1991 240 Starts, runs for a few seconds then dies...

[hawkboy647]

I purchased a 1991 240 with 166k. The day after I got it home the car began stalling immediately after starting. Now it starts, runs for a 4-5 seconds and then stalls. It repeats like this over and over but never stays running. Fuel tank is 3/4 full. I replaced the in tank pump (and sender), new fuel filter, new main fuel pump, and new fuel pump relay. While troubleshooting why the main pump was constantly running with the ignition in the on position I found that the previous owner's 'mechanic', had disconnected two yellow/red wires (both fuel pumps) and jumped power from another fuse to fuse #4. I took the jumper wire off and reconnected the yellow/red wires. The fuel pumps seem to be acting appropriately now. They prime for a few seconds when the key is turned on and I'm pretty sure they are running when the engine is running (though not 100% sure). I suppose it's possible that they are not but the engine doesn't run long enough for me to check.

The fuel regulator looks to be new and pulling the vacuum line reveals no fuel, so I'm relatively certain that it is OK.

The OBD is throwing no codes, 1-1-1. On a whim I disconnected the MAF and started the car and it ran. It ran poorly but it did not stall as long as i gave it some throttle, I think that rules out any fuel delivery problems. Reconnect the MAF and it starts nicely..runs for a few seconds, then stalls.

Any ideas?...I have a MAF on the way but I'm not convinced its the answer because it the old one checks out ok as per the Haynes manual's diagnostic procedure.

I have the intake manifold off, cleaning it, new gasket, and installing a new oil separator and flame trap. While I'm in there I'm cleaning all of the electrical connections I can find. The TPS is covered in oily soot.

Any ideas would be appreciated. Love these old 240's and trying to keep this one alive the rest of it is in fantastic condition.

[adrian22]

classic symptom of faulty MAF sensor-change it and it will cure it