1993 940 Hesitation on throttle

tranmkp · Post by **tranmkp** » 22 Dec 2013, 18:20

Car has initial bogging when stepping on the throttle firmly - Car is regina system

replaced coil wire - no
replaced crank sensors - no
replace fuel pump relay - yes - car runs fine for a few months = problem is back now -

I guess it just has to be the fuel pump?

hillbilly · Post by **hillbilly** » 24 Dec 2013, 10:15

Does the engine rev smoothly if you gently try to accelerate?
Does it run OK after you get up to speed?

If so, when were the spark plugs last changed?

steve

tranmkp · Post by **tranmkp** » 27 Dec 2013, 15:38

spark plug wires -

Kirby J · Post by **Kirby J** » 07 Jan 2014, 13:41

I have had the same problem. It was the fuel pump. They will sometimes "fail soft" and give you lower than needed pressure without failing completely. Save yourself some time and money ad replace it now before you have to get a tow

Kirby J

tranmkp · Post by **tranmkp** » 15 Jan 2014, 16:13

no start now - replaced spark plugs - replaced map - replaced fuel pump

fixed for a while - then all of a sudden - bogged and now no start...

lummert · Post by **lummert** » 15 Jan 2014, 20:37

Did the tach bounce up and down?

tranmkp · Post by **tranmkp** » 15 Jan 2014, 22:25

The car has not stop while under way only bogging under throttle - it may then die - I have not noticed the revs -

I do have new crank sensors - prior to new plugs the car would stop when water misted - a short somewhere - new plug wires and when misted it did not stop - even misted the coil.

Like I said I replaced the fuel pump/map/wires/crank sensors/plugs. I have not taken apart the coil to look for corrosion.

Three symptoms - bogging under heavy throttle (soft pedal and it was fine) - occasional popping/thumping/stumbling at idle ( stopping sometimes) - or just no start at all.

My tech is a top level BMW/MB guy, doing volvos as a favor to me cause I send the beemers and bezes to him - the volvo is giving him diarrhea. He does not like volvos.

This is the only problem that this car has ever had - I am not going to bring up the AWD issues with the 99 XC - I would be better off maintaining a helicopter.

tranmkp · Post by **tranmkp** » 17 Jan 2014, 13:54

Turned out to be the Coil - No error codes - MORAL - symptoms like mine should be approached from the upstream side. Start with the coil first then workd down to the plug wires MAP and FPR -

I will say that it does idle very smooth now. - In the south, (texas) we do not get much corrosion that you yanks do.

Thanks for all the replies.