Cold Start Issue 1.9gti 8v

[mannings 1]

First apologies for another post on a cold start issue with a 1.9 gti, but I am at the end of my tether. I have read and understood (to the best of my capability) a lot from the this and other forums but to no success. Desperate to get the 205 out on the road for the first time in 15 years and this start up issue is my final big issue. The story to date:

 

- Took out old 2.0l Turbo from a previous project and returned an 8v into its rightful place (also did full respray so she looks a treat in OEM spec)

- Engine seemed to start fine when first kicked when we had a screw driver jabbed through the AFM with some cold start up the nostrils to fire her into life

- Once all air filter, pipes and stuff fitted then the problems started with the cold start. She will run beautifully once warm at 950 rpm idle and pulls like a dream so that set up is good once running

- Before warms its the usual story, can keep it broadly alive with the throttle (although will still die uncontrollably at times whilst getting warm) but will just die in seconds without throttle open

- I have replaced and check the SAD is doing its job open when cold and closed when warm. Pinching SAD intake when warm does affect idle either, so I think SAD is not the issue. Also had a theory about the ECU at one point but that wasn't it either. And replaced all the temp sensors going into the ECU in case they were not reporting correct info

- I have tried to follow the factory resetting guidance to make sure all various screws and mixtures are correct, which I think they are, however when starting to me it smells rich but maybe that is just rich versus the smell of a modern car!! All my fiddling with screws generally just made the running worse not better. Got it back to its best position from my knowledge but still doesn't help the cold starting issue.

 

I really want to fix this myself after all these years and keen not to have to take it to someone to fix for me, but running out of ideas and knowledge. My gut feels that its something AFM related due to the fact that when we bypassed the function of the AFM in the first start it did idle if only for 10 seconds or so  (however worth noting that when I have tried to repeat the behaviour by holding open the additional air bypass in the AFM I haven't made it do it again, so maybe it wasn't the AFM)

One question that I am unsure about is if there is a difference between the 1.6 and 1.9 AFM? Maybe I have fitted a 1.6 AFM to a 1.9 block and it doesn't like it?

 

(Note: once lock down eases I am in the south Essex area, so if there are any 205-gurus in the area that can help I would be very appreciative of any and all guidance.

 

Got a multimeter and bags of enthusiasm to sort this out, so would welcome any suggestions. Cheers

[PhilNW 44]

Checked timing?

[mannings 1]

I have left the cap where it was from purchase of the engine, so no. Good shout. Would you suggest starting at the extremes and working across the range or from the centre of the dizzie cap location range and then working out? (if I am correct that this engine timing is done through the angular adjustment of the dizzie cap?)

[PhilNW 44]

Yes angular adjustment of the dizzy, try and find a position that just gets it running when cold and then refine it later if that is the problem 

[mannings 1]

Thanks Phil, am I right in thinking there is no timing mark to allow you to use a timing gun off the flywheel? so its a bit of guess work based on how it runs?

 

[PhilNW 44]

There is a plastic cap covering the timing marks tdc and 10 degrees at the top of gearbox akward to get at under the pipes and wiring

[welshpug 1,661]

they would have done from the factory though quite tricky to access, you can adjust it manually with just an 11mm spanner and a good hill, rotate the body of the dizzy with the car running till the revs start to rise then back off a touch, then drive up a gradient in a high gear, if it pinks then back off a touch, if it doesn't pink you can add a little more.

 

the fuel you use will affect how much you can use, modern fuels can affect it quite a bit over the old 4 star.

[mannings 1]

Thanks for the advice, will give it a go and report back. @welshpug, the hill part might be tricky as SORN at the moment due to cold start issue FYI

[DamirGTI 342]

Try adjusting the TB like so :

 

- turn the throttle stop screw out so that it's off the throttle leaver , then wound it back in until it barely touches the throttle leaver (can use feeler gauge to spot the contacting point) when it does wound it 4 full turns in and stop . Reset/re-adjust the TPS switch after you've done this .

