I'm trying to figure out what would cause one or two cylinders to run rich in my OBD1 S52. Been chasing a problem for months with hesitation until 4k rpms and done about everything i can think of, one thing that hasnt changed is cylinder 6 spark plug shows rich condition and cylinder 4 looks a tad rich but not as much
Things to note:
-Compression check good (less than 5 psi difference across all cylinders)
-leakdown provided no answer, everything good with nothing out of the ordinary
-checked for vacuum leaks multiple times, home made smoke test and essentially dousing everything in carb cleaner showed nothing
-replaced maf
-rebuilt vanos
-replaced crank and cam position sensor
-replaced coolant temp sensor
-replaced intake temp sensor
-replaced injectors twice (both new sets)
-replaced and swapped around coil packs (no change regardless)
-replaced spark plugs twice (both new, checked gap each time)
-replaced fuel pump, filter, and FPR
-replaced o2 sensor (have a new bosch sensor to try too)
-replaced ecu
-installed new sssquid chip
-tried different known good ICV
-tried different known good
-replaced battery
basically everything electronic and fuel related has been replaced and mechanically the engine seems great, just not under 4k. after a battery reset the idle searches and will dip when coming to a stop until after some time learning. then from a stop and cruising it hesitates and bucks until above 4k. i initially thought is was the vanos but after a rebuild the problem still exists. it seems like the initial battery reset idle problem and the hesitation are related but not 100% on that. its awesome above 4k but cruising on the highway and from a stop its terrible
i need the r3v gurus help on this, im about to hesitate this POS into a wall. the only thing electronic left to replace is the knock sensors and the wiring harness (which i have both) but was wondering if anyone had any input.
spark plug picture and video will be in next post
update: redid timing and main exhaust sprocket seemed off a tooth so moved it according to the pelican procedure and now all are rich, still has hesitation
Things to note:
-Compression check good (less than 5 psi difference across all cylinders)
-leakdown provided no answer, everything good with nothing out of the ordinary
-checked for vacuum leaks multiple times, home made smoke test and essentially dousing everything in carb cleaner showed nothing
-replaced maf
-rebuilt vanos
-replaced crank and cam position sensor
-replaced coolant temp sensor
-replaced intake temp sensor
-replaced injectors twice (both new sets)
-replaced and swapped around coil packs (no change regardless)
-replaced spark plugs twice (both new, checked gap each time)
-replaced fuel pump, filter, and FPR
-replaced o2 sensor (have a new bosch sensor to try too)
-replaced ecu
-installed new sssquid chip
-tried different known good ICV
-tried different known good
-replaced battery
basically everything electronic and fuel related has been replaced and mechanically the engine seems great, just not under 4k. after a battery reset the idle searches and will dip when coming to a stop until after some time learning. then from a stop and cruising it hesitates and bucks until above 4k. i initially thought is was the vanos but after a rebuild the problem still exists. it seems like the initial battery reset idle problem and the hesitation are related but not 100% on that. its awesome above 4k but cruising on the highway and from a stop its terrible
i need the r3v gurus help on this, im about to hesitate this POS into a wall. the only thing electronic left to replace is the knock sensors and the wiring harness (which i have both) but was wondering if anyone had any input.
spark plug picture and video will be in next post
update: redid timing and main exhaust sprocket seemed off a tooth so moved it according to the pelican procedure and now all are rich, still has hesitation
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