My mechanic and I acquired a "project" 1989 Ranger 2.9 ltr V6 from a previous owner who was trying to get it running and then lost interest in it. It had a new rebuilt motor and after I had it towed to my mechanic's garage he got to work on it -- and got it running. Over the past few months he has put in a new fuel filter, new plugs, new coil, new wires, new dist. cap & rotor, new distrubutor module, new pressure reg. and new computer. He has also patched in test parts such as a TPS Map Sensor, Oxy. Sensor, and so on. Fuel pump pressure is good, and he has checked the valves to make sure they weren't too tight. He has also checked the grounds and made new ground wires when he had any concerns. In spite of all this he has never succeeded in getting the truck running right. It starts right up and performs ok initially, esp. in colder weather, but as soon as it warms up (after about a mile of driving), it starts surging and bucking. If we drop down to a lower gear on the automatic and keep the revs up, we can keep it going -- but that's about all. My mechanic (also a good friend) runs a backyard shop, but he's been in business for 40 years and he doesn't miss much when it comes to diagnosis. However, he's baffled. About the only thing we haven't done is to take the injector head off and have it cleaned professionally. But he doesn't think the symptoms point in the direction, so he's reluctant to spend my money on the process. When I told him that I knew of a Ford Truck forum which seemed to have some pretty sharp contributors, he said "go for it." He said that his pride was no longer a concern and he just wants to get the truck running right and out of his sight. At this point, he has put far more time into it that he would ever charge me for.

Thanks for any suggestions.

Bill T.

 

What happens when you pull codes?

 

I'll ask my mechanic tomorrow. He doesn't have computer diagnostics at his shop, but I know that when he first got the truck and was having trouble, he took it to a shop in town where he has "visitation rights," and I remember him telling me that they pulled so many code errors that it was impossible to draw any conclusions. I supposed that I could encourage him to get it done again, but I don't know that the results would be any different. Anyway, I'll ask him tomorrow and see if he has anything to add.

 

I checked w/ my mechanic. He said he took it to two different shops "uptown" and "all the codes came up." In other words, the computer was indicating that everything was bad, even though he had put in a number of new parts (distributor module, plugs, plug wires) at that point. Also, it was running (and is still running); it just won't accelerate smoothly or run at any speed, e.g., above 30-35 mph.

Sorry, I know that this probably doesn't help much.

 

A basic Ford EEC-IV code scanner is only about 35 bucks at Kragen's, Autozone, etc. Well worth it to have around. You would need to pull the KOEO codes to start with, and just go down the list one at a time. I can't believe that ALL the codes would be coming up, there are a lot of them. And just because a code comes up doesn't mean that sensor is bad, it can be a bad connection/loose or broken wire causing it. Has this vehicle been under water at some point, possibly causing electrical malfunctions in the wiring? Any way to find out? Anyhoo, as I said, you need to deal with the codes one at a time. With a code scanner you can clear all the codes from the computer's memory, and scan it again after a few minutes running to see what comes back up. Maybe the problem is in the computer itself. I've never heard of that type of symptom associated with a computer malfunction, but I suppose it's possible. Or maybe someone replaced the computer at some point with a used one that's not for that particular application. Just tossing out ideas here as they occur to me, I may be way off base on these. -TD

 

You should follow TD's advice. Clear the codes (disconnect the negative battery cable for about 20 minutes or so) and then run the vehicle around town. Shut the truck off and turn it on a few times, try for 10 minute intervals. Then pull the codes and post them here. We can probably help you get going on resolving them in the most logical order.

You can even pull the codes yourself without a scanner if necessary: Pulling Ford EEC-IV Codes

Has a compression test been done?

 

Thanks, guys. These are some good suggestions. Looks like we need to pull some codes. It'll probably take a while, because I'm working 12 hr. days right now and can't lend a hand. So don't go away. But I'll relay the info to my mechanic and encourage him to do a little code work. He's definitely an "old school" grease monkey and not into high tech diagnostics. Seems like his head knowledge & experience leads him in the right direction about 95% of the time, but he's striking out on this one. If the code scanner is that cheap, I might look for one in Seattle (where I work). Maybe Shucks Auto has it in stock. There's one on my way home, so maybe I'll check.

-Bill T.

 

No to offend, but I think your mechanic is stumbling on the technology. Go to Schucks and borrow the scanner if you don't want to use the jumper or multimeter method. Schucks will loan you a scanner for a $200 deposit; it's fully refundable.

Pull the codes, making note as to if they are KOEO, KOER, and/or CM codes. The problems associated with the codes must be repaired in that order. For example, a KOEO code can trip a KOER code; fixing the problem that causes the KOEO code sometimes cures a KOER or CM code. This is why they are fixed in the noted order. And if I'm not mistaking, there is a specific code that indicates bad ECM (computer). Don't spend another dime on parts until a proper diagnosis has been made.

BTW, TD has give you good advice.

 

On my 86 with a 2.9 it used to buck surge and die.....then start again before I had a chance to pull over.......I found a loose wire in the harness that goes to the injectors...it seems that 2 of the strands that were holding the wire together were just touching and not connected.....sometimes one has to grab the wires and give'm a shake......the best diagnostic tools wont help if the wires that sends signals are broken or Mr. Green is chowing down.....Other than this and that what have you got to lose...