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acceleration stutter


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Hi folks I have a problem with my stevens turbo 1988 carb model, problem is when accelerating hard boost starts to build then car shudders as though it is cutting out loosing power then will give sudden burst of power and accelerate normally only to repeat fault when you change gear and continue to accelerate.The problem does not show if only light throttle pressure is used avoiding boost. I have changed the spark plugs as someone sugested but fault still there I was wondering if this could be caused by either the fuel pump or ignition coil ? Anyone got any ideas

Cheers ric

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Hi mate, I have an 88 turbo as well. It sounds very much ignition misfire to me. If the spark plugs are new i would recommend a new set of HT leads as well as a new ignition coil. Sounds like its breaking down under load. Dont get conned into expensive performance set as waste of money especially for diagnosis purposes. Get yourself the NGK leads from paul matty's or the like as they are a good set and wont break the bank, same with the coil as i have fitted an aftermarket one before and it lasted a whole 3 and a half minutes.

Also :

Make sure your not overboosting.

Check the accellerator cable isn't fouling anything.

The spark plug gap is correct (not wanting to teach you to suck eggs or anything pal)

See how you get on with that lot first mate. You could also change the fuel filter as i have known that to cause problems before. Unfortunately these things tend to just take a little time to track down. Its often cheaper to replace these items before going down the garage route and getting caught up in the labour charges.

Let us know how it goes cheers Chris

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Hi mate, I have an 88 turbo as well. It sounds very much ignition misfire to me. If the spark plugs are new i would recommend a new set of HT leads

Same symptoms and new leads cured mine. Looked at the old ones and the plug nearest the

cambelt (number 4?) had broken core at the end of the rubber boot where it was stretched to

reach having been badly routed.

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Voltage demand, being the amount of voltage needed across the plug gap to make a spark, varies depending on engine conditions. One of the highest demand times is sudden throttle opening. Boost presure also increases demand.

The amount of voltage available depends on the design of the system, and the engine rpm, but very significant is that any degradation in condition of coils, plugs, leads, low tension wiring (amount of voltage / current delivered to coil primary) will reduce the available voltage.

What this means is that as the condition of these items degrade, you first notice it through poor performance as you open the throttle and it first comes on boost (also starting performance may be affected). Ultimately you will get misfires coming in under other conditions, as the deterioration goes further.

As said in posts above, if you've e done the plugs, next likely culprits are leads probably followed by coils. I have also seen on the esprit mailing list a general consensus that the cleanliness of the coil to lead connections can be a cause.

It's also the sort of thing that any garage/ mobile engine tuning service can help check, as they can measure the available voltage delivered by different parts of the system.

............. that's fightingtorque!!!

www.fightingtorque.com

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