Mechanics

INTERMITTENT POWER LOSS & SPUTTERIN

1998 Vauxhall Astra

Engine Performance problem
1998 Vauxhall Astra 6 cyl Front Wheel Drive Automatic 92000 miles

Hi my 98 Astra mk3 1.6 16v has a problem with intermittent power loss.

When I lose power it is (and I say this as I always make the same journey when it happens) up hills and in the same place each time.

I have recently had the fuel filter changed and didnt have the problem for 9 days afterwards but then lost power, today the car slowed to a stop uphill, I have in the past been able to put my foot to the floor and the car works through it.

When the car develops this problem I notice a sputter from the engine but when I pull up for a few minutes usually turning the engine off and then restart the sputtering has stopped and the car runs fine.

After the 9 day period when the fault occured it happened once each way and then hasnt happened again till today, 4 days later. I have noticed that the weather has been fine and dry in the period the car has been ok, but today it has been foggy and damp, and on previous occasions it has rained.

I have thought that maybe it is an air filter problem and am tempted to have the air filter replaced for an induction kit as I planned to anyway.

Other things I have been told that could be the problem are crank/throttle position sensor and a sticking egr valve.

What are your thoughts and what would you recomend.

I must say that before the fuel filter was replaced the nature of the fault was much worse, the car could cut out if I didnt pull over and the sputtering was much worse. Also the problem seemed to intensify once id had the centre section of the exhaust system replaced and thought it would be the cat converter but I didnt think this was the problem as changing the fuel filter wouldnt effect the cat also this could just be coincidence.

It might also be worth saying I dont feel the car has as much power as it should do. The problem while I am patient is begining to try it.
Avatar
Markyboy132310
March 17, 2009.



Hello .. thanks for the donation .. much appreciated

First ... remove and clean the CKP (crank position sensor) when this is dirty or worn and especially in damp conditions it sends bad signals to the PCM (computer) this should set a DTC and light up the MIL .. but not alway's ... it generally causes cutting out at random times so your fault is a little different but it cannot harm the vehicle for it to be cleaned .. if it looks badly worn then replace it ..

Second .. does the MIL (malfunction indicator light) show on the dash display .. is it on all the time .. does it come on when the vehicle cut's out ? have you ever had the vehicles computer read for fault codes after this "cut out" has occurred ?

Third .. How much fuel do you normally have in the tank .. is it alway's full ... 1/2 full .. 1/4 full .. have the fuel pressure checked ? if you normally run with just 1/2 tank ... try filling up (full) the tank and trying the same journey under the same conditions ?

Let me know


http://www.2carpros.com/forum/automotive_pictures/266999_AAA2_273.png


Dave H
Mar 17, 2009.
Hi Dave thanks for the reply for some reason ive only just read it when doing another search nothing came through to my email.

I thought I had resolved this issue because after my muffler exploded due to back pressure my mechanic diagnosed a faulty ignition coil.

I had the ignition coil spark plugs and leads replaced and all was fine. Until last week. Im having the same problem in the same places etc etc etc and now I think I can feel the back pressure when I hit the gas.

Obviously there is an underlying problem as it was only 6 months ago that I replaced everything any suggestions would be great.

Ive taken it to 2 mechanics but I have had no joy or solution - could I have fried the PCM?

Tiny
Markyboy132310
Oct 25, 2009.
I forgot to mention there are no warning lights come on, my headlights start 'jumping around' a bit like the power is effected and unfortunately it is reading no fault codes atall (and ive had it tested about 5 times)

Its getting a bit aggrevating now

Tiny
Markyboy132310
Oct 25, 2009.
OK this finally should answer everything, I dont get any warning lights atall, and I dont really stick to a particular fuel level, I fill up full everytime I get to 1/4 tank but the problem is persistant at all fuel levels

Tiny
Markyboy132310
Oct 25, 2009.
First ... remove and clean the CKP (crank position sensor) when this is dirty or worn and especially in damp conditions it sends bad signals to the PCM (computer) this should set a DTC and light up the MIL .. but not alway's ... it generally causes cutting out at random times so your fault is a little different but it cannot harm the vehicle for it to be cleaned .. if it looks badly worn then replace it ..

It could also be a faulty MAF (mass airflow) sensor causing rich (too much) or lean (too little)fuel through the engine .. but again this should be setting fault codes !!

It could also be a faulty fuel pressure regulator or a faulty fuel pump !!

It could be a bad PCM (computer) but i have never seen these symptoms caused by a bad PCM !!


http://www.2carpros.com/forum/automotive_pictures/266999_AAA2_111.png


Dave H
Oct 25, 2009.
Thankyou very very much I will let you know how I get on, this is a great site and your advice is invaluable.I guess ive been visiting a few bad mechanics because I asked about MAF & CKP and they didnt check it for me

Once again thankyou

Tiny
Markyboy132310
Oct 25, 2009.