Erratic running, 1.8 16V engine.

handyman · Post by **handyman** » 28 Dec 2009, 13:03

Our 2001 estate has decided to develop an annoying and difficult to trace running problem.

The engine will run fine for about half an hour and then seemingly loose power, almost as if it is running on three cylinders or in the 'get you home mode'. It will still rev but has a lose of power. The service light is activated during these bouts, but will be fine if turned off or left to recuperate.

I have tried new plugs, injector cleaner, replaced coil pack, checked all electronic connections physically.

I am now thinking along the lines of cleaning the ADI unit, changing the ignition pick-up, checking cambelt tensioner (cambelt change is imminent), checking aircon pump bearings, checking alternator bearings.

Car has done 170K miles.

Do these symptoms sound familiar to anybody with the same engine? I'd like to run it down to Citronut and his Lexia, but do not want to risk the journey.

Handyman

Post by **CitroJim** » 28 Dec 2009, 16:13

Sounds a bit like a failing MAP sensor to me Handyman.

Might be well worth a trip to see Malcolm as a Lexia session would go some way to nailing it very quickly.

Maybe Malcolm would come to you?

addo · Post by **addo** » 28 Dec 2009, 20:51

Sounds like some of what I've experienced on a 2 litre 16V motor. No really ragged running, but a definite stumble and appreciable power loss.

At present I've plumbed in a pressure gauge between the manifold and paralytic converter, to see if it's loose inside and sporadically choking. Trouble is - bad weather has prevented me from putting the gauge up in a visible position, as the wipers would snot it!

citronut · Post by **citronut** » 28 Dec 2009, 21:03

is it possible for the idle stepper motor to give these symtoms,

regards malcolm

Post by **RichardW** » 28 Dec 2009, 21:22

Heat soak causing the crank sensor to go wobbly?

addo · Post by **addo** » 28 Dec 2009, 21:35

I replaced both of these, with negligible difference. My next target is the poxygen sensor, which is overdue anyway.

handyman · Post by **handyman** » 28 Dec 2009, 21:56

I think Jim has hit the nail on the head as I had seen similar symptoms on other cars and a blow through of the pressure tube resolved the problem. I do have another MAP sensor so I can easily change that.

The symptoms do not seem to be the same as the ignition sensor if it was faulty, it either works or does not work. The engine runs fine for a period of time and then goes 'sick'.

Experience with faulty ADI units tend to be more random, with bad idling and cutting out. Neither of these symptoms are present, yet!

I will keep you posted.

Handyman

bxman · Post by **bxman** » 30 Dec 2009, 09:01

ADI
Alzheimer's Disease International maybe ?

Forgive my ignorance

handyman · Post by **handyman** » 12 Jan 2010, 23:44

Update to the erratic running, which is now identified and cured.

Turns out to be the insulation rubber to the sparkplug on the coil pack, even the secondhand replacement had the same problem, but different pot.

Fitted another clean unit and Hey Presto!, fault gone. Engine now runs really sweet after all the attention it has had to track down this gremlin.

I dug out an old Sun coil/KV tester I used to use, which will shove about 30KV through the pack, connected it up, turned off the lights and watched the display of the pretty lights as the insulation arced everywhere.

The secondhand coil packs were from 2.0 twin-cam engines, and contrary to popular myth, they are exactly the same as the ones fitted to later 1.8i 16V engines.

Next bit of good news, Lexia3 on its way.

All I need to do now is repair the pinhole leak in the ZX heater hose.

Handyman

citronut · Post by **citronut** » 13 Jan 2010, 09:21

i have seen coil packs on SAXO's die due to oil in the spark plug tubes,

regards malcolm

csrdad1950 · Post by **csrdad1950** » 13 Jan 2010, 10:06

Coil packs,bring back the old rotar arm,more reliable and less costly,easier to identify and fix,dont make em like they used to!!!

handyman · Post by **handyman** » 13 Jan 2010, 11:48

Cannot say I agree with you there, CSR, I have found coil packs are more accurate and less prone to breakdown than any form of moving ignition component, whether coil or magneto. Anything that is not dependent on a mechanical system is less stressed and more reliable, especially for the delivery of electrickery.

Malcolm, I do not think it was oil contamination that has caused the insulation breakdown, just wear and tear. I will have a look at the rubber connector at some point.

How is the snow on the coast? Its diabolical here in the Sussex Alps!

Handyman

French Car Forum

Erratic running, 1.8 16V engine.

Erratic running, 1.8 16V engine.

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coil packs