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  1. #1

    Default changed motor in my 95 suburban k1500 4x4 and having some issues.

    ok im going to try to explain this the best i could since i been going thru this issue for a month now. ill try not to miss anything.

    about 8 months ago i bought my truck. 95 suburban k1500 with 350 tbi.

    i started to have white smoke on start up coming from the exhaust which turned out to be valve seals in the heads. i went and bought brand new machined heads with all new parts including rods, valve seals and lifters or rockers, ( things that sit on top of rods in the heads. ) basically brand new everything.

    truck drove fine with no more smoke for 3 months. then one day i got a bad knocking sound. turned out piston # 7 was beating up the spark plug pretty bad.

    so i went and bought a used motor, i even heard the motor running before it was pulled from the truck.

    i swapped my brand new heads on to the replacement motor, my intake, and my throttle body cause the t.p.s sensor on the replacement motor was different so i needed my throttle body.

    i put new head gaskets and intake gaskets. i adjusted the valves correctly. ( yes i did ). and then i put motor in the truck.

    i connected everything and then i filled motor with all fluids.

    once i try starting motor to set the timing it ran very rough. i unplugged the lil clip under the glove box to set the timing but when i plug that lil clip back in the timing notch jumos around with out staying still.

    i turned the distributor to get timing good and now i have the motor sounding 80% decent, i still cant get it to run and idle like it should plus i get quite a bit of WHITE smoke and water out of my exhaust pipe.. water looks black when i stick my finger in the exhaust but that could be from the exhaust pipes carbon build up.

    i checked my oil on the dip stick and it does not apear at all to have any bubbles in it nor is it a white milky substance either. the oil still looks new to me and un polluted.

    i checked my antifreeze level and it is where it always was..

    now 3 of my neighbors plus my self all said we smell gas out the exhaust pipe when it it smoking while the truck is running. and also when i turn the truck off i get a bit of smoke coming out of the throttle body itself.,

    my plugs and wires are new, my distributor cap is new. but the shaft and rotor is from the replacement motor i picked up as my shaft has stripped screw holes where the distributor screwed down to.

    i ran the truck for 30 mins straight and during that 30 mins. the smoke was light at times and them some times more smoke then previous few minutes.

    the truck revs perfectly fine when i give it gas in park and it sounds very powerfull but it just dont idle correctly. and i get alot of smoke and water out of the exhaust.

    i did get a code for the m.a.p sensor but i changed the sensor and problem is still there.

    i really hope i did not buy a bad motor, but i dont no what else to do or how to figure out whats wrong..

    so basically, im having a very hard time setting the timing, the truck dont idle like it should, and i get alot of smoke n water with a strong gas smell out my tailpipe when trusk is running. and then alot of smoke out of the throttle body when i trun the truck off.

    if anybody can help me i would highly appericate it. i do all my own mechanic work myself. i have all my own tools i could need, and i cant afford to go to a shop or buy another motor, i just bought the truck, then had to buy new heads, then had to buy a replacemnet used motor..

    i cant afford anything else..lol

    thanks in advanced.


    also here is a video of the truck, and in the video you can see the timing light does have pauses and breaks in the speed that the light flashes at times..

    and some pics of the oil on the dipstick. even after running the truck for 30 mins plus.

    video..




    pics...





    Last edited by kickerfanatic; 04-08-2012 at 12:25 PM.

  2. #2

    Default

    That's a long list of issues there. First off, if your piston was hitting your spark plug originally, then you may have had either 1) wrong head gaskets (not thick enough), or 2) wrong spark plugs (too long). Could have been a rod bearing going bad, but probably not the most likely, since you had just changed heads then it started.

    Now, On to the current problems. Lets try and first identify all of your issues, as it sounds like you may have a few different problems. Correct me if I'm wrong on any of these.

    1) Rough idle
    2) MAP code
    3) White smoke/fuel smell

    First and foremost i'd say you need to do a compression check, since it's a used engine and you did change heads. make sure you're in the 160-180 range on every cylinder.

    next, rough idle/MAP code. Check for vacuum leaks. if you have a big leak somewhere, gonna throw off your MAP and cause bad idle.

    #3, could be because of either the cause of 1/2, a poor head gasket seal, fuel pressure regulator, or bad o2 sensor. IF mechanically you're sound (compression, fuel pressure), then the computer is overfueling the engine at idle due to either vacuum leak or not reading o2 levels. did you keep stock exhaust? if you put headers on, can cause problems without other mods.

    get some updates here and will try and help more.
    1986 Chevy G20 Tow Rig - 5.7 TBI conversion
    1978 Mustang II King Cobra Road Racer - Holley 650, MSD 6AL, 5 speed, 10 point Roll Cage, 9" posi, fuel cell, custom interior.

  3. #3

    Default

    Quote Originally Posted by dualdj1 View Post
    That's a long list of issues there. First off, if your piston was hitting your spark plug originally, then you may have had either 1) wrong head gaskets (not thick enough), or 2) wrong spark plugs (too long). Could have been a rod bearing going bad, but probably not the most likely, since you had just changed heads then it started.

    Now, On to the current problems. Lets try and first identify all of your issues, as it sounds like you may have a few different problems. Correct me if I'm wrong on any of these.

