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1997 Suburban Hard Starting when under 150 degrees

This is a discussion on 1997 Suburban Hard Starting when under 150 degrees within the Technical / Maintenance forums, part of the General Discussion category; I searched the forum, but no other threads really matched my problem. For the past few months my suburban has ...

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    Registered User bensblueburban's Avatar
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    1997 Suburban Hard Starting when under 150 degrees


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    I searched the forum, but no other threads really matched my problem. For the past few months my suburban has been very hard to start when the engine is completely cold or not very warm. It started giving my problems in August and is still giving me problems. It started with taking 2 or 3 cranks to start it, but it eventually got so bad that it would take 17-20 cranks to start the engine. I first thought it was the fuel pump, but it checked out fine. I also did a check valve test on the fuel pump and that was fine too. I replaced my cap, rotor, fuel filter, plug wires, and plugs thinking one of those might be the problem. The hard starting was still present. I got 2 bottles of Chevron with techron fuel injector cleaner and put it in my gas. After a long road trip to South Carolina, my cranking went from 17 down to 3 cranks to start the engine. Since the fuel injector cleaner helped, I bought 2 more bottles again and drove to Nashville and back the next weekend. This time the injector cleaner did not help. Now it is consistently taking 3-4 cranks to start my engine. I am afraid I am going to wear my starter out by cranking so much.

    As long as the engine is still at least 150 degrees, it starts easily, but and lower and I start to have problems again. I saw somewhere that it could be a coolant temperature sensor, but thats hard to believe since the fuel injector cleaner helped alot. The fuel injector cleaner isn't helping anymore.

    Does anyone know what my problem could be? I am getting really tired of throwing money at the problem and not getting any results.


    Thanks,
    Ben
    1997 GMC Suburban K1500
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    315/70/17 BFG All Terrains
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    Detroit Trutrac
    Cherrybomb Extreme true dual exhaust
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    Registered User bensblueburban's Avatar
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    Re: 1997 Suburban Hard Starting when under 150 degrees

    bump...
    1997 GMC Suburban K1500
    RCD 6" suspension lift
    315/70/17 BFG All Terrains
    4.88 Yukons
    Detroit Trutrac
    Cherrybomb Extreme true dual exhaust
    MT Classic II wheels
    Ranchhand Bumpers
    NGK Iridium plugs
    Amsoil
    APC Clear Corners & turn signals
    Wheatley 89 Tune
    Powerslot Cryo rotors & hawk pads

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    Registered User dave89iroc's Avatar
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    Re: 1997 Suburban Hard Starting when under 150 degrees

    get a scanner that reads data on there, and see what it thinks the coolant temp is
    ASE Master Certified Technician

    2000 Silverado 6.0 4L80E 2wd
    *RIP*1994 Z71 SCLB 355, Dart Heads, 10.5:1 CR, PM rods, CC XR270HR

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    Re: 1997 Suburban Hard Starting when under 150 degrees

    Your Suburban is giving the same symptoms mine started with. Since it was overdue anyway, I also replaced the normal tuneup items but that made no difference. The battery became borderline and the engine would start right away when jumped. The starter was working fine but I replaced the battery anyway but the monster still required a jump to start.
    Now, it refuses to start cold without a jump and even then it puts up a fight.
    The engine will start right away when warm but refuses cold.

    My to do list:
    I have read several posts suggesting that I clean the MAF (be sure to follow correct procedure and use electrical cleaner, not carb cleaner) and the IAC. I also want to check the fuel pressure even though the pump cycles normally. I have even read suggestions about using a 'Seafoam' cleaner to clean the vacuum and intake system.

    Copied text in bold italics, sorry but I do not have the original author's login:

    Mine has never clogged up badly enough to need to be removed but I think you can still remove it on the GenIII tb's up until they introduced "drive by wire" in 03. Its a very delicate little thing so if you remove it be very careful, and don't touch the pintel thing (the part that sticks into the tb) with anything but cleaner. Hose it down with electrical parts cleaner until its no longer gummed up and put it back in.

    I've always maintained mine by firing cleaner into the little passage on the throat of the tb just in front of the blade. But on my roommates 99 TPI 350 we had to take it out and clean it. There's usually two screws, torx head or star bit iirc, just pull the connector unscrew the screws and pull the IAC out.

    Clean the tb too, just shoot it with clener then wipe it with a rag, make sure you get the ring of carbon that has undoubtedly built up around the throttle blade and the rim of the blade itself. Oh and getting cleaner down the tb will make it a little reluctant to crank because the fumes don't burn. So it may take a little gas to get it to turn over and hold idle for a second or two.

