What is not true about the 2.8's ECU? It controls just as much of the engine as any other computer does. And other systems are really no more complex.

 

yes. I sometimes stick it to myself. just to keep it real..... im still jenni from the block

 

i really dont consider anything non-EFI as having a true ECU. my r6 has an "ecu", and its carbed, but really, not the same thing. there is a difference between avoltagedependant response loop and an actual computer which will interperet input data and make corrections according to its programming. the 3.1 and 2.8, and hell, even many 350s including the crossfire system, see a voltage from sensor x, and are locked into a specific behavior. a"true" ECU can read an additional variable and decide how to optimize, and record changes and results and "decide"the best fit.

thisis why I run speed density in my car. I dont want a computer telling me what AFR to run

 

Just what is that extra variable that you believe these computers do not read. These computers do read data from sensors and make changes. They are also capable of seeing when a component is failing and compensate for it.
So what is it that these engine control units don't do that does not make them true engine control units.

 

Thats correct it functions more like a PCB then a true ECU.

 

ok first off? the shops a bunch of idiots, im going to tell you what they probably did, they probably pulled the distributor and forgot to mark its position prior to pulling, put it all back to gether and couldnt figure out how to get the car into set timing mode, so they times it by ear and adjusted you idle screw up to compensate, the bad part about all of this? the ECU controls engine RPM on all MPFI 2.8 liters, it even says on there DO NOT ADJUST IDLE SCREW! there is NO way you will get that car running properly without a GM Tech 1 Scanner now, they completely confused your computer.i will agree though, the 2.8 and 3.1 computers are what i call "stupid Computers"

 

I believe it is not an actual computer, although I dont know for sure. i say this mostly because the years that these cars were built didnt have the computer chip technology to hold and maintain fuel trim tables while calculating corrections.the 1980s was the mac classic era [&:]. From my understanding of early ECUs, they could not make corrections to a fuel trim table. instead they were givena table and the engine was locked into specific behavior based on MAP and engine speed, aka speed density. I guess if we want to split hairs, we would say the 2.8 has an ECU, but does not have a true PCM. regardless of how you want to cut it, electronics in this era were pretty primitive and shallow. Try tuning a MAF car (and i dont just mean adjusting fuel trims, because the PCM will pull them back to stock over time, i mean tuning the MAF) and its not hard to see why early SD computers arent really seen as "computers". you can accomplish about the same thing with a board of resistors. Engine speed drives up the voltage, which drives up the speed of the injector along a curve specified by your resistors.

 

Your confusing an ECU or ECM with a later PCM. One is for engine control only because there was nothing needed for the tranny. The other, Powertrain Control Module, is so named because control is added to the transmission. Though the early systems may seem archaic to you they did quit a bit in their time. For instance the chip in my 91 will have 10 different maps programmed on it for the system to choose from to use. Weither it be a PCM or ECM, neither are AI's.
Seems that the way you think you could argue thatDOS is not a true OS like Windows Vista.

 

yet that cars computer does not optimize around a given afr like the later do, which is the point we were trying to make. I didnt get them confused. in fact, if you look at my post again I clearly statedwhat was meant. the early cars do not self optimize the cars tune. you cannot do this with any speed density or similar system car.

 

First off, You have to pull the distributer to replace the intake gasket. So If they had to mess with the timing its because they did not put it back where it was or they screw something up and they are compensating by adjusting the timing. A car should never run worse after a intake gasket replaced. Infact most cars run better due to micro air leaks that form over time. Many times I have repaired hard to fix rough idle complaints with a intake gasket. Replacing your intake gasket should not make your injector dirty. They most likely have something together wrong or they broke something. Adjusting the thottle cable to fix an idle issue is just plan wrong. Your car has a idle air control motor to handle the idle. Sure sounds to me like that is the area that is having a issue.Most vacuum leaks on these type of fuel injection will cause high RPMs unless the vacuum leak is on a single cylinder (Like a brake booster hose).

Take it to another garage, When I was turning wrenchs had I done a intake gasket and the car ran worse when I was doneI knew I had to figure out 100 percent why If it was not something I did then the service manager would decideweather I was fixng that for free or he would talk tothe customer about the repair. As quick as a fuel injector can be cleaned he would have never let that customer drive home in a stalling car. He would have offered the customer a great deal ontheservice but if the customer refusedhe would eat the cleaning and chauk it up to bad luck and keep the customer happy.

Second , Spector I will disagree with you on the 80s fuel injected ECU. There is/was function of Block Learn that remembered how the car was driven and took into account variation it parts. So two cars exactly the same would not do they same things with the same sensor input unlike a PLC dumb controler. Also major differnts between the newer style computer and the old ones is the fact the program is not burned to a chip. Any change in programming ment a new chip back then. I know there where cars out they that had 4 chips installed in the first year trying to get the drivablity right. The newer ones are much more flexable. I lasted just long enough in the trade to see the first Vett get reprogrammed with a new fuel mapping with a new chip. That would have been 89. Infact there is very little change in computer system 86-95. If there was a major differnts I think you would see a big jump in fuel milage. My 89 cav gotthe samemileageas my 98 with the OBD2 system when driven as a comuter.

Now when you step all the way back to the CCC(Computer Controled Carburator) that was a dumb "If / Then" type controler.