1994 Isuzu Rodeo running rich

My daughter's Rodeo started missing right at the time it would shift into 3ed. I found the plugs soaked in oil, cleaned plug well out and fixed it for 3000 miles. When the problem came back, I noticed black smoke. I'm convenced that it is running rich. I had more oil in the plug well but this time the fix did not last. Some days it was fine and some days it was very bad. She complained about using too much gas. We got her another car and I brought this one home to fix and sell. It set for 2 weeks, and now it does not start at all. I can not read out the codes, the plug does not seem to be behind the drivers kick plate. the ECU is, in fact there are 2 boxes and I do not know which is which. This is a 3.2 v6. I've changed the fuel regulator. The O2 sensor seems just fine. I attached a couple of wires so I can watch it in the car while I'm driving it(back when it was still running). Now, after I crank it, it will try to start but not very hard. I pull a plug and it is soaked with gas. I can watch the gas pressure and see the injectors hit each time the engin turns. All plugs are black so I do not think any one injector is bad. I've checked the MAP and the throttel feedback. Any ideas what could be causing this to dump so much gas into all 6 cylenders?? Could any one tell me how to read out the codes. I've been trying to find a dealer that would talk to me but the only Isuzu service person in town has been on vacation. Fuel injection is MFI, 6 injectors that all hit at the same time or so I'm told. Also, is there a good online place where I learn more about this car? Not only can I not find the leads that would let me read out the code, but the color codes on the wiring harness does not seem to match. My manual seems to be lacking.

Sorry, I can't help you but I just purchased the same vehicle (94 4x4 with 95k) and is there any major problems I should expect while going through the miles. I posted the "4x4 not engaging" post. Thanks for any info. Aaron

I found my code reader leads under the carpet on the drivers side. The oil in the spark plug well is leaking O-rings under the valve covers. A new set of valve cover gaskets will have new a new o-ring set.

As far as using too much fuel, my 94 Rodeo only gets about 15mpg highway. Sounds pathetic to me, but I'm told thats about right for a rig with all the extra 4x4 gear underneath it.

As far as your fueling prob goes, the only thing I can think of is dirty fuel injectors that can't close all they way like they should. I'm no expert on fuel injection, but I don't think they are supposed to be activated all the time. They open and close at set times. Thats why you can hear them clicking while the engine is running.

Thanks for the reply. Could you describe the code reading leads. I've dug 2 plugs from under the rug and found 2 other when I took the plastic panel. The book pictures a flat plug board with 3 connections. All I'm finding is normal plastic female 1 and 2 wire plugs simular to what is pictured for the 2.6 and 3.1 engins and older models.

I can't remember exactly what it looks like. I can get you a digi-cam pic tomorrow afternoon.

The one and only person at the dealership is suppose to be back from vacation tomorrow. I'm going to take a late lunch and go see if he will talk to me. He should be able to tell me which wires to use and maybe have a few ideas about why it is flooding. Thanks for the offer. I've been considering the fuel injectors but I don't understand them all going bad at the same time. On the other hand, you pull a plug and this doesn't even know that it is missing. I can not hear a miss so, maybe 2 bad fuel injectors are not very noticeable. Thanks again.

most likley to be causing concern would be leaking injectors flooding cylinders
try this to start it press accelerator to the floor this will prevent injectors from spraying fuel while cranking do not pup the pedal just hold it too the floor and crank for a while it should start
leaking injectors cause black smoke on start up and poor economy
as far as oil in plug towers valve covers need to come off to fix that one tower seals need replacing
let us know if you get it started

thanks, I will try that this weekend. What surprizes me is that I pulled 4 plugs, the easy ones, and they were all wet. I expected a injector to go bad one at a time. On the other hand, with a 130,000 miles on it, it is good time to clean them up and test test them if I can. I've been reading everythng I can find about them on the I-net tonight. Thanks again for the help. Jim

I have the Haynes techbook which will decipher the codes. The connector can be either in the kick panel or under the steering wheel. My 94 V6 4X had it under the steering wheel.
After you jumper it, there will be a series of flashes which will repeat continiously.
It will start off with a 12 code, 3 code then any stored codes then finish with a 3 code.
The connector you are looking for will just be hanging down somewhere. It is not a box or anything like that. Just jumper the wires and turn ignition to on. I check this board occasionally. Email me for code decipher . [email protected]
The haynes repair manual hints at all the points mentioned so far.