    The MAF is also very delicate, just unplug the connection, loosen the to two worm gear clamps on either side of it with a flat head screw driver, then loosen the ones on the tb. If you have a stock intake it may take a little bit of maneuvering to get the tube to swing up 90 degrees from the air box, also mind the rad hose that's held to it with a little plastic clip, it will resist removal if its still connected. Then take the intake tube off. Remove the MAF and without touching the delicate bars and resistors on the unscreened side hose it down with electrical parts cleaner.



    -----------------------------

    My guess is the IAC, MAF, or the fuel filter. But here are some other things you might try.

    Run a can of seafoam down the PVC vacuum line.

    Take off that little hat they put on the engine with a socket

    Let the engine get all the way up to operating temp

    then reach all the way to the back of the drivers side valve cover and uproot the PVC valve

    It will usually yield pretty easily but if not just pull the vac line off of it and swing it around.

    pour some seafoam into a cup and let the engine sip at it through the vac line.

    You can stall the engine with the stuff and let it sit, I think its a bit hard on things so I usually just let it sip though [COLOR="black"]half a can then shut it off.

    Wait ten mins, then start it up again, it will smoke profusely, and it may take a little bit of throttle to make it catch.

    Then after the idle has recovered let it sip its way through the rest of the can

    I had a friend with a Lincoln navi that was having idle and staring problems and seafoam helped him, so it might be worth a try.

    Pulling the negative battery cable for ten mins will reset any stored codes, as well as resetting the adaptive systems. That might be worth a try too.
    I hope to get home early enough to check into some of this tomorrow....

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    Re: 1997 Suburban Hard Starting when under 150 degrees

    I put a brand new battery in it in march of 2009, so the battery is probably fine. Its always reading at around 14 volts. I have also seafoamed the engine the last time I changed the oil, so thats been done. So you think its probably the IAC or the MAF sensors? What does the MAF sensor look like when its dirty?

    Where exactly is the IAC sensor on the throttle body?
    1997 GMC Suburban K1500
    RCD 6" suspension lift
    315/70/17 BFG All Terrains
    4.88 Yukons
    Detroit Trutrac
    Cherrybomb Extreme true dual exhaust
    MT Classic II wheels
    Ranchhand Bumpers
    NGK Iridium plugs
    Amsoil
    APC Clear Corners & turn signals
    Wheatley 89 Tune
    Powerslot Cryo rotors & hawk pads

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    Re: 1997 Suburban Hard Starting when under 150 degrees

    The IAC is toward the firewall on the driver's side of the throttle body. The body of the IAC is cylindrical and about 2 inches long. It is mounted with two screws diagonally opposed. You will want to be careful with the lower one, it is hard to see and hang on to. I magnetized mt torx so it wouldn't drop.

    I removed and cleaned my IAC this morning. It was heavily carboned up. Carb cleaner spray and a toothbrush cleaned it right up. Don't yet know if the cleaning helped...it is still off until the rain quits.

    As for the appearance of a dirty MAF, I cannot say. All the posts I have read are sure to mention using only electrical parts cleaner for this one. This morning I found a can of MAF sensor cleaner at NAPA and will be trying that eventually. I didn't want to get soaked or soak the sensor in the rain so I've put that off until tomorrow.

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    Re: 1997 Suburban Hard Starting when under 150 degrees

    Okay, thanks. Its been raining hard here all day too, so I haven't been able to do anything yet. Can you post your results after you reinstall the IAC and clean the MAF? If it works on your, I'll be sure to do it on mine. Thanks for all your help! I haven't been able to find anyone that has the same problem or has ever seen this problem. Even mechanics I've talked to.
    1997 GMC Suburban K1500
    RCD 6" suspension lift
    315/70/17 BFG All Terrains
    4.88 Yukons
    Detroit Trutrac
    Cherrybomb Extreme true dual exhaust
    MT Classic II wheels
    Ranchhand Bumpers
    NGK Iridium plugs
    Amsoil
    APC Clear Corners & turn signals
    Wheatley 89 Tune
    Powerslot Cryo rotors & hawk pads

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    Re: 1997 Suburban Hard Starting when under 150 degrees

    96' 5.7ltr

    I have this EXACT problem right now! Mine started about 3 months ago with a second crank start and now im up to about 10. Once it starts from cold or warm it runs 100%.

    The truck starts first crank when hot.

    So far I've only installed new plugs, checked the MAF (spotless), cleaned the crank position sensor (kinda oily?), inspected the cap and rotor (near mint), checked the fp relay (known good), confirmed fuel pump prime (key on and off). I have yet to check fuel pressure at first start when its cold or slightly warm.

    Tried replacing the fuel filter last night but the fittings are rotted. Ill be sparaying pb on it for the next few days then try the fitting again. if that doesnt work im going aftermarket w rubber on each end.
    Last edited by 8716valver; 10-28-2009 at 06:47 AM.

