Massive Loss Of Power/power Cutting Out?

[Tom Fenton 1,525]

Following on from my "Ignition Amplifier" topic I'm still struggling with an intermittent major loss of power from my 205, standard apart from a K&N 1.6 8v.

 

The symptoms are as follows; occasionally a massive misfire/lurch, sometimes when driving along regardless of what gear, it suffers a complete loss of power, as if someone has cut the ignition, however it returns back to idle speed and does not cut out, but will not rev up at all. Now it has started doing the loss of power thing at junctions occasionally, so the throttle pedal will not make the car rev up, it sometimes backfires, but does not cut out.

 

So far I've changed the ignition amp, dizzy cap and rotor, coil, tachymetric relay, HT leads I am confident are OK. When it does the loss of power thing the fuel pump is definitely still running.

 

I'm now leaning towards the AFM being the culprit, unfortunately I don't have a spare to swap over to try, the only spare Jetronic AFM I have is a 1900 one, and this makes it run like a bag of cr@p.

 

The only thing I'm unsure of is the function of the switch on the throttle body. Could this be playing up and causing a problem?

 

Any input welcomed, cheers chaps.

[GLPoomobile 958]

I may be wrong, but my understanding is that the TPS only 'does' anything at fully closed or fully open, telling the ECU to adjust suitably at those points. Anywhere in between and both contacts are open, doing nothing.

 

CAPS is your friend for this sort of thing.

[Ethos 0]

Tom I had this on my mi16 conversion, I thought it was my coil at first. Revs dropped down to idle then shot back up again etc...

 

I tweaked....

 

Fuel line had a slight kink

Positive feed from battery to junction box was loose

Moved battery back as it was touching the afm plug (could of been hitting it when moving)

 

Hasn't happened since, so hopefully it's simple as simple for you too. Check all earths are tight / good etc...

[Sandy 189]

As GLP has alluded to, you could disconnect the TPS and it should drive normally, indicating whether or not the TPS is playing silly. Fuel starvation sounds probable too.

[DamirGTI 325]

Could be dizzy signal cable the one which goes from the dizzy on to the ignition amp connector

 

Rgs !

Damir

[Tom Fenton 1,525]

Cheers for the thoughts guys.

 

I think my next move is to put my wideband lambda on it, at least that way I can see if it goes lean when it does its little trick, indicating a fuel problem, or if it goes rich, indicating an ignition problem. There is already a boss for the sensor in the exhaust.

 

I'll also try disconnecting the throttle position switch and see if that has any effect.

[jackherer 543]

Have you checked the wire and plug coming off the distributor is secure?

Edited July 27, 2008 by jackherer
edit: too slow, Damir beat me :)

[Cameron 16]

I had a problem similar to this, it turned out that the AFM wiring was so old and brittle that in some positions it broke the circuit. So it was basically running without an AFM - ie not at all. Pretty terminal unless you like wiring.

[Tom Fenton 1,525]

It was something I looked at I must admit, and it doesn't look too clever, time for some belling out back to the ECU I think.

[adamc 0]

i had a very simular problem, after replacing a lot of things i found it to be the AFM, i must of shorted it somehow, after changing it i never had a problem!!

[Tom Fenton 1,525]

Cheers guys, I've got another AFM on its way to me shortly, so I'll swap that in and see how things go.

[Tom Fenton 1,525]

Well as an update, the "new" second hand AFM arrived this morning, I've changed it over and it seems to have cured the fault, fingers crossed. Will have to use it for a bit to see if it re-occurs, but looking good for now.

[Pugnut 9 1 Cars]

my 1.6 used to do this and it was the coil, and its quite common for new coils to display the same fault.

 

backfiring suggests an intermittent loss of spark.

 

hopefully the afm does the trick though

[stufarri 98 3 Cars]

I have a similar problem to the one Tom had.

 

Did you manage to sort this issue with the AFM Tom?

 

Mine loses power and cuts out - when I de-clutch it stalls. Sometimes stalls when idling too.

 

It is driving me mad!

[Tom Fenton 1,525]

The air flow meter sorted it yes.

[Paul_13 212 1 Cars]

I had a similar problem, I fixed a few bits at once so I couldn't eliminate what it was.

Broken AFM clip

Dodgy earth and cable

Earth loose on block

Fuel pump was dying

[DrSarty 90 1 Cars]

Glad you seem to have got it sorted. What a wealth of quick knowledge this forum has.

 

I was thinking a sudden fuel shortage (kinked line etc), or alternatively the engine taking a massive gulp of air through an intermitent air leak. The latter I think would cause backfires too.

 

Fingers crossed it's sorted.

[billybluesky 1]

I have a similar problem to the one Tom had.

 

Did you manage to sort this issue with the AFM Tom?

 

Mine loses power and cuts out - when I de-clutch it stalls. Sometimes stalls when idling too.

 

It is driving me mad!

 

just read your post dont know if you fixed your fault but i had the same problem it turned out to be the air filter bracket had broke and was resting on the air flow meter wiring/plug causing it to lose power and not pull but just tick over hope it helps