Injection Issues - Is This Correct?

[axnutty 10]

Ive a few niggles with the injection on my new 1.9 Gti:

 

The ISS is wound all the way in for starters which is a bit worrying. The emissions test recorded a very low 0.67% CO, and the car hunts for idle (but does idle - ie not stall). Hot starting is a real issue, whilst cold starting its on the button, but wont idle at all.

 

Now Im new to injection systems, spending most of my time playing about with carbs of one sort or another. So I took it this was a good time to start learning! I have drawn out a very simplicated (and crude) injection system for the 205 as below:

 

Dont laugh!

 

Maybe someone would put me right if Ive got this wrong?!

 

Now the lack of cold idle is the SAD playing up Id have thought - so I shall ignore that at the moment.

 

The low CO reading I would take as incorrect adjustment of the AFM....

 

...except the ISS being wound all the way in leads me to wonder if theres an air leak somewhere?! Could this be feasible?(If I turn the screw at all, the engine revs rise drastically) I also noticed today that if I remove the vacuum advance pipe off at tick over there is no vacuum. Is this a commen problem? Ive yet to strip the throttle body to see whats going on inside. (Although it has been cleaned inside - just not be me - so maybe something is blocking it?) Also I noticed that the throttle spindle isnt sitting on the throttle stop. If I turn it back by hand I can just make it close, engine revs drop to a decent level too...but this could also be sealing up an air leak with me pushing on it perhaps - like a worn spindle bearing??

 

As for the hot start issue I hope this lies in the ignition set up. All the general service parts are new so I dont really see what else it could be. The dizzy is only set up statically at the moment.

 

 

Have I got the right idea here or is there anything else I should be looking out for?

 

Basically tomorrow I shall remove the Throttle body, clean it again, and see if I can see a reason for no vacuum. Clean all surfaces, check for spindle play to see if the bearings are worn, and rebuild. I shall also see if Ive enough spare piping to replace any breather hoses that look suspect. After all that and if that works - I shall go for adjusting the ISS to gain a good tickover at operating temp and getting a dynamic ignition set up. Is this the right way about things. Are throttle bodies prone to wear on the 205?

[Richie-Van-GTi 71 2 Cars]

check the bolt is on the oil filler in side of plenum, vaccum advance pipe is on TB and dizzy, pipe from bottom of plenum to SAD is secure and in good order as thgese are all common areas for leaks on intake. Other than that check the inlet gasket and throttlebody seal arent 'hissing' and pipework to AFM from TB is in good order.

If it turns out your TB is duff Ive got one for sale in for sale forum.

[axnutty 10]

Right I removed all of the air inlet tract and inspected it all. The air intake hoses are all ok. The oil breather pipes did look a bit suspect so I replaced those.

 

I removed the throttle body completley and it was all spotless inside. I blew the airline & sprayed carb cleaner down the ISS holes and the vacuum hole. No crap came out though - so I presume all was ok.

 

I checked for play in the throttle spindle but bar some end float - which I presume is normal - it seemed ok.

 

I was worried about the gap surrounding the butterly when open though - see pic below:

 

Throttle body

 

IS THIS NORMAL?!

 

I undid the butterfly screws and played about a little bit to see if I could make it a bit better. In the end I think I suceeded a little bit, but theres still a gap. I understand that at throttle closed some air is required for tick over but I presumed this would come soley from the ISS.....I guess I maybe wrong about that!?

 

I rebuilt everything using O ring sealant on all the, erm... O rings, and silcon blue on any bolts going into the inlet mani.

 

There are no leaks from any joints. Well no hissing anyways, so presumably not.

 

Current situation:

 

There is now a vacuum for the vac advance on anything BUT tickover. Which I guess is correct and backs up that the butterfly is fully closed. However if I run the car with the vac pipe off at the throttle body and suck down it myself it makes no difference what so ever to the engine revs. Which I would have thought it would have done. IS THAT CORRECT?

 

The car idles near perfectly. I understand some very minor fluctuation is normal for these systems.

 

Hot starting seems to have improved.

 

Still some cold start issues with the SAD but then I expect that as I havent touched it yet.

 

So i seem to have solved alot of the issues! Im guessing a leaky hose somewhere was the culprit as thought.

