Running poorly/misfiring, code 33

[JeepsAndGuns]

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.

[1project2many]

It sounds like the MAP readings when the engine is running are pretty close to accurate. I think I would move away from trying to get MAP readings to display on the laptop during KOEO and move toward diagnosing the driveability issue. MAP codes can be set by a very poorly running engine.

Assuming the spark is working and the timing is close, I believe the next test I would make is to ensure all eight injectors are firing. Injectors not delivering fuel can seem very much like a spark issue. I would probably start with a noid light at each injector connector, cranking the engine and watching for the light to blink consistently. Then I might do my best to get the engine to start and I would use a screwdriver to "listen" to each injector click or use a special tool that indicates when an injector is clicking to try to determine if there's a problem with injectors.

[TriumphR3]

I remember one time I had a contact in the connector on the ecm that went to one of the injectors that became intermittent. Vehicle ran very poorly. It was very difficult to determine, but I finally found it.

[JeepsAndGuns]

It sounds like the MAP readings when the engine is running are pretty close to accurate. I think I would move away from trying to get MAP readings to display on the laptop during KOEO and move toward diagnosing the driveability issue. MAP codes can be set by a very poorly running engine.

Assuming the spark is working and the timing is close, I believe the next test I would make is to ensure all eight injectors are firing. Injectors not delivering fuel can seem very much like a spark issue. I would probably start with a noid light at each injector connector, cranking the engine and watching for the light to blink consistently. Then I might do my best to get the engine to start and I would use a screwdriver to "listen" to each injector click or use a special tool that indicates when an injector is clicking to try to determine if there's a problem with injectors.

Would have not thought to check the injectors. They were new when I put the MPFI system in. Bought them as "new take off" that had been removed from a new crate engine. They did in fact look new and un used.
I might have in total, less than 10k miles on it over the years since I built the system. I know that means nothing as even brand new parts can go bad.
Of course it might not be them and could be the wiring.
I have a set of noid lights somewhere, just gotta dig through my storage to find them. Not even sure if they have ever been used!
Checking the fuel pressure was one of the first things I did when it first started acting up. It was good and steady.

I will start digging into that and start checking things (weather permitting) this weekend. The weather has been real hit and miss here, and I do not have a garage or car port. So I am at the mercy of the weather.

[JeepsAndGuns]

I had some time this morning to work on it.
I dug around and found my noid lights. I also found a spare injector pigtail.
Before I started the engine or did anything, I unplugged all the injectors and using the spare pigtail, I added some lengths of wire to it and did a quick quick check on the injectors.
I tapped the wire to the battery really fast to simulate firing. They all clicked with no issue.
I did not remove them and they did not have any pressure, so I can not comment on the spray pattern.

I fired it off and one at a time, I unplugged a injector and plugged in the noid light.
The engine seemed to make a small noticeable difference when I unplugged each injector. Every few seconds I had to reach over and hit the throttle to keep it from dying.
The light appeared to be good/normal on all cylinders. No breaking up, no going out, and no issues I could tell. It looked the same on every one.

I tried again to check/set the base timing, but it will not run on the base timing. It either will start for a second or two then shut off, or just not start at all.
So with it running on timing control, I decided to give the distributor a little turn, maybe 1 degree.
It seemed to improve the idle, and it stayed running on its own. It still did not run great, but at least now it would not die.
I tried again to run it on base timing with no luck. Every time I try to run it on base timing, after I rest the ecu, I have to hold the gas pedal to the floor to go into clear flood mode to get it to start.
Just for the heck of it, I cranked it back up and pointed the timing light at the marks. My timing light has the dial on the back you can set to whatever degrees you want, and it will make the timing mark like up with tdc.
On this engine, it is a royal pain to get to and see the timing marks because of the design of the alternator and ac compressor brackets.
But from what I could see, the timing mark was hovering around zero degrees or just a tad retarded with the timing light set to zero.
I thought this was odd, as it should be around 24 or so degrees.
So just just for the heck of it, I turn the distributor a little more. The timing starts moving advanced.
The engine starts running a little better and idle improves. It now will throttle up and down almost normally. Idle almost sounds normal.
In total, I feel like I turned it almost enough to make me think it was one tooth off.
I marked the dist body and the rotor position, and I swear I got it back in the right spot, but anything is possible.
I tried again to run on base timing so I can check it and still it will not run on it. If I unplug the timing wire, it will not start at all. If I unplug it while running, it dies instantly.
With it running now, idle and reving up seem almost normal, but I am not going to try and drive it until I know the base timing it set right.
It is however, running very rich. At idle, it is running 11.5-12.5 on the wideband. I did not have the laptop hooked up to it to see any data.

