: 1978 Ecu problem flooding

11-14-10, 09:47 PM
I have a 78 Seville that I have been working on that quit running. It is flooding over real bad. It seems to be the ECU. If I disconnect the fuse at the Ecu fuel pump it will run somewhat, the coolant temp, air temp, fuel pressure all test good. I have put a noid light on injector wire and it seems to flash dim some times then a bright flash about every ten flashes. I did try a used ECU, but the guy I got it from was not sure if was good and the numbers were not the same. I posted this in the engine section with no luck.

11-15-10, 07:02 AM
map sensor? inside the ECU... check my last posts, there is a whole lot of messages on how to test the MAP sensor..

11-15-10, 09:50 AM
What motor is in there?

11-15-10, 11:19 AM
it has a 350 engine

11-15-10, 01:42 PM
Fuel injected? Diesel? Maybe look at the sensors that help control fuel.

11-15-10, 09:38 PM
I had that problem a long time ago with my Seville; so long that my memory is foggy. I remember having problems with my connection to the in tank fuel pump. I think it was a green wire near the rear bumper. If that't the fuel gauge wire then I'm mistaken. I also had to replace a keyswitch. The car would almost start while it was cranking or seem to be started but when I let off the key it would die. It was a faulty keyswitch

That FI system could really drown a set of spark plugs. I've never seen anything like it since. I killed a couple sets of plugs in one week trying to figure it out and I hated to throw them away. I put them in my 350 Cutlass and that car wouldn't start. I had to put the old plugs back in the Cutlass, warm up the Cutlass, swap the plugs and I could get it to start and eventually get those plugs working again.

I rolled that beautiful Seville and bought another one with a spun bearing. While I was replacing the engine I switched it to a carb so I wouldn't have to do any more troubleshooting on the side of the road. I had lots of issues with that FI system. If you have a fuel pressure gauge keep an eye on it. I think that's how I figured my keyswitch was bad because the fuel pressure dropped when I let off the key.

11-16-10, 08:07 AM
thanks for all the input. I am able to dry the plugs and reuse them. the oil is a different story, I have changed it twice and it needs it again because of the fuel in it just from cranking and testing.

10-20-11, 03:11 PM
I know this is an old post but I figured I would chime in here in case the issue has not been resolved. Most likely it is 1 of 2 issues. Either the diaphram on the fuel pressure regulator is shot which will cause fuel to leak into the throttlebody through the vacuum hose. Or the map sensor is bad on the ECM. To check the fuel pressure regulator pull the vacuum hose off and see if gas is coming out of the vacuum port. If it is replace the regulator. If there is an issue with the ECM do a google search for Bruce Roe and Cadillac EFI. This guy fixes 77-79 Cadillac ECM's. He even has a test bench built to test all of the functionalities of the ECM's. He also has an article online somewhere showing how to replace the factory map sensor which is built into the ECM with a common 80's GM map sensor. Good luck.

10-20-11, 06:37 PM
Did not see that this is old...