I have similar problem... But if i just wait for about 30 seconds ( Could be more ) I can tell by the volt gauge ( After market )dropping suddenly that the relay had come in.. Then i just wait 5 or so seconds and it starts perfectly. No idea why the signal to the relay is taking so long to do its thing, and i havent been able to find any data on the subject, but at least now i know whats happening i know it will start. I was thinking on changing GPR to a manual system, but havent got around to it yet.