 

 

The ISS is now undone 1 or maybe 3/4 of a turn...which is an improvement of having it wound all the way in! I would have thought it should be more. IS THIS CORRECT?

[Richie-Van-GTi 71 2 Cars]

definatley the right way to go about it but the butterfly should close properly, I suspect this is the cause of your issues.

[Guest srack]

i do not see anything bad on 0.67% co. its little bit high (well, around here, to pass MOT you need min of 0.50%).

if you ask me

your problems are at the AFM.

reset him up with someone that can fix those stuff, using euro4 reading machine, to make sure the co is right.

 

sad sensor isnt your problems for hot start, if you mentiod that you've got problems on hot start, i would look at the afm, injectors, and vacuum issues.

[mattmk1 0]

Check that when your throttle/butterfly closes, you should hear a click from the throttle position sensor(tps). If theres no click youll have to adjust the TPS until you can hear it.

Edited December 20, 2006 by mattmk1

[axnutty 10]

@mattmk1

 

Ive checked the TPS and its set up spot on. So its not that.

 

Ive heard that by adjusting it so it never quite clicks at throttle close you get a better response at low revs and round town driving. Ive not done this yet as I dont want to deviate from factory settings at present till its working right. But anyone else confirm this?

 

@Richie-Van-GTi

 

Youve pm

 

 

 

 

 

 

 

 

So can anyone else confirm that the throttle butterfly should totally seal at throttle closed. From the pic below is mine wrong???

 

 

Piccy - throttle is being held fully closed here btw!

Edited December 20, 2006 by axnutty

[pug_ham 244 3 Cars]

Cold start sounds quite normal, usually you need to feather the throttle for up to 30 seconds to get anything resembling an idle straight from a cold start. Does it have a slightly higher idle after a few minutes running that drops down again once starting to warm up?

 

Hot starting can vary everytime & can depend how hot the car was when it was switched off (fuel evaporation) but also when warm the initial fuel pump buzz doesn't happen so it takes a crank or two more to start.

Ive heard that by adjusting it so it never quite clicks at throttle close you get a better response at low revs and round town driving.

No it won't. It just means the throttle switch isn't closed when the butterfly is so its not switching the fuel shut off that usually happens to cause the jerkiness on light throttle in traffic which can make you look like a novice. You soon learn to cover the clutch in slow traffic & develop lightening left foot reactions to save face. Although once set up properly you shouldn't really suffer from it anyway.

So can anyone else confirm that the throttle butterfly should totally seal at throttle closed.

I've just looked at the one throttle body I could find in a quick search downstairs & there is a small gap around the butterfly plate on that one. They won't be an exact closed fit, they aren't machined for each other that closely.

 

If I get chance tomorrow I'll have a look for another (or take one off an inlet) & check that but I'm pretty certain non of mine have been so good closed that there isn't any light around the sides like yours.

 

The only thing I think is wrong with this picture is the airflow through the SAD. I think its draws from the inlet manifold back into the pipe before the throttle body. I think this because of an experiment we did in science at school to create a vacuum. (The vacuum advance works in the same way).

 

When you sucked down the vac advance pipe did you get any resistance at all & which end was connected where when you tried this? If you were sucking against the distributor end then the vac advance capsule is dead. If you did there isn't exactly much movement anyway & I don't think it will make a noticable difference at idle. It works when you open the throttle butterfly & create the vacuum moving the distributor inards.

 

Graham.

[axnutty 10]

I've just looked at the one throttle body I could find in a quick search downstairs...

 

Wow thanks for that Graham! Thats dedication to the cause! Feel slightly guilty for making you have to go get up

 

When you sucked down the vac advance pipe did you get any resistance at all & which end was connected where when you tried this? If you were sucking against the distributor end then the vac advance capsule is dead. If you did there isn't exactly much movement anyway & I don't think it will make a noticable difference at idle. It works when you open the throttle butterfly & create the vacuum moving the distributor inards

 

The connected end was the vac capsule end...there was definite resistance, but just no change in revs - which I presume there would be. But as you say the car was only sat at idle - so maybe all is well after all. The actual vac advance unit on the alternator seems very insecure and wobbly though...rather suspect.

