I installed a BBK TB today and get the check engine light after a little driving. I did everything BBK said to, got RPM to 500 with IAC unplugged. It's weird the light doesn't go on until a couple minutes of driving, and I notice no effects from it.

Standard operating procedure when check engine light comes on: perform quick test (aka "pulling codes"). See www.dalidesign.com/hbook/eectest.html for instructions, or get a good manual with instructions. Once the computer tells you what problem it is seeing, then you can focus your diagnosis on that system/circuit.

I went out and bought a diagnostic tester w/ LCD. It pulled 536 and 538. The book says 536 is Brake On/Off circuit not activated during KOER. 538 says Insufficient RPM change during KOER Dynamic Response Test. There's another 538 for trucks only that says Invalid Cylinder balance test due to throttle movement during test. Anybody know how to fix these?

I just redid the test and got 111 everything passed. So why the check engine light and roughness at 1100 rpm?

The Insufficient RPM change during KOER test means you didn't goose the throttle when it told you to.

I haven't seen 536 before but I'm guessing the computer wanted you to push the brakes and you didn't.

Yeah I fixed all that, now I have a pass. Without the engine running I did a test and got No EGR Flow. Anybody know how to fix that?

There are probably many possible causes. It seems that many EGR codes are fixed by repairing/replacing the DPFE sensor.
If you search for "gtest.pdf" I posted a link here to a file that contains Mitchell's EEC-IV diagnostic article (almost 200 pages) for a '95 Explorer. The diagnostic procedures and tests won't be that different for you '94. If you're up to a complete and thorough discussion of diagnosing of your truck's condition, that would be a worthwhile read.

Ok. I got 327 and that traces back to DPFE according to the pdf file. I also got 341, which indicates octane shorting bar is not in place. Would 341 be because I have a chip which requires 92 octane? And for 327, would that cause my check engine light to go on at 1100?

Thats really odd. Btw there was two pieces of tape holding the little black grommet down did you take that off? Also did you tighten the vaccum line? I sent a piece of line with a tube on it that was allready connected to the TB.

Yeah I used the spacer and the tubes are connected.

Did you reset the ecu.

Yes.

dont think it has anything to do with your TB...just a coensidence. I would just replace the DPFE and go from there. The way you originally described the problem sounds like the DPFE because the computer doesnt start the EGR functions untill its out of warm up mode. most CEL's that only come on after a peroid of time are either EGR related or O2 sensor related...everything else you will usually get an instant code. as for the shorting bar code...probably the chip...i would think they would have taken that into consideration...what chip do you have?

Husky, I have the same year and got the same sode (327)...replaced O2 sensors, EGR valve, PCV, Cleaned MAF...Still got code...
Finally replaced the EGR sensor and POOOOOF no more CEL.
Now the gas mileage has increased...truck purrs like a kitten...$49.99 at autozone.

I have an Apten chip. I guess I'll try the DPFE and then EGR if that doesn't work. My o2 sensors were replaced when my headers went on, around 5 months ago. I found some DPFE symptoms and they say something about roughness when letting off the gas, which is what I get.

I have a somewhat similar problem. I have a 93 Explorer, XLT, 5 speed stick, V6, and 150,000 miles. I have put on a Flowmaster CatBack system, K&N Filter, and bored 1" holes in the intake box for better breathing.
Recently, my check engine light comes on after about 2-5 minutes of driving. It may flicker on and off or may just stay on, until normal operating temperature is reached. Once normal operating temperature is reached, the light goes out and stays out. If the engine cools down too much, the light comes back on. Every once in a while, it seems that the light comes on after a hard bump. Though that is not for sure at this point.
Any suggestions, before I break down and buy a code reader.
Thanks

Originally posted by Sailormilan2
I have a somewhat similar problem. I have a 93 Explorer, XLT, 5 speed stick, V6, and 150,000 miles. I have put on a Flowmaster CatBack system, K&N Filter, and bored 1" holes in the intake box for better breathing.
Recently, my check engine light comes on after about 2-5 minutes of driving. It may flicker on and off or may just stay on, until normal operating temperature is reached. Once normal operating temperature is reached, the light goes out and stays out. If the engine cools down too much, the light comes back on. Every once in a while, it seems that the light comes on after a hard bump. Though that is not for sure at this point.
Any suggestions, before I break down and buy a code reader.
Thanks



my 92 Ranger did that I got some Throttle Body cleaner and gave it a real good cleaning and it fixed that problem.

thats not going to do anything since the only thing the TB does is regulate air flow to the engine via your foot. it sounds to me like you have a wiring problem. Probably O2 or CTS......might want to check the CTS first..its on the lower intake manifold just behind where the thermostat is. im not sure if yours will have a 2wire sensor or one (probably 2 since they are all aluminum intakes) but i would check the wireing on that as best as possible. try to back probe the sensor and check resistance (ohms) and then run it and warm it up good.....then check the resistance. I think the resistance should change at least 2 ohms but dont quote me on that. if all that seems to be good then check the wires on the O2 sensors because they are heated until the engine is out of warm up. if they arnt getting a 12v feed then you will get a CEL untill the engine warms up.

All I can say is that it worked for me I did it almost 2 years ago and I sold my truck in July and never had a problem with it after I cleaned it...

probably a coincidence