agent712

We're running an RE Ameryia (sp?) ecu right now and having some bad idle problems... Seems that whenever the second cooling fan (or a/c) kicks in it starts idling really bad. It's almost like it's revving itself... just sets there and goes vroom... vroom... vroom... vroom... vroom.... Don't know the exact rpm (it's my brothers car so i dont' drive it alot), but revs somewhere from 1100-1800 rpm. It's getting really annoying so we decided to just replace the ecu since that's when the problem started. But, as I was looking into a pfc I found someone who was having the same problems with the apex computer. I think he got it fixed, but it scares me. I don't want to spend 1300+ on an ecu plug tuning only to have the same problem.... this is the thread If you scroll down you will see a post from scotx mentioning something about "having a 94 PEG with the A/C recall (little black box near the ECU)". What is this? Is there some sort problem here and there with this "little black box near the ecu"? I'm thinking if this is what's causing the problems we're having right now, then we'll just get one of these little things, pop it in, and have a good idling car again?

Thoughts?


Thanks
Chuck

agent712

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agent712

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agent712

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spurvo

Can't say I know everything about this, but...

There is a little black box next to the ECU that senses power load conditions and raises the RPMs accordingly. Examples of this are the A/C being turned on, the heater blower fans (interior) set to 3 or 4, the running lights (which will also include the headlights if you switch to the second position on the stalk) being turned on, or the rear defrost being turned on. The manual calls this the "E/L sensor" for electrical load. Where this becomes important of course is the effect on the idle. On my car, I usually idle around 600 or so, and when I kick on the lights, it goes up to 850 to 900. This is true of any of the aforementioned electrical components. Note, however, that this little box was in the car from the beginning. I'm pretty sure idle is adjusted through the ISC valve, which is a little air bleeder valve on the throttle body (backside) that the ECU can control to change the idle to fit various needs, such as warming up and the like. So perhaps the ISC valve is opening too much on your car.

Now, there was a recall for the car for the 93's, and beginning 94, the circuitry for fan (cooling up front. They should BOTH come on by the way. They just rotate at different speeds to achieve low med and hi) was changed using another little black box. I think the major change here was to allow the cooling fans to stay on in the car if the temp was over 226 F for two minutes before the ignition is switched off. The fans will stay on for ten minutes after shutoff, sitting at med speed while the coolant is over 226 F (due to the engine coolant temp switch being open), and slowing to low speed for the remaining time when below 226F. BUT, I don't think this should effect idle speed at all. So I would look to the E/L sensor, and see a) how does it change idle speed (either through the ISC, or through timing, but I REALLY think it is the former), and b) is the idle speed controller doing it's job properly.

This help?

agent712

Well, I think that helps... I know the car has always idled over 1k rpm since he got it. If this little black box went bad, would it more than likely mess up the idle quality? It's never idled real nice... but after we put in the different ecu it just totally went bezerk...


Thanks
Chuck

agent712

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