1993 1.9 205gti Not Starting (motronic)

[Sy_ 0]

Hi All,

 

Right, here's the symptoms:

 

From cold, the engine turns but won't fire.

 

If you disconnect the Air Flow Meter it starts and runs very roughly (if you keep jabbing the throttle), until the AFM is plugged back in where it runs ok (with a bit of smoke - maybe running rich?).

 

From hot it will start again without disconnecting the AFM. Smoke disappears after it's warmed up.

 

I've checked the AFM pinout resistances (Ohms) as:

Between 2 & 4 (flap closed): 37.7

Between 2 & 4 (flap open): 756

Between 2 & 3: 356

Between 3 & 4: 355

Between 4 & 5: 2.66k

Which seems roughly in line with the recommendations for this AFM (Bosch 0280202202) on this site.

 

My next ports of call are ECU, then engine temp sensor (wherever that is) or even another AFM, but I'm at a bit of a loss with the Motoronic system so any help really appreciated!

 

Cheers,

 

Sy

[welshpug 1,657]

temperature sensor I'd think, IIRC about £15

[Sy_ 0]

Cheers for the reply - I take it you don't mean the sensor that's in the AFM?

[Guest markiboy2007]

when its started, and you plug the air flow meter back in, does it drive ok, or does it kangaroo all over the place??

 

the reason i mention is that i had similar symptoms with and old vauxhall runnin the motronic system, wouldnt start with afm plugged in, eventually get it started, plug the afm back in, and it would either die, or run very rough, when u try to drive, its was very jumpy.

 

turned out that it wasn't holding fuel pressure, dodgy aftermarket FPR, replaced it with a standard regulator and it ran fine.

 

is the gate on the afm 'flapping' like mad when u try to drive it?

[Sy_ 0]

No, it seems to run ok when the AFM's plugged in - well, as well as they ever do....

[Guest markiboy2007]

hmm pro not relted to that then but thought it was worth a mention, hope you get it sorted mate!

[Ahl 4]

temperature sensor I'd think, IIRC about £15

I'd agree with that. You can get them from GSF.

[Sy_ 0]

Well, it was the engine temp sensor, 2 months of me p1ssing about and a £6.52 solution.

 

Thanks very much for your help Welshpug & Ahl - if you're ever in Warwickshire I'll buy you a pint!

[Sy_ 0]

Ok well I spoke too soon didn't I?

 

She didn't start this morning with the AFM plugged in, despite 2 suceessful starts on Sat - guess the engine must've been warmed slightly.

 

Any other ideas?

[Sy_ 0]

Update on this,

 

It was the ECU temp sensor, which looks like this:

 

 

 

Not the coolant temp sensor which only has a single blade type connector, and looks quite different (and coolant p1sses out when you remove it).

 

Thanks to the replies who pointed me in the right direction

[welshpug 1,657]

definitely a DOH!!! moment there