Cold good, warm bad...

[hopster 0]

Hi,

I'm new to the forum but would really welcome some advice.

I've bought a 1988 1.9 so I think that means its got the XU9JA engine. It doesn't get used much but when I tried to start it a few weeks ago there was no power to the starter motor and I traced the fault to a rusty spade connector on the solenoid. I cleaned it up and it now starts fine. I only mention this as background because I had to drain the coolant and remove the radiator. I also changed the oil and filter whilst I was there.

 

Before doing that work it ran well but since then it has developed a fault. It runs fine when the engine is cold and pulls as it should but as the engine warms up, say after a mile, the engine gets more hesitant at mid-range engines and then reaches the point when it feels as if its running on three cylinders getting progressively worse. I've limped home put it back in the garage but when I start it the next day it runs fine again, until warm.

 

My conclusions:

It's unlikely to be ignition related because it runs fine initially but five minutes later runs worse and worse.

It's a fuel pressure issue? But why would that only affect running after five minutes.

It's likely to be fuel injection related where a sensor is not adjusting for the warming engine.

It's suspicious that this has happened just after the work I did and I'm wondering if I've dislodged something or failed to reconnect something.

 

Other details:

The engine generally is in really good shape and the hoses and connections around the AFM all look good.

A visual check doesn't reveal anything unusual

All the gauges give readings as you would expect regarding temps and pressures, cold and warm.

 

Thanks for reading this and I'd be really grateful for some wise guidance.

 

Best wishes

 

Chris

 

[DamirGTI 342]

Actually , it is very likely to be ignition related ... this commonly tends to go bad while warm and under load - ignition amp. and coil .

 

Also , it might be the fuel pump going bad .. not yet , but "going" .

But i'd try first with the : ignition amp. and coil ... if you have known good spare try to test replace , one by one ignition amp. especially not so much the coil (early cylindrical coils rarely go bad) .. and see what happens .

 

Obviously check the spark plugs , leads , dizzy cap and arm . Could be also one spark going bad , if you can isolate that particular cylinder which seems to be missing try to swap spark plug , mix/change place with another working cylinder .. do the same with the ignition lead and injector . (one by one)

 

Can't really think of anything that might've been knocked off on the front around the radiator to cause this issue . But you never know , double check around all the areas where you've been working .

There was no need for the radiator removal anyway , starter motor you can reach from down below or sideways ..

 

D

 

[hopster 0]

Hi Damir,

I appreciate your help and will follow your advice. 

Best wishes

Chris

[karabas 21]

Hello, I faced with exactly the same problem last year. Every word you wrote is what I lived half of the year. I could only drive when I took off the ECU temp plug and hung somewhere with another sensor plugged.
When I replaced the fuel pump my problem was solved.
I think the explanation is,  the ECU opens the injectors longer time up to a certain temperature (60 C) so that enough fuel flows with more air coming from the SAD.
I solved mine with Damir's recommendations.(thanks again)
Hakan

[hopster 0]

Thanks for your comments Hakan. I've ordered a new ignition amp and HT leads and spark plugs. If that doesn't help I'll look at the coil and fuel pump.

Best wishes

Chris

[DamirGTI 342]

For the ignition amp. , you'll need some thermal paste too .. better quality amps usually have it included in the box with the amp. , but if there isn't any you'll need some .

 

 

D

[hopster 0]

Thanks Damir. I have some thermal paste for the job. I've ordered a few things, including the ignition amp, from Autodoc but it's taking a very long time to arrive. I wonder if others have experience of them.

Chris