Technical RPM drop when i dip clutch ??????

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Technical RPM drop when i dip clutch ??????

Josho190

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Hi first post so go easy lol :)

Purchased a 1999 fiat punto 1.2 60 S Team. The problem i am having is that if u dip the clutch after the car has gone over 2300 rpm the rpm drops to 500 - 450???? Which stalls the engine!! The car idles fine at 900 rpm and as long as the rpm stays below 2300 its fine. The only other odd thing is the fuel injector light flashing on every so often just before the car stalls ?????? Any sort of help would be excellent.

Thanks very much
 
I Had the same issue last year, i recommend you try some injector cleaner - wipe the throttle body with some + a J cloth, then put the rest in the fuel tank

Secondly, check the condition of your spark plugs, HT leads and coils. Replace if they seem abit poor. You can get Coils for £18 each on ebay if you are short on cash(y)
 
It sounds like the engine is running weak (revs but no substance). Injectors need to be cleaned, but also check the MAF/MAP sensors.
 
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Sorry to say that I don't quite understand your description of the problem; are you saying that if you're driving the car (>2,300rpm) and depress the clutch the revs reduce so quickly that they fall away and the car stalls. You see a glimmer of the engine warning light when this is happening?

One other possibility to add to the good points above;

With an engine running at >2,300 rpm there's quite a lot of suction on the induction side of the engine, drop the accellerator and the butterly valve closes which turns suction into vacuum. If that vacuum is compromised in any way (ie air leaks into the induction system) the engine may go sufficiently lean as to stall.

How could it be compromised? One possibility is the inlet manifold gasket and another the brake servo vacuum system/hose - if either is compromised they could leak, in-extremis. On other cars I had it was the butterfly valve/throttle(injector)-body spindle end bushes wearing - air is litteraly sucked in through the bushes and makes the engine go momentarily lean.

This may be hard to see and test on the Punto as by recollection the throttle position sensor sits on the end of the butterly valve spindle. You my need specialist help with that.

Certainly if the lambda sensor sees lean (and cannot compensate with extra fuel) it'll show up as an error on the engine management light, as the engine fades away.

Hope that helps.

Jules

PS - I had this happen on a Renault 5 Gordini (non-turbo) I bought in the 80's. I had a similar problem (even at tick-over/died on the overrun). Turned out the inlet manifold had gone porous - a specialist tested it on a bench and painted it with silver Hammerite!

PPS - if you've got carb-cleaner stand the car of the drive and when already warm run it at 2,3-2,500rpm then drop the revs; does it stall? Try again this time as you drop the throttle spray carb cleaner around the throttle spindle, inlet manifold, brake vacuum union (you may need a couple of goes at this, testing a different area each time). If the engine holds on then you'll know you've an air leak. Otherwise stick with changing everything bit by bit.
 
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It's misfiring mate that's what the flashing light mean....first of all go for cheapest options...change spark plugs, HT leads, coil packs (dunno if yours is SPI but probs is), clean throttle housing, if all else fails change injector...can't see ot being a compression issue if it only does ot every now and again tbh
 
some good answers ,but my cheap way of ascertaining this fault would be to start with a vacuum test on tickover and then at higher revs
gauge should show 18 to 22 on tickover and outside these parameters should indeed point to the problem
see here for guidance
http://moodle.student.cnwl.ac.uk/mo...wmedia/toolsEquip/hpt/measuring/vacgauge.html

on the 8 valve mk2/2,5 punto its so easy to fit as you just pull the pipe off the inlet manifold where it goes to the breather (its a 5 second job) and plumb the gauge in,i now check every pumto i get in plus do a fiatecuscan thanks to yani

theres a gauge on the bay at the moment on £5 if funds are tight
 
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