I have a 88 bronco 2, with a 2.9l.
The vehicle had a bad fuel pump when i purchased it, have since replaced the map, 02, tps, in tank pump, and fuel filter. I have also cleaned the iacv(which isn't that old) and throttle body. have checked all vacuum lines and fuel lines. OK now the problem, when cold, it runs like it's not getting any fuel. used to run worse until i replaced the tps which was the last code i got with the exception of system running lean. I know it IS running lean but replaced to 02 anyway. idles for a few seconds then stalls, if you try to drive it, it just stalls. So I am guessing under load when cold it isn't getting the fuel it needs. once the engine warms up it runs better, but not perfect. Don't know a whole lot about engines so if anyone know's what this could be please let me know! thank you in advance for the help.
planning on bringing it to someone next week if i can't fix it first.

 

did you check the fuel pressure at the rail? try this : pull the vacuum hose off the back of the fuel pressure regulator and see if gas drips out.. if so, that means the fuel pressure regulator is junk.. i have the same motor in my ranger, and when you test the fuel pressuer at the rail, it should read 35-41psi.. that might also me the high pressure fuel pump.. located on the framerail.. mine was junk when i bought the truck.. but.. keep postin problems.. i'll help all i can..


late

bubhead

 

forgot about this.. but your stalling problem could be the pcv valve.. sounds dumb, but mine had the same problem.. mine was stuck open i believe(which causes a MAJOR vacuum leak..) also check your vacuum hose coming from the intake/injectors to the vacuum modulator for ATF.. if tranny fluid smell or drips, then vacuum mod. is junk.. you might also try new plugs and wires.. check your coil, ignition module, cap, and rotor out too..


late

bubhead

 

forgot about those....plugs, wires, dist., rotor, all new. not sure about the coil, but the ignition mod has been tested and it was good. have also checked for fuel in vacuum hose from fpr and none present. i have also cleaned the pcv valve. don't have any way of testing fuel pressure. also not sure about the vacuum mod, can't find that in the manual i have.
other things i have noticed are....the black box on the drivers side by the head lights, has a vacuum hose coming from the...well don't really remember where it came from lol but I think it might go to the fuel tank has two caps and one is missing...also haven't tried after replacing the tps but before that when I first started it (cold) if i removed the vacuum hose coming from the map sensor, it wouldn't stall. oh and i have replaced the map sensor too. and the only other thing i can think of that isn't right is the exhaut manifold on the passenger side has the hole in it, that i think there is supposed to be something hooked to it, isn't there? mainly because i have no way of testing the fuel pressure, my plans were to bring it to someone and let them trouble-shoot it for me, the shop down the road said they would diagnose for $40. I have spent more than that on differant sensors already. I was hopeing someone here might have had the same problem or have some inexpensive tests i can do before i have to turn it over to a (maybe) pro.
any more information would be appreciated.

 

Don't throw sensors (money) at it without diagnosing and identifying the failed componenet(s) first. With that said, next proceed to check for codes along with a good visual of electrical componenets/connections/etc and vacuum lines/fittings. Correct any problems you find. You may wish to do a pinpoint test on the engine coolant temp sensor (the one that is part of the engine management system, not the temp gauge) next. Should the ECT sensor fail in a manner indicating a warm engine, it will pass that info on during a cold start, causing a lean mixture. Finally, I would do pinpoint tests on the intake air temp sensor (if equipped).

 

as mentioned above, all the vacuum lines look good, electrical connections also look good. The only code I am getting is koer code 41 system running lean. otherwise it gets 11's. How do you test the coolant temp. sensor? That is one of the things i have been wondering if it could have something to do with it. thanks for the help

 

I just checked that code 41 KOER; my reference says HEGO (HO2S) sensor voltage low/system lean. A good manual or CD will have flowcharts that will lead you through the diagnostics for this code. I don't have one for your model year, sorry.

On edit:

I saw you're comment "and the only other thing i can think of that isn't right is the exhaut manifold on the passenger side has the hole in it". Where is your O2 sensor relative to this hole and how big is the hole?

 

I wish I could find something that would give me the proper procedure for following up the code 41, but I most likely don't have the specialty tools required for the testing. I have most ALL hand tools and air tools, but only have about 7-8 differant specialty tools. Fuel pressure tester is one that i don't have. The hole in the exhaust is maybe 1.5inch and has a collor that sticks out about 2inchs. I know on most vehicles there is a hose attached to that the returns some exhaust into the air box but since this vehicle doesn't have a maf sensor I guess it doesn't have the same configuration. I could be WAY off on that as well.

 

If that hose is the hose I'm thinking of, it doesn't actually feed exhaust into the air box. It feeds ambient air that has been warmed by the hot exhaust manifold into the air box. There's a baffle that fits over the exhaust manifold through which cold air is drawn over the warmer manifold to warm that air (hope all that made sense). That may not be an exhaust leak, unless the exhaust manifold has a hole in it.
The other possibility is that you've lost the plug in the exhaust manifold for the nonexistant EGR tube. EGR tube, however, normally feeds off of the driver's side manifold on the years that had EGR systems ('86-'87).
Normally with any trouble code, the first thing to do is check the circuit and make sure there are no breaks or bad connections. One thing that can cause a "false" 41 is running the KOER test with the engine cold. You need to "preheat" the O2 sensor before running the test. Make sure you've done that. Beyond that, the first thing the pinpoint tests usually say to do for an O2 sensor code is to check the fuel pressure.
I don't know about your area, but just about every library I've been to around here has an auto repair section in the reference section that has good manuals which contain proper diagnostic information. Another possibility is to contact Ken00 who moderates the BII forum. He seems to ahve access to some of the pinpoint tests and is often willing to share.

 

Check for a cracked exhaust manifold. I had the same problem.almost drove me crazy trying to find the problem.Hope this helps

 

Sears sells a pretty good fuel pressure gauge for 30 - 35 bucks

 

did you check your engine temp sensor it is located btween injector 3 and for you will need a 25 mm socket to take it out sometime cleaning it will do the job it gets carbinized beware not to touch the little pin in the midle when you clean it let it soak