My ’92 Dodge Stealth R/T (DOHC, non-turbo) is giving me a headache. When I first got it, the engine would fire up immediately, run for a few seconds, and then stall. Interestingly, if I manually powered the fuel pump by connecting the battery positive to the fuel pump test lead, it would keep running without issues. Following the service manual, I used my multimeter to check the wiring for both the fuel pump and the MFI relay, and everything seemed to be in good order.
Thinking the ECU might be the problem, I decided to tackle the common capacitor issue in these older units. Upon opening the ECU, I found that the 100uF capacitor had indeed leaked, damaging the surrounding solder resist. However, the underlying traces looked intact, and I confirmed continuity with my multimeter. I carefully cleaned the board and replaced all the capacitors.
After reinstalling the ECU, the car wouldn’t even start anymore – it would just crank. This time, I noticed the MFI relay in the passenger footwell clicking on and off when I turned the key, a sound I hadn’t heard before. Even with the fuel pump wired directly to the battery, it still wouldn’t start. I checked for spark by pulling a spark plug, grounding it, and cranking the engine, but there was no spark. To check for fuel delivery, I put a piece of paper towel in the spark plug well and cranked again, but it came out completely dry. So, the fuel pump is running, but it seems like the injectors aren’t firing.
Frustrated, I removed the ECU again for another inspection. The only thing I could find that looked even remotely suspicious was a single trace connected to the positive leg of the 100uF capacitor. To be absolutely sure, I soldered a tiny jumper wire across it to eliminate any possibility of an intermittent connection. Reinstalling the ECU brought me back to the initial problem: the car starts briefly, then dies. And just like before, it keeps running if the fuel pump is directly powered. Now, the MFI relay is no longer clicking. Since then, I’ve changed the oil, spark plugs, and cleaned the K&N air filter, but the starting issue remains.
Could my ECU be completely fried? It’s clear the capacitors leaked long enough to cause some damage, even if I can’t see it all. Or is there something else I should be checking before I consider replacing the ECU? I’ve checked all the fuses, and the only blown one was the 60 amp ABS fuse in the engine bay (no idea how that happened). Any advice on what to check next would be greatly appreciated before I assume the ECU is toast.
