace it for no reason, They are a bit pricey... But let me know what you think I should do, I would about do anything right now...

Thanks a lot for your info goody94q45

Oh it has about 185,000 miles on it....

only things that have been replaced are:

Spark PlugsRegular Maintenance Items ((oil, air/oil filter) and now the fuel filter) ect...Mass Airflow SensorNothing major

Car doesn't burn oilDoesn't smoke at all...runs great except on acceleration

[goody90q45]

But as far as the Fuel Pump goes, I don't know the pressure i'm running at, and I don't have the tools to test it. But I can say this much, Sometimes my fuel pump makes a sizzling noise, and sometimes, it sounds like a 12lb bumblebee in my trunk... lol... It sounds really weird.....

Buzzing bees?.......It's the fuel pump. The fuel pump control unit (FPCU) should also be replaced at the same time. New they would cost you well over $1000 but you should be able to pick up the pair in the Infiniti Parts forum (Drew, PopPop, others) for a little more than $120.

There's a couple of current threads with the same topic in the Infiniti Online Mechanic forum. The summer heat must bring out the worst in the Q's fuel pumps. Do some reading there and you'll see that this is an easy DIY once you have the parts in hand. Q45.org should also have step-by-step instructions for this. Good luck.

[KPotter]

Ok thanks, I cant afford to get them both right away... Which one should I replace first, FPCU or the Pump?

[96Qowner]

Which one should I replace first, FPCU or the Pump?

The pump first. It'll fry the FPCU if you don't. It's a 3-speed pump - it sounds like it's not functioning at the highest speed. You might want to pull the FPCU and look for any burn marks inside. Again, look at the writeups at Q45.org:

http://www.q45.org/techhelp.html

[Q45tech]

It's a 3-speed pump

It's an almost infinitely variable speed pump depending on the battery/alternator voltage and the variable resistance of the FPCU and the condition of the pumps commutators and brushes.

WE tend to call it a three speed pump because the FPCU has 3 distinct voltage drops.

A brand new pump at a certain fuel density, temperature, voltage will have a higher speed than a old used pump under the same conditions.

As the pumps age they slow down and slow down further until they are so low you can hear the acoustic frequency of the pump.

[KPotter]

ok... thanks... But I have one last question... People keep telling me its the fuel pump... I hope it is, so I can replace it and the problem will be fixed...

My car somtimes runs fine... The colder the temp outside is, the better it runs all together... The warmer, the worse it runs... But like today.... It ran fine and had lots of power... Untill the engin got to the normal operating temperature the it ran very poorly... So is this still suspected to be the fuel pump??

Thanks alot guys for your help...

[96Qowner]

What psi are you running after the fuel filter?

Either the pressure will be low or not. If it is, your FPCU is probably misbehaving from trying to power the failing pump. If not, then you have multiple problems. Heat would be a factor in a weak FPCU.

So, two things (after reading Q45.org):

1. Pull the FPCU and examine it for fried circuits

2. Check fuel pressure along the rpm curve (or jumper the FPCU into high-speed mode and check pressure)

(both are no-cost)

[maxnix]

Test to verify.

[KPotter]

I will do that... When I can... But is there anything else that I can test while I am at it, in case the pump or control module are not bad, or not causing the problem? Since its intermittent, I seem to think there might be something else wrong... But I have been trying to figure it out for a while... I replaced the fuel filter and it seemed to help some... Today on way from work and when I took my girl to work, I ran pretty well, had power and decent take off.... But if it would just only do this all the time I would be satisfied... When I get fixed whats wrong with the car, I'm planning on moding it... body kit, rims, and whatever else I can find.... If anyone knows of a place online that I can get stuff for my car, let me know... Either there isn't much to get or I'm just not looking in the right places...

Thanks a lot guys, You are a lot of help