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Chev trouble codes

426rider said:
When I put my foot on the brake(to shift out of park) the idle drops and will start to stumble. This brake system does not have a vacuum booster.
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Is it a hydo boost? Something must be putting a load on the engine when you step on the brake.
What are the IAC counts when warm in park? If the idle speed actuator sol is intermittant it could explain the issues your having.
What brodcast code is your ECM? It should have a 4 letter code on the label in a format like ASDU, ATXK, etc.
 
Yes its Hydro boost. It says IAC pos =86 at the beginning of my run and 60 after my run. I just drove around for about 5 min or so. I got some stuff to look at. If you would like to check it out I could send you the file and you can get Datamaster for free. Kinda nice to be able to clear the codes with a push of a button. Code 36 has not come up again yet. Cleared it this afternoon. Will check on the broadcast code. BMHM is the code. I would like any help trying to figure this out.
 
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426rider said:
Yes its Hydro boost. It says IAC pos =86 at the beginning of my run and 60 after my run. I just drove around for about 5 min or so. I got some stuff to look at. If you would like to check it out I could send you the file and you can get Datamaster for free. Kinda nice to be able to clear the codes with a push of a button. Code 36 has not come up again yet. Cleared it this afternoon. Will check on the broadcast code. BMHM is the code. I would like any help trying to figure this out.
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I'm no expert by any means but willing to help with the little I do know. Do you have a link to data master?
The IAC pos at idle when it levels off is what I was looking for. I think your onto something with the ide speed actuator sol.
 
If you go here http://www.ttspowersystems.com/DataMaster_downloads.html
This is a list of available software. The first 20 logs you record are free and after that if you want to log you have to pay, but you can view/play these logs, and anyone's logs all you want.
Again my truck is a 95 k3500 4x4 7.4l 454 vin engine code N -it will help get the right software.
There is quite a bit of tuning info here. I believe it is mostly for 8192 baud though.
http://www.fullsizechevy.com/forums/showthread.php?t=126937
 
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Here is a zipped file with my datalog in it. Lets see if I can attach it. Nevermind it is to big to attach here. Yeah that solenoid is a dealer only part and they are closed for the weekend. In the histogram it shows that I am running lean by using the Sterm vs MAP and the Lterm vs MAP readings.
 
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DM35x31 is the datamaster program you used correct? I'm having trouble loading the file you sent me.
:EDIT: Never mind I got it to work.
 
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OK first off I've had a few :beer: tonight so........
From what I see there are a few things wrong in your log though they are all probably caused from the same issue. In the log the IAC is open way too far at idle but I don't think it's defective, I think it's doing what the ECM is telling it to do. This could be do to the actuator sol not doing it's job. The IAC being too far open is causing it to run way lean. (It's definately way lean though I'm not sure of the reason.) Your getting lots of knock counts and the retarded timing that goes with it. I think this is because it's way lean causing hot spots and probably pre ignition.
Only thing that doesn't make sence is that it's lean at the top end mostly and the sol shouldn't effect anything much above idle. It's possible that it's run lean for some time and you just didn't know it. Does it tend to pop out the intake when you give it gas under heavy load? If I were you I would check thoroughly for vacuum leaks.
Maybe tomorrow when I'm sober I'll look again.:haha:
 
Yes it is very possible that it has been running lean for a while. In the past it has given a pop out the intake but very rarely. Lately it is much worse. I have checked for vac leaks a couple times. Will check again with propane and watch the readings to see if it goes rich.

Thanks for lookin, I appreciate it.
 
Had any luck with this? After a bit of thought the lean indications aren't effecting things all that much but are a symptom of something wrong. In the long term BLM it's showing lean but short term INT it's not so bad. What's happening is the ECM is doing it's job and adding fuel (BLM) to keep the mixture stoich (INT). It's doing this to compensate for something. What that something is, is the magic question. I don't know. Do you have a bad exhaust leak probably before the O2 sensor?
At any rate this may or may not have anything to do with your original issues and probably not the source of the knock.
Sorry I wish I could be of more help.
 
I do have an exhaust leak. There is a crack in the driverside manifold. However that has been there a while(probably 3+ years). I don't believe that is what is causing my truck to die when in gear though. (only been happening now for about 3 months) I will get back to it wed, no time on the days I work. Again thanks for your input, every little bit helps.
 
Well the ex manifold was not cracked but the gasket was leaking bad. I replaced the gasket a lil bit ago and it leaked right away. One of the surfaces was warped so I filed it flat and installed a new gasket. Sealed up but not running any better. I think I may have found a vac leak on the pass side at the intake gasket and will replace those next week. Will let everyone know when/if I figure this out.
 
Still not running better. Intake gaskets are replaced. I can't find any vac leaks but still seems to be running lean. When I disconnect the MAP sensor vac feed and plug it off, it starts to run rich, and stays running when shifted into gear (wich is more than it has done in a while), starts and idles without hitting the gas when the engine is hot or cold. I hit the throttle and some black smoke comes out but then revs nicely. When I plug the MAP vac line back into the sensor it starts to run rough (lean I imagine) and will not start without using the gas.

I have 2 map sensors here and it acts the same way with both of them. One is on my 4runners chevy 4.3l and that runs fine so I don't think the MAP is bad.

Could the computer be reading the info from the MAP sensor wrong? Bad PCM?

Is there anything else that rings a bell with anyone?
 
When you unplug the map it should be going into open loop mode which basically means it doesn't learn or adapt to variables like map and O2......
Does it have a trouble code when you do that?
Did you ever figure out the idle actuator issue?
 
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I replaced the idle speed control actuator solenoid and noticed no change. I did get the check engine light but didn't actually check the code. I figured it was the map code. I will go do that now just to be sure.
 
Well I unplugged and replugged in quite a bit of stuff today.

I got codes

12=normal
15=under temp
33=map high
34=map low
36=IAC TPS kicker fail ( has to do with the idle speed control actuator/solenoid)
42=EST monitor error( PCM has open or grounded IC or bypass circut)
45=O2 rich
54=Fuel pump relay fail

this is the first time for code 54 for me. Now I see what EST monitor is. 33 34 42 and 45 I would expect.
36 is probably because I disconnected vacuum from it for a little while.
15- I will check voltage at the Coolant temp sensor tomorrow. It is fairly new(april) but is a shmucks part
 
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Have you checked your timing with a light?.....Don't get stuck on the idea that it's running lean. It could be a by product of something else wrong. It's not physically running that lean, the ECM is adding alot of fuel to compensate for something.......For some reason the ECM is also keeping the idle high, probably because it just won't run lower. Is it possible you have some mechanical issue? Did you rule out EGR? Double check everything distributor related. Reluctor phasing and gap. Make sure the low voltage wires are correct....How's the coil? Could you swap out with the 4.3 coil?......
I still don't know what's wrong with your truck. Just giving ideas.......
 
426rider said:
Well I unplugged and replugged in quite a bit of stuff today.

I got codes

12=normal
15=under temp
33=map high
34=map low
36=IAC TPS kicker fail ( has to do with the idle speed control actuator/solenoid)
42=EST monitor error( PCM has open or grounded IC or bypass circut)
45=O2 rich
54=Fuel pump relay fail

this is the first time for code 54 for me. Now I see what EST monitor is. 33 34 42 and 45 I would expect.
36 is probably because I disconnected vacuum from it for a little while.
15- I will check voltage at the Coolant temp sensor tomorrow. It is fairly new(april) but is a shmucks part
Click to expand...

Are all those codes from you un-plugging stuff?
 

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