Hey all, i've been following this site for some time now but this is my first post and I'm hoping somebody can help me out.

Recently my L05 has developed a intermittent lack of power problem. Driving along between 50-100 kmh if i let off the gas then get back on [a corner for instance] the engine lightly surges, sets the ses light [code 43] and feels like it only has about 100hp!! There is no noticable miss, black smoke etc. its just gutless until i shut it off and restart then its fine.

last night i tried winaldl for the first time and sure enough i couldnt duplicate the problem but there are some questions i have about the data i logged.

- the IAC counts seemed real high [100-145] causing the high idle [1500 rpm park 1000 in gear], whats the deal with that? is that a funtion of the ecm in aldl mode? Normally my engine idles perfectly down to 800 park, 5-600 in gear.

- my O2 sensor had some pretty wild voltage swings with little or no other input changes [constant speed, steady tps, steady map]
How Normal is this?

- My BLM's are showing high [130-140] is this probably due to the Fuel correction required because of the headers and cat back system?

I have attached the log file if anyone cares to take a look.

Thanks for your help

 

Well, 43 is EST circut, which usually means the knock sensor is picking up knock (or false knock) and is retarding your total timing drastically... hence the power loss. Your ideal blm is 128, within a few is ok. Your o2 will fluctuate at idle, which is normal. At WOT, the ideal o2 reading is 880mv.

 

i know the feeling i feel like that every day now. like an idiot i sold my mid 13 second iroc and bought a 2002 chevy pickup with the so called (yea right) 285 hp 5.3 in it. the problem you are having is that the computer is taking all the timing out of the engine. tell you what race a 5.0 mustang with it like that. I beat one on 7 cylinders and that check engine light on with the iroc. you have more than 100 hp it just is not what you are used to. my problem was the knock sensor it was kind of broken when we installed the headers. i slaped a new one in and there was not another problem with it.

 

DON'T run the 10k resistor between the A and B pins. Just plug in the ALDL cable and go. If you put a resistor between A and B, as you found out, it puts the ECM in diagnostic mode...which is almost useless.

 

Thanks V8 astro

I'll remove the 10k and try to log some more data. Hopefully I can figure this think out soon.

 

why to you say diagnostic mode is almost useless? what exacly is the ecm doing that is different?

will the ecm still output the datastream to pin E without the 10k?

 

interesting. Mine did that same thing when i first got my crate going a few weeks ago and took it for a drive. Set the 43. Never did it again. I wonder what would cause it? I hooked up my laptop and only found a few knocks during average driving. Hmmm.. maybe a sporatic misfire or interfierence.

 

hmmm.. how ironic... it just did the same crap again on my way home.

 

I've got this same problem! If I set the timing on 8* then I don't get this code. If I set it on anything before 8* after a while of driving it will set this code and not have any power.

I hooked my laptop up. It doesn't seem to knock that much, maybe one every 30 mintues of normal driving conditions at either timing setting.

 

Having the same problem, got worse when I was retarding the distrib. I advanced little by little and the problem disappeared. Might want to fiddle with your timing if you're getting an intermitent code 43. BTW, the code 43 can also be set if the car is too far retarded and the ecm can't do it's self diagnostic check. The ecm will advance the timing to get a coupld spark counts to verifty that the ESC and knock sensor are working. If the ecm max's out it's timing and still no detonation (dissy way too retarded) then it'll set the 43.
Running lean also sounds like your problem. You'll get a pretty bad hesitation when you run those high BLMs. Adjust your fuel pressure to get the BLMs ALL below 130 and above 108. If there is that much of a swing in the BLM then it's time for some eprom tuning.

 

Is there a way to use winaldl to see if you timing is too far advanced? I moved my timing up to like 10* and I still don't get but a few knock counts while driving.

 

prevost is right about that. Tahts the same problem i had. Got rid of it by advancing to 8 deg btdc. If you only see a few counts, then your either still fine w/ no detonation or your knock sensor isnt picking them up properly. 10* isnt that much so if it only shows a few randomly distributed counts then your fine. That one you refer to may be the ecm doing the check at medium loading.

 

In diagnostic mode the ECM sets the idle to a specific RPM for all conditions and some other things like that I believe. I think it's silly because if you a real program like WinALDL you don't need to put it in that mode.

I haven't come across an ECM that I had to use the 10k resistor on. So try it without and see if it works.

 

Thanks for the info. After hearing about the knock sensor self check I'm thinking it's the knock sensor thats at fault. The engine surges a couple of times then the ses light comes on and its gutless [advancing timing looking for knock, not finding any and pulling a ton of timing out]. I'm going to change the sensor....I'll let you know what happens

 

when it happened to me a second time when the car had the stock timing set . I felt nothing during the time it set the 43. Id be going up a hill or accelerating and it would just set the code. The first time it happend to me the dist slipped and it started bogging and it set the code shortly there after. If the engien feels as though its running poorly, there is probably something else at work thats causing noise or interfierence thats triggering the sensor or the knock sensor/module is faulty.