My 205 Has A Cough

[hanpug25 2]

I've had a read through a few pages of posts, but can't find any problems exactly the same as this.

 

I'm back in a 205 after a few years driving 'sensible' cars. It's a 1990 steel grey 1.6 gti. Other than the following issue, its fit as a fiddle and pulls stronger than any other 1.6 I've owned ( I've had a fair few).

 

The issue only rears its head at motorway speeds, 70ish/3500rpm. Every now and again it coughs - feels like it looses all power for a split second and the revs drop by few hundred rpm, but literally only for a split second. It also only really happens when the cars warm.

 

From what I've read, could it be the ignition amp? As the rev counter drops?

 

Any advice would be fantastic, before I start throwing money at the wrong solution...

 

Thanks.

[jackherer 543]

Certainly does sound like the ignition amp, and it might just need new thermal transfer paste on the back between the amp and the heatsink.

[hanpug25 2]

Certainly does sound like the ignition amp, and it might just need new thermal transfer paste on the back between the amp and the heatsink.

Is the head sink the alloy plate its bolted to?

 

Thermal contact paste a conductive paste? Would copper slip do the job?

 

Cheers.

[jackherer 543]

Yes, the heat sink is the alloy plate. Copper grease wont do, you need proper thermal transfer paste, either from a PC/electronics supplier or a motor factors. Also make sure the back of the amp and the heat sink are spotlessly clean before you put the paste on.

[hanpug25 2]

Thanks, I'll give it a go.

[hanpug25 2]

Would this sort of stuff do the job?

 

http://www.maplin.co.uk/p/servisol-heat-transfer-compound-2ml-re96e

[Hheppy 9 1 Cars]

had a similar problem myself back in March, turned out the connector had come loose on the ignition amp, I had similar symptoms to you.

[jackherer 543]

Yes, I've used that exact product successfully in the past.

[hanpug25 2]

Cheers guys. I'll order the stuff anyway and check the plug when I leave work.

[hanpug25 2]

Wee update...

 

After the car conking out completely at 6 am coming off nights (it started fine once cooled down), I changed the amp for a usd one i had. It ran fine for a day, but this morning started blipping again. the old one's been removed, cleaned and put back on the ally plate with some fresh heat transfer paste, so will try again tomorrow.

 

Failing the above working, i'll buy a new amp and mayby try a new coil too as it seems to be getting quite warm.

[DamirGTI 342]

It's not always the case , but when the amp. goes bad it tends to damage the coil as well ..

 

What kind (brand) of amp did you fit as an replacement , and which was the original one ?

 

 

D

[hanpug25 2]

It's not always the case , but when the amp. goes bad it tends to damage the coil as well ..

 

What kind (brand) of amp did you fit as an replacement , and which was the original one ?

 

 

D

Both were the blue Bosch ones and both were used (ones been in the garage for at least 8 years) Collecting a new coil tomorrow as it looks pretty old and the amps cost more.

 

Cheers

[DamirGTI 342]

Blue Bosch ones are really the best and most durable amps , thus , i suppose that the problem is somewhere else either the coil , the wiring , dizzy or even a spark plug (i had an intermittent misfire once which was really annoying and kinda hard to pinpoint the cause .. also appeared only while the engine was warm - it was one faulty spark plug ! no breakdown evidence what so ever while examining/testing the plug , was something internal within the plug which was obviously heat related ..)

 

D

[hanpug25 2]

New ignition amp and coil fitted and the problem is still apparent - extra annoying as I've had to cancel a trackday

 

Guess its on to checking the wiring.

 

I'd assume I can rule the TPS, AFM & fuel pump relay out as the tachometer blips every time I have the issue. It's steadily getting worse, to the point of the car now totally cutting out. Only when warm and over 2000rpm.

 

Any ideas

 

Thanks

[jackherer 543]

If the tacho is blipping then yes, it is definitely ignition.

 

I agree that wiring is the next thing to look at, I'd start with the small signal cable on the distributor.

[Anthony 1,003]

With the engine running, try jiggling all the wiring around in the vicinity of the coil and amp along with the timing signal wire coming off the dizzy.

 

I had an intermittent issue like this a few years back and I eventually traced it to a broken wire a few inches from the dizzy timing signal wiring plug. Cable tying the wire to something that didn't move "fixed" it until I had time to sort it out properly as it stopped the cable flexing and making/breaking the connection.

 

If the tacho drops out as well when it hiccups then I'd certainly say that it's something ignition or timing related somewhere - if it was fuelling related the tacho wouldn't drop.

[hanpug25 2]

Ok, after a few months without issue, the problems back, worse than before.

 

It happened near to home so had the multimeter on it. Cranking fine, fuel at the rail, voltage at injectors, 12v at coil, 12v at ignition amp, but no spark.

 

I have changed:

Coil

Ignition amp

Dizzy cap/arm

Dizzy signal lead

Plugs

Leads

Tachometric relay

 

Some new, some used. I'm now left with ECU, or a wiring problem in the loom. Are there any places to check continuity/voltage to rule to

The loom out?

 

Could it be something inside the distributor?

 

Thanks.

Edited September 30, 2014 by hanpug25

[S@m 156]

Assuming you can get it started and that you haven't already tried it, i highly recommend Anthony's suggestion above of giving the relevant wiring plugs and connections a wiggle whilst the engine is running to see if you can replicate the issue.

 

I had a similar problem with my mi16 which i found by doing so, after changing amps/coils etc aswell, it was a dodgy connection.

[hanpug25 2]

Assuming you can get it started and that you haven't already tried it, i highly recommend Anthony's suggestion above of giving the relevant wiring plugs and connections a wiggle whilst the engine is running to see if you can replicate the issue.

 

I had a similar problem with my mi16 which i found by doing so, after changing amps/coils etc aswell, it was a dodgy connection.

Sorry, I should have added that I've jiggled the coil, amp and dizzy wiring whilst running with no issue.

 

Guess its looking like wiring testing...

 

Thanks for the reply

[DamirGTI 342]

If theres no spark what so ever and also no fuel at the injectors then could be broken dizzy pick up coil (coil windings) .. haven't seen that yet on a 205 dizzy but did on other cars distributors with the same pick up coil system ..

 

D

[hanpug25 2]

Right. Sorted at last.

 

Thanks to damirGTI for all of the advice. Turned out to be a failed coil in the distributor.mchanged the dizzy and had a trouble free few weeks.