Hello all. This is my first time on this side of the board, usually I'm over in the Ranger section. Dad and I recently purchased a very rough running 1987 BII, with a rebuilt transmission, transfer case, and the guy claims the people at Jasper put in a 4.0L cam in when they had the transmission out.

Having said all that, this thing has PROBLEMS! The first thing I did was a complete tune up consisting of new plugs, wires, cap, rotor, pcv valve, and air filter. Ran awful, so we reset the timing with the computer unplugged, and that helped a bunch, but still runs awful. Put the $30 Wal-Mart code scanner for my Ranger and Dad's 94 F-150 on there, and it came back with an ECT sensor out of range, Oxygen Sensor always lean, and EGR valve not opening. So I replaced the ECT sensor, warmed it up, and took a test to discover the codes for both the Oxygen Sensor and the ECT sensor had vanished. the EGR pipe is broken off at the exhaust so I'm not even going to mess with it right now. Re-ran the test and the ECT sensor out of range code reappeared.

I've tested the resistance at the plug for the ECT to make sure that there wasn't some super-resistance in the wire, and found it to be 18.91 Kohms. In comparison, my 87 Ford Ranger tested 18.70 kohms. So I don't think its the wiring. Next up, I guess, is testing the O2 sensor. Bottom line is, the plug wires are on, all the spark plugs should be firing, but it still has one heck of a miss, and you can't rev it up hardly at all. Running it with the computer unplugged seems to make it run a little better, but its still heavy on the miss. Any advice on what to check, or what to do next, would be greatly appreciated!

You guys have a great day, and thanks for the help.

 

i would start by checking your fuel pressure. there is a schrader valve on top of the fuel rail,push it in and see if you have pressure,if not check your fuel pressure regulator.sounds like you might have a fuel problem

 

I'm wondering that too. After replacing the O2 sensor, and rewelding the bung i just broke off (hehe, whups!). Could one of the injectors be clogged up so bad that its just not firing? I've checked the wires and they're on good and tight. My truck has one broken connector so if it wiggles loose, it acts just like a miss.

 

i had the same problem with my b2 a while back the very rear injector wire would come loose and act like it was skipping.i repaired that and has been good since..the injectors could be clogged,but i would start with checking the fuel pressure

 

Definitely will check the fuel pressure on that and get back to you. But definitely I'm interested in the little quirks like that, little things that go wrong that you just wouldn't expect. That way I have an idea of what to look for if the obvious checks out fine. Thanks for the help!

 

You might want to consider the cam i would assume that you still have a 2.9 in it and if thats the case youre 2.9 computer might have a problem with seeing a 4.0 cam. I dont know how close thes cams are in specs but if you have a speed density motor and a non mass air flow . this might be pissing youre computer off . Mass air flow motors are usualy pretty open to upgrades for the most part where as speed density motors arent . speed density has preset programming for that motor and it doesnt like to see change.

 

Whenever you have a rough running problem, install a new (I always kept a spare in the glovebox) TFI module! It can be bad and not throw a code and will mess up the rest of the system.

> My truck has one broken connector so if it wiggles loose

I zip tie all my connections, TFI, coil, SPOUT, etc.

 

Well I tested the fuel pressure tonight and got somewhere around 32 psi on the fuel rail. In my Hanes Ford Ranger/BII manual it states the pressure at the fuel rail should be 40 psi. But I've read 35-42 is okay. So think a fuel filter change would bring the pressure and flow back up to snuff? Its just about the only thing we haven't changed yet. O2 sensor is getting replaced too as it was completely covered in soot and I think it was junk.

I'm wondering about the cam. I've got a few other things to try before I give it up. I haven't seen a mass air flow sensor on a 2.9L yet, they have what they call an "air charge sensor" so I dunno if that's supposed to be similar or not. But I'm like you, I don't know the specs of a 4.0 cam and I'm not sure it was a good idea they put that in there.

So I'll keep tinkering and let you guys know what I find. Oh, as for the broken connector on MY truck, don't worry. its not coming off anytime soon .

 

Well I've got some updates for you. I checked the fuel pressure and determined it was about 32 psi. Everywhere I've looked says it should be 35-45 psi. Thinking I might be able to gain a few more psi by changing the filter, I took the cartridge off and there's no filter installed at all! And to top it off I found a pretty good amount of grit in the cup. So my guess is some of that grit got up in the lines and plugged up the injectors. Sound reasonable to you? So I'm thinking my next step is probably going to have to be removing each injector and cleaning it. I'm not sure any kind of fuel injector cleaner i dump in the tank will be adaquate for that, do you?

Thanks!

 

Installed the new fuel filter tonight, and changed the ICM. No change to report here. However I pulled the vacuum hose off the fuel pressure regulator so I could get a vacuum reading of 14in. That's not so good. Then I noticed gasoline started pushing its way out the vacuum hose of the regulator. So I'm having a feeling that the regulator gave up the ghost too. Guess this will get repaired when I pull the injectors. I think eventually, we'll have a brand new truck! I'm hanging up my wrenches for the night. Take it easy and I'll report what I find in the coming days.

 

Hello all. Just to keep you updated, I installed a new Fuel pressure regulator last night and that seemed to help it some, but its still running rather rough. Did change the ICM and that did not help. Ran another vacuum test and got 18 this time...its getting better. Pulled all the spark plugs and they were all covered in a thin layer of soot, but still firing. Ran a compression test on the cylinders and got the following.

1. 140 (all units in psi)
2. 150
3. 160
4. 165
5. 170
6. 160

The thing idles smooth, but cylinders start cutting out at higher RPMS. It has a tach, but I don't trust it because when the engine is off it points almost straight down, rather than stop at 0. It moves when the engine is running, but its way out of calibration. Is there a fix for this, or is it toast?

Other than flushing the injectors, I'm really out of ideas. The only other thing I can think of is the truck has almost 185,000 miles on it, perhaps the cam sprokets and chain are wore out and it jumped time?

Ideas and suggestions are greatly appreciated! Thanks!

Definitely suggestions would be very helpful.

 

may need a new distributor drive gear, if it wasn't installed with the new cam. timing set could be worn out. sounds also like you might as well do at least a top end rebuild / valve job -- may be worn components / burned valve(s) throwing your compression test off, and were those readings from the dry test or wet test or average of both?

what probably happened to your tach is the 0 rpm stop pin is gone. not sure if there is a quickie fix other than to maybe put something in for the missing pin, or find a tach from a junkyard or pay the extra $$$ from a Ford dealership or check lmctruck.com and see if they have replacements.

I would seriously consider at least replacing all 6 injectors with OEM replacements. sounds like they could be worn and / or clogged as well. you may also want to check the in-tank filter/pump too.

hope this helps.

 

How plugged up is the cat ??

 

> I took the cartridge off and there's no filter installed at all!

Yes, they came like this from the factory on many BIIs. I never could decide if it was a factory mistake or if on the EFI vehicles (vs. 2.8) it is suppose to be empty because the filter will come apart under pressure. I put filters in mine.

I think there might be one in the tank. I do think the lack of a filter clogs the injectors. You can have the injectors rebuilt for $25 each.

re:4.0 cam
Does it even fit, are you sure it has even been replaced, or that the previous owner said that to discount a problem they could never fix?

 

My '89 doesn't have a cartridge for the fuel filter, it is a one piece inline canister filter. These B2's are finicky about the fuel filter, I change mine during the annual tuneup.