laundry list of codes

sleeper

sleeper

Former LOD President
I finally got around to pulling the codes from my '93 yesterday, and there were a handful.

113 (IAT was/is open)
176, 177 (Left o2 not switching, rich/lean respectively)
332 (EGR not responding)
524 (problem in low speed fuel pump circuit)
543 (fuel pump monitor circuit shows no power)

And a couple more that were user error during the test. The car runs and drives, so I know the fuel pump is working. So I don't know what is up with the 524 and 543 codes. That might be from messing up the test on one of my earlier attempts. I did disconnect the reader while the car was still running and it almost died, so that might have thrown those codes.

IAT code was KOER, so it's probably not an old one from forgetting to plug it in. I just cleaned out my garage, and I had an IAT in my hand, the question is, did I throw it in the box with all my other old mark 8 crap, or did I throw it in the trash with all the engine covers and underhood plastic trim crap. Same with the EGR.

EGR code came up KOEO and KOER. I did have an EGR around from my '97 (if I didn't toss it), are those the same gen 1 to gen 2?

Looks like I need to buy an o2 sensor, throw an IAT and EGR at it if I have them around, and retest. hopefully the fuel pump codes go away on their own. If not, well, as long as the pump works, whatever.
 
budpytko, I wouldn't throw sensors at it. They're expensive and it's just an educated guess. What happens if you're wrong? Throwing parts at a car is never the way to fix it.

The first part of diagnosing any drivability issue is to ensure that you have adequate fuel, spark, and proper vacuum. AFTER that is when you start messing around with sensors.

Your car can still run and drive with a faulty fuel pump, poor fuel filter, etc., so I would start there. Measure your fuel pressure and compare it to spec. If it's out of spec, this could be the reason for your O2 and fuel pump codes. Check the fuel pump if you can and once you're totally positive that you have the proper amount of fuel and the pump isn't to blame (or if there's any faulty connections, etc.), then you can move onto testing your O2 sensors.

A great way to test an O2 sensor is to take a torch to it. You can measure the voltage of the sensor with a flame against the metal shroud of the sensor that goes inside the exhaust. Don't worry, O2 sensors are designed to withstand very high temperatures. The flame will burn out all the oxygen surrounding the sensor, which will simulate a rich condition. Taking the flame away will simulate a lean condition. When you remove the flame from the sensor, make sure that the voltage change is IMMEDIATE. Just because the voltage values may be accurate doesn't mean that the sensor isn't shot. O2 sensors need to be VERY responsive in order to function properly.

Regarding your IAT and EGR, I would try cleaning them out first (or if you have a spare that you know is functional, that works too). It's very common for either of them to clog up with carbon build-up. Sometimes cleaning them works, sometimes it doesn't.

Let us know what happens. Good luck.

EDIT: To budpytko's credit, O2 sensors CAN throw other codes. I suggest trying the first method I suggested with your fuel pump and testing the O2 sensors prior to messing around with the IAT and EGR codes. Then again, cleaning them only takes a couple minutes. Couldn't hurt, right? :-D

EDIT 2: I just had another thought: These cars run a tad rich for a stock, naturally aspirated vehicle. I don't know the exact ratio, but I know that it's closer to around 12:1 (Stoichiometic/"Balance" is 14.7:1). Imagine you had something as simple as a dirty fuel filter (could be anything at this point, which is why you need to test for pressure, etc., but we'll use "fuel filter") that sends back pressure to the fuel pump. The fuel pump gets stressed, so maybe it throws a code or two? The stressed pump ends up creating a lean mixture that fails to richen and throws an O2 code. Sounds familiar, doesn't it?

This isn't to say that this is definitely what's wrong with your car by any means, but it wouldn't surprise me.

I'm anxious to find out what's wrong with your car. Can you tell? LOL boredom strikes again!

GL
 
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Alright, i guess i should give some symptoms.

CE light comes on at steady cruise, light load, car warmed up. Generally only happens on the highway. There is usually a slight stumble preceding it.

