Starting And Rpm Issues

[matt g 5]

Hi everyone.

Can anyone shed some light into my cars current issue please.

 

It's a H reg 1.6 gti running all standard equipment.

On initial startup from cold when turning the key the engine fires up and instantly revs to around 2500rpm then dies. After 5 or 6 attempts of the same the engine catches and runs but sounds a little lumpy but ticks over.

When not under load the engine revs freely but when being driven it won't rev over 4500rpm.

 

Anyone have any ideas please? It's the last niggle to sort before mot time

 

Thanks in advance

[Tom Fenton 1,542]

Are you expecting it to start off the key and run with no throttle input at all? If so you are asking a lot if the 80's injection system with no closed loop idle control.

Even the very best set up cars may need just a touch on the throttle from a cold start to keep them running for 5 sec or so until they stabilise.

Yours from your description doesn't sound well setup to be honest.

[matt g 5]

Hi. Thanks for the reply.

 

I'm more concerned with the inability to rev through to redline under load. Your prob spot on in saying it needs setting up correctly. Does anyone know of a mobile tuner that covers the South Wales area?

[Anthony 1,003]

What happens when you try? Does it feel like a really severe misfire like it's hitting a rev limiter? If so, ignition amp would be my first suspect - a limiter like symptom around 4000-4500rpm is their usual failure mode.

 

They're almost certainly different issues though - as Tom says, it's fairly normal to need to give it a little tickle of throttle to keep it running for a few seconds after cold starting, even if it is set up correctly, whereas no matter how far out the idle side of things is, that shouldn't really impact how it runs under full load.

[nomis 12]

I've spent decent amount on trying to get my 1.9 running as smooth as I can by replacing lots of the usual bits, such as hoses, leads, etc. It idles pretty much fine and pulls well...

 

But it always needs a bit of throttle to start.

 

The rpm issues sound very different to though, as mentioned by those with much more knowledge than me above.

[welshpug 1,661]

whereabouts in Cardiff are you Matt?

[matt g 5]

Hi guys. Thanks for the replies. I will try another ignition amp and go from there. Fingers crossed.

 

Welsh pug. I'm in Pontprennau. Near junction 30 of the m4

[matt g 5]

Hi all.

 

Just a quick update on my woes.

 

Tried changing the ignition amp but the symptoms are still the same.

It's still a pig to start when cold but fine when hot so I'm suspecting the SAD valve. Will check that tomorrow.

 

My major concern is the rev limiting at 4000rpm. Either the tacho is reading incorrectly, I have a limited Ecu or my car is possessed by a non revving entity. I'm open to all ideas.

 

Thanks everyone.

[toolie72 67 1 Cars]

I'd suspect fuelling issue myself, like lack off

OR a big air leak which would also lean mixture

 

What's plugs like?

 

Sad will probably be fine (and it's a knob to change!) very rarely go wrong

[matt g 5]

Just had a quick look at the plugs. All are black and sooty.

[toolie72 67 1 Cars]

Not lean then

 

Out of ideas-I'd have guessed fuel and/or mixture

[jackherer 543]

What was it doing immediately prior to you removing the plugs and finding them to be black and sooty?

 

If it was idling it might just mean it is running rich at low load and/or RPM, it could still be lean at high load/RPM.

 

As I think has already been suggested run it to 4000 RPM or whatever the highest it will go to is, cut the ignition, coast to a halt then take the plugs out.

 

Also was the new ignition amp known to be working? When you got it was it already mounted on a heatsink plate?

[Gaz205 50]

What was it doing immediately prior to you removing the plugs and finding them to be black and sooty?

 

If it was idling it might just mean it is running rich at low load and/or RPM, it could still be lean at high load/RPM.

 

As I think has already been suggested run it to 4000 RPM or whatever the highest it will go to is, cut the ignition, coast to a halt then take the plugs out.

 

Also was the new ignition amp known to be working? When you got it was it already mounted on a heatsink plate?

Out of interest what does this test for when running it to 4K then coasting? When you say take the plugs out is it to check to see if they are flooded with fuel? Edited July 24, 2017 by Gaz205

[matt g 5]

Hi all.

 

Plugs were checked when the car had been idling. It does not have any mot at the mo hence test driving it is a bit ropey.

This is the final issue before it's mot.

Is it possible I have fitted the wrong Ecu? I have several here but all have the same part no.

[Anthony 1,003]

1.6 GTi ECU should have a part number ending 340.

 

For the sake of completeness, the AFM should end 056 and injectors should be blueish in colour.

[Leslie green 111]

Try moving the distributer to see if it makes any difference .mine sounded like it was missing and wouldn't idle till I moved it forward a bit .

[matt g 5]

I'm going to have a tinker on Sunday guys. Thanks for the replies. Will keep you posted

[matt g 5]

Ok. So took the fuel rail off to check the injectors are firing and fuel is 100% getting fired into the chamber and giving me a nice soaking in the process. Pulled all the plug leads off and earthed 4 plugs and 100% have spark.

Car did run very briefly and sounded great but after switching engine off it won't start again!

 

Does anyone have any ideas or is anyone willing to pop over and help me dig a very large hole to bury the car

 

Cheers all

[matt g 5]

Help!!!!!!

 

Checked every connection to make sure it's in the correct place. Tested the sad, airflow meter and throttle sensor ( by following the forum guide. Top work)

Reassembled everything, turned the key. Fired straight up and idled at 2k

 

Let it tick over for a while. Tried adjusting idle but with the screw all the way in it's still at 2k. There is slack in the throttle cable.

 

Turned it off. The plugs are sooty but then tried to restart it and it won't run!!!

 

Would anyone be willing to come and take a look please. I'm obviously happy to pay for anyone's time.

 

Thanks.

[steve@cornwall 100]

When it won't start try pulling the fuel pump fuse and trying again to start.

[matt g 5]

Will give that a try. Thanks Steve

[TAG 25 1 Cars]

I worked on an 8 valve where the hose between the bottom of the inlet manifold and the SAD had become brittle and cracked, causing an air leak.

The problem had only appeared when the chap had someone fit 205-spec power steering to the car, the pipe must have been agitated in the process.

[matt g 5]

She lives. Little blue headed no good waste of space Little bas###d.

Changed the Ecu temp sensor and it's now purring. Mot on the weekend and hopefully she's back on the road.

 

Thanks for all the help and suggestions everyone.