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98 4runner timing issues

Discussion in '3rd Gen 4Runners (1996-2002)' started by ectech, May 11, 2021.

  1. May 11, 2021 at 6:17 AM
    #1
    ectech

    ectech [OP] New Member

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    Hello everyone! I'm a bit stumped with an issue that I am having and am reaching out for some possible expert advice. Here is what I have done so far and where I am at. I have a 98 4runner 3.4L 2WD 310,000 miles that I recently swapped heads due to a burnt valve as well as replaced the timing belt. After removing and reinstalling everything, I went to crank the 4runner and it would just crank but no start. At this point I removed the top timing belt cover, checked the timing, thought I was 180 degrees off due to the crank to cam turn ratio. I removed the belt lined the cam pulleys up with the timing marks, manually turned the crank, clockwise 5 full rotations to assure all marks stayed in line. At this point my crank is lined up with the 0 and confirmed TDC by removing plug #1 and manually checking with a long screw driver, the cam pulley marks are at 12 o clock, aligned with the given marks. After putting everything together, I try cranking again and it sounds as if the timing is off. It cranks but no start and if I give it a couple tries I get blow back out of the throttle body. This led me to believe that the intake and exhaust valves are not working together in time. I then thought that maybe I aligned the cams wrong by getting the cam marks mixed up, since we have 2 dots on the RH to align and 1 dot on the LH cam. I removed my valve covers to find that on the RH cam, the 2 dots align, rotated the engine 180 degrees to check the LH cam and the single dots align. Now I am looking at RH and LH cam pulley, aligned with their timing marks, both cam gears are positioned to where they both have the single dots aligned and my crank pulley is at 0 degrees TDC. I am scratching my head on this on. Does anyone have any suggestions on where to look next?
    The only things that I've done outside of FSM instructions was replacing the knock sensors, knock sensor harness and soaking both ends of the fuel injectors in lucas injector cleaner, overnight. I had them standing up in a container half the night right side up and the other have upside down. I understand that soaking the injectors may have been ineffective for the most part but I thought why not... I have also used a multimeter to check the given FSM specs on the crankshaft sensor,cam shaft sensor, fuel injectors and coil packs.
    I appreciate that there is a community out here to reach out to and would like to thank anyone in advance for their input.
     
  2. May 11, 2021 at 8:08 AM
    #2
    ectech

    ectech [OP] New Member

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    I took a ride back to the house to get some pictures for you guys and I noticed something that I'm not understanding. I have everything aligned as pictured but when I rotate the engine 720 degrees, my cam pulley marks line up, the came sprocket marks line up but the crankshaft pulley mark is off this much. What is the explanation for this?RH.jpg LH.jpg aligned.jpg 720 Degrees.jpg
     
  3. May 11, 2021 at 8:24 AM
    #3
    negusm

    negusm New Member

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    I know when I did mine, I got the marks all lined up with the marks on the belt, rotated things around and it looked "off" at first. I even took the belt off, counted teeth, double verified everything was on perfectly. It doesn't take much for the crank to look "off", when it's really correct.

    If you got a quality belt with marks on it and verified the marks are identical to the old belt, and everything lines up when you install, it's correct.

    If you are off one tooth, the car will run but will have a slightly different sound. On the first belt change for my car, I was confused at first because the tooth count wasn't quite right from the original belt when I counted out the teeth. I put it back on with everything lined up and the car sounded like it did 2 years prior! Somehow it had jumped a tooth, it sounded just a little different. I chalked it up to the old exhaust. The engine is a non-interference engine so it didn't hurt it.
     
  4. May 11, 2021 at 8:31 AM
    #4
    negusm

    negusm New Member

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    So I reread your top post. When you swapped heads, did the Cams get changed too? Where did the new heads come from?
     
  5. May 11, 2021 at 9:00 AM
    #5
    ectech

    ectech [OP] New Member

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    Yes, the cams came with the heads.
    The heads came from American Modern Engine. They are resurfaced OEM heads, not aftermarket and are stamped accordingly.
     