Thanks for the offer. I have the Haynes manual. That is what I'm going by. They describe the 1994 v6 3.2 as having the wires behind the drivers side kick board. Other's have them in the console and behind the dash. I removed both plastic pieces that make up the center console. I found 4 wires, 2 came from under the rug and and 2 were behind the plastic kick panel. Haynes shows it as being 3 contacts on a little flat panel. Everything that I found was the normal plug thay you expect to see if there are options not installed at the factory. We took one cover off to the left of the steering wheel. Since you found yours close to the steering wheel, I will take the other plastic covers off and see if I can find somethig that is taped up inside the console. Apparently the 3.2 engin is different then the 3.1 and the 2.6. I don't know why they could not cable them all out the same way but they didn't. What I think I'm going to find is that that the o2 sensor is failing and that most likely is because of all of the black crud I'm blowing out the exhaust. I get check engin about 10 minutes after it starts smoking. The other thing that makes it a mystery is, when it was running, sometimes it would run perfect. Compared to my little Ranger, it has all kinds of get up and go. Then all at once it would start stumbeling and a bit later the smoke would show up. Thanks again. I Hope it is there. Jim

Hi there:

Just wanted to point a few things out!

Firstly, The 3.2 engine is isuzu's while the 3.1 is a GMC engine, VERY different. The other thing I wanted to point out that when looking under the kick panel there are two sets of single wires, one set might be disconnected, I think this has something to do with the code reader however on my 92, the connector is located under the dash on the passenger side. The other set of single wires which are used for devactivating the ignition timing, DO nOT disconnect this wire, the engine check light should come on when this wire is disconnected.

Hope this helps!

Thanks for your update. All told I found 4 sets of wires. 2 buried under the rug and 2 hanging next to the ten box. I think the box is the ECU but I'm not sure. There is another box right above it. I took the plastic off from around the radio last weekend and the panel next to the steering wheel. I had a buddy that wanted to try shorting them but, I do not want to burn out the ECU. So far, I've found 4 wires but I can not confirm for sure which to use. None of them match what Haynes say's they should look like. I think, your comment about the 3.2 being a Isuzu engine may explain why this does not match the book. I think I've lost the codes. I disconnected the batery and later remembered that the ECU drops the codes with no power. I tried cranking it with the gas wide open and the plugs were dry. I was never able to start it though. It was a cold weekend and I did not do much with it. Thanks for you ideas. Jim

Hi there: My brother thinks that the two wires that are unconnected near the ECU (yes thats it hanging behind the kick panel), are power for the code reader. It is not ID'd in the Hanyes book. I'm kind of upset about that also. If you want to spend the 100.00 dollars for the helm book go to www.helminc.com, This is what the dealer uses.

About the wires under the rug, sorry I'm not too clear on that but what are the colors, these are important!

I also want to point out an excellent site fro trouble shooting these typs of problems.

Visit www.2carpros.com select search by subject and you will see solutions to all kinds of issues!

Thanks for the links. I joined 2carspros and I will probably get a wiring diagram for my Ranger from helminc. The shop manual I saw cost $45. which makes me wonder if I'm looking at the right thing, considering that one for my Ranger Ranger cost $170.00. Maybe Ford just gets a lot more thiers then Isuzu. A fuel regulator cost me $72 and did not fix it. I can not afford to keep easter-egging so I'm thinking real serous about the manual. Its late tonight but I will get a better description of the wires tomorrow night. If I could have matched the color code at the connector to the color code at the ECU I would have have felt better about trying them. If I blow the ECU it will probably cost more to replace that then what I'm going to get for the car when I sell it. I've called the one and only trained service person in Raleigh 5 or 6 times but I've never been able to talk to him. They don't refuse, they just say he is too busy.

