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88 Ranger code 41 *solved*


2trux

Well-Known Member
Supporting Member
TRS 20th Anniversary
Joined
Oct 22, 2014
Messages
184
City
Albuquerque NM
Vehicle Year
1989
Transmission
Manual
Hey all, I have an 88 Ranger I bought cheap with the engine out. I have rebuilt the 2.9, put in all new sensors including the O2. The fuel pressure is 34psi while running (new pressure pump and filter). It had some old gas in the tank which I stupidly did not remove. I added 10 gal of gas with Seafoam. When first started the truck seemed to miss a lot, after running it for quite awhile it seems to be running much better. when running the KOER test I get a code 41 and sometimes a code 18. the truck seems to be running rich and when I pulled the O2 sensor it was covered with soot.
For the code 18 it has a SPOUT plug which seems to work as the timing changes when I put it in.
There is a possibility I don't have all the electrical connected, I did the best I could not having taken it all apart.
I know a bit about these trucks as I have an 89 Ranger and my son has a 90 B2 which we rebuilt.
Any ideas on where to start?
 
As you are messing with it and getting it to run better and better, you need to write down the codes as you get them, but then take the battery cable off for a couple of minutes to erase the codes and then read the codes again. As you work through getting it running, some of the codes may go away. The code 41 says the O2 sensor is telling the computer it's lean all the time. You said it looks rich now, so that code my have left.

When you read the codes again, check for 18 again after disconnecting the battery. Was the code 18 a memory code or a hard fault? Hard fault would indicate it's missing all the time. A memory fault would indicate a possibly a loose wire somewhere. You could wiggle the wires around and see if the engine timing changes suddenly, like it would with the SPOUT connector disconnected.
 
Well after a lot of testing and swapping parts from my 89 I determined it must be an injector problem (these were new). I changed them out with an old set and the black smoke went away. I ordered a new set and the running rich issue seem to have gone away. It looks like the first set I bought were a much higher volume than I needed. I am still getting the 41 code so I am going to try the old O2 sensor.
I replaced the TPS because I was intermittently getting a code for that. It is now getting a code in KOEO for TPS below minimum voltage (code 63), and KOER TPS signal out of range (code 23).

Can the computer from my 98 be used on this to test?
 
98 has the later OBDII computer. I doubt it will work.

Have you figured out what injectors you had and what worked the best? I had some problems with my 2.9 running rich at idle, and after trying everything, am thinking it might be the injectors being faulty or wrong. I have been looking for a reference to tell me what size was stock and how to determine what size a injector is. Is it color of the plastic, or is it written on it somewhere?
 
Sorry I meant the computer from my 89. I did try it and it seemed to not run a good.
The injectors I first bought must have been the wrong ones as it was running super rich. I bought a new set and it seems to be running cleaner now.
It seems to idle OK when cold and dies sometimes when hot. The engine seems to cut out momentarily when the RPM's are run up so it runs very jerky.
 
Sorry I meant the computer from my 89. I did try it and it seemed to not run a good.
The injectors I first bought must have been the wrong ones as it was running super rich. I bought a new set and it seems to be running cleaner now.
It seems to idle OK when cold and dies sometimes when hot. The engine seems to cut out momentarily when the RPM's are run up so it runs very jerky.
What are the part numbers of the injectors that worked well?
 
I've seen poor O2 sensor grounds cause rich running and a lean code together. A 41 indicates oxygen sensor lean, that's not a diag, it's a symptom. If the engine was out I'd check all the grounds before spending a bunch of money.
 
I just tested it again, got codes 21,41,73 while engine running. it was not fully up to temp. (About 1/4 way up on the gauge.)
Since my first go-round I have replaced the in tank fuel pump and fuel gauge. the tank had a lot of dirt in it that I cleaned out. My fuel filter was full of dirt so I replaced it. The spark plugs look good. (They are new) All the engine sensors are new. The fuel pressure is 32PSI.
I have tried 3 TPS's 1 new Standard, 1 used Standard, 1 used FORD. They all seem to act the same.

