So months ago the bronk was running strange so I went to do a self test. Would not start or flash the ck engine light. The scanner at work wouldnt read codes either. I tried some common items and solved the issue. So now I swapped the cluster and my ck engine light is on all the time now.
Codes pulled 31,67,81,82,84. I think from what I was looking, they are all for the AIR system which has been removed from the bronk long ago. I think 1 is for the Neutral safety switch. 88 Bronk 5.0

Codes pulled 31,67,81,82,84 Lets take them one at at a time:

Code 31 - EVP signal return lower than expected. Basically this means that the voltage coming back to the ECA (computer) from the EVP (EGR Valve position) sensor was lower than 0.5 VDC.

There are a host of things that could be the cause but the most common is either a stuck EGR valve or a "dead spot" in the EVP sensor itself. To troubleshoot Code 31, begin by applying a minimum of 14 Hg of vacuum to the EGR valve itself at the barb. This is usually enough vacuum to free a stuck valve. Release the vacuum supply quickly and listen for the valve to snap shut. If the valve will not free in this manner a very small screwdriver or allen key can be used to gently lift up on the pintle of the valve THROUGH the small holes in the side of the lower half of the valve body. Be extremely careful to only lift on the pintle at the center of the valve otherwise damage to the vacuum diaphragm inside the valve will result.

In the rare event that this does not clear Code 31, Replacement of the EVP sensor will be necessary. However, it is the stuck EGR valve that causes the performance issues NOT the EVP sensor that isn't moving.

Code 67 - MLPS (Manual Lever Position Sensor) was out of range OR AC clutch circuit closed during diagnostic testing OR NDS (Neutral Determination Sensor) circuit failed

The most common reason for Code 67 to rear its ugly head is due to the Air Conditioner being ON during the diagnostic test. If it is ON during the test Code 67 only proves it. The fix is to run the test again with the A/C turned off.

Occasionally, the MLPS can be the culprit. If it is suspected that this was the cause for Code 67, make certain the MLPS is mounted to the transmission securely. Also make certain that the gear select linkage in the truck is not loss or exhibiting any "slop" or play in it. This can keep the MLPS from dropping into the "park" location where it must be during the diagnostic tests.

The third option is an electrical circuit failure internal to the E4OD transmission itself. Fortunately it is the least likely reason for Code 67 to manifest. Troubleshooting this failure is best left to a transmission specialist.

Codes 81 and 82 - both indicate a failure of Pins 11 and 51 of the ECA (computer) to return to zero volts when the engine is shut off. This particular Code almost always occurs as a result of damage to the wiring harness or the air management solenoids mounted near the ignition coil. The repair for these Codes is tedious but troubleshooting can be accomplished by taking a voltage reading at each terminal on the TAB and TAD air management solenoids. At least ONE (1) terminal on each solenoid must have +12VDC (battery voltage) with the key in the ON position. If not, the wiring to the solenoids from the ECA must be repaired.

Code 84 - EVR EGR Vacuum Regulator (solenoid) circuit failed. The first and most obvious check is to ensure that the EVR solenoid is indeed still connected to the wiring harness. If it is then, disconnect it and take a resistance reading across the terminals. The resistance must fall between 30 and 70 ohms. If it does, not, replace the EVR solenoid. If it does, take a voltage reading on each terminal of the EVR connector. One terminal MUST have +12VDC (battery voltage). If neither has this voltage with the key ON, repair the wiring between the EVR and pin 33 of the ECA.

With the sheer diversity of the Codes represented here, I would actually be checking the main engine bay wiring harness for damage. Many of them can be traced back to damaged wiring and the main harness can be susceptible to damage so inspecting it along its entire length is advisable if there are no other apparent causes for the Codes being triggered.

It is important to mention that once you have troubleshot and/or repaired some part of the system that you clear the Codes from the computer and re-test as Codes remain in memory until they have been cleared or power to the computer has been lost for at least 7-10 minutes.

Well there are no emissions junk on the bronk anymore, all been unplugged and removed when I swapped the 5.0HO into it....So other then the code 67. Bronk is a AOT/AOD so its not the E4OD, and the AC doesnt work in the bronk anyway so it wasnt on lol. I didnt think there was a range sensor on the AOT like the E4OD. The ERG valve is just there with no vac to it, line undone. The sensor is still plugged in tho.

You need to wire in resisters into the tab/tad wires to eliminate those codes. Also need an egr eliminator thingy which is just three resisters. I think rjminjection has what you need. Should be under $15 for all three. A quick google search should pull up what you need. Ie 88 bronco egr eliminator.

Ive done this to mine and have zero codes relating to such. Only codes i get are telling me my e4od is missing, which it is.

Then why waste everyone's time by asking how to troubleshoot fault codes? The system will not operate properly with equipment missing and the computer will FOREVER give fault codes because it isn't getting the information it needs from the equipment that has been removed. The short answer here is, "It cannot be fixed." Oh you can spend a bunch of money throwing resistors and gadgets at it to "fool" the computer but the truth is, you aren't and the things the computer changes to compensate for fixed resistance values in place of dynamic values will eat the engine alive compared to the longevity you will get if everything was functioning.

You do not need any of the junk dude.. And it will not "eat the engine alive"

Myths.. That's what those are is myths


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5.0Flareside said:

You do not need any of the junk dude.. And it will not "eat the engine alive"

Myths.. That's what those are is myths


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Click to expand...

HMMMMM.....Ever see a piston destroyed from pre-ignition? EGR helps to eliminate spark knock from pre-ignition. There is a built in timing change to make more power in these engines. Down side is that spark knock will show up. Eliminating egr helps nothing. "But mine doesnt do it!" Yeah, many wont have the problem, but does that mean that none do? Far from it! Catalytic converters.....they're only a problem if theres a problem upstream from it causing the converter to fail (like someone deleting the AIR pump). MYTH.....NOT HARDLY!

I disagree on anything Obd-1.. But I'm not the senior tech.. Just seen a hell of a lot of em built and not have issues..


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From 140k-200k with no issues. No egr, no tab/tad, no air pump, cylinder head air ports blocked, no charcoal canister purge valve. I am running a high flow cat for emmisions. 94/5.8 with 95 maf swap. Only engine light is for auto trans which i dont have anymore. Runs like a rapped date 120mph+ with fifth gear to go!

I never asked to solve the issues, just sayin what codes I got, and any info on them caus I couldnt find any info on them. I did say all the emissions junk had been removed so If you didnt read my post fully thats not my fault and no need to get all worked up over it.

Post #2 pretty much says it all. Some are caused by the deletion of emissions equipment, some are possible wiring faults.

It was just wierd how my ck engine light was never on till I swapped the cluster and my self test would never run till the cluster was changed too. Strange