    Last edited: May 11, 2021
  6. May 11, 2021 at 11:52 AM
    #6
    Ahdofu

    Ahdofu New Member

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    ectec,
    As I recall there are two white dots on the crankshaft timing pulley (see picture below). One of the white dots has a corresponding red marker on the tooth of the pulley. That white dot needs to be perfectly aligned with the V marker on the body of the engine when everything is at TDC. Next when you install the belt and assuming that it is a new belt, you'll have three lines on the belt. The first two lines should line up with the cam markers. The third line should line up with the second white dot on the crankshaft timing pulley.

    upload_2021-5-11_11-47-26.jpg
     
  7. May 11, 2021 at 12:51 PM
    #7
    ectech

    ectech [OP] New Member

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    The key on the crankshaft is only going to allow that sprocket to go on one way and Once that is lined up correctly, the crank pulley notch should be at 0, correct? Am I missing something?
     
  8. May 11, 2021 at 12:53 PM
    #8
    PhantomTweak

    PhantomTweak New Member

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    None. Bone Stock. EXCEPT: Brushguard, tow hitch, both welded to the frame. It's good to have friends and a fully equipped garage!
  9. May 11, 2021 at 1:37 PM
    #9
    Ahdofu

    Ahdofu New Member

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    No you have it correct except with one caveat. The tiny white dot is more accurate than the marker on the harmonic balancer. If the position of that dot is off by a slight amount, the timing belt tooth can easily be positioned off by one tooth. Having said this, the engine should still run but not as well. I concede that the fact that you cannot even get the engine to run, says this cannot be it even if true. On a secondary note, I take it that you have already ruled out ignition as a culprit. Right?
     
  10. May 11, 2021 at 2:48 PM
    #10
    ectech

    ectech [OP] New Member

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    I've hooked a light to the plugs to confirm that I have spark. What more should I test ignition wise?
     
  11. May 11, 2021 at 3:52 PM
    #11
    Ahdofu

    Ahdofu New Member

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    No looks like you have the ignition part covered. Have you checked on fuel delivery? If engine does not run, there should be some fuel residue on the plugs (i.e. they'll be wet). When you replaced the heads, did you perform a compression check too? Also are the cam pulleys correctly mounted? The one marked RH is the passenger's side & LH should be on the driver's side.
     
  12. May 11, 2021 at 4:25 PM
    #12
    Ahdofu

    Ahdofu New Member

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    One other question. Does the OBD show any codes? And since we're at it are the fuses OK too?
     
    Last edited: May 11, 2021
  13. May 12, 2021 at 3:12 AM
    #13
    ectech

    ectech [OP] New Member

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    I had taken some parts off of the engine to double check a few things. Before putting it back together, I decided to just go down to the crank sprocket to confirm timing is 100%. Now that I am certain the timing is correct,
    I am going to get everything back together and follow through with a few suggestions that yourself and some others have made. We have some pretty bad weather coming so it will be in a few days.
    I will start by pulling my wires and double checking the fuel delivery.
    I haven't done a compression test.

    No codes and I've checked continuity on all fuses.

    I appreciate you taking time to give input. I am open to all suggestions.
     
  14. May 19, 2021 at 12:27 PM
    #14
    ectech

    ectech [OP] New Member

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    I went over everything, got it back together and after persistent cranking,I got it started. I am 100% sure timing is correct. The idle is rough and shaky but it will stay idling for the most part. If I gas it,the engine revs but after letting off it will sometime back fires a few times through the exhaust while hunting for idle. If I attempt to put it in gear it bogs down and kills. I've run it for as long as 30 minutes multiple times to try to get a code and still have no code. I pulled the plugs and all of them are black and even look slightly wet from fuel.
    For my compression, I have 180 across the board
    I also hooked a fuel pressure gauge and this is something I'm not sure of. I am tapped in with a banjo adapter on the rear passenger side fuel rail. When I turn the key into the on position I have no fuel pressure but if I bump the ignition I get 20 psi and if I bump it again it goes to 40 and will hold.
    Shouldn't I be getting something whenever I turn the key on?
    I've gotten under the vehicle and had someone put the key into the on position and I do not hear the fuel pump prime, either.