Other symptom is that it takes a second to start when it hasn't been run in awhile. As if the pressure is leaking out of the fuel rail.

I think I still have a spare fuel rail... is a gen 1 and gen 2 fuel rail the same? I'm thinking probably not. Compatible at least? anyone know? Or does the FPR come off?

I think I have a fuel pressure gauge somewhere, and that's easy enough to test, so that's probably a good starting point. But if I turn the key, the rail should pressurize very quickly. So maybe there is something to that monitor circuit code, maybe the pump isn't activating until the car starts cranking. Is there a seperate relay or something to handle the turn on when you first turn the key, when it runs for 20 seconds?

Considering I have a spare EGR that worked when it came off my '97 (can someone confirm it's the same?) i'll just toss that on if I go in that far. Given the symptoms, EGR should be coming on about that time, so that's probably a good place to start.

As for the IAT, assuming I didn't toss my spare (i don't think i did) i'll just plug it in and see what happens. This could be a leftover code from forgetting to reconnect it after removing the intake tube, though.

For the o2 sensor, if i go to the trouble of removing it, i'm replacing it. One of those things that it's more the pain in the ass factor than the cost. Since i'm getting two codes for the same o2 not switching, one rich, one lean, there's a decent chance that it's bad. But since it's such a pain in the ass, I do plan to look into the EGR and IAT first. Although the EGR looks like a giant PITA on the gen 1. Hell, I might even have a spare o2 sensor around. I replaced the fronts as PM on the '97, and deleted the rears. I probably threw them out, though.

If the fuel pump is the problem, it'll get a fuel pump when it stops running.

Honestly, I think this car lost respect for me. I've treated it too nice so far, too many new parts (okay, used parts). it needs to be beaten like a red-headed stepchild until it remembers who's boss, then I can pull the codes and see what it still thinks needs to be fixed.
 
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Well, if you're willing to replace them, go for it, I suppose. The symptoms you describe make it sound more and more like an O2. The PCM switches from the MAF to the O2 as top priority for fuel delivery under light loads after entering closed loop, so it would make sense. Can't guarantee it, though. If you have a torch lying around, I'd use it before putting them in. At least you can still return them, ya know?

As for the hesitant starts, that can be a whole slew of different things. It could be a result of low fuel pressure, so you might as well check that first, seeing as how it may lead to your other problems. What about the battery voltage? Have you measured it before starting it up after it's been sitting for a while?

Sorry, I can't help you with the compatibility of the fuel rails or EGR.
 
I've always thought the best tactical approach to multiple code is to clear them and monitor frequently to see which one returns first.
 
Also, an easy way to check the EGR valve is to connect it to a cheap vacuum pump. Start the car, apply vacuum, and the engine should stumble and try to stall out if the EGR opens.

If that checks out OK, check the vacuum hoses and the EVR which is the valve that applies vacuum to the EGR.
 
bill, thanks for the tip. i'll try that before i go after the EGR valve. Working on the '97 was so much easier. No EGR, and the 02's were all the way at the end of the headers so they were easier to access :)

The car is still sitting in the garage. It got cold and i haven't done any work on it. I need to get an air ride compressor before it can go anywhere anyway.

And I did find my spares. I have an EGR, an O2 with extended wires, an IAT, and a few other things, so I can just throw a few parts at this and see what happens. I think the o2 is the biggest problem and most likely bad.
 
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I replaced the o2 sensor and pulled the codes again. KOEO, no codes, KOER, EGR flow low and some code from not giving it WOT when it told me to goose it.

I've determined that I can live with an EGR problem. If this was a gen 2, i'd fix it, but the valve is in a piss poor location on this one so f it. If the light comes back i'll pull the bulb.

The o2 sensor was a major pain in the arse. I ended up buying a new one anyway. And my IAT sensor from the gen 2 is different - but the code was from leaving it unplugged. i put a multimeter on it and it's fine.

I bought an air compressor relay on ebay and installed it on the ABS side. I also pulled the solenoid on the front bag that was leaking and found that one of the o-rings had rolled out of it's groove when i installed it. I fixed that so hopefully the leak is gone. Now i just need a compressor and a relay and i'm ready to rock.

