My car has an annoying roughness to the way its running. This is a replacement motor that i reconditioned and installed a week ago. on the first drive it was smooth and sweet, then slowly deteriorated in last few days. Feels as if the timing is out. Engine rocks around on idle and slightly pops out the tail pipe at all loads, accelerates steadily (with vibration) then hesitates for a second at around 3000rpm in 3rd. power seems a little below what i expect of it, but is quite rough and vibrates a lot at every rpm. No error codes and a/f gauge reads stoich. on both banks.. im totally puzzled!! i have been reading up about CAS failures and i guess its my last ditch effort to replace that. Do my symptoms seem correct for a CAS failing? i thought the car just doesnt work if so.. I have replaced/ checked: throttle body MAF TPS Idle stepper Valley gaskets Spark plugs leads Coils, dfi fuel filter fuel reg injectors O2 sensors PCM vacuum lines Parts that are already new: fuel pump engine mounts got the clutch kit re-balanced just in case..no difference.
Do a compression test and see if all cylinders are equal and closely examine each plug as you remove it to locate the offending cylinder (if its compression related). Good Luck.
This may sound stupid, but is the engine mounts replaced with new ones during the change of the motor?? Is it new??
Mounts are NEW. Motor was a low kay replacement that i did a few mods to, and replaced all gaskets and seals. It ran PERFECT for the first few days then started to run rough. Hadnt even opened her up properly yet! had only revved it to 3k so far, just to ensure everything was ok
Upping the compression and getting more air in will affect your vacuum at idle, the ECU should compensate for it. Just try resetting the ECU by removing the positive battery terminal for 10 seconds, and then resetting your idle. After reconnecting the battery, rev to 2000rpm for 10 seconds. See how that goes.
Well to tell you the truth, it may sound stupid but replace the oil. Use magnatec. My idle is smoother. Particularly for you with a recon engine. It's a cheap option, and it's obviously still bothering you so it may be worth a try. Thats what came to mind when you mentioned the engine was fine in the first few days. You didn't do an unusually large amount of kilometres?
When i fitted the loom to this motor i forgot to bolt an earth point to where it was meant to be originally (battery to block behind the p/s pump). so i ended up bolting it to another point close by. seems as though it didnt like that too much. Today i spent ages trying to bolt that earth point to its original position. seems as though idle has improved. [Berlinarator] yet to change oil again tho, mite look into that. ive only done like 20km so far, and havent even revved her past 3k