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    Re: 1997 Suburban Hard Starting when under 150 degrees

    I replaced the cleaned IAC and installed a new FP relay this morning before work. It made no change. I did keep a finder on the IAC while my boy turned the key....I can feel that it is functioning so I assume it's been fine all along.

    I removed the MAF. It appeared clean but the tiny wires did tae on a shine after being sprayed with the MAF cleaner spray from NAPA. I will install the MAF this evening.

    Still have not gotten my hands on a fuel pressure guage.

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    Re: 1997 Suburban Hard Starting when under 150 degrees

    I have 52-53 psi while cranking.

    When running I have 60.

    I'm changing the fuel filter hopefully tonight in hopes that it's clogged.

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    Re: 1997 Suburban Hard Starting when under 150 degrees

    After spraying it off, I replaced the MAF this evening. The beast still would not start on its own. After cranking for many times I jumped it. It fired up only with me choking it by hand. After it got warm I Seafoamed it (through the PVC line) and cleaned all I could of the throttle body without removing it from the engine.
    After a 45 minute cool down it started on the first crank but after 1 1/2hrs it was again refusing to start. On a whim, I loosened the gas cap. After three coughing attempts the fire was lit and it ran normally.
    Although I recently changed the filter I aim to do it again. It isn't likely that I will be able to get to it until late this weekend though.

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    Re: 1997 Suburban Hard Starting when under 150 degrees

    Problem solved for me!

    My fuel filter was totally clogged. I ended up cutting the old one out and replacing it with a 3/8 barb filter and rubber fuel injection lines.

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    Re: 1997 Suburban Hard Starting when under 150 degrees

    False alarm! I still have the starting issue...

    Doing the fuel pump and crossing my fingers.

    So is Delphi the best or Delco?

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    Re: 1997 Suburban Hard Starting when under 150 degrees

    Going with Delphi

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    Re: 1997 Suburban Hard Starting when under 150 degrees

    I was in a real bind and needed the Suburban today. I changed out the fuel filter to a cheaper, less restrictive one. It made no difference. On a whim I also tried pressurizing the fuel tank. I blew about 30 psi into the fank while trying to start. I had hhoped this would boost the pressure from the pump in case it was too low. Still no change. To get through what I needed the truck fo I primed the intake before each cold crank with about a shot of gasoline.

    I;m running out of options and cannot affort a pump right now. GRRR

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    Re: 1997 Suburban Hard Starting when under 150 degrees

    Installed the Delphi. Starts as soon as I turn the key.

    Buy the pump asap!

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    Re: 1997 Suburban Hard Starting when under 150 degrees

    How bad did the Delphi hurt in the wallet?

    If indeed the pump is going out I will have to defend it a little. I hear folks trashing the AutoZone pumps but this one has lasted longer than the factory original, in terms of mileage. Not that I am pleased with 100,000 miles on an in tank pump. I've had two factory pumps in 'f'body Trans Ams last for over 300,000 and my foot was usually in the tank on those!

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    Re: 1997 Suburban Hard Starting when under 150 degrees

    I picked it up for 109 at napa. The delphi strainer was like another 7 bucks or something.

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    Re: 1997 Suburban Hard Starting when under 150 degrees

    I bit the bullet and replaced the pump too. Thing starts beautifully now. Thanks for all the advice guys!

    I noted the strainers were horribly dirty. I would have changed those and given it a try but when lowering the tank my son lost control of the jack. Both fuel line couplings broke off. Ah well, less risk with a new assembly anyway.

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    Re: 1997 Suburban Hard Starting when under 150 degrees

    Did you two check your fuel pressures (before starting and while running) before you changed your pumps out? I've checked mine and the pressures check out fine. I think they were 54PSI(pump primed) and 60PSI(engine running). I wouldn't say my problem is the fuel pump after my pressures checked out fine, but you two are making me think it might be something with my fuel pump now.(Eventhough my fuel pump has passed several tests). I even pushed down on the schrader valve on the fuel rail when the engine was cold and not primed to make sure the backflow valve on the pump was still working.

    I'm just hesitant to drop the tank on a suburban with about 20 gallons left in there. Its HEAVY!

    Also, my gas gauge started giving me the wrong readings about 3 months ago, so I don't know if that could be connected to this problem or not...
    Last edited by bensblueburban; 11-03-2009 at 08:42 PM.
    1997 GMC Suburban K1500
    RCD 6" suspension lift
    315/70/17 BFG All Terrains
    4.88 Yukons
    Detroit Trutrac
    Cherrybomb Extreme true dual exhaust
    MT Classic II wheels
    Ranchhand Bumpers
    NGK Iridium plugs
    Amsoil
    APC Clear Corners & turn signals
    Wheatley 89 Tune
    Powerslot Cryo rotors & hawk pads

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