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73-87 Chevy _ GMC Trucks => 73-87 Chevy & GMC Trucks => Topic started by: cditeodoro on November 09, 2014, 06:52:58 pm
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Ok so my truck runs like craps as soon as it goes into closed loop. New motor New cts tps map tb gasket iac o2 fuelfilter and fuel pressure is 12 psi. I cleaned all grounds and reconnected them. After countless hrs researching I'm leaning towards the Bosch o2 I have is no good. Any help would be greatly appreciated. Oh no vac leaks either
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Oh yea the motor has an rv cam in it also, and I've swapped distributors with my brothers to see if that was the problem and still runs like crap. Also my 02 is not in manifold it's right below the flange in pipe because the manifolds are off newer style truck.
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See attached
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I don't really have access to a scan tool. Could u use a meter to test it or no.
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Try an NTK o2. I have the same truck, had to change it and was warned to stay away from bosh o2 s as they give problems.
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I'll get a new 0 2 today and see what happens. Will post results thanks
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Ok put a new ntk o2 sensor in and replaced egr valve gasket. Truck still runs bad. I noticed when I pulled the vac line on the driver side of tbi ( which is hooked to egr solenoid) some fuel leaked out! What is going on here? I'm at the point of selling this thing after putting new motor if I can't figure it out
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Where are you located? ;D
You can make a scan tool or even buy a cheap one for OBDI and unless you are going to junk it, it's a worthwile investment. So if you remove the EGR sol vacuum hose fuel comes out of the port? How much fuel are we talking here?
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It doesn't pour out but it's wet and is def fuel. I don't know why fuel would be coming out of It. Just so we're clear it's coming out of tbi port not solenoid end. I'm loosing my mind
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Located in Delaware.
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Can you post a vid of it?
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You want a video of truck running or just the leaking ? I will post first thing in the am. Hopefully we can get this thingfigured out . Possibly tbi rebuild?
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what part of delaware im in Harrington. but think vile wants to see how much fuel
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Ok I did a video but it's not loading for some reason. I live in Newark it's about a hr and change from Harrington. Didn't notice any fuel out of port this morning. It runs great when first started and then as soon as it goes to closed loop? The idle goes all to heck and you have to feather the gas to drive while it's stumbling and sometimes backfire through tbi.
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If the c\e light is on the auto parts should have a key to plug into the aldl terminal a to b,or just make a jumper then read out flash code.44 is a lean code
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This is a guess and if you have or can get ahold of a good ecm I would switch
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I understand 44 is a lean code I just don't know what's causing it.
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Can I only get a ecm at junkyard or can I get a reman from pep boys
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Maybe a friend this way your not paying for something that's not bad. Idk if you could even find one at the junk yard
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My brothers got a 88 van g20. Maybe I can snatch his and see if it makes a difference. I think I'm going to rebuild tbi this weekend too and see if that helps. I'm just confused why it only does it after it's been running for 5 min and once it gets warmed up it runs a lot better. It's still not running 100% but it's a lot better
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Ok so I just found an exhaust leak right before o2 sensor where the bung got welded in. This is probably the reason for the code 44 but could it be the reason the truck runs like crap when it goes to closed loop?
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Unplug the hose from the EGR valve and see how it runs.
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Egr is new. I thought egr doesn't work on idle? I'll give it a try what the heck
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Exactly. If the EGR solenoid is stuck open the EGR valve will open with the engine idling and it will run like poop
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Unplugged egr and no difference. I bought a tbi rebuild kit with new fuel pressure regulator. What about the coil that's bolted to the manifold? Could that have anything to do with it? The one that's on the truck is the original.
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Did you check for vacuum leaks, spray around the base of the throttle body with some carb clean. See what happens
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I 'rebuilt tbi today and still have problems but I think the fitting coming out of intake for transmission and cruise is leaking. I sprayed it while truck was runing and I noticed a change and could hear it sucking the brakclean in. I will pull that out and Teflon tape it and see if I can seal it up
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dont use brake clean. it burns funny and can produce toxic fumes
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Ok pulled the fitting out Teflon taped it and no more leak. But truck still runs like crap. It has to be something dumb I'm missing. I'm not getting and codes now and the truck seems to run "ok" when it's warmed up. When it's first started in open loop it's fine but as soon as it goes into closed loop it searches at idle and stalls and when I drive it has no power and I have to feather the gas just to take off or it will pop out of the throttle body. I'm at a loss and now I just hate to look at the truck.
