So I got a ecm pigtail at the junkyard and finally had some time to try and fool with it today. I have just been super busy lately.
I made me a new wire for the MAP signal. I just laid the new wire on top of the harness as it was just temporary.
I still could not get any reading on the datastream of the map sensor with the engine not running. Everything else seemed to read ok.
I started it and it still ran like crap, I had to keep it running with the throttle.
I did get map readings with the engine running. About 70-80 at idle, and it would go up if I opened the throttle.
After keeping it running for a few min, it would idle on it's own, but barely, and still ran like crap. Then after idle for a short bit, it would stall.
I had to run into town to do a couple things and finally found a vac gauge at the parts store.
I disconnect the vac line going to the charcoal canister purge and hook it up there.
At idle, it is around 5, maybe a little more in-hg. When I open the throttle a little, and the datastream shows 50 kpa, the vac gauge read about 15 in-hg.
Vac seems to go up when I open the throttle, then drops down at idle.
However, this engine has never really had high vac at idle.
This is the camshaft I have in it: https://www.compcams.com/xtreme-ener...c-290-401.html
I figure since it was made for carbs, and having 110 LSA is probably the reason for the generally low vac at idle.
However it has never been a issue before and it has been great and trouble free for years after I tuned it.
I will attach two log files.
One was from several years ago. I have no idea what I was doing, but it appears I made a short trip down the road and back. You can see what everything read while it was running normally.
Then I will attach the file I recorded this afternoon.
I started the recording, waited a couple seconds then started it. You can see from the tps readings, I was having to keep the throttle open to keep it running. I did let it idle for a little bit and it roughly did, then I opened the throttle some for a bit then let it idle again. It did, but still poorly, and then it stalled. I waited a couple seconds then stopped recording.
It looked like the map went real high as it shut off. I do not know if it was just the result of the engine stalling, or it was the reason the engine stalled. I tried watching it a couple times but do not see one thing standing out at me.
The files are the dates I made them.
$0D, 16197427 ecm converted to MPFI.
Jeep/AMC 401
I removed the new wire and hooked the old one back up and it did not really seem to change anything.
I have also cut all the zip ties and pulled off almost all the wire loom to inspect the wiring and have yet to find any spots with issues.
I double checked I was getting 5v to the map sensor, ground, and when using a hand pump, map sensor voltage lowers as vac goes up.
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