Cruise control wont't control above 50 mphcruise control
Posted 17 December 2018 - 03:08 PM
Anyway, I realize the issue may be in the cruise control module in the engine bay. So basically any who could tell me if I need to replace or can it be rebuilt.
Thanks for the guys (or any girls that might be here) you all have never let me down.
Posted 17 December 2018 - 05:06 PM
2004 Lexus IS300 - Soon to be NA-T
1988 Conquest TSI - SOLD/Parted out
Magna Intake, MEGASQUIRT 2 (V3 Extra fw) Direct Coil Control - EDIS 4, 292m cam, Synapse Synchronic 40mm WG, Synapse Synchronic BOV, T3 TD06 20G turbo w/ .80 housing, 95 lb injectors, Treastone turbo manifold, ST springs, KYB GR2 shocks, MK1 front camber plates, Drilled/slotted rotors and braided brake lines, HD valve springs, SR20DET 3-row Radiator. MK1 Short Shifter, Da Funk Loc motor mount, Transmission Tuff-pan, Stedebani poly trans mount, Cusco front strut brace, TEP rear strut brace w/ battery tray, AEM UEGO wideband sensor.
Click the pictures for larger images:
Posted 17 December 2018 - 06:06 PM
The vacuum canister is for the HVAC controls only. It doesn't store enough vacuum to operate cruise control.
3 things to check
The cruise control cable moves freely and doesn't bind in any way.
The filter on the actuator under the metal plate needs to be replaced if it's the stock one. I used a cotton ball to replace mine.
Make sure the vacuum pump works and is connected. There's a vacuum pump next to the radiator overflow bottle that is only for the cruise control actuator. The relay for that pump is on the fender next to the wiper motor. Vacuum line should go from pump to actuator then to a white check valve and finally to the intake.
Posted 18 December 2018 - 01:49 PM
Posted 18 December 2018 - 03:42 PM
Posted 25 December 2018 - 01:29 PM
How would I check if the vac. pump is working?
Also, dam that's one clean engine bay. (NICE).
Posted 25 December 2018 - 10:09 PM
Posted 25 December 2018 - 10:32 PM
You'd have to clip the quick disconnect with the pump if acquiring from a junk yard, then get some cheap vacuum adapters to shrink the tubing down. Splice in the new connector for the pump and you're good to go.
Edited by Turbo Cary, 25 December 2018 - 10:33 PM.
Posted 25 December 2018 - 11:32 PM
Off topic but a good size glass jar like a pickle jar and a vacuum pump it makes a great brake bleeder. Glue 2 pieces of brake line or similar size tubing to the cap of the jar. One tube connects to the vac pump. The other to a brake bleed screw. The tube that gets the bleed hose also gets a small hose for inside the jar running from the cap to the bottom of the jar. That way you can see the bubbles coming out of the brake lines. I've used this to bleed brakes, suck up engine oil, drain a power steering system. I've even used it to remove gear oil from a diff that didn't have a drain plug. It's a handy little tool you can make practically for free.
Posted 26 December 2018 - 01:01 PM
My main suggestion is due to the factory pump being 30+ year old plastic versus a newer aluminum bodied part readily found across the nation. Your idea for a cheap-o Mighty Vac is a good idea. MV's cost anywhere from 250-500 depending on capacity.
Posted 26 December 2018 - 10:08 PM
Posted 26 December 2018 - 10:48 PM
Typical issues with the cruise control are:
1: obviously leaks in the vacuum hoses to/from the cruise actuator itself.
2: leaks at the vacuum pump. I've seen the hose split/leak underneath the rubber cover piece of the pump.
3: that little vacuum sensing switch fails. When this happens, the cruise will work fine when the engine is not loaded too heavily (i.e. when engine vacuum is high).
4: the relay controlled by the vacuum sensing switch fails. So the switch can't trigger the relay to send electrical power to the vacuum pump.
5: air filters in the cruise actuator are clogged as ucw458 posted.
6: where the cable exists the cruise actuator you'll see a small plastic square-shaped thing... sometimes the cable gets frayed inside this two-piece plastic gizmo. The cable passes through the firewall and makes a U-turn underneath the dash to grab the linkage above the throttle pedal. Kinks and binding in the cable, or wires/air ducting under the dash that are hanging low can get in the way of this linkage.
7: Underneath the dash the end of the cruise control actuator cable is clipped to the dash metal structure... via a rectangular shaped piece of metal with a slot cut in it. That clip fits over the metal part of the cable sheathing to anchor it to the dash/chassis structure. If the clip is missing, or is in the wrong part of the sheathing, then the whole cable flops about when the cruise control actuator tries to pull on the throttle linkage. With the engine OFF and the throttle pedal "relaxed" to the idle position, ideally there is very little slop between the cruise cable sheathing and the throttle pedal linkage. The closer the clip is to the end of the sheathing the better - until you go one slot (you'll see slots in the end of the sheathing) too far and there is NO slack at all... you need some slack to make sure the cruise control cable doesn't keep the throttle pedal from relaxing to the idle position.
8: an incorrect replacement cruise control cable was installed - basically if the ends of the cable (the parts sticking out beyond the protective sheathing) are too long then most of the cruise control actuator's in/out travel range is wasted absorbing this slop. This is not too likely; consider it a last resort once you've ruled out the other possibilities.
I think you can test the vacuum pump and the vacuum sensing switch by unplugging the hose at the base of the throttle body. Cap the port but not the hose. This should force the cruise control system into using the vacuum pump only. So go for a drive and try using the cruise control... if it works at all then the vacuum switch and pump are at least trying to work... the bug is elsewhere. (hoses, jammed cable, etc.) You'll notice during this test drive that your dash vent controls may not work either because we've disconnected their vacuum source. (they may work for a little while based on the vacuum trapped in the reservoir/canister unit)
Posted 29 December 2018 - 10:11 PM
Check valves are rubber flappers.
Break down the actuator to get to the check valves and clean the goo (that used to be a filter but now is not) off.
Posted 10 January 2019 - 05:34 PM
Mid you all I do is strip out the cable core and fish it through the existing sheath. Works well when you got the right part to start with. So, make note that RockAuto does not carry the right part for our speedometers. Regardless of the image and part number ATP Y-861. Amazon has the same part number but actually has the right part.
I've pretty much lost daylight as of this writing, but I have made note of all of the info and will endeavor to start figuring out the source of the fault. I'll check back hopefully with good news, if not with more questions.
Edited by madmanperez, 10 January 2019 - 05:36 PM.
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