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New problem??? Code reading HELP! PLEASE READ!!!!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Kyle89K5, Aug 18, 2002.

  1. Kyle89K5

    Kyle89K5 1/2 ton status

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    Got the code 45 squared away, but I don't think I got it squared away correctly. I switched ports on the EGR vacuum line going into the computer itself and it smoothed it right up, now the truck is acting like it has an awful vacuum leak. It's also giving me a code 42 and a code 43 on occasion. I pulled both these up and looked at what they meant, but they are NO help. Can anyone hear give me any advice. I have to have the truck back today. The truck idles fine and runs good, till I start down the road, then it acts like it is loading up something fierce. It REAL tough to get up to 55 mph.

    PLEASE HELP!!!
    Thanks

    BTW, this is a bone stock 89. The only changes made in the motor department are a .30 over bore and a K&N filter.
     
  2. YtseJam

    YtseJam 1/2 ton status

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    Re: excessively rich exhaust mixture???

    18436572 firing order

    I've seen many guys cross #5 & #7
    That'll do it.
     
  3. Kyle89K5

    Kyle89K5 1/2 ton status

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    TTT FOR HELP!!!!!!!!!!!!!!!!!
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    So what do the codes mean? You gotta spell them out.

    If the truck was running fine before, (so obviously everything was correct then) changing vacuum lines around will do nothing but make diagnosis and troubleshooting more difficult, by perhaps covering up the real problem.
     
  5. Kyle89K5

    Kyle89K5 1/2 ton status

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    Here's the codes:


    42 EST circuit grounded (HEI module failure)
    42 Front oxygen sensor lean error (Cadillac MFI)
    43 ESC control failure, spark retard too long
    43 TPS out of adjustment
    43 Knock sensor signal
    43 Front oxygen sensor rich error (Cadillac MFI)

    The vacuum lines that I switched are only one. Where the EGR ties into the computer, there is an EGR port and a vent port, when I switch the two, I get either a smooth running truck, or a stumling idiot.
     
  6. HarryH3

    HarryH3 1 ton status Author

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    Where are you looking to get the codes? There should be only ONE possible answer for what each code means, for your particular setup. If you're trying to match up codes for multiple vehicles, you'll drive yourself insane. /forums/images/icons/shocked.gif Look up the error code for the fuel injection system that is installed on your truck. Then you can narrow things down a bit...
     
  7. Kyle89K5

    Kyle89K5 1/2 ton status

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    Those are the codes that I pulled from the codes website on the links post. The codes in the Chiltons book I have are both dealing with the electronic spark control. /forums/images/icons/confused.gif

    Would a battery that is graveyard dead be causing an issuficent spark through the coil? My battery is GONE (getting another new one today), I'm having to either jump start the truck or use a battery charger and start it every 10 minutes or so.
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    So it almost sounds like the EGR is open at idle, allowing EGR into the mix when the truck is idling. Thats obviously not correct. I'm not saying replace the EGR, but something is either telling it to open at idle, or it is stuck, if it is in fact, open at idle. I haven't messed with the EGR much yet, but on earlier ones, the vacuum signal was only present when the throttle was at a certain point....before or after that point, no vacuum meant the EGR valve was "closed". (on yours throttle position is obviously calculated from the TPS) Not sure how your EGR is setup, could have an electrical connection on it that opens/closes, but if it does or doesn't, it'll have a vacuum line going to it, from what I've gathered.

    TPS out of adjustment is probably a problem there as well, EGR should only be in at cruise, but not sure if EGR would even be "in" with JUST the TPS showing the throttle open more. VSS should be integrated with this I'd think. I'd suspect the TPS is incorrect as well, but not sure if that could be a result of something else. Basically the ECM monitors the voltage at the TPS, whatever voltage is showing is *supposed* to relate to how far the throttle is open...if the TPS is not adjusted right, it can obviously be showing voltage that indicates the throttle is open, when its not.

    Knock sensor signal makes sense if EGR is being introduced...it will "see" the rough idle and should report a lot of engine knock. Spark retard too long makes sense in the EGR scenario as well...ECM sees knock, ESC tries to retard the timing until knock goes away, and can't retard the timing enough to do so. O2 sensor reading lean could be the same issue as well...EGR being introduced into the engine at idle would lean it out.