    1) Rough idle
    2) MAP code
    3) White smoke/fuel smell

    First and foremost i'd say you need to do a compression check, since it's a used engine and you did change heads. make sure you're in the 160-180 range on every cylinder.

    next, rough idle/MAP code. Check for vacuum leaks. if you have a big leak somewhere, gonna throw off your MAP and cause bad idle.

    #3, could be because of either the cause of 1/2, a poor head gasket seal, fuel pressure regulator, or bad o2 sensor. IF mechanically you're sound (compression, fuel pressure), then the computer is overfueling the engine at idle due to either vacuum leak or not reading o2 levels. did you keep stock exhaust? if you put headers on, can cause problems without other mods.

    get some updates here and will try and help more.
    my exhaust is same exhaust when i had original motor on, straight piped to the magnaflow super 44 series muffler. my oxygen sensor looks ok and is not throwing any codes. ( catco was eliminated ),

    where would i check for vacuum leakes ? and where is the FPR located at. ?

    heads were same identical casting number as ones i took off when i changed them, and the spark plugs were motor craft from autozone as advanced cheapest plug for my car was $5. autozone had motor craft for only $2.99 a plug.. head gaskets were felpro brand and same size as original.

    and i did not do a compression test yet..

    s there anything i can do or try before i do the annoying compression test ? thanks man for your help. i appericate it.

  4. #4

    Default

    FPR is located IN the throttle body. Try running a fuel pressure test on it, there's not bung to hook onto so you have to have a gauge with a line adapter to test it. Vacuum leaks you just need to check all of your vacuum line connections. make sure you don't have any cracked/broken hoses. make sure there's no open vacuum ports on the TBI/Intake. I really would do a compression test too just for peace of mind.
    1986 Chevy G20 Tow Rig - 5.7 TBI conversion
    1978 Mustang II King Cobra Road Racer - Holley 650, MSD 6AL, 5 speed, 10 point Roll Cage, 9" posi, fuel cell, custom interior.

  5. #5

    Default

    Quote Originally Posted by dualdj1 View Post
    FPR is located IN the throttle body. Try running a fuel pressure test on it, there's not bung to hook onto so you have to have a gauge with a line adapter to test it. Vacuum leaks you just need to check all of your vacuum line connections. make sure you don't have any cracked/broken hoses. make sure there's no open vacuum ports on the TBI/Intake. I really would do a compression test too just for peace of mind.


    ok i will do the compression test probly tomorrow after work. but today i will check vacuum hoses and all.

    but one thing that comes to mind when you mention open vacuum ports is the intake that was on the replacement motor has a breather hose on it and my intake from my old motor did not.. it has a big screw/bolt in the hole where the new intake has the breather hose.

    would that breather hose make a difference ? should i try to start the car and while its idling hold and cover the open end of the breather hose to see if there is any difference in the way it idles or sounds ?

  6. #6

    Default

    are you talking about the pcv valve? a bad PCV can cause issues there too. If in doubt though, you can plug off almost any vacuum line for testing, except the one to the MAP sensor.

    you should have 2 large vacuum lines from the intake though. one to the pcv valve, one to the brake booster.
    1986 Chevy G20 Tow Rig - 5.7 TBI conversion
    1978 Mustang II King Cobra Road Racer - Holley 650, MSD 6AL, 5 speed, 10 point Roll Cage, 9" posi, fuel cell, custom interior.

  7. #7

    Default

    Quote Originally Posted by dualdj1 View Post
    are you talking about the pcv valve? a bad PCV can cause issues there too. If in doubt though, you can plug off almost any vacuum line for testing, except the one to the MAP sensor.

    you should have 2 large vacuum lines from the intake though. one to the pcv valve, one to the brake booster.

    yes, the pcv valve hose that goes into the throttle body has oil in and so does the nipple on the throttle body that the hose from the pcv connects to.

    and the breather hose im refering to is in the back on the intake almost right next to the distributor cap.. its not stock, atleast it wasnt on my old motor that died.

  8. #8
    Sr. Engineer
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    Default

    Great advice so far on the white smoke might be brake fluid . Leaking into the booster then engine pulls it in intake via the vacuum line at booster,just a thought have seen this.
    Does not take much to smoke a lot. On the smashed plug look at the rod on #7 bet piston came loose .
    On the timing get engine warm .Then disconnect timing bypass. Set to 0 . Turn truck off disconnect battery for 30 seconds .
    Timing will be set right. Don,t worry what timing is after you connect timing wire.
    Did you connect grounds at thermostat how about cts . is it connected?
    RESIDENT NUT.....MY CLAIM TO FAME .....

  9. #9

    Default

    just noticed antifreeze in the oil..................... fcuk me........................ ****................. smh..

    now i dont no if i should redo the head gaskets or look for another motor.

  10. #10

    Default

    If you have not already done so, change the fuel filter.

    This can also cause an undesirible idle.
    Pavement sucks... :grrrrrr:



    1994 K1500 4x4 Ext. Cab
    PCM chip and Xenon 8000k bulbs
    350cu.in bored over .050"
    balanced Crank, 10:1 compression
    Flat top pistons,cam,ported heads
    Option Racing Cold Air Intake
    Holley Throttle Body Spacer
    Accell Igition, 45kv coil
    FloTech Headers, no CATs, dual exhuast
    Goodyear Silent Armor A/T 305/70-16
    Pioneer SupertunerIII CD USB Bluetooth
    Kicker ZX200.2 ZX Amp
    Kicker Audio COMP 10" Subwoofer

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