    Any words of wisdom or suggestions?
     
  15. May 19, 2021 at 1:03 PM
    #15
    ectech

    ectech [OP] New Member

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    I just learned that the fuel pump for this engine doesn't prime so that can be disregarded.
     
  16. May 19, 2021 at 4:54 PM
    #16
    Ahdofu

    Ahdofu New Member

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    Compression values are excellent and just as good, they're all the same. You've confirmed timing but are the cam pulleys correct? Although they came with the heads, have you confirmed that the one marked RH is on the passenger side & vice versa?

    The plugs that you pulled, why do they look slightly wet? They should be all dry. I would have also checked the camshaft and crankshaft position sensors but you're not triggering any codes so they may not be it. What I find strange is that you don't even see a fault code. What OBD tool are you using?
     
  17. May 19, 2021 at 5:15 PM
    #17
    ectech

    ectech [OP] New Member

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    Yes this all has been confirmed more than once.
    I'm not sure why the plugs would have fuel on them. I can't recall if they were pulled after it bogged down and killed. Maybe the injectors shot but no spark before it killed.

    I have a Scangauge II.

    Another question maybe worth asking...
    The only sensors that I changed in this process were the knock sensors. I bought them last minute and did not order OEM. I was told that there were 2 different ones, distinguished by the plug color and large price difference. Is there any possibility an incorrect knock sensor could be the culprit? Maybe put my originals back?
     
  18. May 19, 2021 at 6:54 PM
    #18
    shake007

    shake007 New Member

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    Some tips when I did mine. I’m sure you have the cams lined up but for the crank shaft pulley make sure this marking (the dimple on the gear, I marked it blue) is at the 12 o clock position aswell with the cams. Also if you put a new crankshaft position sensor make sure it’s sitting flush against the bracket it sits on if not check the sensor, there could be a rubber ring around it preventing it from sitting flush. I encountered this when I put a new one in and it was the sole reason it wouldn’t start. Goodluck

    13271227-BD28-4816-BDAC-104C97113E72.jpg
     
  19. May 19, 2021 at 7:29 PM
    #19
    ectech

    ectech [OP] New Member

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    Thank you for the tips.
     
  20. May 20, 2021 at 5:10 AM
    #20
    Ahdofu

    Ahdofu New Member

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    The OBD tool looks like a capable unit but I am still dumbfounded why you don't see any codes.

    Hmm.. meaning somehow the knock sensor is altering the ignition timing? I have no experience on how to check a knock sensor but you can certainly check the ignition timing by using a strobe light. In your case this gets further complicated as you do you not seem to have a stable idle but if you do manage it, it may help in ruling out ignition timing.
     
  21. May 20, 2021 at 6:21 AM
    #21
    ectech

    ectech [OP] New Member

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    I have the intake off already in order to hook the fuel pressure gauge up so I'm thinking the same thing to rule it out while I'm here. I also had ordered fuel injectors that originally weren't going to be here in time to be put on before I had everything back together. They'll be here early next week and if the rain keeps holding me up, I'll be changing those along with the knock sensors.
     
  22. May 20, 2021 at 8:18 AM
    #22
    ectech

    ectech [OP] New Member

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    While I'm triple checking the vacuum line routing I'm looking at the water bypass lines. Does anyone have a picture to where they go out of the throttle body? I don't think they're wrong or causing the issue but I just want to be certain. This was the best diagram I found that only shows the throttle body side.

    Screenshot_20210520-101139_DuckDuckGo.jpg
     
  23. May 20, 2021 at 4:11 PM
    #23
    Ahdofu

    Ahdofu New Member

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    Must be from the same file. I see this one as well.

    upload_2021-5-20_16-9-34.jpg
     

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  24. May 21, 2021 at 7:10 AM
    #24
    negusm

    negusm New Member

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    2001-2002 are different than other years. No IAC. Make sure you have the right factory manual for your car.
     

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