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WinALDL DataLog

BGKYK5

BGKYK5

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I finally broke down and got an ALDL cable. The truck in my sig has been running rich and a little rough. I had expected to see a bad O2 or coolant temp sensor, but both seem to be working OK. It is definitely running rich though (1V is stoich, correct?). My new theory is that it just needs the standard tune up stuff - plugs, wires, and a check of the injector spray pattern. I am far from an expert at this stuff and I thought I'd get a second opinion so I datalogged a liesurely trip around the block. Lemme have your $.02 - it's more than I have now. :o

And no, I have not checked the fuel pressure yet. :doah:
 

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  • 20081101_110107_LOG.txt
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Next time uncheck raw data etc all you need is sensor data.

Then go to BLM and chose wide average. When your done data logging before you shut down go back to BLM and save table.

Have you checked fuel pressure? :doah: What engine? Specs?
 
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It is a stock '91 L05 TBI engine. I'm not sure I even have the right ECU selected. The WinALDL site lists the ECU for a '90, and for a '92, but I don't see a '91. :dunno:

I think I used the ECU setting for the '90 and I set the "zero throttle" voltage to 4.6 volts IIRC.

Give me a quick "BLM for Dummies" explanation.

Why is the ECU adding fuel if the O2 sensor reads rich? Less than one volt on the O2 sensor is rich right?

Edit: I think I am mixed up - the O2 sensor range is 0 to 1 volt and stoich is about 0.45 with higher being rich and lower being lean. The sensor still shows rich at 0.6-0.7V.
 
Disregard what I said in the first post, I opened another file, not yours...:doah:

WinALDL ECM set to 1227747. The numbers on 90 and 91 are different but they are exact ECM.

WinALDL voltage for TPS 100% is 4.60 volt but .54 for 0% (idle)

BLM is Block Learning Mode 128 is ideal, above 128 is adding fuel and below 128 is taking fuel away. These are the number you use to adjust fuel tables when adjusting a chip. Open your WinALDL and click on BLM, at the bottom is were you can set to wide average. As you drive you should try to fill in as many of these cells as possible (without driving into something) It does not work at WOT (Wide Open Throttle) so stay below that when logging data.

Your right on the O2 sensor voltages.

Your TPS looks fine except it goes to 0 quite often, this may be an issue, check wires, plugs and it may need replaced?

Your BLM are all looking rich so the O2 seems correct too!

Battery voltage is also a little low, is the battery old and weak? Or check charging system. Data is usually closer to 14-14.1 volts while running. Yours were as low as 12.6 and mainly 13.5

HTH :D
 
Oops, I set the "zero throttle" voltage to 0.47 volts (not 4.6 which is the max). It was reading -1% with my foot off the pedal 'till I adjusted it.

The battery is a brand new Optima Red Top. I have an electric fan that really taxes the charging system when it is on. Time to step up to a bigger alternator.

I'll did use 1227747 for the ECU, 4800 baud is correct too right?

So it sounds like the next step is to do a regular tune up and double check the TPS.
 
I have never changed my baud rate and it is set at 2400...

The data logged is only partial data to what's going on. Like a snap shot once in awhile. I looked through some old data's and have never seen a TPS go 0 at all let alone that many times, so I would start there.

How old is the O2 sensor? They do wear out and go bad, sometimes slowly. Fresh plugs, cap and rotor can't hurt if you don't know how old they are...

EDIT: When I said check wires and plugs in a previous post I meant to the TPS.
 
I was trying all kinds of different settings and WinALDL started working at 4800 baud and 1227747 for the ECU. I'll try 2400 baud too just in case it makes a difference (unlikely). I'll check the TPS too. I have not swapped out any sensors (or spark plugs or wires) since I bought the truck a year or so ago. I would guess the PO didn't either. The O2 sensor is switching rich and lean, but it is rich 90% of the time. I'd guess that it works, but I wouldn't mind swapping it out for a heated one at some point either.
 
I'm not sure about the baud rate, I have done many ECM and never changed it. Maybe it changes itself when hooked up? Doesn't do anything when I tryed sitting here not hooked to an ECM...

I've never tryed a heated O2, mine runs fine all the time with a standard O2 in the collector of the header... I'll have to look someday and see how often it goes open loop.

Rich all the time could be to high a fuel presure. Hows the return line?
 
Don't think I'd worry about a heated O2 sensor if its switching rich/lean. You *need* a heated sensor only if it doesn't get hot enough to work right, sounds like yours does. As does mine, far back in my headers, beyond where conventional "wisdom" says you need one.

I've got heated O2 sensors in GM bags still, but one won't get installed until the non-heated fails.
 
I agree with Eagle mark about the TPS going to 0 a lot. Wide fluctuations in TPS voltage are interpreted by the ECM as acceleration and it will richen up the mixture.
Could be a bad TPS.
 
I did a couple quick checks.

With the engine off and my foot off the pedal I am seeing 0% TPS, floor it and I get 96%. I'll look at it some more, but any problem is probly a nasty intermittent one.

I did the timing light trick and the injectors look Ok to me. Pretty uniform cones and they both look the same. I am seeing fuel puddling on the back of the throttle plates a bit, but I guess it hits there and has to find its way to the edge of the plate.

I did notice that some plug wires weren't giving me a uniform flash from the timing light, so I'll replace the spark plugs and wires to make sure I don't have a miss caused by the ignition system.

A quick check of the timing showed about 15-16 degrees advance at idle. Does that sound right? I know that isn't the proper way to check timing, but it was just a quick check since I already had the timing light out.
 
Timing should be set to zero with the EST wire disconnected. Once the EST wire is reconnected the timing should jump about 20* advanced.
 
Hey man. What's your fuel pressure and how old are those injectors. I've had one wear out enough that it wouldn't close all the way allowing fuel to continue to drizzle out. This resulted in the O2 sensor telling the ECM theres too much fuel and then the resulting chain reaction. I've been in the same boat as you my friend only I didn't have the luxury of a scanner:D. Turned out to be a leaking fuel injector. I would check your fuel pressure and check out the injectors. Especially if it sits for any length of time. Just my $.02

Just for giggles, swap out the injectors from your other engine.
 
I'm sure the injectors are the original ones. I don't have a way to measure fuel pressure - I guess I should invest in one. I did think about swapping injectors. As long as I am pulling the injectors out I should get an injector pod spacer, don't you think. :thinking: :D
 
I've got a fuel pressure gauge if you want to use it and if your going to have all the TBI stuff off, you might as well take the manifold off then drill and tap for direct port nitrous injection.:D Let me know.
 
If I am going to go to all the trouble of drilling and tapping for NOS, I might as well swap in a GM Perf Parts ZZ572 and then drill and tap the manifold. :D
 
I replaced all the spark plugs and plug wires today. I needed to do it anyway and it would eliminate one variable to try and wrap my brain around. The #4 plug came out smelling strongly of fuel. It runs much smoother now. I'm guessing the miss on #4 was causing it to run rich (though the O2 sensor doesn't sniff the even numbered cylinders :dunno: - I have true dual exhuast). I looked at the TPS wires they seem OK from a visual inspection standpoint. I was going to swap on the TPS from my spare '89 engine, but it was a different style. I also double checked the timing it is right at zero with the EST unplugged. I found a couple suspicious unconnected items. Dunno if they are supposed to be connected - they were not connected on either of my engines and the '89 always ran well.
 
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