Getting codes w/out scanner

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Apr 3, 2002 | 10:10 AM

chrisw8925

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Getting codes w/out scanner

I'm looking for a detailed procedure for obtaining the codes from my '93 Aerostar 4.0 without the use of a scanner. Suspect bad O² sensor and well documented issues w/ RABS system. I'd like to rule out any other issues before replacing parts. Thx.

Apr 3, 2002 | 01:09 PM

aerocolorado

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Getting codes w/out scanner

[updated:LAST EDITED ON 03-Apr-02 AT 02:14 PM (EST)]Check this information from a previous post:
Aerostar Topic #202 . "RE: Check Engine Light"
04-Jun-01, 04:24 PM (EST), scroll down to the 7th reply for links to pulling codes.

Apr 16, 2002 | 03:38 PM

airharley

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From: Escondido, CA

Getting codes w/out scanner

I tried to pull up the websites topic #202 states and they are no longer available. Anyone has the procedures handy for pulling the codes? A friend of mine is PCSing to N.C. and needs to take the family truckster. Only problem is the engine has a constanct miss. Checked the resistance on the wires and coils but nothing turned up. It has new spark plugs. So where else do I turn?

Apr 17, 2002 | 03:48 PM

aerocolorado

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Getting codes w/out scanner

I've seen several times lately on other boards where a new plug has turned up rotten. (My theory being it has more to do with poor installation technique breaking the plug). In any event, disconnect each plug wire one at a time, starting the engine in between, to see if you can isolate the culprit. If your plug wires have over 50,000 miles on them I would still replace them, despite what the meter says. Tired wires are the most common (and easily repaired) cause of engine misfires.

From there, the causes and cures become more exotic and expensive. You could be looking at a fouled injector or burned valve. The good news is the coil pack can be eliminated if indeed you have only one cylinder missing - each coil fires two plugs so you should have two misses instead of one.

Apr 18, 2002 | 07:51 AM

airharley

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From: Escondido, CA

Getting codes w/out scanner

I know it's the driver side back bank plug that is not firing. My friend pulled the plug and found it covered in fuel. I told him it was going to be something with the wires or better yet get a code scanner to pull the codes out of the comp. He said the previous owner told him it had a possibly bad O2 sensor. And the airbag sensor is going bad. I'll pass the plug wire theroy on to him and have him pick up new wires. Thanks.

May 2, 2002 | 09:49 AM

airharley

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Getting codes w/out scanner

Ok here is the update. I had the codes pulled. It turned out the #1 Cylinder was misfiring. Next was changing out the wires and Upper O2 sensor. After that the misfire was gone. Now I have a rough idle. Found the fuel rail wasn't tightened all the way down and the connectors weren't fully engaged on the injectors. Did some more snooping and found the throttle bypass valve was bad. Changed it out. Still runs rough but not as bad. Now it has a tendancy to fluctuate idle in nuetral and in gear. In gear is the worst of course because of the load on the engine. I am going to check the EGR valve system to make sure the valve isn't clogged or bad.

May 3, 2002 | 03:36 PM

aerocolorado

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Getting codes w/out scanner

Unstable idle conditions can be caused by dirty mass air flow sensor (MAF) or idle air control valvle (IAC). MAF is attached by two Torex screws on the air transfer hose just after the air filter box. Use care when removing as it is extremely delicate. Spray the fine wires with electronic cleaner and replace. Note the air flow directional arrow when replacing.

The IAC valve is bolted to the side of the throttle body. It is approx. 4 inch long, with smooth, quarter-sized cap on one end and a two wire connector on the other. The IAC is an electromagnetic coil that surrounds a small metal pintle pin. Variable strength signals from the EEC causes the pintle pin to move in or out, thus varying the air flow into the TB. Aiflow at idle is kicked up when engine load increases, such as when transmission or A/C compressor engages. Unbolt and clean with electronic cleaner,carb cleaner, WD-40 or similar agent that will remove any gum or varnish accumulation from around the pintle pin. No calibration required.

Try this before replacing any components.