Thermoplastic molding compositions comprising A) from 10 to 98.7% by weight of at least one thermoplastic polyamide having a viscosity number (VN) to ISO 307 of at least 150 ml/g, B) from 1 ppm to 0.95% by weight of at least one polyethyleneimine homo- or copolymer, C) from 0.05 to 3% by weight of a lubricant, D) from 0.05 to 3% by weight of a copper-containing stabilizer, E) from 1 to 50% by weight of a fibrous or particulate filler, or mixtures thereof, F) from 0.1 to 5% by weight of a nigrosine, G) from 0 to 30% by weight of further additives, the sum of components A) to G) adding up to 100%.