ECU Substitution?, Using 1974 ECU in a 1973 |
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ECU Substitution?, Using 1974 ECU in a 1973 |
ThinAir |
Jul 16 2020, 10:44 PM
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#1
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Best friends Group: Members Posts: 2,543 Joined: 4-February 03 From: Flagstaff, AZ Member No.: 231 Region Association: Southwest Region |
My stock 1973 2.0L has developed a problem. Intermittently, the engine will start stumbling and then die. Sometimes reseating the 14 pin connector/harness on the relay board will get things going. Other times I have to just let it sit for awhile. I've noticed recently that when this happens it also smells like it is flooded and when starting it I have to floor the accelerator.
A long time ago I had a similar problem with my son's 1970 that ultimately was resolved by replacing the ECU. Hence the following question: I have available a working 1974 ECU. I'm wondering if I can swap ECUs with no other modifications to see if the problem goes away and stays away. Brad Anders' FI page states that the 1973 should use only a particular ECU, but in his chart of the preferred setup he states to use the 1974 ECU. Would it be harmful to any component to swap the ECUs and test my theory? This problem came up just before leaving for a summer road trip and I won't be able to work on it until just before Labor Day, but I'm hoping to figure out a direction now so that I can jump on it when I get back home and get the car ready for the RRC. |
JeffBowlsby |
Jul 17 2020, 08:33 AM
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#2
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914 Wiring Harnesses Group: Members Posts: 8,548 Joined: 7-January 03 From: San Ramon CA Member No.: 104 Region Association: None |
Its hard to understand why folks even contemplate intermixing critical parts to a functioning FI system. The 73 2.0L ECU is the most common 914 ECU available, recommend the correct part be located.
That said, 'stumbling then dying' sounds like it might be a clogged fuel filter or a failing coil. If it smells like it is flooded, then the need to 'floor it' to start, those are opposing conditions. If its getting too much fuel, look for other sources - leaky injectors or cold start valve. Use a fuel pressure gauge to see what fuel pressure is doing under different engine operating conditions. It could also be running rich causing the hard starts = failed/failing MPS diaphragm. The simplicity of the D-Jet FI is that each of the these discrete components can be isolated and their function verified to find the culprit. |
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