The connector you are looking for has a yellow, red and black wires. I have a 94 V6 also. They were taped together with white tape and coming down by the ECU but long enough to reach the brake pedal. It had a white connector on it.

Ok, I've made progress although I'm not sure I want to announce to the world what I've done. This is embarassing. When I started this some months ago when my daughter first had the problem, I checked the spark plug wires. Since then a lot of things have happened, but today I decided to go back and recheck everything and of course that starts at the wires. Before this I never knew that wires had 25000 V's and fired 2 plugs at the same time. So, if you loose one wire, you loose 2 plugs. In the good ole days, when they cost $7.00 to $15.0 I replaced them because they looked bad or I saw sparks flying after dark. Anyway I found a bad wire and put a new set (the better half of a hundred doller bill) on and now it at least starts. Apparently I've pullled the wires so many times I've abused them. I do not know if the origional problem is fixed or not because I do not have plates or insurance on it. Now that it runs, I will go get that done tomorrow, get it out on the road and see if it makes it all the way to the local MacD. Thanks for the color code of the wires, I have found 4 sets of wires. I will be able to compare the colors and select the correct wires tomorrow. I did finally talk to the service department and they told me that the wires wire next to the center console on the drivers side but even after taking the radio and all of the plastic that makes up the console out I did not find them. I've ordered the shop manual and as my luck goes, I will probably have this figured out before the manual even gets hear. I'll sell the car in the spring, when I do not need 4wd any more. I sereously doubt that the next owner will have much interest in a shop manul so unless my wife changes her mind about selling it, I will probably have a manual available. Next time I will spend the $50.00 bucks on the spark plug wires, then buy the manual. I guess you would call that a lesson learned the hard way.

Did you ever find out the problem, mines doing the exact same thing?

Yes, As I mentioned above, part of the problem and confusion was caused by the spark plugs. I had pulled them so many times that I broke one. All my life a bad wire made the engen run rough but, I discovered that each coil drives 2 plugs in series at 25000 volts. Thats twice higher the the voltage on a color TV picture tube. If you loose one you loose both and end up running on 4 cylenders nice and smooth. Just a loss of power. At 25kva apparently they do not worry about the plugs being wet with gas because it is running fine and I still have what seemed like flooding. It does run rough whin I start it in the morning but smooths out within seconds. I just got it inspected and passed the emissions test, not perfict but at least it passed. My daughter drove it for about a month and the running rough and black smoke started all over. It comes and goes. I had alread spiced wires into the O2 sensor so I pulled them out and put a meter on it. It certenly looked bad, stayed down below .5 volts and never appeared to leave what they call open loop for the 5 or 10 minutes I watched it. I puled the O2 sensor, it was dirty with the carbon of the the unburned gas. The heater appeared OK then heater voltage was ok, I cleaned it up and, when I could not find anything wrong, put it back in and tried it again. That fixed the problem, don't know why but I suspect that the plug is bad. I added a wire that I can bring into the cab and monitor the heater voltage. I think the heater wires are opening at the plug. I gave it back to my daughter but left the wires on. I'll know for suer if it ever occurs again. The codes read out is the longest 3 wire yellow connector. About the 5th time I went looking for it, I found it burried under the rug. It still had the white tape on it. It goes into the cable close to the ECM behind and at the bottom of the plastic next to your left foot, in front of the drivers door. The read out was 44, running lean and I know better because it was pumping globbs of black smoke while idle. The O2 sensor said it was leane so the ECM just kept dumping more gas into it. I did not want to cut the wires but I bet, if I pull the fuse to the O2 heater, I will see the problem. I did get the manual, if there is something simple I can look/check for you, send me a note. Even though the readings seemed to improve when I installed the new $74.00, fuel pressure regulator, it made absolutely not difference. Now that I know, I would make that a 3 or 6 choice is I was easter egging it. Good luck.

So to sum it up, what your saying is the O2 sensor is bad? And you had a broken plug, how was it broken?

