Transmission wiring harness help

I am having an issue that I beleive is my wiring harness, below is a post that I put in the modified 2nd gen forum of my problems, since then I have replaced intake gaskets, maf, 4 o2 sensors, plugs and wires. I took it to a shop and they said it seems like wiring is messed up or possibly the computer, I beleive it is the wiring because when I pulled the trans a wire got snagged and pulled fairly hard on the harness, i doubt the computer would just go out at exactly the same time a do a transmission swap, and also the whole ground issue that I was having (stated below) makes me think that it has to be wiring.


99 sohc 5 speed swap done about 6 months ago. Ok so truck was running like normal, maybe a slight miss that had been happening for a while, I bought a 1354 transfer case and a 4wd trans to convert to 4wd. The swap went fine except when I tried to start the truck it would just keep blowing the starter fuse so we figured out that if we undid the ground from the battery to the starter it would start so we ended up running a new ground cable from the battery over to the alternator bracket. I figured that was the last of the problems, until I drove the truck, it was hesitating really bad and seemed like it wasnt running on all cylinders. after driving for a few days it got noticeably worse to where sometimes i could barely break 1500 rpm especially when the engine was cold. I noticed a bad exhaust leak on both sides so I took them back off and retried, I dont think they are leaking anymore, When i would floor it, it would seem to have about normal power. I started getting codes 1131, p1132, p1151,p1152, which says both forward o2 sensors- lack of ho2s- 11 switches- sensor indicates lean, and rich. I dont understand how they both can be reading rich and lean at the same time. At first a neighbor mechanic took a look at it and said it seemed that when he touched the pcm wires that it fixed it so he greased up the terminal and I left, after paying him I realized that It wasnt fixed. I ended up replacing all o2 sensors with ones from the junkyard because I dont have 200 to spend on all four, and the first day this started I looked into my exhaust, no muffler and the o2 sensors were glowing bright red. I also thought that It could be intake manifold gaskets so I replaced those, after replacing all those it now runs a million times better, but I got the same codes back and still dont have nearly as much power as I used to and you can tell there is still a miss or something, it still hesitates a little bit when partial throttle, and seems that randomly I get all power back for a short amount of time. Another wierd thing that confused me was i pulled the wires at the coil to see if i was getting spark to all cylinders and the first day when i pulled the passenger side wires it made no difference in idle, now today after i replaced all of that, the passenger side wires made a difference, and the driver side dont. My next thoughts were to clean maf check for more vacuum leaks, change pcv, change spark plugs and wires, but I have no money at the moment haha so that will have t wait a couple days. Does anyone have any idea what could cause this damn problem, It doesnt seem to make any sense to me. Oh and I used 4 low today and it is the most badass feeling going from a 2wd auto to 4wd 5speed haha.

I guess I am asking for any other possibilities but im pretty sure its the harness and if so what would be the best way to go about replacing it, all the ones at the junkyard are already hacked up ufortunately.


Thanks, Chase

did you try what I suggested?

Did you try what I suggested on your other thread - remove one O2 sensor connector to see if the PCM reported that one disconnected? If the sensor connectors are crossed the PCM will richen the Air/Fuel mixture trying to achieve a rich condition from the O2 sensor on one bank then the other. When the mixture gets very rich the cats overheat.

It has been at the shop so I have not gotten a chance to check but I will tomorrow or monday the next time I see it. I will be very interested to see if that is the problem, I never would have thought that I could have crossed them but that is a definite.

So I ended up pulling the passenger side upstream o2 sensor and the code came up for the right sensor. Now my parents drove the truck back from the shop a few days ago and said it drove totally normal, then yesterday when I drove it to see if it was it still drove the same crappy way it normally has been. Today after I unplugged the o2 it totally drove completely normal, not once did it ever act up, I drove it again after turning it off for a few min and It was completely fine still, so im not sure if it just happened to drive good like it did for my parents, maybe it was the o2 sensor that i unplugged that did it, or maybe i moved some wires, either way I pulled the whole tranny harness and I am going to get a new trans harness from the junkyard in the next few days to replace it hopefully it fixes it.


