HELP!! 88 B2 wont pass low idle emissions in my state.

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pblake

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Hello I recently bought a 1988 ford Bronco II XLT 4X4. It has been sitting for about 10 years before I came along.
I did some basic stuff to it and she fired right up and seems to run really well but when I took it in for the first time to get my state IM test done, it failed on the HC at idle speed. MAX is 220 and it got a 257, so close right? so I ordered the typical tune up stuff and took it in again(2nd test free). It got a 369! What the heck? Shouldn't it have gotten better? So on line I went, here is what I have done so far;
pre IM test, fresh out of the field.
Dropped fuel tank/restored fuel tank
Fuel pump
High pressure fuel pump
Fuel filter's
Fuel lines

Post failed IM test
6 spark plugs
Wires
Distributer cap
Rotor
Oil change
Cleaned upper intake
Fuel additive(injector cleaner)
Additive for ethanol where
Additive " guaranteed to pass IM"
2 tanks of Premium Gas(46 gallons)
1 tank of "Clear 88" ethanol free gas.(23 gallons)
Checked vacuum lines for leaks
Tested PCV, TPS, Air flow and other throttle related valves and sensors.
And a ton of driving on a temp tag.
So I just took it in today expecting it to pass with flying colors, well it got worse. I got 465 out of the maximum 220. Every thing at high idle is good between 54-94 of the max 220.
Other than catalytic converters I don't know what els to do. The truck seems to run great, its even peppy and thats hard to get out of the ford 2.9 V-6.
Any tips and tricks or suggestions would be greatly appreciated.
Thanks!
 

Shaggy

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Doesnt a tune usually increase RPMs?
 

miesk5

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Yo pblake,
Welcome!
"High hydrocarbon (HC) readings usually indicate excessive unburned fuel caused by a lack of ignition or by incomplete combustion. Concentrations are measured in parts per million (PPM). Common causes include a faulty ignition system, vacuum leaks, and fuel mixture problems. Circumstances that can lead to a high HC emissions are:
* Incomplete combustion due to fouled spark plugs.
* Improper timing or dwell
* Damaged ignition wires
* Poor compression
* Vacuum leak
* Ineffective or faulty air management system (ECM control of air/fuel ratios)
* Catalytic converter intervention and HC concentrations
High HC readings at the tailpipe are an clear indication that there is a problem in at least one part of the system, but an HC reading that appears within "normal" ranges or is only modestly elevated is not necessarily a reliable indicator of proper or even acceptable system performance. HC readings at or near "normal" are possible, and not uncommon. From a malfunctioning engine equipped with a properly functioning catalytic converter. In such circumstances, truly elevated pre-catalytic converter HC levels will be masked by the catalytic converter and the potential for an HC problem must be further evaluated in the context of other readings of abnormal gas concentrations and AFR / Lambda readings." by http://web.archive.org/web/20060615114619/http://www.interro.com/techgas.html#anchorfour
 
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pblake

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I will be working on it again this weekend. I think i am going to start with the intake manifold to be sure its not just a bad gasket (again). Im also going to remove, clean and reset all the emissions components like oxygen sensor, TPS and what not.
Ill let you know how it turns out.
Thank you for the info.
 

muddrivermike

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Hydrocarbons are Unburned fuel. When I was in the shops it was usually the distributor timing off. I cant remember if the timing needs to be advanced or ********. Out side of that as mentioned above, anything that wouldn't produce the correct spark to burn the fuel. Now you can either adjust your timing, run hotter plugs, Orrrrr you can try pulling a vacuum line to lean out the mixture and see if that makes you pass then hook it back up.

This censoring on here is ridiculous. I cant even say "re..tar..d -ed" for the timing.
 
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chazzone

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Do you have a reason to suspect the intake is leaking? If it had an air leak it'd be running lean, the opposite of what you have going on now.
Did you use Motorcraft plugs? It makes a difference.
Did you gap them properly? It's better to have a wider gap than closer.
What condition are the plug wires? Are they Motorcraft?
I'd definitely check timing. Advancing timing can mean a more efficient burn, thus lowering unburned hydrocarbons.
I'd also throw a coil on it. If the spark isn't hot enough, it'll have increased UHC.
I'd also make sure that the thermostat is correct. If it's not getting to operating temp, it'll run rich.
 
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pblake

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Do you have a reason to suspect the intake is leaking? If it had an air leak it'd be running lean, the opposite of what you have going on now.
Did you use Motorcraft plugs? It makes a difference.
Did you gap them properly? It's better to have a wider gap than closer.
What condition are the plug wires? Are they Motorcraft?
I'd definitely check timing. Advancing timing can mean a more efficient burn, thus lowering unburned hydrocarbons.
I'd also throw a coil on it. If the spark isn't hot enough, it'll have increased UHC.
I'd also make sure that the thermostat is correct. If it's not getting to operating temp, it'll run rich.
I figured, intake sensor detects to much air therefor turns up the fuel mix.?. I dont really know. I did use quality parts but they were not motorcraft... I never did find out what was causing the high readings on the IM test but I did find out that in my state (Utah) a 1988 is considered a "classic" and is not required to pass the IM test. lol. So I do have my Bronco on the road but it is now registered as a classic and has Vintage plates on it :)
 