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So I have been looking around for answers and someone told me that my oil pressure sending units can have an effect on the truck running bad. My gauge doesn't work. It's on 0 all the time. It used to work with old motor in truck but after I put new motor in it hasn't worked. I have 2 I think one is next to distributed and one is by oil filter. He told me one of them has a fuel pump relay in it and he had similar problems to what I'm having and he replaced both andit fixed it . Does anybody know if there's any truth to this or is he full of shoot?
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Yes there should be 2 senders\switches,and one will run the fuel pump in case of relay failure.Backfire through throttle body tells me to lean or timing way off
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I know the timing is good. I had to replace master cylinder about a month ago. Is it possible my booster is causing a vacuum leak? My breaks seem fine though.
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You're sure you don't have #5 and #7 ignition wires reversed?
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Oh and the oil pressure gauge has no factor in it.
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I'll check plug wires in the am to make sure they are right. I'm also going to check booster for vac leaks
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Well checked plug wires and they were where they were suppose to be. Plugged booster line to see if it had a vac leak and truck still runs poop. Whatever the computer reads in open loop is the suspect because when it's first started and in closed loop it doesn't stumble real bad and has smooth throttle response.
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How does it run if you unplug the engine coolant temp sensor? (Keep in mind this will set a DTC)
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check your wires to the o2 sensor make sure they are not rubbed or pinched anywhere. the o2 sensor does kick in about a minute after start up
Ground in wire to ECM terminal 9 or Open in wire to ECM terminal 14.
Code 44- This code will be set whenever the ecm perceives a lean exhaust condition. The main causes for this is a grounded O2 sensor, low fuel pressure, restricted injectors, contaminated fuel, exhaust leaks or bad air switching valve. The condition met to set the code is a low O2output voltage (less than 0.2V)around a minute with the ecm is closed loop.
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It runs better when the cts is unplugged. My o2 wire looks good and it hasn't thrown the lean code since I got the leak fixed. My driver side exhaust manifold touches the frame on the truck because manifolds are off a newer truck. Could that have anything to do with it? Basically when I first start it in the morning I can smack the throttle real quick while in park and it revs great, no stumble, no pop. Then after about 3 min of running great it's like somebody turned the switch and it runs bad, searches at idle and if I smack the throttle it will pop out the throttle body or just bog. It will run like that until the temp gets up and slowly run better. Once the temp is up I can blast on it and no popping out of tbi but power is not what it's supposed to be at all and the idle seems lower than normal in gear, and it will still do weird stuff sometimes at idle almost like it skips a beat if that makes any sense. So I'm not sure why it gets better as it gets hotter. I was thinkin maybe I missed a ground so ewhere when putting the new motor in. I have one from battery to head on pass side and frame to battery and firewall to head on pass side and cts is grounded to intake and I have a ground by the distributor that is bolted to intake. Am I missing one ?
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Sorry but you guys loose me when you talk about ecm grounds and stuff. I've looked at my ecm up under the dash but that's as far as I got because I don't have a clue. Is there a ecm ground somewhere that I should check?
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ECM grounds should be at either 2nd bolt\stud from front on pass side of intake or at drivers side of t\stat housing bolt\stud.Check them with engine running with a volt meter positive lead to ground wire and negative lead to negative battery post,should be less than 1\2 volt
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Well I give up! :( I just saw the regulator housing is cracked probably from ovrrtighting after I rebuilt tbi so maybe the guy in Harrington wants to buy it cheap.
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what regulator? fuel pressure?
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Yes. Still runs but that's it for me I'm not putting another dime in the truck
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Check the fuel pressure
If your unplug the o2 and cts and drive it
Does it run ok?
If so just leave em unplugged
Or try plugging em in to a sensor that's just Laying on top of the motor
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Well I fixed it! Put a carb on it and it runs excellent. Thanks for everyone's help. I love not having fuel injection. Lol