HDI flat spot problem!

[busteredwards]

My 2002 HDI seems to have a slight 'flat spot' around 1500-1800rpm, seems to clear when I put the foot down but its annoying for normal driving, it feels similar to a petrol car only firing on 3 cylinders then back onto 4 (best comparison I can think of! ) the car starts & idles fine & is ok above 2000rpm, could it be a 'lazy' injector??...are these cars prone to anything which gives same flat spot??

Thanx in advance!

[eoin27]

Most likely the air flow meter (MAF) is either dirty or malfunctioning. Its not telling the engine about how much air it needs before the turbo kicks in at 1800rpm.

[busteredwards]

Hmmm...I'm sure I'v heard of something similar before, are they easily cleaned/changed? I'v got a pal with the same car, might try swapping them over & see if it cures it.

[eoin27]

Hmmm...I'm sure I'v heard of something similar before, are they easily cleaned/changed? I'v got a pal with the same car, might try swapping them over & see if it cures it.

Excellent Idea. Be careful when doing it tho. its a very sensitive piece of kit

[Welly]

Would be worth checking the vacuum lines for splits/leaks too, also check the vacuum solenoids on the bulkhead (I think there maybe 3 on yours but 2 of them should be the same) you could try swapping them about to see if things inprove? this shouldn't flag an engine check light but I can't confirm this although I'm sure it's been done on here before with no probs.

[Doggy]

Would be worth checking the vacuum lines for splits/leaks too, also check the vacuum solenoids on the bulkhead (I think there maybe 3 on yours but 2 of them should be the same) you could try swapping them about to see if things inprove? this shouldn't flag an engine check light but I can't confirm this although I'm sure it's been done on here before with no probs.

It can tell if the solenoids are disconnected electrically, but doesn't 'know' about the vacuum pipes - therefore should be OK to swap so long as the ignition's off when making changes

[busteredwards]

Thanks guys...I'll try all possibilities at the weekend.

[Bogbreath]

My Y plate has very similar symptoms, particularly in 4th?!? I was under the bonnet "fiddling" with the air-con this week and noticed slack in the accelerator cable, I've adjusted it and the problem appears to have gone away!!

[muffindell]

Don't tighten the cable too tight else this will cause the ECU to throw an error and subsequence trip to dealer to plug and sort.

[eoin27]

Don't tighten the cable too tight else this will cause the ECU to throw an error and subsequence trip to dealer to plug and sort.

Really? ELM 327 my friend, check it out on ebay.

[carsten0]

Mine dos the same. It is a 1999 110bhp. Mabey that is the way they suppose to be

[muffindell]

Yeah, I thought my cable was a bit on the loose side, tightened it up and it threw the throttle pot out of lower/higher parameters. Only a trip to the dealers sorted the problem.

[Bogbreath]

I didn't tighten it just removed the slack so that when the pedal was pressed it did something, rather than wait a bit then do something..........