Just replaced the ISV....is ECU reset required?

[mmacneill123 0]

Hi guys

 

Just had to replace in rapid succession the Mass Flow sensor and the ISV so idle is a bit all over the place atm though I am no longer head-butting the steering wheel as it randomly opened and shut (slightly exaggerating but not much :-) or spluttering to a halt at traffic lights on roundabouts (no exaggeration at all :-) )

 

I assume an ECU reset is a good idea or do I just wait for things to settle down?

 

My reviews of resetting the ECU range from amazingly simple - disconnect the battery for 15mins, let it idle for 5-10, drive around a bit hard-throttling in 3rd and 4th to having to hook it up to VAGxxx change parameters and all sorts..., or even just disconnect the Mass Flow Sensor (forces a reset to the default MAP?)

 

Any advice?

 

Cheers!

[jekel 10]

Hi guys

 

Just had to replace in rapid succession the Mass Flow sensor and the ISV so idle is a bit all over the place atm though I am no longer head-butting the steering wheel as it randomly opened and shut (slightly exaggerating but not much :-) or spluttering to a halt at traffic lights on roundabouts (no exaggeration at all :-) )

 

I assume an ECU reset is a good idea or do I just wait for things to settle down?

 

My reviews of resetting the ECU range from amazingly simple - disconnect the battery for 15mins, let it idle for 5-10, drive around a bit hard-throttling in 3rd and 4th to having to hook it up to VAGxxx change parameters and all sorts..., or even just disconnect the Mass Flow Sensor (forces a reset to the default MAP?)

 

Any advice?

 

Cheers!

 

I've replaced all those and more at once and idle was bang on straight away. At worst disconnect battery, as you say, and idle should be perfect when reconnect. I've heard bout people resetting with VAGCOM but my mechanic reckons every 30 starts or so and it's effectively reset itself anyway, i've never vagcommed and never had issue.

If idle is all over place sounds like something else wrong to me, sure the isv and maf you put in is ok? I've got spares of all those things I know are bang on, plus spare ecu and most other things, I'm in South Shields, if ya get no joy, and want to call round and try known good isv maf etc. give me a shout, normally best way to diagnose for sure

[fla 9]

i think the ecu reset procedure is in the wiki. Its slightly different to just disconnecting the battery when you use VAGCOM, although i dont think its vital when you replace the isv.

[Jim Bowen 1]

I'm not too convinced with the ecu reset procedure, i just disconnect battery, leave it a while and then drive about for an 1hr

[seanl82 23]

I agree Jim, its a very complicated procedure every time you disconnect the battery, and considering the amount of DIY work guides that was included in the owners manual, this would have surely been mentioned if it was required. A good drive will see the ECU re-learn all values I've no doubt.

[GusPW 0]

Idle values should sort themselves out in a minute or so of idling.

Clearing the fault codes might help, maybe it's still in a protective map due to stored fault codes? If you don't have vagcom to do this then disconnecting the battery should do it.

I've never bothered with the whole complicated procedure, I think clearing the codes using vagcom(which seems to wipe learnt values as well anyway) and then drive about a bit seems to work fine as long as you have corrected the original problem.

[mmacneill123 0]

I've replaced all those and more at once and idle was bang on straight away. At worst disconnect battery, as you say, and idle should be perfect when reconnect. I've heard bout people resetting with VAGCOM but my mechanic reckons every 30 starts or so and it's effectively reset itself anyway, i've never vagcommed and never had issue.

If idle is all over place sounds like something else wrong to me, sure the isv and maf you put in is ok? I've got spares of all those things I know are bang on, plus spare ecu and most other things, I'm in South Shields, if ya get no joy, and want to call round and try known good isv maf etc. give me a shout, normally best way to diagnose for sure

 

Thanks everybody for the replies, I was too busy on Saturday with idle tribulations after changing plugs and leads (and unintentionally destroying a new lead for lack of sufficiently long nose pliers!). I went from fastest coolest thing on the road during the test-drive to spluttering at a roundabout as I watched arcing down a plug-hole

 

That is super-good Jekel, I have an inkling something is still amiss so may well - idle is fine on startup, rough after a few minutes until the engine warms....if you are driving you suddenly feel an increase in power and things have smoothed out. Had the distributor and cap changed too in the quest for smooth running (and because a bit fell off!) so am running short of ideas. Have you found a mechanic you can trust, I am having real trouble finding reliable and/or knowledgeable!!

 

Just invested in a VAG-COM reader but the adapter has not arrived yet, it will be interesting to see if anything is recorded.

[jekel 10]

Thanks everybody for the replies, I was too busy on Saturday with idle tribulations after changing plugs and leads (and unintentionally destroying a new lead for lack of sufficiently long nose pliers!). I went from fastest coolest thing on the road during the test-drive to spluttering at a roundabout as I watched arcing down a plug-hole

 

That is super-good Jekel, I have an inkling something is still amiss so may well - idle is fine on startup, rough after a few minutes until the engine warms....if you are driving you suddenly feel an increase in power and things have smoothed out. Had the distributor and cap changed too in the quest for smooth running (and because a bit fell off!) so am running short of ideas. Have you found a mechanic you can trust, I am having real trouble finding reliable and/or knowledgeable!!

 

Just invested in a VAG-COM reader but the adapter has not arrived yet, it will be interesting to see if anything is recorded.

 

Just messaged with my number mate, conact me andd pop it round on a weekend maybe and we'll have a look.

Never use anything but the proper VW tool for taken leads off, might have spotted ya problem, or one problem just there, correct leads and correct removal and replacement absolutely vital on VR6's, and never anything but top quality leads, I only ever use Dubsports 10mm race leads, got a spare set of 8.5mm red Bremi's in garage, standard VW's (which are Bremi's) and probs another set of 10mm's and few others kicking round garage. Got 2 removal tools too, one for the 10mm's and 1 for normal so can get them off and refitted properly, the cheapo ones often will not connect down properly, could be your problem. Don't pull anymore off with pliers, pop it round and we'll do it properly, I'd always use dialectric grease too which got here on VR6 leads.