I did find something kind of wierd, though. There was a connector hanging down by the exhaust, with something broken off plugged into it. It had been hanging by the cat so it was a bit melted and unrecognizeable. I couldn't tell what it might have been, I coulnd't see anything within range of the wire that was unplugged or broken. It was a square connector with 2 wires. I unplugged it and hung it out of the way.
 
sleeper said:
I did find something kind of wierd, though. There was a connector hanging down by the exhaust, with something broken off plugged into it. It had been hanging by the cat so it was a bit melted and unrecognizeable. I couldn't tell what it might have been, I coulnd't see anything within range of the wire that was unplugged or broken. It was a square connector with 2 wires. I unplugged it and hung it out of the way.
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Where at by the exhaust? Which side? I can't think of what it might have been off the top of my head but I'm curious.
 
Dave, we should have taken a look at Steve's Gen 1 yesterday when we were at Jeremi's.

Get the color of the wire and tracer, and I'll check my car and shop manual for it.

Since you said it was on the driver's side, it might be a DPFE wire, which would explain your EGR code?
 
Drivers side down by the exhaust... hmmm, I think it's possibly the brake pressure switch. :rolleyes:

Does the cruise control work?
 
driller said:
Drivers side down by the exhaust... hmmm, I think it's possibly the brake pressure switch. :rolleyes:

Does the cruise control work?
Click to expand...

CC does not work. Where does this switch go? There is a brake manifold of some sort down there but it didn't look like anything was broken or unplugged. I do want cruise though. If I can't fix it right, how can I fool the car into thinking it's fixed so that CC works?
 
I'm fairly certain all the '93s had the brake pressure switch mounted to the firewall below the brake booster/reservoir. It should have a 2 pin harness ( circuit 10 LG/R & circuit 148 W/PK)connector. It is a redundant cruise control disconnect for the brake system. Normally the BOO switch activates the disconnect but if it fails, the brake pressure switch opens the circuit at a relatively low brake circuit pressure.

This is the same switch involved in the infamous recall that has been known to lead to vehicle fires. The switch is hot at all times and I do believe it is protected by a 10 amp fuse. A faulty switch can supposedly overheat and ignite a brake fluid leak at the pressure switch. The authorized dealer fix was a new switch assembly and I believe an in-line fuse of a lower rating.

The circuit is normally closed and opens with application of the brakes. As such, if it is unplugged the cruise control will not work. I suppose one could shunt across the harness wires and bypass the switch but it would be defeating the safety redundancy of the circuit.
 
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I had the recall done on my navigator. Were 93's part of the recall? If so, i'm in business.

Looks like there's a small manifold below the master cylinder / booster, mounted on the frame rail, that used to have a switch or sensor attached. The switch is broken off and there appears to be a small leak from the broken off stump. It's hard to tell because of the corrosion / melting on the piece that was left in the connector, but it very well may have leaked internally and melted itself apart, just without causing an actual fire.
 
I did a quick internets search and it looks like the '93 is on the list. I'll call a couple of dealers tomorrow :)

BTW, I got the suspension put back together and took it for a drive today. It seems to run a bit smoother with the new o2 sensor.
 
sleeper said:
I did a quick internets search and it looks like the '93 is on the list. I'll call a couple of dealers tomorrow :)

BTW, I got the suspension put back together and took it for a drive today. It seems to run a bit smoother with the new o2 sensor.
Click to expand...

Please take photos of the mechanics face as you drive up the lift in that flat black m8. :eek:
 
Mad1stGen said:
Please take photos of the mechanics face as you drive up the lift in that flat black m8. :eek:
Click to expand...

LOL, I was thinking the same. :D

Yes, the '93s were recalled. I still have both my '93 and '96 to get done. PITA to schedule an appointment at my local dealer though. I've had the '96 there before but not the '93. I want to watch the guy who gets to pull the '93 out of the parking lot to the service bay. :D
 
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