 

- open up the big brass air bypass screw say 1 and a 1/2 a turn or 2 full turns (again from fully in out counting ..) .. this one you'll need to set afterwards more precisely once the engine is up and running heated up on the operating temp (with some load ON as well .. like lights ..) .

 

- check that the throttle cable isn't too loose nor too tight .

 

.. additionally :

 

- allen screw on the AFM , turn it fully in till it bottoms down then back out counting 7-to-8 turns and stop .

 

 

And try to start it up like so from cold .. see what happens .

 

 

Mix and match of 1.6 and 1.9 engine management parts wont do any good , wont make it non runner or undrivable , but it will make it notoriously fiddly to set up properly so that it runs smooth (as "smooth" as jetronic can be anyways) , mixture will be off as well (on a rich side with the 1.6 bits on a 1.9) .

 

On a 1.9 engine , you should have , last three dig. part No. :

1.9 ECU - 359

1.9 AFM - 109

1.9 Injectors - 702 (yellow)

1.9 Dizzy - 066

 

D

 

 

Edited February 28, 2021 by DamirGTI

[mannings 1]

OK so some updates and more questions:

 

@PhilNW I have it on good authority that the timing is bang on as was checked when we first got the car started (but I wasn't there that day), so unlikely to be timing as this was set up with a gun off the flywheel.

 

@DamirGTI I can confirm the following:

- 1.9 ECU - 359 - confirmed is a 359

- 1.9 Injectors - 702 (yellow) - Yellow Injectors and confirmed as the correct 702 version (previously confirmed by PN)

- 1.9 Dizzy - 066 - confirmed is a 066

- 1.9 AFM - 109 - This is not a 109 but a 0 280 202 097 - is this compatible with a Jetronic LU2 set up?

- Throttle cable is not loose or tight

- Tried to find the Throttle Stop Screw on the LU2 throttle body but to no luck, can't see anything anywhere that would set the throttle arm stop. Am I being thick? Looked in Haynes and online but can't find what looks like my throttle body with a screw for setting the throttle stop point.

- Set up the mixture and idle as suggested but made matters worse. Did get the car to get warm but then would not idle once warm. Played with idle screw from the 2 turns out position but didn't seem to help matters.

 

So now left wondering if I need to just get myself a 109 AFM and try again?

 

Thanks for your help and can send pics if useful

 

 

Edited March 1, 2021 by mannings

[welshpug 1,661]

throw up some pictures.

[DamirGTI 342]

AFM 0 280 202 097 is from a 1.9 DFZ engine .. low compression , 105Hp engine , not ideal as all the AFM's are adjusted differently .

 

Which 1.9 engine you have ? presumably 1.9 D6B , but can be DFZ as well or a few others ... hard to tell from the outside as they all look the same , including 1.6's .

 

If it's for real 1.9 D6B engine , yes it'll be best to source proper 109 AFM .. or adjust this the DFZ one so that it suits the D6B engine , that'll need to be done with an aid of exhaust gas analyzer or WB probe/gauge .

 

Anyhow , seems to me that the current problem isn't necessary to blame on the AFM ... sounds more like the engine starves for air during warm up period . 

 

Throttle stop screw is this small one at the back :

 

 

Adjust it as said above , it's the first adjustment from where you need to start "playing" with the idle , by turning it in you increase the throttle butterfly angular opening = more air can enter in the manifold , which results with higher idle speed .

 

D

Edited March 1, 2021 by DamirGTI

[welshpug 1,661]

also definitely get a 109 afm, 097 is for the 105 bhp 1.9.

[PhilNW 44]

3 hours ago, mannings said:

OK so some updates and more questions:

 

@PhilNW I have it on good authority that the timing is bang on as was checked when we first got the car started (but I wasn't there that day), so unlikely to be timing as this was set up with a gun off the flywheel.

I seem to remember that the Haynes manual says fix/sort the ignition timing before any messing about setting up the injection system. 

Glad you have eliminated that side of the system/problem.  

