I owned the '90(sig photo) prior to, and 4 additional IDI's since joining this group 12.5 years ago. I've never had to mess with the injection pumps or pump timing. I recently finished up head gaskets on the '93 w/Banks Sidewinder I picked up in August. The PO was a lady who's estranged husband had clearly done a fair amount of tinkering around under the hood. She couldn't provide a lot of color on the history other than he jacked up the glow plug relay wiring(beyond recognition and usefulness), and as a result of starting fluid, the head gasket(s) as well. She ran him off and the truck set for and extended period of time. When I put the injection pump back on, the static timing marks were aligned. I felt like this was a good place to start considering the unknowns.
When I got it running, it idled very smooth, but poured a ton of gray smoke. An intolerable amount. When warmed up, it stalled when returning to idle after revving. I advanced the timing from static, and I feel the smoking improved (small but noticeable), the idle remains smooth, and the stalling condition seems to have gotten better, but black smoke rolls with any revving and it seems grossly under powered. I've done a lot of research and reread threads addressing pump timing. While there is a lot said about pump timing and exhaust smoking, there aren't many remarks regarding pump timing and idle quality. What is the window between pump timing advance and retard where idle quality remains generally unchanged? I'm feeling like I need to baseline some variables in attempt to find a quality starting point on the timing. Some will say that the pump must be timed properly first, but I'd like to make sure the fuel screw and other factors are normalized first. Someone leaned on the pump timing adjustment boss previously, as part of it is fractured off, making it difficult to adjust the timing.
Thanks in advance for responses.
When I got it running, it idled very smooth, but poured a ton of gray smoke. An intolerable amount. When warmed up, it stalled when returning to idle after revving. I advanced the timing from static, and I feel the smoking improved (small but noticeable), the idle remains smooth, and the stalling condition seems to have gotten better, but black smoke rolls with any revving and it seems grossly under powered. I've done a lot of research and reread threads addressing pump timing. While there is a lot said about pump timing and exhaust smoking, there aren't many remarks regarding pump timing and idle quality. What is the window between pump timing advance and retard where idle quality remains generally unchanged? I'm feeling like I need to baseline some variables in attempt to find a quality starting point on the timing. Some will say that the pump must be timed properly first, but I'd like to make sure the fuel screw and other factors are normalized first. Someone leaned on the pump timing adjustment boss previously, as part of it is fractured off, making it difficult to adjust the timing.
Thanks in advance for responses.