Car Wont Rev Above 3000 Rpm

[supersub14 1]

Hi, my mates 1990 1.9gti wont rev above 3000 rpm?

 

Ive heard that this is some sort of ecu fault? We have checked the air flow and its fine and so is the distributor. I tried a forum search but didnt know what to look for?

 

Can any one help? Will a new ecu fix the problem or is it something else?

 

Thanks

[hexhamstu 9]

Hi, my mates 1990 1.9gti wont rev above 3000 rpm?

 

Ive heard that this is some sort of ecu fault? We have checked the air flow and its fine and so is the distributor. I tried a forum search but didnt know what to look for?

 

Can any one help? Will a new ecu fix the problem or is it something else?

 

Thanks

 

If you have access to another running gti, try swapping the ignition coils and then ignition amps. If not you can usually get both of these for around £20 all in.

[supersub14 1]

Does it need to be one from a 1.9 gti or will any do?

[Tesstuff 222]

A collapsed cat can also produce that result

[dcc 855]

1990 is pre cat afaik. so unless a little kitten has fallen alseep in your tailpipe, you shouldnt have a worry with a cat!

[DrSarty 90 1 Cars]

Has anything happened to the throttle cable/linkage? Could just not be giving you WOT.

 

An ECU swap is also pretty simple too. King HT lead between coil & dizzy 'breaking up'? Severely crapped up air filter or some blockage in the plastic inlet just under the slam panel.

 

So from this and the other replies, it could be management (ECU swap), spark breaking down (ignition components), air starvation (inlet system) or fuel starvation (ECU).

 

There's a possibility that the AFM's f*cking the mixture about too by not fully opening.

 

What about timing, i.e. dizzy set-up or lack of vacuum advance (if some form of advance mechanism exists - forgotten: had 16v for 5 years)?

Edited May 26, 2009 by DrSarty

[supersub14 1]

hmmm.. could be a bit more complecated than we first thought then...

 

throttle cable linkage is fine and the air flow seems to fine as well. Suppose an ecu swap is next thing to try.

 

Ive never had to chanage one before. Is there a link on the forum on how to do this? First things first tho, where do i find it lol

[dcc 855]

under the dash, next to your right knee! you will see it is held up by a few bolts i think, one of the most annoying jobs to do on a 205 imho, give me another job to do any day!

 

Its a case of unplug and replug once it is free, but i dont think you need to remove the old one to test out a new ecu! just unclip the big plug and connect new ecu!

Edited May 26, 2009 by dcc

[EdCherry 34 1 Cars]

the cable linkage might be fine but you have checked the adjustment, take off the elbow from the trottle body and make sure when the pedal is all the way down there is no more travel in the butterfly.

[supersub14 1]

ok, ill check the throttle again and ill swap my ecu into his next chance i get.

 

thanks for the tips...ill prob be back asking more questions soon enough if it doesnt cure it lol

Edited May 26, 2009 by supersub14

[miamichris 9]

my xs was doing this sort of thing John, the cause was 6 bent valves... head rebuild is in progress!!

 

take it he's tried replacing the fuel/air filter, dizzy cap, rotor arm etc? sometimes its the simple things!

[hexhamstu 9]

have you tried the ignition amp and coil yet?

[pug_ham 242 3 Cars]

What was done to this prior to it developing this fault?

 

If the cambelt has been changed its possible they didn't used the right timing pin holes in the crank pulley & its a couple of teeth out.

 

Graham.

[supersub14 1]

Thought id leave an update on this.

 

Car has been sat in a field for year or two so that didint help. It was previously used for hillclimb rallys so engine has had a tune up in its past life but i dont know exactly what was done. As far as i can tell its still got all standard parts, but heard the cam had been reprofiled (whatever that does lol).

 

Ignition and coil are fine afaik. When rev's reach 3000 rpm the limiter kicks in, but its at a slower rate than normal. To me it sounds like its being electronically limited.

 

Ive bought a replacement ecu off fella on this site so when i get it ill plug it in and she how she drives. The part number of the ecu in the car is 0 280 000 359, but in my 92 cat model its 0 280 000 345 so i wasnt sure if id of fitted it that it would of worked properly? Would it...??

[Luca20516VT 0]

If the exhaust had a flow issue great enough to stop the revs from rising above 3000RPM, you would know right away...

 

An engine choked by a blocked exhaust would rise slowly in rpm even in first gear and at low RPM. Does it rev fast and strong to 3000 then stops and maintains 3000, or slowly revs to 3000RPM?? If it revs fast and strong then i would say ECU related like a limiter of some sort.... the Late model motronic ECU might have limp mode??? you might have an air leak inbetween airflow meter and throttle body or a dodgy sensor.... maybe knock sensor that may set off the limiter....

 

Or else hardware issues like the cam off timing or bent valves, but then it would still rise slowly in RPM to the 3000 not fast and hard.

 

Just some thoughts

[miamichris 9]

If it's bent valves then I would just set it on fire and save yourself the hassle

 

Got it home yet?

[supersub14 1]

Yeah Chris. Home and all ive a thread on here somewhere about it.

 

Got car working - wasnt ECU as yous thought. Disconnected a plug from a sensor on the air intake and away she went. Think it was summit to do with the choke??

 

Its this sensor circled:

 

 

What is it???

[boombang 2]

throttle position sensor.

[supersub14 1]

that was the problem then. Cheers

[pug_ham 242 3 Cars]

Throttle switch is just an open closed switch & simple as they come.

 

Closed circuit at idle or WOT (full throttle) & open circuit in between with no readings.

 

With it disconnected the ecu won't be getting the idle or WOT voltage afaik.

 

Graham.

[supersub14 1]

With it disconnected the ecu won't be getting the idle or WOT voltage afaik.

 

without me sounding like a muppet, what doest that mean if its not getting the voltage?

 

Car seems to idle fine with it disconnected and drives 100%

 

Its not something i know a lot about unfortunately