 

Edited March 1, 2021 by PhilNW

[mannings 1]

Ok thanks everyone. Bidding on a 109 off Ebay at the moment and will report back once I get more time to tinker this weekend. Thanks again  

[mannings 1]

So I have now fitted the new 109 afm and reset the throttle position and screws as described above thanks @DamirGTI. 

Engine seems to like the new afm better but problem not fixed. 

The engine starts easy and then revs high to around 2000rpm for about 15 seconds then drops down and dies. 

I tried to a number of variables between 1 and 2 turns on the idle screw and 7 to 8 turns on the mixture screw on the afm.

Didnt change the behaviour. 

Any ideas on what to check next as feels like it's closer than ever to getting sorted. 

[PhilNW 44]

Engine seemed to start fine when first kicked when we had a screw driver jabbed through the AFM with some cold start up the nostrils to fire her into life

- Once all air filter, pipes and stuff fitted then the problems started with the cold start. She will run beautifully once warm at 950 rpm idle and pulls like a dream so that set up is good once running

 

Am i understanding it correctly - It runs from cold OK with a AFM flap slightly open but the throttle flap closed?

 

Have you doubled checked the timing?

 

The engine starts easy and then revs high to around 2000rpm for about 15 seconds then drops down and dies

 

Is this without any use of the throttle pedal/flap?

 

I tried to a number of variables between 1 and 2 turns on the idle screw

 

Do you mean the bypass screw or the throttle stop?

 

Edited March 7, 2021 by PhilNW

[mannings 1]

To confirm:

 

- it did run once with the when first fired up and didnt seem to die with a screw driver in the afm. But i can't now get it to do that anyway, so maybe a red herring. I can only get it to run from cold with feathering the throttle 

 

- confirmed that timing was correctly set and when warm it drives and revs very well so think it's not timing. 

 

- no throttle applied today when it was revving to 2000rpm and then dying 

 

- bypass screw yes, not throttle stop 

[PhilNW 44]

As Damir said above, sounds like air starvation at cold idle

 

Try screwing the throttle stop screw in by 1/2 turn at a time (to let more air through the butterfly flap) to see what happens (just to get it to run  - if it will)

 

If it works you will have to follow the procedures Damir stated above 

[mannings 1]

Ok thanks. Will give it a go and see how I get on. Cheers 

[mannings 1]

Afternoon pug heads, another frustrating day on the GTI (made worse by also seeing a very tidy grey F reg 1.9 same as mine stretching its legs around the southend area...salt in the wound!!)

 

With the new AFM I have been able to get it to run from cold but at the expense of the idle. I let it warm up fully just now to see if I can get it to a normal idle once warm, but nothing I did with the idle bypass screw, throttle position screw or mixture screw did much to change it. Also now when I blip the throttle it almost always dies completely. Will run at 2000 to 2500rpm happily with no issues but any throttle kills it.

 

I also tried to pinch the SAD pipe when it was still cold expecting it to make it stall or at least labour. It did nothing of the sort. Held revs at 2000rpm so clearly getting its air from where else then I guess. Maybe this is part of my problem? could I have air getting in somewhere else that is messing up the measurements from the AFM? Maybe a poor gasket seal or something else split or cracked?

 

Really confused now as expected the revs to drop as the engine warmed up and SAD closed, but again didn't do this, just merrily revved away at 2500 rpm.

 

Tried every combination of throttle position (always resetting the TPS), bypass screw and mixture screw.

 

Any news ideas would be really welcome as running out of new angles of attack.

 

 

[welshpug 1,661]

if the idle air bypass screw does nothing and its idling at 2000 rpm there has to be quite a significant air leak.

[mannings 1]

Ok thanks that was where my head was going. Will investigate and report back.. cheers 

[mannings 1]

Just wanted to check something. Looking at pics on line it looks to me like the breather pipe to the oil cap and the feed to the sad comes off the air intake after the afm. My induction kit has those two pipes going straight from the air filter to them bypassing the afm sensor. Could this be throwing off the set up? Seems odd that the ram air induction kit would be designed with suck an issue if this is not right, but did seem odd that it was basically the wrong side of the afm. 

 

Could this be causing me issues? 

[mannings 1]

*such not suck