91 D21 SE 4x4 3.3 swap

[MidnightSun]

After finding out I was doing the wrong test on the Power Transistor, resistance to measure continuity vs directional continuity, I tested again. I was getting a .5-.6 v reading on both old and replacement transistor. Leads me to believe that I need a new ecu. The ecu code only showed up a couple separate times, as mentioned before, but it did show up.

Does anyone have any other ideas of things to check before ordering an ecu up?

[jp2code]

Originally Posted by MidnightSun

Does anyone have any other ideas of things to check before ordering an ecu up?

Maybe your grounds. ??? Like the little cables that go from the body of the truck to the engine.

I don't know, really. I do wonder if there is some wiring you missed when going from VG30e to VG33e - particularly with the injectors. I didn't reuse the VG33e injectors because of the wiring changes that were needed. I wished now that I did, but maybe you are running into problems that I didn't get to.

If you get a replacement ECU, make sure to get one that gives a 30 day warranty. That doesn't sound like much, but that means you can slap it in your truck fast when you get it to make sure it actually works. If it doesn't, send it back.

[MidnightSun]

The only grounds i took off were the two on the intake manifold. Eventually ill want to get a new ground from the battery, its wearing a bit but still giving good ground. Theres one flat ground that hasnt been connected since i got it, on the drivers side.

When i did the injectors I just compared the wiring diagrams and matched the wire going to the ecu, with the other wire going to the companly shared wire. Soldered and shrink wraped. Ill have to look and see if the wires are on opposite sides of the connector. Wouldn't think that it would cause problems.

I was thinking the same thing after the problems started, "I shoulda just left it alone! " Once it runs again ill enjoying having the easy connectors, haha.

[jp2code]

Also, I think the VG33e injectors are built with seals that can stand up against gasoline with ethanol in it.

The VG30e injectors could really use those, but whenever someone rebuilds them, they use the same spec'ed seals that the factory called for. So if you run gasoline with ethanol, they will leak after a few years.

[MidnightSun]

After a few weekends off with never ending rain, i was finally able to put in the replacement ecu, and she fired right up. My afr gauge is showing lean, but it was starting to kind of level out to where it should be. Im gonna get it all put back together and cleaned up on the interior. Also will have to bleed the brakes, and check out the right front wheel. Seems like the back cover for the disc may have been tweaked and its rubbing a bit. Ill be getting some updated video and pictures in the coming days/weeks, depending on time not working.

So glad to have it nearly back. I think I have about 3 weeks left of it being on storage insurance. Since I moved recently, i had gotten a (MN) 04 Pathfinder.

[MidnightSun]

Ugh, the problems cease to stop.
After i got it running, i had it sitting idle as i set up the stereo. About 30 mins or so. Never showed signs of problems. This has been my first weekend off work, so i came back down. (The pathfinder started shifting bad, so ive got gaskets and filters for the tranny and lower oil pan coming tomorrow.)
I go to start the truck and its running kinda shitty, wanting to die cant seem to hold idle. Check a few things and run codes. Knock sensor again. Go through and test. Getting continuity @.3 ohms to the ecu and continuity of .5 Mohms to ground from the sensor. Since its just looking for continuity, it all checks out as good. Connect everything back up.

Now it doesnt start at all. Check codes again. Now codes 21 and 24, for ignition circuit and throttle valve switch. Gonna go through and test those things, see if i dont find anything. Its starting to get to me though. Seems like ive been chasing contless problems since the transfer case locked up.

[MidnightSun]

Went through the tps, wide open switch, closed switch. I ended up not going through the ignition system again. I just went through that last month or so ago. A little lost and discouraged at this point.

Anyone have a tbi manifold laying around they dont want, ha.

[jp2code]

Originally Posted by MidnightSun

Went through the tps, wide open switch, closed switch. I ended up not going through the ignition system again. I just went through that last month or so ago. A little lost and discouraged at this point.

Anyone have a tbi manifold laying around they dont want, ha.

So you are saying the TPS and Ignition switch turned out OK?

It sounds like there is something not reliable in the wiring. Maybe you have a bad ground strap. Just an idea. ???

[MidnightSun]

Originally Posted by jp2code

So you are saying the TPS and Ignition switch turned out OK?

It sounds like there is something not reliable in the wiring. Maybe you have a bad ground strap. Just an idea. ???

Yea, both tested within spec according to fsm.

I know the wiring is kind of a mess in a couple areas. (The horn works intermittently as well) since i had gotten the vehicle there was a small ground from engine to drivers fender that was broke. Nothing was weird before so i never worried about it.

Oh, even weirder. I for some reason wanted to try swapping to my original ecu. Didnt think it would do anything, but it fired right up again? After keeping it running a bit by giving it gas, it seemed like the pump was pumping for a pretty good amount of time. The filter is brand new and i had a new pump laying around. So i decided to pull the bed and swap the pump.

In the process of pulling the bed, i realized the ground strap going from the bed to frame is broke ive got some cable around, so next weekend ill probably work at replacing the grounds and go from there. Ill see if i cant get a video of how its running posted up.

[jp2code]

Wait, so you are trying to do this with a newer ECU? Do you know what year it came from?

Newer ECUs added more functionality and requirements. I know 96 and 97 had OBD2.