Hi,

My 98 1.3 mpi has flat spots on acceleration, is hesitant at low rpm. I dont think the mixture is rich enough. Ive checked for leaks and checked map and hall sensors.

What resistance values should I get on the temp sensor. Im getting about 1800 ohms cold to 180 ohms warm. What effect does disconnecting the plug while running have ( apart from no instrument indication). There is no difference if I do this on my engine. On starting the engine from cold tickover is 800 rpm and it drops to 750 when warm.

Any help and suggestions appreciated.

Edited 22 March, 200917 yr by 4fold
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my first guess would be a vacuum leak but you've already checked that

If I unplug the sensor on my car (1.3spi) the revs drop slightly and idle becomes fairly rough.

If this doesn't change on yours then it's possible that it isn't working properly. Although does the temp guage work ok?

Should stay in the middle while driving along and raise slightly when sat still.

Phil

Hi Phil,

Temp gauge works fine, proves the stat is OK and sensor resistance does vary. It just doesnt seem to have too much effect on the engine. May be the throttle position sensor not picking up and adjusting ecu to different loads. Does anyone have values for tps.

Thanks again for your replies.

I have had this problem before.

Replaced temperature sensor and thermostat which helped a bit.

Only really cured when new spark plugs, ht leads and air filter fitted.

Also had to tinker with the timing but with yours being the mpi you can't do that.

When were the plugs etc changed?

I've also noticed a while ago that when the throttle cable wasn't adjusted properly it wasn't resting on the idle position switch fully and was causing the idle to be a bit choppy.

Phil