Well, tonight’s module install and test and tune session went ok.
Not fantastic, but not horrible either.
The first snag I ran into was right after the install of the digital module. As per MSD’s instructions, I tied the grey tach signal wire into the tach wire right at the distributor cap. To program the integral rev limiter, you’re supposed to ground the grey wire for one second at half your desired rev limit, and the module is supposed to program the limit at twice that rpm.
Only problem is, once I ground that wire, it wants to kill the car completely. I mean like shut right off from 3000 rpm. I then disconnected the grey wire from the tach wire and tried grounding it out separately thinking I had done something wrong, but that did zilch.
Quick searching on the interwebs on the issue revealed squat as well. I’m thinking it might possibly have something to do with the tach filter, but I couldn’t find it anywhere in the tach wire unless it’s buried somewhere way up underneath the dash and I wasn’t about to go down that rabbit hole. Not tonight at least.
Moving on, I put the vacuum gauge on a port on the carb, (I think it was manifold vacuum, but I suppose it could’ve been ported vacuum), and started tuning via the idle mixture screws and the idle speed screw.
I tuned for the highest vacuum reading I could get which was no more than about 12 1/2”, but then the throttle response off idle seemed really lazy. It seemed to like the screws backed out more than turned in, so I continued tweaking it from there. I got it to where the vacuum readings were still pretty close to peak, but where the throttle response was fairly acceptable too.
I definitely could not get the vacuum readings anywhere near the 20-22” that Mark figured I could get. 12 1/2” is the best it would do. I set the idle speed to around 900 rpm in park and 750ish in gear, and took it for a spin. From a part throttle whack, the car is plain violent. The trans kicks down, the tires light up instantly and it gets down and boogies. That part of it is plenty fun!
From a standing start, it’ll light the tires up and walk sideways for a good 50 feet or so, but to me it feels more laboured and isn’t as responsive as I’d like. Similarly, I can hear more than feel the secondaries open, but it just doesn’t seem to pull as hard as I think it should with them open. I dunno, maybe it was because by then the car had some heat in the engine and trans. It’s so tough to tell if it’s feeling a bit lazy because it’s running fat, or because it’s not getting enough fuel. Hopefully the new primary jets and secondary rods will help once they get here.
On a side note, the car for the most part gets largely ignored (despite all those months of hard work, probably due to its half primered appearance) but these jackasses in turbo diesel trucks always seem to feel the need to challenge me. And they always lose.
Lol
I had a guy in a Cummins TD Dodge during the test drive tonight that thought he was gonna dust me at a light and cut in front of me before his lane ended. Unfortunately for him, he learned the hard way that wasn’t gonna happen. Once we were moving I simply rolled the throttle 3/4’s on and walked away from him. By the next light, he was suddenly very interested in what I had under the hood!
😆
Anyways, that’s all for now, comments and opinions on what y’all think is happening and suggestions appreciated, on both the digital module issue, and things to try out on the carb.
Thanks all,
D.
Not fantastic, but not horrible either.
The first snag I ran into was right after the install of the digital module. As per MSD’s instructions, I tied the grey tach signal wire into the tach wire right at the distributor cap. To program the integral rev limiter, you’re supposed to ground the grey wire for one second at half your desired rev limit, and the module is supposed to program the limit at twice that rpm.
Only problem is, once I ground that wire, it wants to kill the car completely. I mean like shut right off from 3000 rpm. I then disconnected the grey wire from the tach wire and tried grounding it out separately thinking I had done something wrong, but that did zilch.
Quick searching on the interwebs on the issue revealed squat as well. I’m thinking it might possibly have something to do with the tach filter, but I couldn’t find it anywhere in the tach wire unless it’s buried somewhere way up underneath the dash and I wasn’t about to go down that rabbit hole. Not tonight at least.
Moving on, I put the vacuum gauge on a port on the carb, (I think it was manifold vacuum, but I suppose it could’ve been ported vacuum), and started tuning via the idle mixture screws and the idle speed screw.
I tuned for the highest vacuum reading I could get which was no more than about 12 1/2”, but then the throttle response off idle seemed really lazy. It seemed to like the screws backed out more than turned in, so I continued tweaking it from there. I got it to where the vacuum readings were still pretty close to peak, but where the throttle response was fairly acceptable too.
I definitely could not get the vacuum readings anywhere near the 20-22” that Mark figured I could get. 12 1/2” is the best it would do. I set the idle speed to around 900 rpm in park and 750ish in gear, and took it for a spin. From a part throttle whack, the car is plain violent. The trans kicks down, the tires light up instantly and it gets down and boogies. That part of it is plenty fun!
From a standing start, it’ll light the tires up and walk sideways for a good 50 feet or so, but to me it feels more laboured and isn’t as responsive as I’d like. Similarly, I can hear more than feel the secondaries open, but it just doesn’t seem to pull as hard as I think it should with them open. I dunno, maybe it was because by then the car had some heat in the engine and trans. It’s so tough to tell if it’s feeling a bit lazy because it’s running fat, or because it’s not getting enough fuel. Hopefully the new primary jets and secondary rods will help once they get here.
On a side note, the car for the most part gets largely ignored (despite all those months of hard work, probably due to its half primered appearance) but these jackasses in turbo diesel trucks always seem to feel the need to challenge me. And they always lose.
Lol
I had a guy in a Cummins TD Dodge during the test drive tonight that thought he was gonna dust me at a light and cut in front of me before his lane ended. Unfortunately for him, he learned the hard way that wasn’t gonna happen. Once we were moving I simply rolled the throttle 3/4’s on and walked away from him. By the next light, he was suddenly very interested in what I had under the hood!
😆
Anyways, that’s all for now, comments and opinions on what y’all think is happening and suggestions appreciated, on both the digital module issue, and things to try out on the carb.
Thanks all,
D.
