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Cruise Control


mark brown
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I’ve started this as a new thread when perhaps it should have continued under the delimiting thread.  Over the last 6 months I have had an ongoing problem with my cruise control:

 

The Cruise Control will work for up to 10/20 mins, then cut out and the Cruise light in the dash starts flashing. Turning the Cruise Control off then on stops the flashing, the cruise light in the dash then illuminates, but the cruise control is non-operational. Shortly afterwards, on most occasions, the engine management warning light illuminates and the red warning triangle in the speedo (Car continues to run fine). The cruise control remains non-operational. After a period of time the warning lights go out, the period of time varies and the cruise control becomes operational again. Sometimes the failed cruise can be made operational by rapidly turning the cruise on and off but there is no consistency in whether this fixes the fault or not.

 

At other times without having turned the cruise control on the engine management warning light and warning triangle will illuminate again for varying periods and during this period the cruise control will not operate. In these circumstances, the timing and circumstances of these warning lights illuminating varies and is inconsistent.

 

Initial diagnosis was the speed converter, attached to the gearbox output, which I understand is speed sensor No1. After changing this, for a couple of weeks the problem was less frequent, but has now returned as frequently as before.

 

In an endeavour to overcome this I am currently doing the following; changing speedo and odometer to UK version, fitted HKS SLD to overcome speed limiter and have removed the speed converter, I am also fitting a new gearbox transducer. Diagnostics at a Toyota dealer have revealed nothing.

 

On the basis the cruise control will be receiving an unmodified signal it will be limited to 70mph. Presumably all I need to do to over come this is put a speed converter into the speed signal wire just before the cruise control ECU.

 

A few questions arise because I am not convinced all of the above will correct the problem, as I initially removed the converter, putting the car back to original spec, i..e kmh and limited to 112mph and the cruise control problem was still there.

 

Firstly am I correct in my thoughts on modifying the speed signal to the Cruise control?

 

Secondly, could a faulty odometer affect the cruise control speed signal?

 

Thirdly, could this problem be heat related, is it likely that the cruise ECU could be failing as it gets warmer?

 

Speed sensor No1 is the gearbox ouput, where is speed sensor No2? Is there any connection with the ABS sensors? As the problem appeared after 12 months trouble free running when it was raining extremely hard and I had driven through some fairly serious puddles/river running down the motorway.

 

Any help would be much appreciated as I want to fix this before going on to a non sequential twin conversion.

 

Mark Brown

TT J Spec

 

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I'll think you'll find either your converter output is goosed, or your odometer output buffer is, it's one of the two from your description. it's going to cost either £60 or £120 to fix.

 

I'm going to propose a solution which eliminates the current primitive converter straight away, to be 'safe' and it might just be the cheapest option.

 

First take the effing converter off the gearbox (kill the person who did that to you), make the wiring good, very, *very* good and move back up into the car.

 

Buy one of Pete Betts speed converters, one of his NEW speed converters (either wait a week so until he's got the gear change timing for the auto box modification implemented or, if your car's a manual box, you can go with his current version - make sure it's the one with a 1:1 output, he'll know what you mean). They're about £60 I think.

 

I'm not going to propose you do it the way I did as I was unecessarily pedantic about modifying the speedo.

 

Cut the signal wire to the speedo (only to the speedo, do NOT cut the common feed to the speedo *and* odometer). Using the cut ends, feed the converter input with the signal from Sensor No 1 and the 8:5 output to the speedo. Everything else should stay the same for now.

 

Afeter this mod everything should be working normally, i.e., your speedo will read in MPH but your odo will almost certainly now be clocking KM *whatever the KM/MILEs light says*. You will be speed limited to 112MPH and, if you have an auto box the gear changes will probably be smoother. The PPS should feel slightly heavier at mid-range speeds (as it's supposed to).

 

Check for a few test runs that your cruise is either working or not.

 

If this doesn't fix it, your odo output buffer is shot (same happened to mine) and you'll need to buy a new j-spec odo from Abbey Toyota in Redhill (they'll mailorder you a new one for about £60).

 

For the moment, lets's assume everything is hunky dory. You'll now need to mod your odo to clock MILES and remove your 112 MPH speed limit. Pete's new speed converter has (will have) a limit on the 1:1 output signal and if you cut the output signal from the odometer (PINK wire) and feed the ongoing signal with Pete's 1:1 output, it will remove the 112MPH limit *properly* (it doesn't divide the signal, it caps it). Unfortunately, it won't deal with an auto box's need for a shift in 3rd-4th timing at speeds above 120MPH, that will be available in a week or so.

 

I can't remember the resistor swap on the odo, let's get to that point first.

 

If we get to this point and everything is happy, the ECTS ECU S2 signal mod will be a doddle.

 

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Paul, and who can I get to do this for me if I buy the parts, (ideally on a Saturday), I thought my problems had gone away, but still have some sort of limit around 120/130mph. Recommendations, preferably near Herefordshire. Is Chris Wilson this side of the country?

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Quote: from Simon on 11:21 pm on Oct. 2, 2001[br]Paul, and who can I get to do this for me if I buy the parts, (ideally on a Saturday), I thought my problems had gone away, but still have some sort of limit around 120/130mph. Recommendations, preferably near Herefordshire. Is Chris Wilson this side of the country?

 

Chris lives in Prees Heath, just South of Whitchurch off the Shrewsbury road.

 

Pete Betts is in Warwickshire, just North of Leamington Spa.

 

 

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Quote: from mark brown on 7:16 pm on Oct. 3, 2001[br]Paul

 

Thanks. The changes detailed in my post are currently being fitted so I can't stop that. Once thats done I'll check it works ok, and then I'll use one of Pete's converters to fix the Cruise signal.

 

Mark

 

Without the padding, can you list what you're doing and the state it will be in when it's done?

If I've read it correctly, apart from having replaced things that are nothing to do with the cruise control, you shouldn't need to do anything else for it to work. Working well remains to be seen.

 

 

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