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Is there any way to tame down the cruise control? Now that the car is making good power and the tune is good, when using cruise control the car gives too much throttle to speed up a little and takes away too much throttle to slow down a little. Car is a ratchetfoot! Is there any way to tame down the amount of throttle the cruise control gives and takes?
Car is an '89 vette running 165 ECM with 6E ARAP based tune.
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__________________ '89 MAF car, tune by me with help from this forum. 383 with Eagle forged internals, AFR 195 streets, 230/236 cam, HSR intake with custom plenum, Hooker 2151's, Crane CD ignition, 2800 stall, built 700R4, Nittos, Zex 225 shot. Best so far 10.66 @ 131.08.
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Cruise is controlled by a separate module. You will need to hac it and find out what part of the circuit controls the feedback loop. There is nothing in the ECM for this. Except to pull some timing to reduce the power and responsiveness of the engine.
I had that same problem once with a 2600 lb car and a large engine.
It would always overshoot the throttle adjustment, especially at slower speeds <65mph.
I had to re-engineer the cable connection to the throttle lever.
I had to add some slop in the connection, and limit the total throttle movement added by the cable. It fixed the problem enough to eliminate the surging at highway speed.
Some cruise control controllers have a DIP switch that can change the gain of the system. I don't know about factory GM units though.
In some cases it may be possible to swap the vacuum diaphram that controls the cable to something smaller with less power and less travel.
In some cases it may be possible to swap the vacuum diaphram that controls the cable to something smaller with less power and less travel.
Or modulate the vac source maybe? Some sort of solenoid to prevent vacuum buildup in the diaphram and only send vac to it when the system is on, doesn't seem that hard to rig up with a 12v vacuum solenoid pocketed at the JY, some wiring diagrams and some beer.
Mine does have a vac diaphragm controlling the cable, I'll have a good look at it tonight and see if I can adjust the cable somehow, or add a little slop to it. Never thought of that. Probably wouldn't take much.
I have same problem but again only <60 mph. tI think the issue is agrivated by my 7.4 TBI unit. Sequential throttle linkage might be the ans.
If you're good at welding you could extend the length of the throttle lever where the cruise cable attaches. Then, same movement of cable = less throttle opening.