Also I have 1 round grey connector near the driver side firewall that has a green and black/green stripe wires that I cannot find anything to connect to it. It is a male connector.
 
I've seen poor O2 sensor grounds cause rich running and a lean code together. A 41 indicates oxygen sensor lean, that's not a diag, it's a symptom. If the engine was out I'd check all the grounds before spending a bunch of money.

Thanks for the input. I will check the wiring for the O2 sensor. I have a new one and the original one and they both act the same. I will also check to see if I have all the grounds connected and if the connection is good.
 
@franklin2
The # on the OEM Ford injector is the 10 digit # on the side of the injector next to the electrical connector. I have two old sets of injectors that came out of '87 2.9's, and they are both 0280150727. From what I found in the past, they are 14lb injectors. I replaced them with 15lb Accel injectors that worked well, though I suspect the mileage has suffered as a result (or the engine just needs a rebuild). I've added a couple links that you might check out.


@2trux,
I have found that an old ignition module connector can cause intermittent problems and code 18. Make sure you have a ground bolted to the back of the passenger side head. It's the ground for the O2 sensor.
 
@franklin2
The # on the OEM Ford injector is the 10 digit # on the side of the injector next to the electrical connector. I have two old sets of injectors that came out of '87 2.9's, and they are both 0280150727. From what I found in the past, they are 14lb injectors. I replaced them with 15lb Accel injectors that worked well, though I suspect the mileage has suffered as a result (or the engine just needs a rebuild). I've added a couple links that you might check out.


@2trux,
I have found that an old ignition module connector can cause intermittent problems and code 18. Make sure you have a ground bolted to the back of the passenger side head. It's the ground for the O2 sensor.

Thanks for that info.
 
I just tested it again, got codes 21,41,73 while engine running. it was not fully up to temp. (About 1/4 way up on the gauge.)

I've posted in another thread, but I have a related situation. I'll keep you updated if I figure anything out, but I'm sort of working on mine in the middle of a hundred other projects. you know how it goes.
Anyway, that 21 seems typical of not warming the engine up yet. I've run the test a few times cold and get that, as soon as it warms up its fine. As for the 73, there's a point in the test where you're supposed to go WOT just for a second, and this may be the cause there if you didn't do that. I bit the bullet on the $30 innova tester (pick it up at vatozone, its cheaper than amazon if you want it).
 
I've posted in another thread, but I have a related situation. I'll keep you updated if I figure anything out, but I'm sort of working on mine in the middle of a hundred other projects. you know how it goes.
Anyway, that 21 seems typical of not warming the engine up yet. I've run the test a few times cold and get that, as soon as it warms up its fine. As for the 73, there's a point in the test where you're supposed to go WOT just for a second, and this may be the cause there if you didn't do that. I bit the bullet on the $30 innova tester (pick it up at vatozone, its cheaper than amazon if you want it).
I have the Innova tester. I also have been doing the WOT during the test. The 73 code seems to have gone away.
The new strange thing is the harness to the O2 sensor has 4 wires with one of them cut off. The cut wire goes to pin 49 on the ECU. The wire colors don't match the schematic I have, but I assume the ground goes to the black wire on the O2 sensor. The other 2 wires are white which I assume go to pins 49 & 29 on the ECU. I can't tell which goes to which wire or if it makes any difference.
 
I would have to check, but I'd assume that's the heater wire.
I don't -think- all the trucks had/need it depending on year and such
 
Here's a wiring diagram for the '89 2.9. For some reason it doesn't show pin 49 connected with the O2 sensor.
'89.jpg


This page is from the Ford "Engine/Emissions Diagnosis" manual that you use with a breakout box. You'll see in the diagram that pin 49 is the O2 (HEGO) ground wire (that goes to the back of the passenger side head as I mentioned before). If fixing this ground doesn't solve the code 41 issue, you should read the rest of the page, and the note on "HG16" of the following page also.
O2 testing.jpg

Quick test 3.jpg
 

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