1987 Chevy R30, 454, 7747 ecu. Some background - under light load, under 2000rpm I was getting a severe lean surge. After months of diagnostics, tuning, reworking grounds, etc... I replaced the injectors and the issue went away. Drove for a short time, started getting a CEL for lean, which progressively got worse to where it started lean surging again. Like extreme surge/bucking. Heavy throttle I can push through it. Changed injectors again and problem went away for a short time.
I am now on my 4th set of injectors in less than a year. I'm using NEW Delco branded injectors. Thankfully Amazon has a great return policy and I've just been sending old ones back.
I tolerated the issue for a few months and finally got fed up and replaced injectors again. I got about 100 miles before the issue started rearing its head again. It is like at low duty cycles the injector can't cycle fast enough because when I put a load on it there are no issues. It is like they are sticking at low duty cycle. Something I have also noticed is that the idle gets high and it gets super rich at idle. When it is running good, fuel pressure is rock steady at 15psi (aftermarket remote FPR). When the injectors are acting up the fuel pressure gauge is fluctuating between 12-15 at idle and as soon as I get up through the surge conditions the pressure is steady at 15 again. When I put in new injectors it is again steady at 15 at idle. This is a pattern. The current injectors are just starting to have the issue where I have the CEL but not the surge yet and fuel pressure at idle is fluctuating 14-15.
I've been through the entire harness. My last update was new connectors for the injectors and I found some very poor splices where a previous owner had repaired a few wires by twisting together and taping them. Now those connections have been soldered.
During that year I pulled and flushed the fuel tanks. They had been replaced at some point because they were super clean inside - no rust, dirt, etc... New fuel filters. I changed gas stations/brand thinking maybe contaminated fuel. I've tried Marvel Mystery Oil in the fuel, Lucas injector cleaner, Seafoam, etc... Once the injectors start acting up, they don't come back. I've pulled injectors and replaced their screens with no change.
I'm really at a loss at this point. Like at the point of throwing on a carb level of frustration.
Does anyone know how many amps the injectors should be pulling?
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Originally Posted by brian617
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