ECU question

[SFCRangerDoc]

I'd check the throttle plate like I mentioned earlier. You may well have to tweak its positioning, and your idle may be perfect. I'd do that at least, before I returned it. There is a throttle set screw on the side of the TB.

Ok at the risk of jinxing myself I "may" have sorted it out. time will tell when the car has sat overnight and is cold.

I adjusted the throttle screw like you said to do. I have the car warmed up and idling maybe around 850-900ish in park and 750ish when in drive and my foot on the brake. When it starts up initally it goes to about 1-1100k and then drops down. I do notice the idle fluctuates when in park (wonder if thats the potentially bad IAC). When car is in drive the idle is smooth and steady. I may have to do some further adjusting perhaps...dont know what will happen with a cold morning start.

Of note, the results above are also including putting the spout connector and the FPR vacuum line back on.

 

[2stroke]

That sounds a lot better, and as far as the fluctuating idle, I think you just notice it now. The device on the IAC that pushes the plunger is not a solenoid. I have heard it refereed to as a stepper motor. I've noticed they often switched quickly between steps creating an wavy idle if you listen carefully. The average person will never notice this, as its only a change of a couple of rpms. I have considered adding a restriction plate to the IAC to combat this, as well as reduce the cold start rev. When I start mine ice cold, the IAC fully opens, and quickly revs to 1500 rpm or so. It instantly drops to 1100 rpm for a cold idle, however. My 94 explorer (which is still parked in the back yard ready for my crazy mind to go to work) is perfect. It fires up smooth, idles 1000 rpm for a minute, until it settles down to 650 for a warm idle. That is the ideal for these motors IMO.

 

[SFCRangerDoc]

That sounds a lot better, and as far as the fluctuating idle, I think you just notice it now. The device on the IAC that pushes the plunger is not a solenoid. I have heard it refereed to as a stepper motor. I've noticed they often switched quickly between steps creating an wavy idle if you listen carefully. The average person will never notice this, as its only a change of a couple of rpms. I have considered adding a restriction plate to the IAC to combat this, as well as reduce the cold start rev. When I start mine ice cold, the IAC fully opens, and quickly revs to 1500 rpm or so. It instantly drops to 1100 rpm for a cold idle, however. My 94 explorer (which is still parked in the back yard ready for my crazy mind to go to work) is perfect. It fires up smooth, idles 1000 rpm for a minute, until it settles down to 650 for a warm idle. That is the ideal for these motors IMO.

Mrs doc reports the expy started up on the first crank this morning and idled much more normal! It was about 33 degs and ice on the car. She started it with the defrost and blower on max too. Looks like it may just have needed some adjustment to the throttle plate to get the air mixture right and get the TPS reporting the right data to the computer. Will report back later on this week with final results.

 

[Rhett]

Mrs doc reports the expy started up on the first crank this morning and idled much more normal! It was about 33 degs and ice on the car. She started it with the defrost and blower on max too. Looks like it may just have needed some adjustment to the throttle plate to get the air mixture right and get the TPS reporting the right data to the computer. Will report back later on this week with final results.

That's great to hear! Mine idles at about 650 once it's going. I'm on my second IAC at almost 180,000 miles on the truck. My first one probably still works...I only replaced it because I had a bird chirp that I couldn't find (turned out to be the cam position sensor/drive unit).

33 degrees!! It was 70 here yesterday. Stay warm.

 

[SFCRangerDoc]

That's great to hear! Mine idles at about 650 once it's going. I'm on my second IAC at almost 180,000 miles on the truck. My first one probably still works...I only replaced it because I had a bird chirp that I couldn't find (turned out to be the cam position sensor/drive unit).

33 degrees!! It was 70 here yesterday. Stay warm.

Yeah, this "cold snap" for CA is kinda odd, but gives me good cold weather starting testing!!! lol

I think I'm going to change out the IAC anyway, it appears to be the original and the gasket is starting to fall apart. If everything remains good I think I'll keep the computer after all!

 

[SFCRangerDoc]

I wanted to post up that things are indeed back to normal with the expy! Apparently that throttle plate set screw was all i needed to adjust. I would have thought the ECU could have figured out how to make the car run properly without having to do that, but I guess not. I appreciate all the time and thoughts you all have put into my saga over the last few months! This is truly one of the best and most helpful forums I've ever come across!

 

[smegun]

i was woried someone shorted one of my drivers testing a fuel injector only one of my spark plugs had dry carbon powder and there was a little valve tick and weak horses and a little hollow spot in the rythem ...replaced everything in engine management first but then swaped out the ecu ...its better now its an old engine used a little sea foam in the crankcase too may have got it but im still going to change the timing chain next and oil pump
the idea of solid lifters are more bullit proof

inside the ecu is non sympathetic the rom is not socketed and its not easy to work on welded in if i think of it now i would of changed the drivers out the caps are ceramic chicklets were to buy injector drivers there hearty transistors tied to the base of the case and should be replaceable



there must be a programmer with a card slot adapter a card slot adapter is old school also needs an interface to usb