Time delay estimation of two sensor signals
Comment: As a new user I am not allowed to add a comment to your question - hence this approach.

You mention that you do get a peak from the cross-correlation but that the lag estimation is incorrect.  This implies that you know the correct result - is from a calibration signal or ..? And what is the lag roughly?

Could you explain what the signals look like (sinusoidals for example)?  Also what is the SNR, sequence length, sampling frequency? Have you filtered the signals before sampling - if so how?

If the offset is incorrect it might be related to insufficient time resolution. Using a sampling frequency $f_s$ means that your time resolution is $T_\mathrm{s}=\frac{1}{f_\mathrm{s}}$.  If this time resolution is not sufficiently small you may get an estimate that does not agree with your expectations.

There may be other techniques but this depends on the signals you have - and also if you for example know that the lag is always a fraction of a period time of a periodic signal. Some more details could help with this.