The MacDonald Partnership withdrew from a deal after coming up against "unexpected problems".
A spokesman for Merseyside-based Jensen confirmed on Monday that the directors had recommended going into administration to "give the company breathing space."
Doug MacDonald, director of MacDonald, said: "Jensen is a terrific company and the car is a first-class product.
"Regrettably we have come up against irresolvable issues and have consequently withdrawn from the deal.
"However, at some stage we might consider looking at the company again."
MacDonald was understood to have put forward a proposal which would have seen it invest capital in Jensen and become a majority shareholder.
Workforce redundant
Production was then likely to move abroad, to a cheaper country such as South Africa.
Jensen, which makes the £40,000 Jensen SV8 roadster, last week made its entire workforce redundant.
Its 40 workers were laid off on 30 June and officially made redundant on Friday - they were told not to turn up for work on Monday.
Jensen, famous for its Interceptor car, was established in the 1930s and ceased production in the late 1970s before its reinvention at Speke in the 1990s.