    I'm still a relative newbie to this stuff, but I'm trying : )

    My suggestion would be to go buy a scanner and service manual. (not one of the cheap code readers either) The first time you start thinking about replacing parts, think about a scanner that runs around $140...it doesn't take long at ALL to reach that $ figure when throwing parts at problems.

    You'd be able to see knock counts, TPS voltage, O2 sensor voltage, and I *think* timing advance. At least you could troubleshoot TPS quickly, and see that its working correctly.

    if anyone disagrees with what I've presented, please let us know, I'm still learning /forums/images/icons/smile.gif
     
  9. dyeager535

    dyeager535 1 ton status Premium Member

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    Didn't get mine posted before you put this out. : )

    Don't think you'd start throwing codes based on battery voltage if the thing would run. Most all the ECM stuff is 5 volts or less (O2 is millibolts..haha...millivolts..for instance) so I doubt battery is your problem. But since you need a new one anyway, replace it, and pray for a miracle : )

    BTW, scanner will show charging system voltage too /forums/images/icons/smile.gif
     
  10. Kyle89K5

    Kyle89K5 1/2 ton status

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    Is it just me, or does everything keep coming back to the EGR? When I close the EGR by hand, the truck dies, when it is open, it runs. Is that right, press up on the EGR through the holes and it's closed? I'm new to this FI stuff myself, I certainly do apreciate your help.

    Thanks
     
  11. dyeager535

    dyeager535 1 ton status Premium Member

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    Ok, does it throw codes at idle with the EGR hooked up correctly?

    If you are throwing codes at idle with EGR hooked up, and none if you disconnect it, then I'd obviously suspect EGR.

    I thought on all EGR's "up" on the diaphram was open, and "down" was closed, but I also know there are at least two types of EGR valves, so maybe up is closed on some.

    You mentioned horrid vacuum leak, is there vacuum on that line to the EGR at idle? EGR should only be present when vacuum is high and the vehicle is moving, (so only at cruise)...doesn't make sense for there to be vacuum on that line at idle the way I'm looking at it...
     
  12. Kyle89K5

    Kyle89K5 1/2 ton status

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    Let's see.

    At idle, no codes. The only time I'll get codes is when I'm at part throttle or the motor is under load (test drive)

    There is vacuum on the normal port, but none on the vent port.

    At idle, with the EGR hooked up to the normal port (non vent) then then only code I get is a code 45 rich exaust mixture, but no other codes. This sounds to me like I've got vacuum present at the EGR valve when it should be normally none.

    If that's the case, then switching it to the vent port would fix that problem until I increase above idle, then it has no vacuum in which to open up the EGR valve and thus giving me neww codes and horrible running.

    Does this sound like it makes ANY sense?
     
  13. dyeager535

    dyeager535 1 ton status Premium Member

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    Rich mix at idle? If EGR *was* being introduced, it should be lean.

    Again, not knowing how that EGR works, its hard to tell what is "right". Is it a vent so that when the EGR valve needs to move, it can do so faster? That would make sense I guess.

    I'm kind of stumped here...unless the injector's are leaking or something, I don't see how a rich mixture can happen, without some other codes...if TPS settings were incorrect, that should show at idle as well. IIRC, you can set the idle speed mechanically (still has a screw for that on the throttle body, right?) but idle mix is controlled by the ECM.

    O2 sensor sounds like its working, since the codes change from rich to lean, right?

    I don't see horrid running being a problem with EGR either though, even disconnected, it shouldn't be a noticeable (to you) problem. If anything, it *would* run richer at cruise, but obviously, you'd see some other fault, like EGR, too rich, etc.

    A dirty/malfunctioning Idle Air Bleed Valve setup on a TPI system can cause problems with idle, such as rough running, I'd imagine it could also cause a too rich condition as well, but I have *no* idea how to adjust/check it, nor if the TBI setups use an IABV either. I'd imagine so, but don't have a manual to show me.
     
  14. YtseJam

    YtseJam 1/2 ton status

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    Did you re-check that you didn't cross #5 & #7 wires?

    The EGR should be closed @ Idle, no vacuum present.

    Also check the Throttle body base gasket. Spray carb clean at the base of the TBI to see if it changes the idle. I've seen them sucked in 100's of times causing the IAC to try and compensate.

