Spoke too soon - EFI rough idle

[dsmith01]

Its an auto computer, A9M I believe. Fuses are okay.

I'm baffled...

[Viperwolf1]

What works? Does the fuel pump kick on with the ignition sw? Do you have spark? See if the relays are all working (12V out).

[dsmith01]

I can hear the relays and the fuel pump when I turn the key. I'll check for spark when I get home.

[dsmith01]

New iac and computer. Same old codes:

Koer - 41, 91, 33
Koeo - 81,82,85,84

[dsmith01]

Well the only other thing I can think it would be is an exhaust leak somewhere. My headers are pretty old and rusty and I was planning on having the exhaust done anyway so I think my next step is complete exhaust replacement.

[dsmith01]

Okay, dragging up this old thread. I finally got the nerve and time to work on this again. Its still not running but with different problems now.

Decided I wanted to try to replace the header and collector gaskets before anything else so I changed those out yesterday and checked the codes. Started right up but now I'm getting wierd codes and the fuel, temp, oil and tach gauges are no longer functioning. I'm getting KOEO 51,22,53,54,35,67,81,82,85,84.

After reading through 10-15 CB threads today I went through everything I could think of. I checked all my grounds - nothing has changed. I checked all the fuses and relays - everything is working.

The new computer is a manual and PIN 30 is connected to PIN 46. Today I tore into the harness to verify. I also pulled the computer and verified there are no burned traces or capacitors. Everything I've read leads me to believe this is a PIN 30 issue but nothing has changed.

I'm trying to think of the catylast here but I've really only changed the gaskets since the last time I pulled the codes.

[Viperwolf1]

51-Engine Coolant Temperature Circuit Open
22-Barometric Pressure Sensor Out Of Self Test Range
53-Throttle Position Sensor Circuit Above Maximum Voltage
54-Intake Air Temperature/Air Charge Temperature Circuit Open

The signal return wire isn't making it all the way back to the ECM. Could be problem in harness or computer.

[dsmith01]

Would that explain the gauge problem?

[Viperwolf1]

Would that explain the gauge problem?

No. That's a separate problem. Gauges are hard wired directly to ign sw. Possibly the switch is flakey. Don't know where your tach gets power.

[dsmith01]

Ok, I can't seem to find my voltmeter so gotta buy a new one tomorrow. I'll check back in with the results. Thanks for your help.

I have got to figure this out. I might never make it to a CCB breakfast if I don't.

[ZOSO]

For a volt meter home depot has a special right now buy one get one free. Its a Milwaukee and it includes an amp clamp that will read DC amps. For 129$

[landshark]

For a volt meter home depot has a special right now buy one get one free. Its a Milwaukee and it includes an amp clamp that will read DC amps. For 129$

oh man i need one.. thanks might have to swing by and pick one up.

[Gunnibronco]

I think that amp clamp will also do AC volts. I had one when I ran my hot tub shop, I miss that meter, amp clamp was super handy diagnosing stuff.

[landshark]

well i went ahead and bought a later model solenoid. I just asked for a 94 bronco one.. which is probably the same as the mustang and a million other cars...



I guess i should order up the ends of the cables and then I can get started wiring some.. ordering my EFI harness right now.

if anyone has insight on the charging system let me know!

[dsmith01]

Got a multimeter and took a look at things today. Good news is that I solved my most recent issues with the odd codes and gauges not working. Bad news is that I'm back to where I was with the system lean codes (41, 91).

Turns out that I over complicated things. Gauge problem turned out to be a bad fuse and the odd codes were because of the the way I jumped the STI input/output and the way my CEL is wired.

Nevertheless, the computer still reads lean (KOER 41, 91) and its running rich. No intake leaks, new computer, new MAF, new IAC, new BP, and now new exhaust gaskets. O2 sensors were new...could they both be bad? Any way to test?

[Viperwolf1]

What MAF are you using? Part number and housing size?

[ZOSO]

are you sure its running rich? if its running rich and your getting lean codes the o2 sensors are not giving the correct feedback.

[dsmith01]

Should be a 55mm housing, the new MAF I purchased was remanufactured and came with the housing. No part numbers are stamped on either but I ordered for a 1992 5.0L Auto Mustang. Autozone shows O.E.M. #E9ZF 12B579-AA, F1ZF 12B579-AA

I'm unsure if it is actually rich or inline with the lean reading. It very well could be a lean misfire. Smells rich though.

[Viperwolf1]

Try running it with the MAF unplugged and codes reset. It should run pretty well if everything else is ok.

[dsmith01]

Have an update and some new information. Today I drove the Bronco over to the exhaust shop to have the new exhaust put in. The entire way there was a popping noise coming from the engine (intake pop maybe). I also noticed that the transmission (C4) wouldn't shift into 2nd unless I let off the gas. Would an intake leak cause this?

I haven't tried running without the MAF, yet. I was hoping a new exhaust would permanently check off exhaust leak on the list of suspects.

[dsmith01]

I think I may have figured it out...

When I picked up the truck from the shop last night the owner had called a friend who worked with fuel injectors over to see if he could spot the problem. He was sure the engine was missing on 2 cylinders.

All this got me thinking if the firing order is right and the injectors are okay, what else could it be. So I went back to the engine rebuild documents and found the comp cam card and contacted comp cams this morning to see what firing order the cam has. Sure enough my cam has the non-HO firing order.

The saga continues.

[Jesus_man]

Does that mean you have the wired hooked up wrong or right?

[dsmith01]

I beleive that means I need a custom tune. Fordfuelinjection.com says you can't just swap the the injector order and this comp cam document says you can't change the plug order on MASS Air vehicles.

[Gunnibronco]

I'm running the 302 (non-HO) firing order and the stock Ford EFI stuff. Just get your plug wires right, and don't worry about the injector firing order. My truck runs great. The injectors that are firing out-of-order won't amount to anything you can feel.

[dsmith01]

I'm running the 302 (non-HO) firing order and the stock Ford EFI stuff. Just get your plug wires right, and don't worry about the injector firing order. My truck runs great. The injectors that are firing out-of-order won't amount to anything you can feel.

You just made my day! I'll swap them when I get home.

[Gunnibronco]

Good luck.

[dsmith01]

No go. Won't start with the non-ho firing order.

[Gunnibronco]

Wait, I just read your signature, you are running a 351W? All 351s are supposed to be the same firing order as 5.0 HO (1-3-7-2-6-5-4-8
), there was no 351 "HO". Only the older 302s are supposed to have the "other" order (1-5-4-2-6-3-7-8).

Sorry if I misled you. If the cam was spec'd for a 351W, put the plug wires back to the other order.

The symptoms you listed may be to a vac leak at the intake. I don't know much about auto trans, but they shift based on vac, so lack of will screw up the shifting. There are lots of ways to check for a vac leak, some safer than others. Spraying starter fluid (or carb cleaner) around the intake, with the motor running, is one way. If the RPMs rise, then you know it is sucking the fluid into the intake & you have a leak.

[Jesus_man]

Spraying starter fluid (or carb cleaner) around the intake, with the motor running, is one way. If the RPMs rise, then you know it is sucking the fluid into the intake & you have a leak.

Speaking of safe, do this with a cold engine to help the safety factor. Probably goes without saying, but singed eyebrows are no fun. Or a burnt down bronco that was recently "finished" is a disaster in my book!

[Gunnibronco]

Yeah, that is the "old school' way of doing it, or maybe "redneck" or "backwoods", I'm sure there is a better way.

Safety "first", or at least "top five".