87 Bronco II timing & emissions issues.

[Outlaw4x4]

Hey all,
I'm new to the forum, as i finally purchased my first Bronco II ive been looking forver for

I took it to the local smog check here in Fairfield,CA they did a 2 step idle test on it, it failed idle and passed 2500RPM test. Hydro carbons were pretty high, tells me its not burning off the raw fuel? Could this by any chance be caused by timing issue or a bad catalatic converter? The exaust does smell pretty bad, looks to be factory cats on it.

The guy i bought it from replaced the cap/rotor/plugs/wires. Ive checked the cap/rotor and plugs since i got it home. cap & rotor looked ok, he had the plugs gapped at .55 instead of .44, and it had burned an edge into the plug diodes so i just replaced them and gapped the new ones at .44 and now it actually can do freeway speeds but not super easily. It does feel as if it lacks major power accelerating. Almost feels as if it hits a flat spot in the rpm range around 2500-3000 or so where it feels it just dont make any power. Could this be caused by a bad cat?

Also.. i tried to check the timing, i checked it with the spout plugged in and the spout unplugged. Warm & unplugged it looks like its 10BTDC but when i plug the spout back in it looks like it jumps to around 28 degrees? Does this sound weird? Any help would be awesome gotta get this thing to pass Cali smog so i can register her. Thanks all

 

[PetesPonies]

Timing is perfectly normal. As for the cat . . hard to say. yes a bad cat can cause these problems. But only you can make the decision to replace them. If they are original, I'm sure they are not operating as when they were new. If you replace them, look smartly and you can find some deals.

 

[RonD]

Hi, welcome to the Forum

The '87 Bronco II should have the 2.9l fuel injected engine.

The TFI ignition system can be tedious to check, here is a good read and how-to:
http://www.therangerstation.com/tech_library/TFI_Diagnostic.html


You could have a leaking, sticking or bad injector, the injectors on the 2.9l V6 fire in Banks not individually, so 3 injectors open at the same time, the 2.9l opens 1, 2, 4,then 3, 5, 6
With engine idling use a small hose as a stethoscope and listen to each injector, you should hear a solid "click" each time it opens.
Also a can of Seafoam in the gas tank can help clean off varnish build up on the injector needles, so they spray instead of drip.

Feel the output of tail pipe as someone increases the engine RPM, should steadily increase with RPM, if it gets to higher RPM and doesn't increase then yes CAT could be getting clogged up.
But replacing a 26 year old factory CAT wouldn't be a bad idea just because.......it's 26 years old

Fuel filter is a $10 part and should be changed, it can limit fuel pressure at higher speed as it gets dirty.
On the Ranger it is below the drivers seat in the frame rail.

On the fuel rail there is a vacuum operated fuel pressure regulator(FPR), with engine off, remove this vacuum hose and smell it for gas smell, the FPR diaphragm can leak and raw fuel is sucked into the intake at lower RPM(high vacuum) causing a rich mix.

O2 sensors wear out like spark plugs do, not as fast but they do wear out.
An O2 sensor works by sending a voltage to the computer, 0.1v-1.0v, 0.1v is lean, 1.0v is rich, O2 should be sending .4v-.7v, the sweet spot
O2 sensors need to be above 600degF to work, as they wear out they tend to send a lower voltage, so a false Lean signal to the computer, it could be the O2 sensors are just wearing out and computer is running engine richer than needed.
There would be signs of that on the spark plugs, blackish residue.

This is the spec page for the 2.9l engine, good info about the speed density system used on the Rangers and B2s:
http://www.therangerstation.com/tech_library/2_9_Page.html

This is a great site for Ford sensor operation and troubleshooting:
http://oldfuelinjection.com/?p=1

 

[Surrey]

Replace your cat.

I had a early-90s Cherokee that absolutely bombed on hydrocarbons (like 10 times the limit or something lol) tossed a new cat on that baby and she dropped to almost nothing.

Everything RonD said is good too, especially if replacing the cat doesn't work, but I would start with the cat...

When you took it to smog check, did you go for a nice long drive to get the cat heated up first? If you take it in with a cold cat your basically asking to fail. - this may be why your higher-rpm test passed, it was starting to heat up by then?

 

[adsm08]

I would start by moving to a state with reasonable emissions testing.

 

[Outlaw4x4]

Sorry for such a majorly late response haha, i've got a ton of projects at the house and this B2 requiring so much time/$$ i've just kinda put it off on the sidelines for the time being. I couldn't agree with you more, California's emissions testing is an absolute JOKE! Unfortunetly, my work says that i stay here, since we only deal business ( at the moment) on California's semi trucks. Gotta love diesel emissions (scam but whatever) lol

I would start by moving to a state with reasonable emissions testing.

 

[wildbill23c]

Haha I agree with adsm, move the hell out of Comifornia to start, then move to a location that doesn't do SMOG testing. Not saying remove the cat permanently, but it may be part of your problem. If the vehicle hasn't been driven much for quite a while things tend to settle and cause emissions problems for a while until the vehicle has several long drives to get all the crud worked out of the exhaust systems, short trips are the worst on a vehicle. I'd start with the Cat, drive it for 20 miles or so, then have it tested.