Hi All,

I want to give me car a good clean. No... I'm not talking about the body work or interior, I mean the engine.

 

My car is 12 years old now and I would like to start cleaning the connectors and making small replacements as I am running idle at about 1,000 rpm and seem to be getting less than 200 miles per tank even on long motorway journeys. I know I should be at an idle of 750 ish, but I don't just want to turn my idle down as I think this will effect performance (correct me if I'm wrong).

 

Although after running an ECU diag, I got the all clear code (55). I only ran Mode II checks and will run Mode I a little later.

I want to start by cleaning the connectors for:

coolant temp sensor,

coil packs,

power transistor unit,

fuel injectors,

mass air-flow sensor,

coil packs,

power transistor unit,

crank angle sensor,

throttle position sensor

Basically all the connector sensors that report back to the ECU. I also want to clean my fuel injector connectors.

Do you think that this will make a lot of difference to my idle and performance or should I replace the EGR, PCV's and Fuel Pressure Regulator and Fuel Dampener as well ?

 

Any other tips or tricks that you know of could help me out ?

Hiya mate.

 

Its a bit of a thing for me -the wiring under the bonnet of my Z. Have done nearly everything on your little list there and was impressed with the results. The car feels alot crisper, idle's better and generally drives nicer. Go for it-you won't be disappointed.

The under bonnet temp does make all those little clips and switches very brittle, like everyone you try to take off, falls to bits, good luck.

 

James. :D

Alot of things do need cleaning or even changing after 12 years. Some one on TT.net posted what he did to perk up his car which involved cleaning the sensors and also replacing the vacume hoses and fuel lines.

 

After 12 years under a hot bonet, the hoses will start to leak even if its very slighty and you dont know it. Vacume hoses will allow air to seep through and fuel lines will create a petrol smell in the engine area which is petrol evaporating from the lines.

 

Stuart.

There's a thread on Scoobynet about replacing and adding a few earths on the block and the chassis on some of the older Imprezas. Apparently there have been some very good results found. Idle has been found to be smoother, starting is easier, cars run smoother (especially when cold). I believe the MLR forum has also had a few good results from this.

 

You might want to replace them too while you 've got your head stuck in the engine bay.

Thanks for this guys,

James,

When you say fall apart, do you mean that they become unuseable and I have to buy new connectors or should I prepare a crate of super glue ?.

 

Stuart,

I've checked the TT.net and think I found the article you were talking about. However it doesn't give me any diagrams to tell me which hoses he means. I guess once I get my head under there I'll find some. I do get the petrol smell from cold when I put the blowers on, it goes away once it's warm, I guess this is due to the heat expanding and sealing the pipes. I'll tighten all the clips and check for leaks.

 

Marty,

I'll check the earths and give them a good clean. Hopefully I won't have to replace any.

From my own experience they just crumbled to bits, replacement seemed the only way to go! Had a few blasts at this and then handed it over to the pro's as some bits were just sooo fiddley and I was getting the hump!

One point that always gets missed here when talking about cracked connectors. If the connector is cracked, it is useless, you will start to get bad contacts and also water ingress leading to corrosion. Unfortunately after 10 years of high heat the plastic becomes very brittle and most connectors will break as soon as you pull on them. If you can, replace them - it will make things a whole lot simpler in the long run. Another point is to make sure the contacts are actually tight on the pins. Over time the gap in the socket widens and eventually you start to get a bad connection.

 

As far as the EGR and PCVs are concerned, the PCVs should be done every 60k miles. You must also remember the hoses when ordering the valves as they will crack as soon as they are moved. With the EGR, it is a different story really. The problem is it is almost an engine out job to replace. You are looking at removing at least the upper plenum, although this may be a good idea - there are a load of water hoses under there that perish over time. They are listed on courtesy as turbo bypass hoses or something. BUT the problem with removing the upper plenum is you need to replace a load of gaskets. Where do you stop???

 

HTH

 

CheerZ,

 

Andy

Thanks Andy,

Now you put it like that it doesn't seem like a small task any more.

Ok, let me put it another way.

I have the following problems :

1) I get a petrol smell when I put the A/C on when the car is cold. The smell goes away when the car warms up.

2) My Idle when the car is cold 2,000 rpm. After 5 mins of driving this makes its way back to 1,000 rpm, but never drops below this.

3) I've recently had a 60k service, including cam belt, water pump thermostat etc.

4) ECU gives me 55, so I'm stuck ????

 

What would you recommend I clean / replace ?.

Or shall I just get the Phillips screw driver out and turn the idle down to 750 ?.

