Alfa 156 1.8 TS rough idle and misfire at low revs - Page 2 - Alfa Romeo Forum
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yes, leak in the inlet manifold is possible.
is it accelerating on its own or is it your foot?
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(Post Link) post #27 of 40 Old 06-08-16 Thread Starter
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It is me. Now I have to take off the manifold to check it...firstly will try to spray the manifold to see if it changes the idle at all. Also noticed that the car runs OK camshaft position sensor disconnected, I remember when it was bad I couldn't drive it, now it is fine...
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on video looks much better than what you described. I presume you know it is normal for idle rpm to be that high when engine is still cold.
from what I can recall, I think my 156 1.8 ts doesn't run with camshaft position sensor disconnected too.
also read it here somewhere, rough cold engine idle on M.Y. 2000 1.8 ts models were due to an ECU software upgrade.
hope it is «just» a vacuum leak in the intake.
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Well it was hot I think...maybe you are right, now after the reset it doesnt sound as bad as I described but there is still this problem of rough driving at low rpms, very hard to drive in 5th at 1500 rpms
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Well it was hot I think...maybe you are right, now after the reset it doesnt sound as bad as I described but there is still this problem of rough driving at low rpms, very hard to drive in 5th at 1500 rpms
Same problem as you reported.
In cold days it work well, in hot days, the hell breaks loose. In intense traffic, soon or later it appears again.
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Originally Posted by ricardoclima View Post
Same problem as you reported.
In cold days it work well, in hot days, the hell breaks loose. In intense traffic, soon or later it appears again.
I found that maybe there is a problem with throttle valve, I think it should be more closed then it is and maybe the main culprit is the idle actuator, which is also a throttle potentiometer that tells the ECU where the throttle valve is. I have tried disconnecting the actuator and nothing happened, the idle is the same, rough but cannot go over 2000 rpm because the potentiometer isn't telling ECU where it is. Totaly confused now...
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people got away with opening the throttle potentiometer and cleaning it. but you have no bolts to open it. you would have to break in through it and glue the plastic housing pieces back together. not a standard job, if I am making myself clear.
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OK, I will try that after I try a different MAF on Sunday
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Changed the MAF, problem not solved, checked the sparkplugs and mixed the ignition coils, sparks are great, so no misfire whatsoever. I will loose my mind over it!
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any chance to check the condition of your catalytic converter, if it's broken, blocked?...
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any chance to check the condition of your catalytic converter, if it's broken, blocked?...
Catalytic converter on a 1998 car in Bosnia? That can't be right . I have the catalytic converter but it is empty, somebody took out of it.
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also occurred to me to check fuel pressure. could unstable fuel pressure also cause this?
edit: if running on lpg the problem persists, then I presume that is not the issue.
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I would also check ignition coil pack condition as well as all connections to it and between the coil packs and spark plugs, specially coil packs 1 and 2 on CF1 and CF2 TS engines.
other than that, could be engine related.

Last edited by alfizta; 31-08-16 at 12:21.
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(Post Link) post #39 of 40 Old 05-09-16 Thread Starter
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Originally Posted by alfizta View Post
I would also check ignition coil pack condition as well as all connections to it and between the coil packs and spark plugs, specially coil packs 1 and 2 on CF1 and CF2 TS engines.
other than that, could be engine related.
Hi! It is still running rough, noticed that there is a hesitation when getting to 2200-2400 rpm, it kind of stops accelerating and after a second continues to accelerate. Haven't had time to change coils, I have to go 70 km to borrow coil pack from my friend to test it.
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you don't need to borrow coil packs from another, as long 2 of them are OK.
engine will run fine with just coils 1 and 2. check these two as well leads the connectors to spark plugs. if you find that one is suspicious switch it with coil 3 or 4 that is in good condition. do the same with any lead or spark plug connector. disconnect coils 3 and 4. this is ONLY true if your engine is a CF1 or CF2 version, like this one (check how coils link to spark plugs!!!)
http://www.alfaowner.com/Forum/attac...1&d=1473068012

but, the way you describe it, still sounds more like a maf or vacuum leak problem. anyway, it is always worth to check the coils.
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