Big_Dad_Energy_83

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I figured, intake sensor detects to much air therefor turns up the fuel mix.?. I dont really know. I did use quality parts but they were not motorcraft... I never did find out what was causing the high readings on the IM test but I did find out that in my state (Utah) a 1988 is considered a "classic" and is not required to pass the IM test. lol. So I do have my Bronco on the road but it is now registered as a classic and has Vintage plates on it :)
Oh man i hope this is how it goes in Los Angeles
 

miesk5

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Yo,

Testing EEC-IV Equipped Engines
ford_ranger_buyers_guide-2.jpg

The EEC-IV equipped engines use an older diagnostic system to monitor and report engine related malfunctions. This system is known as On Board Diagnostics (OBD-I). The Diagnostic Trouble Codes (DTC's) are two or three digit numbers and can be read through the use of a scan tool, an analog voltmeter, or with the Malfunction Indicator Light (MIL) [Check Engine or Service Engine Soon light]. Use one of the following methods to obtain the DTC's and then refer to the 2-digit or 3-digit charts.
Scan Tool Method

(1)
Connect the scan tool to the self-test connectors. Make certain the test button is unlatched or up.
(2) Start the engine and run it until normal operating temperature is reached.
(3) Turn the engine OFF and wait 10 seconds.
(4) Activate the test button on the STAR tester.
(5) Turn the ignition switch ON but don't start the engine.
(6) The codes will be transmitted. Six to nine seconds after the last code, a single separator pulse will be transmitted. Six to nine seconds after this pulse, the codes from the Continuous Memory will be transmitted.
(7) Record all service codes displayed. Do not depress the throttle during the test.
(8) After the test, compare the DTC's retrieved from those in the 2-digit or 3-digit charts.
Analog Voltmeter Method
eec-iv_testing1.gif
eec-iv_testing2.gif
Set the voltmeter to read DC 0-15 volts. Connect the positive lead of the meter to the battery positive terminal and connect the negative lead to the Self-Test Output (STO) pin of the diagnostic connector. Follow the directions given previously in the scan tool procedure. To activate the procedure, use a jumper wire to connect the signal return pin on the diagnostic connector to the self test input connector. The self test input line is the seperate wire and connector wih or near the diagnostic connector. The codes will be transmitted as groups of needle sweeps. This method may be used to read either 2 or 3 digit codes. The Continuous Memory codes are seperated by the other codes by 6-seconds, a single sweep, and then another 6-second delay. Compare the 2-digit or 3-digit Diagnostic Trouble Codes with the appropriate chart.
Malfunction Indicator Lamp (MIL) Method
The Malfunction Indicator Lamp (MIL) on the dash (Engine Light) can be used to retrieve the stored codes. This method does not allow for any system investigation. This should only be used in the field where quick checks are needed. Follow the directions previously given for the scan tool procedure. To activate the tests, use a jumper wire to connect the signal return pin on the diagnostic connector to the Self-Test Input (STO) connector. The self test input line is the separate wire and connector with or near the diagnostic connector. Codes are transmitted with a pause between flashes. Code 32 would be sent as 3-flashes, a pause and then 2-flashes. A slightly longer pause separates the codes. The only way to repeat the code is to recycle the system. The Continuous Memory Codes are separated from the other codes by 6-seconds, a flash and then another 6-second delay. Compare the 2-digit and 3-digit Diagnostic Codes with the appropriate chart.​

Memory Codes
Memory codes are problems that the computer has noticed in the past. If for example there was a loose wire to a solenoid that only lost contact while driving but was making contact while testing the system there would be NO HARD FAULT CODE. The code would show up IN MEMORY. The same would happen for a sensor that only went out of range occasionally. Memory codes come out AFTER the separator pulse.
NOTE: The computer will erase the memory after a certain number of engine re-starts if the problem does not repeat itself. The number of re-starts varies from 20 to 80 depending on the year of the vehicle. The later models keep memory longer.
Key On Engine Running (KOER) Test

1. Make sure engine is fully warmed. If in doubt, run engine at 2000 rpm for 2 minutes.
2. Turn ignition off and wait 10 seconds for system to shut off. Make sure A/C is off and transmission is in Park (automatic) or Neutral (manual).
3. Hook up light and jumper (or tester if you have one).
4. Make sure vehicle is safe to run and start engine.
5. Engine I.D. should be output.
6. Step on brake and turn steering wheel 1/4 turn. If the vehicle has an overdrive cancel switch, push it.
7. If a "Goose" pulse is received, move throttle quickly 1/2 way down and release.
8. Fast Codes are output (ignore).
9. Read codes.
10. See code explanations and check components as necessary. Use FIRST CODE OUTPUT and retest after any repairs are made.​

Key On Engine Off (KOEO) Test

NOTE: On 4.9L trucks with a manual transmission hold the clutch pedal in during this test.
On Diesel engine trucks hold the throttle to the floor during this test.
1. Make sure engine is fully warmed. If in doubt, run engine at 2000 rpm for 2 minutes.
2. Turn ignition off and wait 10 seconds for system to shut off. Make sure A/C is off and transmission is in Park (automatic) or Neutral (manual).
3. Hook up light and jumper (or a tester if you have one). Turn key to ON (do not start engine).
4. Fast Codes are output (ignore fast light flashes).
NOTE: Unhook self test input jumper (or tester if used) at any time during code output to erase memory.
5. Read hard faults.
6. Separator Pulse.
7. Read memory codes.
8. See code explanations and check components as necessary.
Use FIRST CODE OUTPUT and retest after any repairs are made.
Test Hook-Ups

4hup96.gif

Clearing Codes
These codes are kept in memory for 40 warm up cycles. To clear the codes for purposes of testing or confirming repair, perform the code reading procedure. When the fault codes begin to be displayed, de-activate the test by either disconnecting the jumper wire or releasing the test button on the hand scanner. Stopping the test during code transmission will erase the continuous memory. Do not disconnect the negative battery cable to clear the codes; the keep alive memory will be cleared and a new code (19) will be stored for loss of PCM power.​
trs_f_r-2.png
 

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