paulincolo

Hi,
I have relaced the engine in my 1993 ES300. Unfortunately it will not start. I am not getting any spark. The fuel pump turns on and all of the voltages at the ECM appear to be correct. I do notice that the Engine Malfunction light (little engine symbol) does not even come on when the ignition is turned on. I assume this means that the ECM is not doing any self diagnostics. Anybody got any idea's about what I might be missing?

Thanks.

renatodato

Check for fuses, particularly the EFI mini 15 amp fuse under the hood. Most likely, it's not the ECM.

GEORGE_JET

All the voltages on the ECM appear correct? Could you be a little more specific, such as, are you getting the 5 volt reference to the tps? Does the pump run for a few seconds when you first turn the key to the one position, and then turns off? If so, I would suggest checking the bulb for the check engine light.
Since you replaced the engine, I would assume that one of the first steps was to disconnect the battery. Once the battery is disconnected, there are not too many things you could do that would kill the ECM. I would suggest looking for pinched wires/harness. Also verify that the crank sensor has been hooked up.

paulincolo

Basically probed all of the dc power and grounds and most of the voltages as specified in the ECM connector voltage values. The fuel pump comes on but does not stop. I can hear and feel fuel constantly going back through the return fuel line off of the regulator. Jumping the TE1 to E1 pins on the diagnostic port does not do anything either. Measuring the W pin on the ECM imediately goes to 12 volts when the ignition is on. According to the servive manual it should be under 2 volts and then go to 12 if the engine starts. I have not validated all of the engine sensors yet as I was trying to find out why the ECM was not turning on the MAF light. From looking at the schematics I do not see any sensor that would stop the ECM from turning on at least. I will start checking all of the engine sensors to see if they look correct resistance wise. BTW I have checked all of the fuses I can find and they all appear OK. This is going to be an interesting one to find. I will check the 5 volt tps signal first.

GEORGE_JET

Look closely at the harness to make sure that it was not pinched / cut by a bracket of something when the engine was installed (which is why I was asking about the voltages). It is also possible that one of the sensors, such as the cranks sensor is shorting the computer. You could try un-plugging sensors and seeing if the check engine light comes back on (I am assuming that you purchased a used engine, with accessories).

paulincolo

george_jet,
You were thinking the same as me. I finally got some time and found out that one of the 4 ECM connectors (D if I remember correctly) was causing the ECM to not start up (no engine check light at all). After a little bit of dis-connecting and reconnecting of the 5 sensors that feed that connector I found out the MAF sensor was the culprit. After measuring the pins across the voltage divider of the MAF I found that the one end of the divider appears to be shorted. The ECM must have been sensing this since the 2 output volage levels woul dbe messed up and thus not "booting up". This of course meant no spark or check engine light. When I get some more time I will try to see what is wrong with the MAF and try to get it working correctly so that I may be able to get the engine running. At the present time it fires up and then imediately dies. I believe this is because I have the MAF sensor disconnected. At least I have spark though.

GEORGE_JET

Ok be aware that the voltage divider is probably the potentiometer. It has three connections to it. It is basically a resistor, that has a wiper connected to it. The idea is that as the mechanical airflow vane move, the wiper moves, which changes the output voltage (henc the voltage divider).
I do not mean to suggest that the maf is not the problem, I just think that you may be looking at the wrong pins. The fact that it is now starting (even though it will not remain running), is good progress that you should commend yourself for. I am sure that you are already looking for a replacement. When you call around to wrecking yards, or ebay, keep in mind that the toyota camry v6 will have the same maf. Also I would suggest measuring the replacement before you install it.