Serum test levels rise dramatically, regardless of the ester, immediately (within hours). It really is a myth that short esters "kick in" or effect you quicker. The ester has more to do with half life than it does with immediate effect. If you can't feel test enan for weeks, suffice to say you are not very sensitive in assessing yourself. Test levels spike very high the day of test enanthate injection and fall off after that.
"The pharmacokinetics of 2 testosterone esters, testosterone enanthate and testosterone cyclohexanecarboxylate, were compared in a single blind crossover study in healthy young men. Their effects on serum and salivary levels of testosterone, as well as on the serum levels of LH, FSH and proclactin were measured after the injection of doses equivalent to 140 mg free testosterone. Both preparations yielded supraphysiological testosterone levels in serum and saliva as early as 2 h following injection, reaching peak levels 4 to 5 times above basal between 8 and 24 h. LH and FSH levels were suppressed as long as serum testosterone levels were elevated. Nine days after injecting testosterone enanthate and 7 days after giving testosterone cyclohexanecarboxylate, serum and salivary levels of testosterone had returned to basal. The longer activity of testosterone enanthate was also evidenced from more extended suppression of gonadotrophin levels. Although neither preparation is ideal because of the initial supraphysiological peaks, testosterone enanthate appears preferable for clinical use because of its slightly longer duration of action."