Automotive Plastics: Plastic bumper cover identification, polyurethane, repair

Question
I have a bumper cover off of a 1990 BMW 325is which is in need of repair.  The bumper cover is part of an M Technic II ground effects kit.  This kit is a BMW OEM kit. I have a plastic welding kit and have attempted to repair it.  I cannot find out what type of plastic it is.  I have tried the burn test and it has a yellow flame which does not drip, black sooty smoke, smells sweet and fruity.  When I put the heat to it to try to tack weld it, it takes a fair amount of heat to get it to melt.  It does not pool and want to stick to itself.  When you pull the heat away, the surface seems to flake away when scraped with a fingernail.  What is this stuff?  The only markings I can find on it are the date manufactured on it ( 88/12 ).  Is this a thermoset type of plastic and cannot be welded?  Does it have to be repaired chemically? I need some help on this.
Cheers

Answer
Hi Mike, Thank you for providing such detailed description of the polymer you try to repair. I think you are dealing with polyurethane >PU<, a plastic that will respond fine when it comes to dents or bumps. If the problem is cracks, PU is virtually non-repairable unless thickness of material is at least 2 m.m. or a little more than 1/8 of an inch. If this is the case and a back reinforcement of 1/4" (Polyester resin and rivets)can be installed without affecting fitness,and you are patient, I may have an affordable solution. Please write again if the broken parts meet these requirements. Thanks