Thanks, chase

bank 1 sensor 1

When you disconnected the precat O2 sensor on the passenger side the PCM should have reported at least:

P0135 02 Sensor Heater Circuit Malfunction (Bank 1 Sensor 1)

If not, then your wiring was crossed.

When you get the new wiring harness make sure you connect the sensors correctly:

Bank 1 > passenger side
Bank 2 > driver side

HO2S #11 (Bank 1 Pre-cat)
Gray/Light Blue (O2 voltage to PCM)
Orange (sensor return common)
Red/White (Heater output to PCM)
Light Blue/Orange (heater supply)

HO2S #21 (Bank 2 Pre-cat)
Red/Black (O2 voltage to PCM)
Orange (sensor return common)
Yellow/Light Blue (Heater output to PCM)
Light Blue/Orange (heater supply)

HO2S #12 (Bank 1 Post-cat)
Red/Light Green (O2 voltage to PCM)
Orange (sensor return common)
White/Black (Heater output to PCM)
Light Blue/Orange (heater supply)

HO2S #22 (Bank 2 Post-cat)
Purple/Light Green (O2 voltage to PCM)
Orange (sensor return common)
Tan/Yellow (Heater output to PCM)
Light Blue/Orange (heater supply)

Ok so yesterday I went and unplugged the passenger o2 to see if it was hooked up right, I unplugged it then started the truck and let it idle for probably 5 min, went and took it for a drive, about 1 or 2 miles, and it drove completely perfect the entire time, not once did it act up, so I parked it for 5 min and then drove it again and it drove perfect again. My initial thoughts were either the o2 sensor was the cause or when I pulled on the harness I made some wires that may have been the problem stop touching. Then I went and got a trans harness from the junkyard and bought a brand new o2 sensor to replace the passenger side upstream o2. I replaced the harness first to see if it fixed the problem, and went to drive it and the problem was back again so then I unplugged the o2 to see if it would run perfect as it did with it unplugged before, and now it had no effect, it still ran bad. So I changed the o2 with the brand new one, still no effect. I know the front o2's are connected right because the drivers side plug comes off the engine harness and the passenger plug comes off the trans harness, I will check the rears though just to make sure. My next step is to check fuel pressure, maybe my injectors are going bad? I have 210,000 miles on the truck. After i check the fuel pressure my next idea is the computer I have had 2 mechanics tell me they thought the computer is going out, Im not sure how they came to this conclusion but they also said the wiring, which didnt fix it. They are 20 bucks at the junkyard, So it would be easy as hell to replace if I didnt have pats, I guess I have to get the junkyard computer then take that computer with the truck to ford and have them flash the "new" computer to accept my pats system? I called ford and he said it would be 90 for them to flash it but I would need to 2 keys, and he said they could make a second key.

I really hope one of these will fix my problem.

DTCs?

Did you read the diagnostic codes when you disconnected the passenger O2 sensor even though it ran OK? If not, then you didn't learn anything and are wasting my time. Good luck!

Yes I did, it threw a code p0135 like it should have, the o2 obviously had nothing to do with the truck running good as my parents drove it days before and they said it ran perfect with all o2's connected, then I drove it the next day and it ran horrible, it was just a coincidence that It ran good with it unplugged. I even put a brand new o2 in there and it ran bad with the new harness, So I guess so far I have ruled out plugs and wires, 02 sensors, transmission wiring harness, intake gaskets, maf, and pcv. I am going to check the fuel pressure though I cant see the fuel pump making the truck not fire on one side of the engine, maybe injectors but again it seems unlikely that multiple are going out and then getting better at the same time. I have had 2 mechanics say the computer is possibly going bad so besides checking fuel pressure and exhaust leaks again which I believe I fixed I guess Ill get a new computer. Ford said 90 to flash the comp but they also have to make a 2nd key, no telling what kinda money that costs, probably more than I can afford haha, actually thats not even funny.

Thanks for all your help I really appreciate it, Chase

2nd PATS key

Thanks for reporting the DTC when you removed the O2 sensor connector. It looks like you can eliminate the O2 sensors and their associated wiring as your problem source.

