86 B2 refuses to run right at 20k miles

[TheOle86]

After working on my 86 Bronco ii for a couple months and scouring the internet I still haven't figured the ole girl out. It started as cylinder 2 not firing and being solved by replacing the fuel injector to currently having new plugs, wires, all 6 injectors new, cap and rotor, vacuum lines and coolant temp sensor replaced and it still refuses to run correctly. Starting to run out of ideas of what it could be. It has spark fuel and air but it floods badly and doesnt run right. It always starts and idles but is missing. Currently working on checking to see if the fuel pressure regulator is operating correctly. Any other ideas of what it could be???

 

[Uncle Gump]

If you haven't already... do a proper compression test. That is the only way to determine how healthy your engine is mechanically. Take the time to do the test right. If it turns out good... you can rule out all things mechanical.

It's also very important to ensure it has proper fuel pressure. Invest in a gauge... money well spent.

Finally... there are so many junk parts these days... they're all suspect until they're proven otherwise.

Good luck going forward.

 

[TheOle86]

Ok yeah compression test read 150 for all cylinders

 

[RonD]

Check the vacuum hose on the FPR(regulator) common issue, FPR leaks and raw fuel is sucked into the engine flooding it

 

[TheOle86]

Yeah i checked that and it didnt have any fuel in it.

 

[RonD]

Change the O2 if its never been changed

 

[gaz]

If this BII has a 2.9l, did it sit a number of years, unused?

 

[TheOle86]

Ok ive wondered about the 02 sensor. Yeah it has. I dont know the whole story behind it but i bought it last year with a salvage title. It had very light damage to the trunk and got salvaged. I bought it from southern Arkansas and it is rust free. Must have sat for a long time because it only had 16,000 miles when i bought it and ive put about 4,000 on it. Ive also had to change the fuel pump and filters already

 

[Eddo Rogue]

Sounds like it did sit for a long time. Pretty much anything in contact with the gas that sat in it could be toast. You could dump a lot of fuel system cleaner and cross your fingers or go through the rest of the fuel system. But yes, do use quality parts I.E. Motorcraft. I personally feel like you might have some old gas gunk in your fuel tank/pump, or possibly old oil gunk in your engine.

 

[TheOle86]

Changed the 02 sensor and didnt fix it. Pulled plug wires off as the engine was running and found that the drivers side isnt affected as much when plug wires were disconnected. However when we removed one from the passenger side it wouldnt even start up

 

[RC2]

After working on my 86 Bronco ii for a couple months and scouring the internet I still haven't figured the ole girl out. It started as cylinder 2 not firing and being solved by replacing the fuel injector to currently having new plugs, wires, all 6 injectors new, cap and rotor, vacuum lines and coolant temp sensor replaced and it still refuses to run correctly. Starting to run out of ideas of what it could be. It has spark fuel and air but it floods badly and doesnt run right. It always starts and idles but is missing. Currently working on checking to see if the fuel pressure regulator is operating correctly. Any other ideas of what it could be???

I am new here but I don't see that you replaced the TFI control module? It seems from all I have read those are very troublesome on these.Especially with the missing prob. Coil replaced as well? I would assume that not having correct voltage spark or intermittent could make it seem as if stuff was flooding. Fuel filter would be something else to check. Cheap and easy enough to change and never hurts to have a fresh one.A clogged filter can let just enough fuel thru to start and idle but not enough to get anywhere else.

 

[Mechrick]

Ignore items that are common to all cylinders. It sounds like the left bank is down on power compared to the right. Is there separate converters for left/right banks? Maybe the left is restricted. 2.9s can crack heads, does it use coolant? I believe the left and right banks are on different ECM drivers, I'll verify that in the morning. Something else to try is a running compression test. Remove the Schrader valve and test all cylinders. Sometimes valve sealing issues require some RPM to show problems. Could be a drippy injector on the left bank. What do the plugs look like?

 

[TheOle86]

Ignore items that are common to all cylinders. It sounds like the left bank is down on power compared to the right. Is there separate converters for left/right banks? Maybe the left is restricted. 2.9s can crack heads, does it use coolant? I believe the left and right banks are on different ECM drivers, I'll verify that in the morning. Something else to try is a running compression test. Remove the Schrader valve and test all cylinders. Sometimes valve sealing issues require some RPM to show problems. Could be a drippy injector on the left bank. What do the plugs look like?

Somewhere on the driver side bank im getting too much fuel or inconsistent spark because the exhaust smells very strongly of unburned fuel when running which tells me its either flooding that bank or not sparking properly (altho it has new plugs/wires/distributor cap/rotor). Not sure what you mean by separate converters for either bank? It has only one catalytic converter on the exhaust system. It doesnt use any coolant. If the left and right bank are on different ecm drivers then thatd be something worth looking into. And all the cylinders have good compression (150) as well.

I'm thinking ill look into testing the tfi module and double checking to make sure everything is ground right.

 

[Mechrick]

1-2-4 are on one driver and 3-5-6 on the other, so not separated by bank.

I would test for a drippy injector. You would have to lift the upper intake out of the way, and pull the injectors out of the lower intake still connected to the fuel rail (disconnect them electrically). Place some newspaper under the injector tips and cycle the key to pressurize the rail. look for fuel dripping from the pintles.

 

[TheOle86]

I could check that but i just put new injectors on it and know they work properly