Low Compression Issue

[Phil Gti 11]

Hmmm I though that it might be at fault to begin with, but seemed unlikely because the first time it started I was able to rev the car cleanly all the way to the redline. Once the engine warms up it stalls sooner. What do you think? I haven't got a spare AFM to test with,and I don't want to buy parts unless I am sure it is the cause not the symptom.

[oldkiteman 6]

Have you checked mixture with an exhaust gas analyser?

Does adjusting screw in AFM not make any difference?

[Phil Gti 11]

All the settings for air, fuel and ignition have not been altered since the engine ran before removing it from the donor car. Everything is new/clean so apart from a minor adjustment I didn't expect these issues. I may have to pay for a mobile engine tuner to visit and diagnose and tune if I can't be sure which part/s I need.

[Phil Gti 11]

Now the engine will not start at all! I have double checked all connections. Can anyone tell me what the resistance should be the S.A.D when testing with a multi metre?

 

Also does anyone have a good condition working one for sale?

[DamirGTI 342]

As said , don't bother yourself with the SAD .. 100% sure it's not the couse of your problems .

 

If it's now a non starting at all , check the timing belt first if it's fine ie. not jumped off a tooth or snapped , do the visual inspection first and if it seems fine remove all the spark plugs and turn the engine by hand few revolutions in order to verify that it spins freely without locking/binding .

 

Then , if thats all fine , buy an can of 'easy start' spray .. spray some in the inlet tract and try starting the engine - if it starts and runs for a second or so means it has spark and the problem is in fueling , other way around , if it doesn't start means the problem is in the ignition system .

 

D

[Phil Gti 11]

Cheers for the suggestions. I have done all the checks you mention. It turns over by hand or by the starter motor easily. Compression is good. Spark is good. I have had the injectors spraying whilst removed from the engine but still attached to the rail. So fuel isn't an issue. I can't see how easy start will make any difference.

Edited May 25, 2015 by Phil Gti

[DamirGTI 342]

The spark may be too weak to ignite the mixture (even if it looks 'fine' by visual testing) or firing at wrong time/place , same goes to the fueling - excessively lean or rich mixtures are really hard to ignite , especially on a first start ie. stone cold engine .

 

Take the 'easy start' as an say , diagnostic aid ... just a few weeks ago i had an two days chase on my mates 1.3 rallye which developed non starting issue , no matter what i tried checked did and replaced with known good spares - it simply didn't want to start ! no even a cough .

Carbs where freshly fully reconditioned and adjusted , all the ignition parts where brand new (plugs , leads , dizzy cap etc. etc.) and it had what appeared enough fuel delivery and what seemed to me good spark (and felt also 'good' , electrifying myself holding the hands to close to the plugs !) and there was not so much reasons to me to blame the plugs cos they produced spark and where brand new and correct type/brand for the engine - not !! .. by spraying the 'easy start' spray in the carbs i was really surprised that it didn't want to start at all , not for a second , not even a cough ... mentally exhausted of WTF decided to try with the old plugs as we had them still in the garage in the rubbish can and , surprise it started on a first turn of a key with old plugs !

 

So , it doesn't cost much for a can of spray , i like using it as an diagnostic aid on reluctant starting engines . You will not make it start and run (if there's a problem) , but you'll have pretty good clue whats wrong ignition/fueling wise so that you can focus on the suspect area and proceed with the fixing process .

 

D

Edited May 26, 2015 by DamirGTI

[Phil Gti 11]

After a lot of head banging I found out this weekend that I had a intermittent and weak ignition coil. I bought a new one and fitted it. The S.A.D has also packed up. I plugged the S.A.D hoses and adjusted the idle and she she finally roared into life and sat there idling away. No leaks no problems.

 

Even though the bonnet was off, I couldn't resist a quick test drive. So I took it for a drive around the cul de sac and I have a grin from ear to ear now . I have had a few 205's but it has been so long since I drove mine, I started to forget why I love them so much.

 

There are a few little jobs left to be completed and it will be ready for an M.O.T. With any luck maybe this weekend. Then I need to find someone in Kent to paint it in the next few weeks. Recommendations welcome. Also I need a S.A.D unit, but can't source one new. Can you help?

Edited June 1, 2015 by Phil Gti