[fixitmattman]

What you'll probably need a switch mounted to the engine temp sensor that triggers the fast idle.

Your other option is to fit an extra air bypass valve (or IAC) in place and then throw power to it.. it should open, allowing the right amount of air around the throttle plate.

Noooo! If you splice a switch with a resistor in the ect circuit, the engine would think its running cold (to rev up), and there would be no chance of the cooling fan ever coming on to cool the engine. That's a problem because you engine will most likely be at operating temp, and NEED that fan to come on after about 5 min or so but it won't because it's controlled by the ecu that thinks it's cold out.

For another air bypass, I think it would run lean as opposed to revving up as it's not getting the signal from the tps, and not running high idle because the ect is telling the ecu the engine is warm, thus any bypass should be closed or it'll run lean.

I think your best bet would be to rig up a solenoid to the trottle. Again you have the convienience of flicking a switch.

My two cents :roll:

Matt 8)

 

[fixitmattman]

Hrm.. I thought the computer used input from the coolant for the fan and a block temp sensor for the idle. Even if it kept the fan from coming on, it wouldn't be hard to wire the fan to come on whenever you threw the switch.

The car should be adjusting the mixture according to the MAF and the O2 sensor.. not just the TPS. That's all the IAC does is open a passage for air to bypass the TPS resulting in the high idle. But even so.. running lean at 2000rpm wouldn't really hurt anything, now would it?

:? I just don't know.

To my knowledge, the only sensor used by the ecu to turn on the fan is the ect. I personally never heard of a block temp sensor on an escort before (1.9, can't say for a 1.8 ). It would be rather easy to wire a switch into the fan circuit, but why if you don't have to. It would be just as much work to rig up a solenoid on the trottle and have everything run honky dory with no trouble.

The engine will run O.K. without the tps connected (personally done it before), but it is rather unresponsive. Especially when load is applied, which is when it starts to run lean. I know that for an SPL comp it wouldn't be running lean for too long, but because of the load from the alternator, it would run lean. Why take that risk. Lean running engines tend to burn valves in a hurry, and can cause severe engine damage. Given the 1.9's record of dropping valve seats, it wouldn't help at all.

I like mikes idea. Don't know if an RC servo would be strong enough, but instead of powering a small RC servo, you could get the reciever to activate a relay to power a larger solenoid if required. Just make sure to put an off switch on the RC connection for daily driving, or some little kid playing with his car might take control of yours

Matt 8)

 

[fixitmattman]

Yes, on some model lx's there are three temp sensors (fan, ecu, guage). I think it was either 93 or 94 that they changed to two sensors (guage, fan&ecu), thus what I said above, the ecu would always think the engine is cold and the fan would never come on.

The cruise servo is a great idea as well. The only way it won't work is if your car is like mine and has no cruise. But I like that idea though :wink:
You could either splice into the control circuit, or tee into opposite sides of the vacuum line and insert your own additional valve.

I think we need some more input from Xiph0id

NOTE: The Slack Requested has been approved

Matt 8)

 

[fixitmattman]

You'ld still need the control valve for the cruise servo, but if you could rig up an rc unit to the electronic control valve, it would be like everybodies idea all rolled into one

Some escorts only have 1 temp sender 8O Why would they do that? It's 33% less effiicent with 3

Better be careful. If we get too carried away we might get stuck installing it as well

Matt 8)

 

[fixitmattman]

1 more thing I should add about this. From the time I turn on the idle at 2000rpm until I am done with it is about 2-3 minutes. It might in fact be good to use the temp sensor so that the fan does NOT come on. For me every bit of power is important. When you run over 10000 watts on low voltage there are big voltage drops from the smallest things. Low voltage being a relative term and me saying low voltage I mean 17.4 volts.

True that. The cooling fan is a monster of a power eater on our cars. The friggin fan motor has got more power than the engine 8O You sound like you know what your doing in the electronics department. Personally I think with two alternators creating that much power you would need the fan to come on. It's a a fair bit of work (which creates heat) to make that much power. What you could also do is bypass the ect sensor, then rig up a switch with some sort of current regulator to have the fan running constantly, but not at full tilt alll the time. This way you would draw less power, keep your engine cool, get your high idle (resistor in the ect circuit to think its cold), and avoid massive voltage spikes as the fan won't unexpectedly kick in and cause you to loose your competition because you have no power left. :wink:

Matt 8)