Acceleration Problem

Tea drinker

the lead from the coil looks dirty. Remove it, clean it thoroughly and check for damage. Clean all around the outiside of the coil, maybe remove it to inspect/clean.

replacement HT leads would be maybe 30-40 euro in a motor factors assuming the 7 of them. They have various lengths and connectors available usually.

use plenty of rags when cleaning the dist cap, and never use scrapers or sandpaper.

YipYipU

Wheelnut wrote: »

In the first pic there is something that looks like a plug lead hanging down at the face of the distributor cap. Check if this is connected to anything, if it is loose it could be your problem.

This lead is not connected to anything at either end. I'm assuming the blue cable replaced this in the past and it was just never taken out. It's now out. There are 7 cables connected to the cap, 6 of which go to the plugs and the 1 remaining goes to the coil.

Wheelnut wrote: »

In the second pic it looks like there is a bolt missing from the front of the air duct. If the hole goes right through to the inside, the airflow through the hole could upset the air-flow meter.

I had checked this before but the hole doesn't go all the way through so no air is getting in through there.

Wheelnut wrote: »

Finally you say the plugs were changed 2000 miles ago. This is a transverse six cylinder engine (right?). The plugs on the rear three cylinders are a pig to change and it involves removing the manifolds. It's conceivable that a lazy mechanic would not bother and just leave the old plugs in. It might be worth checking it out.

I had done the front 3 myself but couldn't reach the back 3 so asked him to do it for me. This concerns me now as I had never used this mechanic before, though he was recommended by a friend. I guess I'll just have to take his word for it right?

YipYipU

Wheelnut wrote: »

I think you'll find the other three connections on the bottom (out of sight)

Yes the other 3 are underneath.

YipYipU

Tea drinker wrote: »

the lead from the coil looks dirty. Remove it, clean it thoroughly and check for damage. Clean all around the outiside of the coil, maybe remove it to inspect/clean.

Thanks, I'll give it a go.

Tea drinker wrote: »

use plenty of rags when cleaning the dist cap, and never use scrapers or sandpaper.

I have already cleaned inside the cap using a rag and a soft bristles brush. I will be removing it again tomorrow to re-inspect it for cracks.

Thanks again for all the help folks.

Greyfoot

Coil leads can be "tested" by removing them from the spark plugs and holding them say 6-8" from the body of the car and turn the engine over.(be careful not to touch the body as electric shock can be painful)
If there is an arc then the given coil is ok.

Wheelnut

YipYipU wrote: »

... inside the cap .... I will be removing it again tomorrow to re-inspect it for cracks.

You will not find cracks as in the normal sense. What you are looking for is evidence of a phenomenon called "tracking" in which the HT current flows across the surface and goes somewhere useless. It leaves a mark that looks like it was made with a pencil so it will be difficult to see on a black cap. Often the tracking will be between two of the electrical contacts, but it will always start at a contact wherever it goes.

Greyfoot wrote: »

Coil leads can be "tested" by removing them from the spark plugs and holding them say 6-8" from the body of the car and turn the engine over.

I think you mean 6 - 8 millimeters, not inches. This old method is not to be recommended on modern cars with computerised electronics. A high tension spike in the wrong place could make sh*t of an expensive ECU. (Besides, doing it your way will leave nasty scorch marks on the bodywork)

maxamillius

You will not find cracks as in the normal sense. What you are looking for is evidence of a phenomenon called "tracking" in which the HT current flows across the surface and goes somewhere useless. It leaves a mark that looks like it was made with a pencil so it will be difficult to see on a black cap. Often the tracking will be between two of the electrical contacts, but it will always start at a contact wherever it goes.

hairline cracks can very easily appear which over time become bigger,when engine runs hot crack can open wider and spark will get lost!saw it on distributor cap last week!

YipYipU

Ok so I have the cap off again now.

Wheelnut wrote: »

You will not find cracks as in the normal sense. What you are looking for is evidence of a phenomenon called "tracking" in which the HT current flows across the surface and goes somewhere useless. It leaves a mark that looks like it was made with a pencil so it will be difficult to see on a black cap. Often the tracking will be between two of the electrical contacts, but it will always start at a contact wherever it goes.

I'm not really sure where I should be looking for "tracking". In the following pic there appears to be a number of marks which look like pencil marks. Is this what you are referring to or would it be on the cap itself?
The cap itself is spotless now and there appear to be no marks or cracks whatsoever.

kermitpwee

Those flat spots are caused by your throttle position sensor I reckon.

Wheelnut

The second pic shows the inside of a black cap and it looks perfect to me, so that's not your problem. I presume there's a rotor arm somewhere (not in pic) and you should check that for tracking. It's less likely but I've seen it happen.

I think you have illiminated the ignition system (although I'm not sure how we became so focused on it in the first instance). Do the flat spots happen at the same revs every time or can they happen anywhere between 2000 and 4000 revs? If it's the same every time it might point to Kermit's suggestion.

Mar4ix

somebody said, there cant be coilpack and ignition distribution system in same time ....

YipYipU

The feckin' thing won't start . I put the cap back in place and started it up. It ran fine for about 10 seconds then cut out and wouldn't start anymore. I took off the cap again to make sure everything was in place and it was. I labelled all the leads before removing them so I'm sure they're all in the right place.
Should I just give up and call a mechanic?

Tea drinker

That's weird. And a right bloody p1ss off!
Maybe just go over the connections (especially the low tension and high tension to from the coil) again to make sure they are 100%. Perhaps some adjacent connector got loosened?

Hard to say anymore, but you might be right on getting a mechanic to look at it. What you did before as regards cleanign etc looks 100%.

YipYipU

Gonna give it one more try this evening when I get home. If it doesn't work out I may get onto the mechanic.

For the cleaning I just used a rag, a small soft brush and some cotton buds. Seemed to clean it up nicely but unfortunately didn't solve the problem.