Got the engine started over the weekend but still have a few problems. Every other time I start the engine it idles really rough. The codes I get when it is running rough are:

98 - Hard Fault
66 - MAF Related

Now, I believe this could be a relay issue. I tested power to the MAF with the key on and there was none but if I "wiggle" the relays while they are seated in the power distribution block they engage. Is this normal or are they bad relays? They are ford relays from a Ford Explorer.

Other times it starts and idles fine. I pulled the codes and get:

33 - EGR (removed - I have the resistor)
44 - Thermactor (removed)

I suspect these are okay considering I've removed these components and have the proper EGR resistor in place.

In all cases the engine seems like it is running rich even when the idle is normal but I'm not getting any other codes that indicate a reason. Wouldn't I get a code 42 or 92 if the o2 sensors are doing their jobs?

I'll start with replacing the relays. Seems like a cheap potental fix. Hopefully someone will have some insight into the running rich issue.

I'd say bad relay but could be something wrong with the distribution box. Those codes are ok.

It is possible to be running rich and not have any codes pop up. If the MAF is wrong or dirty it could run rich (or lean) until the temp comes up and the system goes into closed loop operation.

I'll start with the relays and post back.

Can you explain the "closed loop" operation? I've heard that term before but haven't been able to figure out what it means in any of the other posts on CB.

Closed loop is when the system is using input from the O2 sensors to keep the A/F ratio in check. It takes a while for the sensors to get up to operating temp. Lot's of info here: http://fordfuelinjection.com/?p=64

Are you running a cat? Mine runs a bit rich too, but I have no cat.

Thanks Viperwolf1, Ryan's site is uber helpful but sometimes difficult to find stuff easily.

No cat. Its not required for me to get emissions but would it help?

Hmm, I'm going to have my exhaust re-done. That might be an option.

if you are running rich i wouldn't recommend running a cat until you address that issue first, cats are made to burn off unburned exhaust, but only so much, a rich running engine will cause a cat to run to hot, which will cause it to melt down and eventually clog, i plan on running one on mine when i swap to efi, but i'll be running a 302 with a 5.0L computer, and a 351w cam for the correct firing order, so ideally i shouldn't have much issue with running rich or lean

as viper stated check the relays first, and keep in mind there might be an issue (loose terminal, bad connection of some sort) in the junction block, also as he stated an incorrect, dirty, or faulty MAF can cause the issue, along with many other sensors, i don't know off hand what sensors are used for runability during open loop, also a dirty or faulty IAC valve is a common issue, but im assuming all is new in your setup?

Most everything is used. I suppose these kinds of problems come with the territory.

Went and bought new relays last night. Replaced them and then tried to start the engine...nothing. Starter solenoid won't even engage. The solenoid is new and the battery was just checked and fully charged 2 weeks ago.

I have another solenoid I can check. I'll try that tonight. More to follow...

If you jiggled the relay and could hear it coming on its not likely the relay but more the socket.

The more I think about it I think it might be the battery. With nothing connected to the battery last night the multimeter showed the battery at 12.25v. When I connected the power distribution block and turned the key to "on" the voltage dropped to something like 11.8v. Will the solenoid even engage at 11.8v?

Its weird because the fuel pump comes on but nothing else seems to be getting power? Headlights won't come on, turn signals don't work but the fuel pump comes on.

Easy way to verify is jump the battery from another vehicle and see if it fixes all your problems. I don't believe that is your problem, as much as I wish it were.

J.D.

Ahh the simple things... At least it was a easy fix!

Ok time to drudge up this old thread. I finally got moved into the new house and had a chance to go out and turn the Bronco over. I'm still having some code problems and exhaust smells really rich - although codes say it's lean.

Timing set to 10* BTD
KOEO - 22, 81, 82, 85, 84 (81-85 seem to be normal since I don't have those emissions systems)
KOER - 12, 41, 91, 33 (No EGR)

I've read all kinds of stuff on the interwebs and am completely lost at this point. I've checked the vacuum lines and I only have lines going to the C4 and brake booster. All others are plugged. I've checked the grounds and all are good.

I'm running the orange injectors with a MAF from a 1990 Mustang - sorry I can't remember the the lbs and I don't have a caliper to check the mm on the MAF but I suspect it is the stock 55mm. Is this too small for the 351w with lightning intake? I don't know - I'm grasping at straws here.

Any ideas?

BP sensor isn't working. Make sure it's plugged in and has no vac hose to manifold. This will affect A/F ratio and cause 41/91 codes. Test for codes again after BP is fixed.

Its definitely plugged in and has no vacuum line to it. I guess I'll replace it and re-check codes. Thanks

Happy to hear you got into a new house and working on your Bronco again. I cannot wait to see your Blue paint in person.

Replacing the bap fixed the code 22 but I'm still getting the 41 and 91. Any ideas?

What's the best way to check if my o2 sensors are wired correctly? Anyone have a schematic for the bcbroncos o2 sensors?

Is the 41 and 91 coming up as a KOER code or a CM code? Try clearing the codes then check the KOER codes again.

Other things that can cause them are exhaust leaks, intake vacuum leaks, wrong or dirty MAF, maybe dirty IAC.

Diagram is here: http://www.oldfuelinjection.com/?p=6

I cleared the codes and ran a few more KOER tests. First test came back with 21, 41, 33 and the second came back with 21, 91, 41. I'm going to replace the IAC - will report back tomorrow.

I don't think you need to replace it. Just clean it out with some carb or brake cleaner.

I too recently did an EFI conversion. The exhaust is VERY rich smelling. Can someone reiterate the possible fixes for that? I was reading in this thread about running a cat. Is that the fix for it?
I was also reading here that there was a potential grounding issue. I found that proper grounding is vital for the system run properly.

Troubleshooting certainly does get harder from there. Just because the exhuast smells rich doesn't necessarily mean you are running rich. Rather, you could be running lean and the computer then dumps fuel to compensate. Or at least thats my understanding.

Definitely pull your codes first to see whats going on. I've had problem after problem on this conversion. Look for intake leaks, exhaust leaks and check your grounds.

Hope you get it figured out. I'm leaving work in about an hour and am going to install a new IAC. Hopefully that will resolve my problems but I'm fully prepared to be disappointed.

I swear I have the worst luck ever.

I got the IAC replaced and reset the codes. It started right up and I let it run for about 5-10 minutes to get it up to temperature. I then turned it off and switched the CEL back on to check the codes. Well, no light blinky when I started the engine again. What the hell!

Turns out the power wire that I haphazerdously placed in the self-test connector fell out. So I go to put it back in and accidently touched the wire to SIG RTN port on the self-test connector. It sparked quickly before I realized what happened.

Now, the engine won't start at all. Let me guess - I fried the computer?

Auto ECM should be ok. Manual ECM might have a fried trace on the board. Not real hard to fix. Should still run though. Check the fuses.