Hi All,
Maybe someone can help me out: I have an 87 740 wagon which I recently started using after 4 years of storage. On a recent trip to New Hampshire, I began having serious power loss that felt like fuel starvation. As I had recently changed my in-tank pump, I figured that maybe my main pump may be letting go, so I changed it too. Unfortunately, this did nothing, and soon the problem progressed to a complete no-run condition. I got out the multimeter and checked the system and discovered that the injectors were barely getting any signal at all. For those familiar with the system, the engine is a b230 with a 117ezk ignition. The computer gets data from the MAF, the O2 sensor, the TPS and the temp sender and determines how long to open the injectors for. The ignition system has no crank position sensor, but gets data from the hall effect switch and sends it to the ecu to let it know when to pulse the injectors. I found a very friendly and helpful shop in Gorham, NH (Gateway Automotive) that had a parts car, and they let me borrow all of the previously mentioned components to try. None of this worked, and so I also tried replacing the radio interference relay, which also had no effect. When I manually grounded out the ecu leg of the injector circuit, the injectors open and i can make the motor run, but the pulse from the computer is very weak (barely enough to make a test light register) and the cranking voltage across the injector terminals is .6v. I know that it should be about 1.5 or 2 at a no-load idle. I backprobed all the wires going to the computer and they are all okay- no resistance. I figure it is most likely a loose ground somewhere, but when I manually grounded all the ecu ground points it had no effect. That's about it for my know how. Anybody else have any ideas?
Thanks,
Nate