    But If you are receiving DTC 42 I would go through the tune up procedure again and double check your plugs, cap & rotor, and correct firing order.
     
  15. Kyle89K5

    Kyle89K5 1/2 ton status

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    Everything checks out fine. I re-ran the valves last night, that smoothed the idle out some as well as just re-did the whole tune-up.

    My problem now is that the runs well at idle and loads up under accel. When going down the road, if you get on the gas, it falls on it's face. That's when I get the error 45, exhaust mixture too rich
     
  16. dyeager535

    dyeager535 1 ton status Premium Member

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    Kind of out of ideas here...you shouldn't be pulling enough vacuum at WOT to hold the EGR open, and the mix too rich would indicate that EGR isn't a problem.

    I'd imagine someone with the right vintage service manual can run through the troubleshooting procedure for that code with you, as it seems you've got it fairly narrowed down now, and the flow charts in the service manual seem to be pretty precise.
     
  17. Kyle89K5

    Kyle89K5 1/2 ton status

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    You've been a TON of help Dorian. Thanks for all the time spent scratching your head with me.

    I went through last night and disabled different sensors at different times tring to narrow it down. I'm kinda hung up on the O2 sensor right now. It will be my test for tonight. The truck is driveable now, but my milage can't be better than 4-6 MPG. That's how fat it's running. /forums/images/icons/shocked.gif

    I'll let you all know how it turns out.

    Thanks again.
     
  18. dyeager535

    dyeager535 1 ton status Premium Member

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    No problem : )

    As to the O2 sensor, yes, a faulty one could leave you in open loop, which would cause some fairly poor mileage for sure.

    As I mentioned earlier, a scanner is invaluable in these types of situations, as is a manual. I *believe* O2 sensors all operate in the same range voltage wise, so you might not need a manual, (alhtough they NEVER hurt) but you could certainly measure the O2 voltage (or see it with a scanner) to see whats going on.

    I'm curious to see what you turn up. If you disconnect the O2 sensor, get a code, you'd *think* the O2 sensor is ok. But the output of it could be incorrect, and you'd still have problems, and yet the ECM might not throw codes. But one would hope that the ECM is designed to "notice" constantly outside of normal range voltages from the O2 and set a code, if it weren't working right.
     
  19. Kyle89K5

    Kyle89K5 1/2 ton status

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    ********BRAINFLASH********

    The wire on the O2 sensor got mangled when we were putting my tranny in many months ago.... I spliced a new peice of wire into it. A LONG PEICE OF WIRE. Would it be possible, JUST MAYBE, that due to the splicing and the length of the wire that the O2 sensor is not getting the required voltage to operate properly? Not that it isn't operating, but operating properly. I know the O2 sensor uses next to nothing as far as voltage (bolts /forums/images/icons/laugh.gif ) but this might have something to do with it.

    I'm sitting at work going INSANE trying to figure this stuff out, especially not having my truck sitting here handy were I can go try stuff. /forums/images/icons/mad.gif

    BTW, the scanner is on the list of tools to buy FAST. As are a subscription to the online manuals that folks are using these days. Don't know how much the discs will cost, but I'm ALL over them now. Saw a set at a shop I called on earliier about this mess. They get new updated books every 90 days. For instance, the manual now calls for the timing to be set at 2.5-3 degs timing rather than 0 /forums/images/icons/shocked.gif
     
  20. dyeager535

    dyeager535 1 ton status Premium Member

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    Unfortunately, I don't think your splice is going to affect it, UNLESS you didn't solder it. I'm sorry, butt connecting is not the way to go, but if you did do that, I'd get in there ASAP and solder it. If you connected it any other way than soldering, then I'm really thinking you may have found your problem.

    As to length, I would try to keep it only as long as the factory wiring. You are right, its very small amounts of voltage, distance will have more effect in a case like this I believe.

    As to the CD manuals, I have yet to hear anyone thats used them. I see them for cheap on eBay all the time, but I'm not sure if thats some kind of scam or what. If its the entire manual, then they are probably a great deal, but if they are bits and pieces or something, a big waste.

    Even if the scanner doesn't get much use, its always fun to plug in and watch : ) I love gadgets.
     

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