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huge turbo lag

Discussion in '7.3L Powerstroke Diesels' started by slyhog022056, May 27, 2020.

  1. slyhog022056

    slyhog022056 Full Access Member

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    Just got my 97 f 250 with 7.3 turbo and 5 speed running again. I am having major issues with turbo lag... namely the turbo doesnt even begin to spool up at all until around 2000 to 2500 rpm.
    It is just flat unresponsive up to that point. Especially in first or second gear. I have to throttle it fully floored to get up to that rpm then the turbo comes in. By then it is time to upshift.
    Is this normal?? the boots are new and not leaking, the turbo doesnt have play in it. the exhaust is 4 inch straight tubing. The valve on the outlet end of turbo is blocked open, air filter is K&N new. The guy i got it from showed me some paperwork showing it had a different blade set and bearings put in not even 2 years ago
     
  2. 79jasper

    79jasper Chickenhawk

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    If the ebpv is for sure tied open, you likely aren't firing on all cylinders, or a major boost leak.

    Sent from my SM-N960U using Tapatalk
     
  3. slyhog022056

    slyhog022056 Full Access Member

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    i cant be 100 % positive it is fully open, dont know which direction it needs to be to be open, looking at it from the top is it supposed to be fully clockwise or counter clockwise? The rod going to it is just hanging and the piston is unplugged. And it doesnt idle smooth like i think it should
     
  4. Dane Rickford

    Dane Rickford Full Access Member

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    I don’t know if this is even a good thought, but you may just have the timing way too advanced
     
  5. slyhog022056

    slyhog022056 Full Access Member

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    wasnt aware the timing can be changed with this diesel. only ever had a 7.3 idi before
     
  6. Dane Rickford

    Dane Rickford Full Access Member

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    I don’t know much about psd 7.3s, but I read on a different forum about a guy who’s 99’ psd was having turbo issues because of timing. But again, I know hardly anything about powerstrokes
     
  7. Dane Rickford

    Dane Rickford Full Access Member

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    Ok, never mind :joker: I was wrong. It appears the only way to change timing is by messing with the timing chain, which I don’t think is a probable issue in your case. Sorry if I caused any confusion, I should probably just stick to what I know LOL
     
  8. 79jasper

    79jasper Chickenhawk

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    With the rod just hanging, it could be closed/closing. [​IMG]

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  9. greenskeeper

    greenskeeper Full Access Member

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    check the o-ring coming off the turbo at the y-pipe connection
     
  10. u2slow

    u2slow bilge rat

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    Did it used to spool faster, and now it doesn't?

    Thinking back to my '95 F350 5spd.... I don't recall the turbo doing much in the first two gears. An empty truck isn't a lot of load. The factory exhaust and intake silence the turbo well.
     
  11. slyhog022056

    slyhog022056 Full Access Member

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    I dont know about before i got it but it just seems like coming in a 2000 is a little bit late. the factory. it does have 4 inch straight exhaust pipes, supposedly the turbo wheels were upgraded. maybe thats normal for an empty truck like you say. as someone said earlier i does have a miss. the injectors are fairly new and i have ran sea foam thru the fuel system a few tijes, i dont know how to go about testing this engine for electrical problems since it is computer controlled. i do remember reading somewhere about problems where the harness goes into the the heads with problems. I have a very good electronics background but cant find much info about signal voltages and timing controls internal from the pcm to the actual injectors. I do have access to oscilloscope for troubleshooting if i know where to start.
     
  12. 79jasper

    79jasper Chickenhawk

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    Injectors receive 110v ac.
    If you look up "7.3 powerstroke breakout box," that might give you some ideas.

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  13. greenskeeper

    greenskeeper Full Access Member

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    check engine light ?

    any codes ?

    check your fuel pressure at the schrader valve at idle and under load
     
  14. unclehoser

    unclehoser Old dog, new tricks

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    I don't know about anyone else, but, for a time, I thought my turbo wasn't spooling up at all. Turns out I just couldn't hear it with the windows up, A/C full tilt, and the radio! It really is MUCH quieter than other diesel trucks I've heard around town. When I open the windows (in the winter here) and turn off the rock-n-roll my old ears can pick it out of the rest of the noise.
     
  15. slyhog022056

    slyhog022056 Full Access Member

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    No check engine light even hooked in my code reader... nothing at all. I will try to hook up a gauge to the schrader valve to monitir it while driving. I did hook up to my 40 ft travel trailer that weighs in at 9200 lbs last weekend and pulling it i didnt get much boost until around 2000 rpm in any gear at all. forget about going into 5th gear even on level road it wouldnt go over 50 mph, i am getting boost because i can hear the turbo whine. but i did notice under load it appears to have a miss. no codes so i dont know how to track down a bad injector or injector wiring.
     

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