Right,

 

1) Petrol smell - remove the plastic engine cover on the top in the centre. You will see the fuel lines coming from the fuel filter - tighten EVERY clamp you can see/can't see (sounds daft but have a good look with a torch and you will find them ;)) This should cure the fuel smell. If the clamps are already as tight as they will go, replce either the clamp or both the clamp and the hose - about 3 foot of fuel pipe should do the lot I think - measure first though ;)

 

2) Clean your throttle bodies and AAC valve. Throttle bodies - remove the boost hoses and clean around the throttle flap - get it nice and clean using a toothbrush/paper towel and some carb cleaner. Be carefull not to let anything drop inside though ;) You have now sucessfully washed all the sh1t back down the plenum and clogged the AAC valve so you need to clean that too. It is on the back of the plenum on the passenger side - there should be a rubber hose (about 1" dia) running down the side of the plenum, bending round at 90 degrees then attaches to the AAC valve. Pull this off the valve and squirt in a good dose of carb cleaner. Thats that done. While you are doing all this remove the negative connection from the battery - leave in this state for AT LEAST 30 minutes so the ECU resets itself and relearns the cruise fueling.

 

Now WHO said we don't need an FAQ for things like this??? :D

 

HTH

 

CheerZ,

 

Andy

A FAQ would be good. I have the Petrol Smell problem. Thanks Andy, I'll be having a go at your cure...

the question is indeed were do u stop,my opinion is do the little things urself in ya spare time,but remember ur car is 12 years old it will cost a lot of money n time to make it go like new,so just love it n enjoy driving ur beast......

 

if its not broke, dont fix it !!!!!!

Top Dog, thanks Andy.

I had my thottle bodies cleaned at the 60k service apparently, but I guess now is a good time to see if the person I took the car too actually did what they said they did. I have no doubt that they did everything they said but I guess you never know. :confused: :confused: .

 

I'll do all this tomorrow, I'll let you know how I get on. Would it be safe to say that if that didn't the problem I should maybe adjust the idle manually or would you object to this ?.

 

 

Originally posted by avalaugh

if its not broke, dont fix it !!!!!!

Would have to disagree with you there mate, for example would you use that analogy for a cam belt :D ;) :p

Originally posted by smw1

Would have to disagree with you there mate, for example would you use that analogy for a cam belt :D ;) :p

 

yup, agree - prevention is better than cure! :p (and usually a whole lot cheaper to boot!!!)

You may well have to readjust the idle - sorry, forgot to mention that ;) To adjust it you need to disconnect the AAC valve so the ecu isn't 'fighting' your adjustments. Let the car get up to temperature, disconnect the AAC, and adjust the screw on the side. Can't remember what base idle should be on manual/auto - it is different, I'll check....

 

HTH

 

CheerZ,

 

Andy

Erm, thats weird, could have sworn the idles were different - apparently its only NA where there is a difference in base idle between auto and manual....

 

Anyway..... On a turbo car, the base idle should be 700rpm (according to the manual). If its an auto this must be measured in neutral. Oh and also make sure all electrics are off/air con is off etc...

 

HTH

 

CheerZ,

 

Andy

I thought the auto was 750 idle?

I remember reading somewhere that the idle should be 700 +/- 50. So I guess I'll idle at 700 unless the car starts hunting.

 

I think it's safe to say that anything between 650 and 750 is ok, as long as its a smooth idle.

 

Thanks for all the info Andy.

There is a difference - BASE idle and ECU controlled idle are DIFFERENT. The base idle is the revs without the ECU opening the AAC valve to control the idle. The ECU then opens and closes the AAC valve to attain a steady idle about 50rpm above base - this makes the idle smooth. I think I need explanation lessons LOL

 

HTH

 

CheerZ,

 

Andy

Ah I understand now. So after adjusting the idle and reconnecting the AAC valve. Do we need to reboot the ECU (i.e. disconnect negative for 30 mins) to be on the safe side ?

Yep - you should do that while you are cleaning the throttle bodies/aac valve ;)

 

Another small hint. When you remove the boost pipes, DO NOT leave them outside - take them inside and put them on a radiator - that way they will go on SOOOOO much easier ;) Also get the engine warm b4 you take them off for the same reason.

 

HTH

 

CheerZ,

 

Andy

Thanks Andy,

I really appreciate the help you have given me.

Have a great Christmas.

I owe you a few beers. :D :D

No worries m8 ;) Have I earned enough points to go and start another auto/manual debate now??? :D:D:D

 

CheerZ,

 

Andy

erm.. I suppose that depends on who you ask and what side you are routing for :D

I do sometimes use the online MANUAL :D:D:D

 

CheerZ,

 

Andy

Well I guess that's ok then. :D.

 

It's Christmas Eve and I'm at work. Sitting at my desk. Some times I wish I worked in MANUAL labour. Maybe I wouldn't get so bored. ;)

Stuart,

 

It's gotta be and early knock off today, though, surely ....

 

I'm off in 45 mins, but the office is quiet today - also bored!

 

I assume you're working in town, doesn't that spell gigantic p1ss up at lunch time for the rest of the afternoon?

 

Always did when I used to work in the smoke:D

 

CheerZ,

John.