Slightly rough idle and a bit stuttery - Corrado STAG

[j33myb]

Hi all.

Got a couple of issues, probably related but would appreciate some guidance if possible.

- Corrado VR6
- STAG300 Plus


1)Car is running okay, but it's fairly rough on idle. Not missing cylinder rough, but just not very smooth. As soon as I switch to petrol, it smooths right out.

2) Car drives fine on LPG, but on very light throttle it seems to 'miss' occasionally and if you increase throttle slightly. No problems with medium/hard acceleration tho.

I have replaced air filter and plugs (Which were in good condition). I trie d to replace the LPG filter but accidently ordered the 16mm inlet rather than 12mm. I blew through the fitler and seemed clear, but will do anyway.
I've not managed to get the settings because I don't run a windows laptop so need access to that. although it is on autocalibrate.

ANy thoughts? The injectors are noisy, but they always have been (Valtek I think?, red tops?). Kit is 2 years old and 40k miles


As I say, car is perfectly drivable, jsut a bit rough and stuttery at low revs and I'd like to smooth it.
THanks all, J

[hardcorepit80]

If you don't have access to a laptop and settings just try to reset petrol ECU or run it on petrol for let say 50 miles to re-teach ECU.
When "adaptation" is on all time, it is recommended to run car on petrol once in a while just to correct any changes(outside temperature etc.)

[Dualtechuk]

Hi, if you cant connect then there is a limit to what you can check, but, if it was me I would have a look inside the injectors to check condition of orings etc. Remove red coil - by taking off 'c' clip - do not turn allen key - unscrew the post the coil sits on and check condition of piston, spring, oring and genrally give it a good clean. If the oring seems worn or mushy then consider a repair kit. Available from
http://www.tinleytech.co.uk/acatalog/Mu ... Emer_.html
If all seems well I would try and get connected then come back on here with what you find

[j33myb]

Thanks dual, will try that. I've never had them apart before - I take it refit is the opposite of removal?

Will have a look at it tonight and hopefully manage to gadge someone's laptop for a night!

[LPGTECH]

Hi look on this short video how to use repair kit on Valtek injectors

https://www.youtube.com/watch?v=A5Uuh07bTyI

[j33myb]

That's a cracking wee guide. I didn't get a chance to take on apart last night. Is it worth doing the injectors regardless? Will probably just order the kit if so as I assume it'll do no harm?

Thanks, J

[LPG Technology]

if anyone was wondering what is the Allen screw on the top of the injector? - to adjust the piston stroke using a special sensor...

[classicswede]

I aume this is a new problem and not something that has been there since day 1?

A issue with the injectors is quite possible, you might get away with just running some cleaning fluid through them if the problem is being caused by contaminants having built up in the injectors.

Idealy you do want to have a look at what is going on with it it ECU wise

[j33myb]

Hi classic,

It's only in the last month or so it's gotten rough. If you were very observant you could detect a very slight difference before, but you'd have to do a couple of switches between to actually work it out. Recently tho it's become rough and quite noticeable as idle. It runs no problem, never stalls or anything, always switches over etc.. and fuel consumption is the same as ever before, just idle and light throttle.

We're about to head off on our honeymoon on Sat so prob not get a chance now, so will post an update after Christmas when we're back.

Was toying with new injectors anyway, just to try them out as these ones have always been chattery- are there any that are much better than Valtek, or just stick and clean/replace if required?

[j33myb]

Still working on this. Managed to get a laptop and checked the settings. Map looks okay. I switched of one bank of cylinders and the engine smoothed out. I t hen tried to dismantle the bank to find the red coils seized solid and would not come off.

Rather than waste time, i`ve ordered a new bank. Fingers crossed. Will continue to update.

[j33myb]

I replaced one bank of injectors this morning and the problem is solved! Injectors are much quieter now too, so quite happy.

Still need to sort the problem of the Audi not switching to gas.

[LPGC]

Seems like you've sorted it.
Did you use the injector nozzles from the old injectors to make sure nozzle sizes are the same as before?

Simon

[j33myb]

I did Simon, thank you.