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[holddy982]

hi guys. i recently changed cam belt and a load of other bits while plenum off, but on restarting after job i find my tick-over to fast roughly 7oorpm-750rpm even when warmed up, i been told i can turn it down with a tech 2 machine, i have borrowed a machine called a MemoScan and it says on machine can-OBDII.. where do i plug it in ???? The plug on the end of the lead from machine has two rows of pins eight in each. any advice please i have never used one of these and i don't think theres any members near to me with a tech2 so its learn as I go.thanks for reading and hopefully helping. Cheers Guys.. Tony

[Andy B]

The diagnostic socket is in the fuse box under you steering column, but if all was OK before the job I suspect you've introduced a fault.  :-/

[Andy H]

Most likely an air leak either on a vacuum hose or due to a misplaced O-ring under the plenum.

I don't think tech2 can change the idle speed and am certain that a generic OBD tool won't be able to.

Even if it were possible you should fix the fault rather than change the idle speed to try to mask the fault.

[holddy982]

Yea I agree but i dont know what i could have done , i cleaned out all the breather and i cleaned all the black deposites on the thrrottle body , could i have one of the butterfles not seating correctly. would the machine show up a fault like mechanical or just show up elecronics

[holddy982]

if i was a fraction out setting the timing belt could that cause my problem

[Andy H]

if i was a fraction out setting the timing belt could that cause my problem

No

The ECU controls the idle speed by monitoring the crank position sensor and opening the throttle as far as necessary to idle at 450rpm (A/C off) or 550rpm (A/C on). If you are idling at 750rpm then either the ECU is still in cold start mode (perhaps because the coolant sensor was disconnected?) or more likely because more air is getting in to the engine than the ECU wants. (Either an air leak or a faulty throttle body).

The ECU fault codes cover electrical problems but mechanical problems can often be deduced from those codes.

If the throttle body has an electrical problem there may be a code for it but unless you tried forcing the butterflies open it is unlikely to have failed while you were working on the car.

[Marks DTM Calib]

Did you clean the throttle body?

If so, are the butterflies actualy fully closing?

I have seen SO many casr where mechancis have botched around a sticking idle valve by winding the throttle stop in

[Andy H]

Did you clean the throttle body?

If so, are the butterflies actualy fully closing?

I have seen SO many casr where mechancis have botched around a sticking idle valve by winding the throttle stop in

Going by the OPs profile he has a 2.6 with DBW (drive by wire) throttle.

I didn't see a throttle stop on mine when I cleaned the breathers (but I wasn't looking for one...)

[holddy982]

now i have had suggetions i did open the butterflies by hand to take them out to clean they were very blackened.I have no cable or throttle stop on this car it is a 2.6 auto all i have is the electrical connection and at the side there is some thing behind a black plate with something that i can only describe as ventilation appatures around it. 2moz i think i will get the hands mucky again and check out all your suggestions,check vac pipes,air intake to plenum and seals, Andy when said possible coolant sensor disconnected do you mean the temp gauge i think i saw it at the back of inlet manifold.the temp gauge reads just as it did before, i think we may be on to something there as it runs at the same engine speed hot and cold, or have i damaged something when taking out the butterflies to clean,.

[Andy B]

..... Andy when said possible coolant sensor disconnected do you mean the temp gauge i think i saw it at the back of inlet manifold.the temp gauge reads just as it did before, i think we may be on to something there as it runs at the same engine speed hot and cold, or have i damaged something when taking out the butterflies to clean,.

There are two temp sensors, one is for the gauge - single wire, and one to talk to the ECU, this is the one that determines if your car needs 'choke' on a cold morning, this has a blue/grey 2 pin connector.

[TheBoy]

Do not be tempted to turn the idle down electronically, look for the fault

If you have a good code reader, look at live data, in particularly, initially, desired idle and actual idle

[holddy982]

hi guys thanks for your input and i will take your advice. where would i find this blue/grey connector, after checking this i will chase down any air leak.    just been out to car the servo pipe to plenum is fastened up tight on the union     but   the actual hose itself can be twisted round a bit,,, if it leaked from here i would have different symptoms like hunting and hard brakes, yes/no   Right then weather permitting I'll set out my stall tomorrow morning and get this sorted if someone can tell me where the blue/grey connector is i will kill or cure the beasty.  cheers lads   I let you know when found culprit thanks.

[Andy B]

hi guys thanks for your input and i will take your advice. where would i find this blue/grey connector, after checking this i will chase down any air leak.    just been out to car the servo pipe to plenum is fastened up tight on the union     but   the actual hose itself can be twisted round a bit,,, if it leaked from here i would have different symptoms like hunting and hard brakes, yes/no   Right then weather permitting I'll set out my stall tomorrow morning and get this sorted if someone can tell me where the blue/grey connector is i will kill or cure the beasty.  cheers lads   I let you know when found culprit thanks.

Right at the back of the block, in the middle of the V  pretty sure they're both on the coolant bridge