The engine and the outside temp was hot, so I called it a day as I had a lot of other stuff I needed to do.

Hopefully next weekend (weather permitting) I am going to pull the #1 plug and make sure I have it at TDC (using a screwdriver) then verify my timing mark on the balancer, then see where the rotor is pointing.
Depending on all that, I may have to pull the dist and adjust it. I can not turn it any more as I a about to hit my power steering pump. (is a large cap HEI)

[steveo]

perhaps if you cannot see the mark, simply bust out the ol' protractor and paint pen, make your own pointer and crank timing mark exactly 180 degrees out on the BOTTOM of the pulley, jack the front of the vehicle up, and point your timing light there.

[MO LS Noobie]

While you have the paint pen out, you might want to scribe a line from inner harmonic balancer hub through the rubber isolator band, to the outer hub. Check it after running the engine several minutes. I have seen several slip, making static timing impossible.

[ony]

hy good to hear you on here and project1 also, may have a intermedeite tps switch or wire, do you still work at john deere?

[NomakeWan]

Intermittent TPS would show up in the datalog as rather glaring spikes in the TPS reading, though.

[JeepsAndGuns]

Couple weeks ago I had a little time and I rotated the engine to TDC on #1 and the piston felt like it matched (using a screwdriver). The rotor was pointing at the #1 terminal, but not perfectly. I adjusted it a little and tried it. It started for a second, ran like pure crap and stalled. It then started raining, so I had to call it quits

Still been busy but finally had a little time to mess with it this morning.
I put it back at TDC after cleaning the timing marks. I readjusted the distributor a little more after looking at it and tested it.
It started but was reluctant to do so, and ran like crap. Would not stay running on its own.
I advanced the distributor a little more and finally got it running on its own, kinda crappy.
I let it run a few min to warm up. I adjust the distributor while it was running and as I advanced it, it started running a little better. Almost sounded normal.
Using my dial back timing light, I adjusted the dist until I got it to about where it should be, according to the tune.
It seemed to rev up and down ok sounded pretty much normal, idle seemed normal also.
I shut it off, disconnect the bypass and try to start it to set the base timing and no dice. Will not start and does not even try to.
I disconnect the battery, hook the bypass back up and have to hold the throttle wide open to go into clear flood mode to get it to restart.
It goes back to running mostly normal sounding.
I try advancing it a little more and try again with no dice. Still will not start (or even a hint of trying) with the bypass disconnected.
I try unplugging the bypass while it is running and it instantly shuts off.

I put the dist back to where my timing light is showing close to what it should be and it sounds almost normal like before.
I drive it around the yard a couple laps, never getting out of 2nd gear (4 speed with granny first gear). It seemed to run ok, but I know it is not right as I know the base timing is still off.
the wideband still shows between 11.5-12.5 AFR, sometimes it goes up to 13.4, but then goes back down to 12.5.

So I can not set the base timing, as it absolutely refuses to start with the bypass disconnected, and while it is running, it is running rich.

I am pretty much out of options and ideas.

Any of you experienced guys want to make a road trip to north alabama and make some money?

[MO LS Noobie]

I feel your pain, I had a '86 Grand Wagoneer that I built a 401 and put the early Holley four barrel digital fuel injection on. Had MSD ignition and a Ford E-core coil. It was my daily driver for 10 years.
When I run in to problems like this, I usually go back and check the basics. Does your distributor control the mechanical advance, or is this computer-controlled? A mechanical advance that's hanging up would cause your erratic timing. Have you put a new distributor cap, rotor, wires, and spark plugs in it? Are you sure it starts misfiring, and not just low idle speed from a faulty Idle Air Control motor? Not having eyes and ears on the vehicle sometimes makes it difficult to diagnose. Sensors that are glitching out and sometimes only be caught with the lab scope, not in datastream or with a voltmeter.

I agree completely with setting up a separate set of timing marks where you can view them easily. A temporary set up can be made by bending a piece of coathanger and securing it underneath a timing cover bolt, and then scribing a mark on your harmonic balancer. Bend the wire so that they line up at 0°, and then use your advance timing light to see what the actual running timing is. I have had Fords only run with the base timing plug (called the SPOUT connector) unplugged and that is almost always the ignition module, but again that is on Ford's.

When you have several systems working together, it is more difficult to diagnose than a factory original, but isn't that all part of the fun? You'll get it, just step away when you are frustrated, and follow the symptoms. Remember we're all pulling for you, we're all the this together (Red Green).