I asked my local dealer about a 2nd PATS key a couple years ago. I think the cost was around $100. I got one from a local locksmith for around $60. However, I believe only a dealer can reprogram a salvaged PCM to match your vehicle. The PCMs are fairly reliable. I would investigate other possibilities first.

Does the PCM currently report any trouble codes?

What do you mean by a "99 SOHC 5 speed swap"? Did you swap from an OHV V6 to a SOHC V6? Did you swap from a 5R55E to a 5 speed manual?

Edit: I did a search of your past threads and learned that you replaced your 5R55E with a M5OD R1. You initially jumpered the 5R55E DTR sensor connector to trick the PCM. Later, it appears you loaded a custom no trans tune but had problems and reverted to the auto trans tune. In February you were losing coolant. What is the current configuration of your PCM tune? Did you resolve your coolant loss problem?

I have not been driving the truck much, but the last time I had the check engine light come on it was just the p0135, although before I stopped driving it like a week ago It was throwing p1131,p1132,p1151,p1152, Im not sure how it could throw a lean and rich code at the same time? Then after erasing those multiple times after replacing things the o2 sensor codes would come up but sometimes be different codes, though usually relating to running rich or lean, most of the time rich. Right before I took it to the shop It threw a IAT sensor circuit High voltage and maf low voltage, also TPS short circuit but I think I unplugged both of those while the truck was running so I think that Is what caused those codes, besides those codes only came up that one time, and I replaced the maf/ Iat, the TPS was replaced maybe a year and a half ago.

I still have the trans park/neutral wires jumpered, with the custom tune because even with the tune I wont start unless those are jumped. When I first did the swap I loaded the custom no trans tune and it drove great for the first couple of days, it was when I tried to load a 93 octane tune the truck wouldnt rev passed 1500 rpm like a rev limiter, then all of my no trans tunes started doint that, so I had to drive around with the stock tune for a while until James Henson fixed the Problem so now it has a 93 no trans tune that has been working fine, unless somehow the tune could be causing problems, hmmm Ill have to revert it back to stock auto tune just to make sure it still runs bad. As for the coolant loss I had noticed I was losing coolant for months but didnt know where it was going, no leaks, etc then I noticed when I was cold outside, and the engine was cold it would white smoke a bit, but go away once the engine warmed up. I threw some bars stop leak into the radiator and as far as I can tell I has stopped it, or it could be the warmer weather, either way I have not had to add coolant in a month and a half and its still full.

SCT X3 Power Flash?

If you have an SCT X3 Power Flash and a laptop then you have the best instrumentation available to diagnose your problem. You can datalog any parameter the PCM has access to. It can tell you if the MAF sensor, IAT sensor, TPS, and O2 sensors are functional. It can tell you the engine coolant temperature, the ignition spark advance and the knock sensor retard. It can tell you when the PCM goes from open to closed loop and back. The one thing it can't tell you is fuel pressure because there is no sensor in the vehicle to monitor fuel pressure. I suggest that you check your fuel pressure.
Ford Explorer Ranger Fuel pressure test procedure

If its good then restore your stock tune and check for symptoms.

Well holy hell I did not realize that I could do that, I am definetley going to try to figure that out tomorrow and see if that will tell me anything. This sounds like it could be a huge help.

Ok I Datalog run, I uploaded to my computer and messed around looking at it, I'm just not sure what exactly I am looking for, is there a way that I could post up my results through photobucket or something, if you wouldnt mind taking a look. I'm going to keep messing with it after I get off work tonight and see if I can figure out what i'm looking at haha.

Thanks, Chase

my email address

Chasethexplorer said:

Ok I Datalog run, I uploaded to my computer and messed around looking at it, I'm just not sure what exactly I am looking for, is there a way that I could post up my results through photobucket or something, if you wouldnt mind taking a look. I'm going to keep messing with it after I get off work tonight and see if I can figure out what i'm looking at haha.

Thanks, Chase

Click to expand...

I'll PM you my email address so you can send me the file.