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Is My Cas Afm Or Tps Dead

BOOZTJUNKEY

By BOOZTJUNKEY,
in General Maintenance

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BOOZTJUNKEY Proficient

BOOZTJUNKEY

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I have suspected my cas to be faulty for some time the last week especially when I start the car it's starts up spluttering with a few revs it would go away also car won't hit boost until warmed up fully I gave always had a pop man miss on idle which turned into miss to the point it has trouble idling .. Idles round 600 and rough as guys I am replacing the tps and cas today but wanna be sure they are the issues any help appreciated my car Is a daily so need it sorted thanks

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BOOZTJUNKEY Proficient

BOOZTJUNKEY

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Changed cas and it is alot better but the miss is still there when it's cold and it still has idle problems it nealy stalls still would the tps be doing that ? I unplugged the afm while the car was going and it just stalled shoundn it keep running ? Ithought It would just have a fluctuating idle with it unplugged? Any body had this issue!

BOOZTJUNKEY Proficient

BOOZTJUNKEY

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I'm starting to look at the worst case scenario here maybe I have blown a ring and might be down on compression in a cylinder I think that because when I first start it ( cold start ) the it's like it runs on 5 cyl :( and under light throttle the ( just easing the power on) the car is hesitant sluggish and surges real bad it's a pig to drive but as it gets to running temp it comes good except from flat spots which I think is timing Im gunna do a comp test tonight

89CAL Grand Master

89CAL

Posted
Posted

600rpm is to low for your idle. You should change it to about 850rpm, or check your base idle anyway for starters.

Have you checked the timing since you installed the new CAS? It might be slightly out which is causing these issues.

Probably not AFM if theres such a noticable difference when you unplug it.. If you know someone with the same type AFM then you could try and borrow theres and see if it makes it any better just to rule it out

From the sounds of it, I'm Leaning towards it being a timing issue. Have a search on here to see how to check your timing

BOOZTJUNKEY Proficient

BOOZTJUNKEY

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Ok I think my timing is all screwed I have flat spots all thru the revs till after 5g and then my car violently jerks back and forth backfires and is a right pig to drive 89 cal I have not got Access to light till tomorrow so will check then.....

God I hope it's timing I suspect maybe a collapsed ring when I cold start it starts up missing kinda Like when there is an injector not firing or a coilpack arcing out

Also when I first start it I need to pump the shit out of the gas and it never starts first go and when It does u have to leave it sit Idling with ABSOLUTLY no throttle

If I try to rev at all it just wants to die and miss to the point if stalling it :(

It was that bad today that when I tried pumping the gas on initial start it was drawing enough energy from the electrics that it was turning my greedy turbo timer of and on as I tried to pump the gas which is seriously not right this is REALLY MAKING ME WONDER WTF

BOOZTJUNKEY Proficient

BOOZTJUNKEY

Posted
  • Author
Posted

Yeah standard ecu it had a tomie chipped ecu but took it out when my cas went because the aggressive timing map and dodgey cas made tha car detonate under load ....

I have suspected my timing to be out because the car is so hard to start in the morning or at first start I don't think I have dropped a ring now ;) I started the car this morn it was hesitant to stars still but it started and idled fine so I think the ecu has started to learn and correct some of the issues I am putting a light on it this Arvo I'll let you no ow I go thanks agajn

89CAL Grand Master

89CAL

Posted
Posted

You can reset the ecu and i think it will slightly advance timing on first start then bring it down as it learns what the engine is doing. I suggest checking base timing then maybe reset your ecu as well. Might work a treat

BOOZTJUNKEY Proficient

BOOZTJUNKEY

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Ive reset the ecu already when I put the new cas in ....

today when I drove it seemed to run a big better which will be the ecu learning as you said as for the flats spots no change as yet but I no it's timing because when my knock sensor lead fell off it felt the same then the timing was being retarded big time as for the light my mates light doesn't have the clip for the trigger wire so have to wait again

  • 5 months later...
89CAL Grand Master

89CAL

Posted
Posted

Cam Angle Sensor: used to determine where TDC of each cylinder so the engine can inject fuel and power the spark plugs

Can also be Crank angle sensor getting the measurement from the crankshaft is some engines

In RB series engines it is the silver thing on the timing cover (exhaust side)

LeCoq Rising Star

LeCoq

Posted
Posted

600rpm is to low for your idle. You should change it to about 850rpm, or check your base idle anyway for starters.

Have you checked the timing since you installed the new CAS? It might be slightly out which is causing these issues.

Probably not AFM if theres such a noticable difference when you unplug it.. If you know someone with the same type AFM then you could try and borrow theres and see if it makes it any better just to rule it out

From the sounds of it, I'm Leaning towards it being a timing issue. Have a search on here to see how to check your timing

I tried unplugging my AFM on my r33 series 2 and starting the car, the car doesnt start at all!!! but when i plug in my AFM and start the car it works. But its got idle problems too. so faulty AFM???

central coast person Proficient

central coast person

Posted
Posted (edited)

i've got the lumpy start up unless i rev it a bit or let it die and 2nd crank around is always as it should be as if it never had the problem, ive always thought it was the hot wire where the AFM is and the switch board ontop just needs re soldering but have never gotten around to it even though i have rebuilt the engine ........... maybe tonight :)

Also if the AFM is faulty it can cause what looks to be lumpy timing just because the engine has no idea of the air volume.

Edited by central coast person

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