I'll try to keep this short!

My son's '91 RS has had problems with drivability. It dies, hunts for proper idle (up and down), smells rich, etc. We recently have replaced: O2 sensor, ignition module, plugs, wires, distributor pickup sensor, fuel pump & relay, oil pressure switch, fuel filter, and ECM.

We were setting initial timing by disconnecting the EST connector, and setting to 4 degrees advance before reconnecting EST. I checked for codes in the ECM, and came up with a 33 (in addition to the EST code from adjusting timing). My book says that a 33 is a MAF - does that even exist on this car?

We suspected a problem with the timing, so we disconnected the knock sensor, thinking that maybe the timing was being retarded due to a faulty sensor. It made no difference.

I also noticed something strange while setting timing. I shined the timing light into the injector spray to see if the fuel delivery looked ok, and one side seemed to be atomizing the spray finer than the other. We suspected that maybe one injector was partially clogged or somehow defective. So, we switched the wiring on the injectors and looked at the spray again. This time, the other injector had the less atomized pattern. This tells me that something in the wiring/ECM is telling the injector to spray like that...

Any suggestions? CTS sensor maybe? Would you suspect injectors?

Any thoughts would be much appreciated!

 

If you have any means of dataloging, that would be a good start.

Getting the MAF code (on our cars read MAP.) it is for high voltage, or low vacume. i would first make sure the MAP sensor is connected, and there is no clog in the small vacume line for it. if that all looks ok, check for vacume leaks. if no vacume leaks, i would try to replace the MAP sensor.

 

throttle position sensor maybe?

 

Have you cleaned the AIC recently. If they get funked up it can make your car run horrible. Take some carb cleaner to it and than add a drop of clean motor oil to the spring/needle to keep it from binding up.

 

We replaced the CTS, and it seems to have helped the idle to be smoother. We're going to clean the AIC today.

Thanks for the tips!

 

Hey, I am having similar problems what is the CTS??

 

CTS = Coolant Temperature Sensor

 

How would you know that thing is acting up?

 

I could be wrong, but I think that what you are seeing is ok, based on the way the injectors spray and using the timing gun. They do not "fire" at the same time (unless when in sync mode I believe, not 100% sure though). I believe each injector sprays twice for every revolution of the crank as well. So basically, using the timing light as a means to inspect is probably just catching the injector (via harness) while it is not spraying thus appearing as though it is not atomizing as well, and would make for a consistent observation since the timing light, crank position, and spray are all linked to the same point.

I would think that moving the timing light wire to different spark plug wires and then observing the spray with the light would confirm this idea, as each time you switched wires, the spray pattern would be slightly different. Like I said though, I'm not 100% sure. Can anybody confirm this?