MA models, how to estimate lagged values of the error term?

[E-Conman]

How can I use lagged values of the error term in an equation? I tried the most common letters like e and u, and they are not working.

[EViews Gareth]

Could you provide context?

[E-Conman]

Could you provide context?

Apologies if I wasn't clear, I would simply like to estimate the following equation:

Y = C(1)*X + e(-1) + e

Where e(-1) is the lagged error term and e is the error term. Similar to MA models which use lagged error terms as regressors

[startz]

Estimate the equation including MA(1). Your "e" will be in the series resid.

[E-Conman]

Estimate the equation including MA(1). Your "e" will be in the series resid.

Is there a way to restrict the MA(1) to have a coefficient of one?

[startz]

I don't believe so.