CoffeeCommando

1998, Ltd, AW4, 4.0 + 0.7 Engine

Yep. Code P0740 ("TCC Malfunction, Mod $18") was the code, but I also have P0171 for too lean. I've had them both for about a month now.

Right at about 43 MPH while driving it shifts from 3rd to OD. Sometimes when I am slowing down really slowly... when it's getting ready to shift from OD back to 3rd it's like it can't make up its mind and starts bucking on me (sometimes, not always). One time the transmission dropped out and completely dropped to idle speed, then picked right back up a second later. It did that, then I put it in third gear (I have an AW4) and the problem went away of course since it didn't have to do any calculation on shifting.

That was about a month ago. After that it rarely give me a few bucking's while driving (going from OD to third).

Also when starting it the speedo will shoot to 100 then back down. Sometimes it will jump around a lot ... until I start driving.

Now, in the past few days I have been wheeling and getting muddy. It has a hard time starting. So much that I have disconnected the SAFC thinking it was that (even though I didn't have a code for high MAP ckt, but I have had problems with it in the past). Then it finally cranked... although barely. After it's been driving a while it'll crank with no problems at all, until now.

Just before it kicked the bucket it was missing while throttling steady (after a 20 mile drive and it was good and warm). Then when I gave it more gas it just sputtered and barely maintained speed until I let off the throttle. As I slowed down enough to turn into the gas station to stop and have a leak it cut off completely at about 10 MPH and I rolled to a stop. After that, no more crank. The only codes I got were P0740 and P0171.

Something else I noticed was while the tow truck was backing it up onto the platform, it has a small fuel drop (I had just filled up the tank with 10 gallons of gas to full... so I was also wondering if I just got water in my tank since it wasn't doing it before then at all) rolling down the front of the tank. I'm curious as to whether that is to be expected from a tank that is slightly over full, or if there is something I need to check. I replaced the fuel pump a few months ago and I made damn sure the top was on perfect and tight, as well as both lines down there were fully seated like they were supposed to. I know that the one that is more like a vent didn't seem like it was air tight (the housing that attaches to the tank, not that actual line I reconnected).

I'm about to go down there and clean the **** out of any connections I find. I have never messed with the NSS but I think I have read that it can cause a no-start. I figured that could have influence.

The TCU is the thing underneath the center-user-storage-trim-thingy in the back, correct? I could have sworn that when I pulled it off of someone's 97 it was under the dash up by the rightside of the driver's foot area under the center console area... but mine was under the back of the central storage area (right above the back of the transmission) underneath all that trim.

Notes:
1. MAP, TPS, IAC, CPS, and CKS are all BRAND NEW within the last 4 months.
2. I'm not sure what type of transmission fluid was put in it a year ago when I changed it, but I followed the Haynes so it was a Mercon of some sort.
3. The vehicle was submerged, transmission included back in early march in salt water. Never had any problems with it after that though... until a month ago.

So with all those facts in place...
1. What can cause P0740?
2. Is it normal for a full tank of gas when leaned forward considerably to have a small drip? And if not would a small air-tight leak like that cause the fuel pump to not have proper pressure.. resulting in P0171 (I have no manifold or vacuum leaks mind you. I have checked)
3. Would a dirty NSS cause no-start/shut off while driving?

CoffeeCommando

....ANYone?

Someone has to have SOMETHING (relevant) to say.

Maybe I just need better luck.

CoffeeCommando

Luck Bump

kenjen11

What brand Crankshaft position sensor did you put in. I put a oreilly BWD in mine and it went out like 4 times. If you don't have a quality CPS in there that might of went out even if it has been 4 months.

CoffeeCommando

just found out I have ZERO fuel pressure. Airtex can kiss my magnaflow. Never buying another part from Autozone simply based off of the fact that they don't do in-store credit for parts under warranty. And they only carry airtex.

They say they never have problems with them, but I am starting to think that they can't handle the bumps and jumps offroad vehicles give them. Only good for soccer moms and ricers. Which I'm sure are 90% or more of the population that would buy them.

CoffeeCommando

BWD CKS from autozone. Hasn't failed.

CPS = Camshaft Position sensor
CKS = CranKshaft Sensor

CoffeeCommando

Is anyone familiar with installing an EXTERNAL fuel pump?

CoffeeCommando

It was the fuel pump. I've got a bosch in there now. Running better now.

Fixed all of my bucking/stalling issues which I have had intermittenly in the past. Namely during the winter in NC.

OEJ

what i have learned from after market sensors is.... that they are all junk no matter what parts store you buy them from. they all come from china. if any of my sensors fail again, i will get them from the dealer only. with that said...

you've got alot goin on here.
it is highly possible that you got water in the fuel vent tube and thus water in your tank; which could be your entire problem. so get some stay-dry for the tank and see what happens. when you put the drygas in start it and let it idle for a good 20min to a 1/2hr, then go from there.

after that, go with the first code you pulled and replace the sensor and keep goin from there. the truck being submergerged as deep as you described definately makes it harder to trouble shoot. it could be anything. just keep it simple and don't over annaylize.

Not to be a wise guy or anything but... water/mud wheeling??? has the highest costs for repair, obviously.

lots of luck.

CoffeeCommando

It was the fuel pump. It's been in there for a week. I didn't have any fuel pressure, if you read.

OEJ

yeah i missed that part jag-0ff. and i meant to be jerk.

CoffeeCommando

Go to pirate 4x4. No one likes you.

OEJ

what are you...12??

Slick761

You talkin bout a booster pump or changing the whole system to an external pump.

Slick761

Btw.... cps is crank position sensor. The tech name for cam position sensor is stator.