No, I had a bad spark plug wire and because they are wired in series, that caused 2 plugs to fail. I believe that the electrical 4 prong plug where the O2 sensor plugs into the cable harness is bad. I removed the O2 sensor, cleaned it up a bit, checked the heater winding, and the heater voltage at the plug, reinstalled it and hooked a high impeadence meter across the sensor wires. What I saw was OK, and the car ran good. I've been driving it ever since and I got it inspected and it seems OK. I think I am fixing it by moving the wires around. I.E. a bad connection in the plug. I have not proved that yet but I did not do anything else to fix it. Thing is, if the sensor tells the ECM that it it running lean, the computer will keep dumping more gas, causing it to actually run rich. Because the O2 sinsor is cold, it never detects that it is actually rich.

I will try that out, Ive heard bad wire connections else where as well, and my readings come up ok, even though the Ck engine light comes off/on whenever

My light came on and stayed on. I had to shut it down and start it again to get the light to go off. A heater would not change very fast. if it got hot and then a wire opened up, it would take a few minutes for it to cool down to the point that it made a difference. Once mine broke it tended to stay broke untill I did something. The problem was, I was never sure what I did to fix it. I'm assuming that I fix it by moving wireing harness around. Now I have the meter in place so that the next time it occures, which can take up to 3 months, I will either eliminate one possibility or comfirm that it is the O2 sensor heater, wire or plug.

I too am having the same problem you guys are having,

I have gotten some Diagnostic codes from my computer but they don't seem to make sense. I was wondering if anyone can help me out here.

the 1995.5 is a 96 Rodeo mostly but OBD I somputer system.

So... When in diag mode... i get a blink .. pause then 2 blinks.

Thats 12... means I am in Diag mode: So far so good.

that happens 3 times as expected....... Then I get 4 blinks.

thats my trouble code ????? 4 ??? it does that a few times and then recycles back to the 12 and loops over and over as such......

So my question is this, what trouble code is 4 blinks. according to that, its a 4 but that's not listed in my Haynes manual or anywhere as a possible code....

I am certain its not a blink a pause and 3 more but if it was a 13 that would tell me O2 sensor...... anybody else every get a 4?

Does any one know what a 4 trouble code is on a 1995.5 Rodeo.

Thanks in advance,

Elwood J. blues

Nothing in the book for a 4 code. Hate to do this but are you ablsolutely sure?? anyway you have no codes stored.

I think so. I put a new O2 sensor on this weekend. I finally caught it when I could measure the voltage while it was still broke. I ran wires into the cab and put a meter on it so that I could I watch it while I drove it some. I could confirm that the heater voltage was ok but the sensor voltage dropped below .2 v and stayed there. I put a new one in and it seems to be working now. About your code read out, the 4 that your seeing is most likely a 44. Watch it and you see 4 blanks, a pause and 4 more blanks then a slightly longer pause. Count the number of times it shows 4 and then devide by 2. I think it will be the same number of times that 12 is displayed. 3 if I recall correctly. I have a new problem now that I have to figure out. My oil pressure is low. I was told by the dealer that it is normal for a Isuzu to have low pressure and I found at least one person in my office that has a trooper and his oil pressure is also low. This week end it went so low that the oil light came on. I put 40 w oil and 16 oz. of STP in it and that seemed to fix it. I wish I had put the 40 W oil in without the STP to see what effect that had. Guess I will wait until next oil change to do that. I looked at what has to happen to check the oil pressure regulator and you have to remove both wheels, knuckle, front axel/differential, just to get to the oil pan. Then from the top you have to remove the timing belt and, pully off of the crank shaft and oil pump (probably need to pull the radiator out also just to get room). All of that just to check a little ball bearing and spring regulator. I can get the oil pressure up to 55 by reving the engin so I'm going to check everything else possible before I tear into the oil pump. I got a feeling this is going to be the last Isuzu I will ever buy. Anyway, I will know in about 4 weeks if the O2 sensor fixed it. It takes that long to fail sometimes. Guess there is a loose wire someplace in side of it.

I forgot to mention, the code, 44, is what I got also. It says it is running lean but if I ran it a bit that way, and watched my exhaust in the rear view mirrow, while I was setting at a light or idleing in the yard, clouds of black, the kind you see when it is running rich, came out. So the O2 SENSOR told the engin that it was lean and the ECM just kept dumping more gas into it.