Club 80-90 Forums

Hi all,
Been quite a time since my first post but i have been working away on the Syncro Doka which has,quite literally,taken over my life!
All the body work and mechanicals have been stripped ,repaired,reassembled and refitted but I have come up against a problem which has got me stumped.On the gas analyser the C02 level is way above the minimum for a test pass and the tickover will not go below 1200rpm (not sure what the tickover speed is but it cannot be that high).I have taken every sensor connector off and cleaned it prior to refitting,spark plugs and leads have all been replaced,the throttle body and air valves have all been cleaned and are hopefully,working correctly.The only thing I have not been able to check is the mass air flow sensor on the air filter body.
The engine starts first time,runs well,does not emit oil smoke and is not overheating.I took her out today for the first time (with trade plates on!)and she goes like stink!
If any one out there has come across this before or can come up with a fix,they are welcome to a free ride on the first off-road session !
Many Thanks,
Dave

check the timing and possibly a compression test.

Also check it's running on all 4 at idle by carefully removing a plug lead one at a time to see if it makes any difference to idle

throttle switch adjusted correctly on the throttle body?
Followed the adjustment procedure for setting the idle and co??

air leak....

Hi Idle is usually attributed to a faulty ecu engine temp sensor, which is the one on the thermostat housing with a plug and two wires. Disconnect when the engine is warm and bridge the two pins. This will simulate a hot engine for the ecu. If the idle drops down then replace the temp sensor. (tenner I think from GSF or brickwerks) 26 quid from VW.

Another cause of high idle is worn throttle body. The shaft gets worn, and the butterfly wont properly close, so the screw in idle adjustment will not work, or will only take it down to a level.

Check your idle control is working, it should buzz when ignition on but engine not started.

If she goes like stink then the afm is prob alright. Easy to check though

here. http://www.youtube.com/user/syncrosimon ... Tn8dyzn9a4" onclick="window.open(this.href);return false;

Good luck.

Simon

leaking vacuum pipe for brake servo ? the braided hose becomes porous, a spray of brake cleaner will show up your air leaks

Very useful video Simon!

Many Thanks to everyone who replied,will apply your suggestions today and will come with update.

CO2?? for starters its not part of the mot test, only CO, HC and lambda are and it should be high. Anything from 13-15%...

Excellent video

Thanks for posting

Well thanks again for everyone who replied with help and comments.
Spotted my deliberate mistake Fullsunian,should have been CO levels,NOT CO2,anyway my engine was pumping out at least 5% CO which failed it straight away as the tester would not accept anything over 2.5%.Went over the whole thing again following all your advice and comments,plugs replaced,leads checked,all sender units replaced or inspected,took throttle body off to check,no excess wear in shaft or butterfly but after checking in the Haynes Joke Book noticed page on CO and tickover adjustment,found both the adjustment screws to be both screwed down tight and seized.Lot of WD40 and swearing finally got them both free and while on the gas analyser adjusted both.
Result---1.5% CO,tickover now 750 to 800 rpm and a brand new MOT certificate!!
Just got the load bed to complete (anyone out there got a decent load bed engine cover available, I have got beer tokens awaiting!!)
and the interior to finish and time to hit the road (and off-road).
Many thanks to you all.

Just be careful.
Adjustment not usually needed, you may have adjusted something to get the CO right, but all the other gasses may well be on the pi$$.
Setting mixture is a balancing act, it is a little short sighted just to set CO.
What you may have done is just remedied the effects rather than curing the problem.

Hi Simon,
Did think that at the time so looking for a tuning specialist with the correct equipment to set correct levels.