How to fry an ecu?

mrnickleye · 09-17-2005, 03:10 AM

I would not just plug in another ECU if the one in there is bad. I would run a full system diagnostic check to see if the first one is really bad.

We had a 89 Cressida in the shop for last month. It would hard start, intermittantly of course, when it was hot. The ECU was bad. But it turned out that the distributor was the culprit, with ultra-high resistance when it got very hot. Somehow the ECU got overloaded and fried from the bad distributor. We replaced both units with ones from the wrecking yard.

Point is...it took the tech quite some time to test all the circuits to narrow it down. Plugging in the ECU may just burn it up if the cause is not found first. ECU=$175...Distributor=$125 Labor=4hrs.

09-17-2005, 03:10 AM	#4
mrnickleye 1000whp postwhore Join Date: Jun 2005 Location: Mojave Desert, Calif. Posts: 1,705	I would not just plug in another ECU if the one in there is bad. I would run a full system diagnostic check to see if the first one is really bad. We had a 89 Cressida in the shop for last month. It would hard start, intermittantly of course, when it was hot. The ECU was bad. But it turned out that the distributor was the culprit, with ultra-high resistance when it got very hot. Somehow the ECU got overloaded and fried from the bad distributor. We replaced both units with ones from the wrecking yard. Point is...it took the tech quite some time to test all the circuits to narrow it down. Plugging in the ECU may just burn it up if the cause is not found first. ECU=$175...Distributor=$125 Labor=4hrs.