 

Cold start sounds quite normal, usually you need to feather the throttle for up to 30 seconds to get anything resembling an idle straight from a cold start. Does it have a slightly higher idle after a few minutes running that drops down again once starting to warm up?

 

Basically yes and yes. First minute youve got to hold it on the throttle but after that it will sit by itself at 1500rpm for 5mins then drop down. Which would indicate a working SAD. But I presumed that a minute delay wasnt exactly normal? Did Peugeot owners have to cope with this when the car was new? IE - Am I expecting too much here?

 

As for the pic then its more like this

[Rob_the_Sparky 9]

Piccy was correct first time. The SAD lets some air bypass the throttle when cold to keep revs up (although the control is crude to say the least, to the point that "control" is over stating it!).

 

Only thing wrong is that there is no sensor on the SAD. It is fed 12V from startup to a small heater. This warms a bi-metallic strip that closes the SAD.

 

TB I think is OK.

 

You can't produce much vacuum (< 1psi) by sucking so I'm not surprised nothing happened when sucking on the vac advance. It is a good way of detecting a leak though (i.e. a dead vac advance unit).

 

On cold starts: not sure what they were like from new but almost every car I have had needs between 10 and 30 seconds of throttle on start-up. Even on a completely rebuilt engine... Only in warm weather can you sometimes get away without it. Not sure of the cause, used to think oil pressure but not true...

 

Rob

[pug_ham 244 3 Cars]

TBH I never had any cold start issues on my 88 white GTi, it always started first turn of the key & idled staright away with no need for feathering of the throttle.

 

I did have to do a little feathering on my black one before I fitted the MP3.1 but I think my ex's was just like my 88 one before the head gasket went & she ignored it thus needed a replacement engine.

 

Now it needs a little help from cold & the SAD dos very little to effect it then.

 

Graham.

[axnutty 10]

Thanks for the help guys. Ive been playing about with it all yesterday and got it so its not half bad.

 

When warm:

 

Idles spot on 1000K with next to no fluctuating. <-

 

When cold:

 

Needs a lot of feathering and generally persuasion for the first minute at least. Then its touchy about idling, stalls at junctions etc, and if i rev it and let go, it drops to 600rpm and then if im lucky catches itself climbs to 1200rpm and then keeps cycling like this.

 

<- But Im thinking a new SAD will rectify this - given everything else throughout the rev range is working nicely. Although I think I may fit a new engine temp sensor as well to be on the safe side.

 

 

 

 

Given the common consensus on the TB butterfly I presume that this OK like you say. The ISS is now set 3/4~1 turn out.... DOES THIS SOUND ABOUT RIGHT? I dont why but I just presumed that it would be more than that.

 

Big thanks to everyone as well for your contributions. I dont mind getting my hands dirty and having a go, but Im on a very steep learning curve so its nice to hear some expert opnions/reassurance.

[futura 3]

I am not sure what ISS stands for but I presume it is the Air/Fuel mixture screw?

If so I think the setting is screw it all the way down and then unscrew it between 3 and 4 turns, not 3 quarters

[axnutty 10]

ISS = Idle Speed Screw. Ie. the screw in the throttle body that bleeds air past the closed throttle butterfly and hence the, erm... idle speed

 

 

4 turns seems to come to my mind too. Although I just checked the Haynes manual and it says turn the throttle stop screw 4 turns after it hits the throttle cam. So I thought that maybe where my confusion is coming from?!

[futura 3]

Oh ok, the screw I am talking about is the mixture one on the AFM

[axnutty 10]

Ah rite. Thats already set up fairly well but its going on the emissions tester very soon for some fine tuning. So am fairly happy with the mixture settings as they are at the moment.

 

 

I was just a bit worried about the lack of adjustment out ISS - just seems to indicate that something is possibly wrong. Like an airleak. The old style (Good) Haynes manual says to connect an airline adapter to pressurise the injection inlet tract and then paint soapy water over all the joints to check for leaks!

 

As already stated I have rebuilt it all with sealant and made sure its all a good fit. So far im fairly happy but this screw just seems to cast a shadow of doubt.

 

I suppose its all fairly clean in there and it doesnt need a lot of air to get through. Im probably just being over cautious and should just get out there and enjoy the dam thing!