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So I've been having a misfire on cylinder 1 for months and an indication of a fault in the injection system. It would usually appear 20 minutes after starting the van and would continue the rest of the day. I decided to change the injectors.
Took off the vacuum hoses, took of the upper intake manifold, changed the injectors, bolted all up (now three times because ot the problem)
Engine starts fine, revs OK for one second and then starts to wobble, stumble. When I press the accelerator suddenly and deep it chokes and dies. When I press the accelerator slowly the engine slowly revs up but stumbling all the time like rat-tat-tat-tat. Like an old tractor.
I got the following codes:0174, 0300 and weird 02 sensor operation.
Below is also a graph of how the engine operates on idle
I am devastated. The van is packed for family holidays and I was supposed to change only the injector spider and now I have a can of worms. Where do I start?
If something were wrong with the MAF I think both fuel trims would be off and both o2 sensors would still have the same pattern. I am trying to figure out what could have gone wrong by simply replacing the injectors?
The engine will still run without a MAF signal but poorly. Maybe it's unrelated, but it still shouldn't be zero since the computer needs the reading to calculate how much fuel to add.
Got the thing partially solved. The NEW injectors I bought were some sort of crap. The next morning the van didn't even start. Checked the ECM fuses and they were blown. Each time I put a new fuse an only turned the ignition, it was blown. I disconnected every plug and started reconnecting one by one, looking at the fuse each time. Everything OK, except when I connected the big injector socket. So one day before my trip and the van is running but with misfire after 20 minutes from morning start.
If you're blowing 10 amp ecm fuses it sounds like a short. I had a similar problem with my tbi after I had a v6 injector installed on one side.
Will agree that fuel pressure would be a problem on later models if you have changed fuel filters and checked regulator.
And of course it could be a old fashioned vacuum leak
July 14th, 2020, 7:35 PM
Engine stumbling, wobbling after injector change
