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NEED HELP 2000 K3500 dually 7.4l
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Formula242
User
Sep 23, 2013, 2:42 PM
Post #1 of 24
(3077 views)
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NEED HELP 2000 K3500 dually 7.4l
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i bought this truck a few years ago with 83500 miles and have put about 14000 miles on it truck has 98k on it.. put a new gm performance engine in through dealer at 84,000 and also a new rear end at 84,000.. new distributor cap, rotor, plug wires and plugs, fuel pump...truck runs like a bat outta hell without a load.. i haul a 24 ft cuddy cabin boat.. and it is the biggest turd ever.. used another truck this past weekend and it was a 1500 dodge with hemi and didnt even know it was back there. any ideas where to start to see why it is so sluggish under load.. this is a california emissions truck.. i have a check engine light on for cat efficiency.. put new magnaflow high flow cats on it and all 4 new o2 sensors.. since this is a cali truck are the cats crual to the engine performance.. dont know much about cali emissions...any ideas or things to try would be greatly appreaciated. about to the point in selling the thing and looking for something else
(This post was edited by Formula242 on Sep 23, 2013, 2:48 PM)
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Sep 23, 2013, 3:04 PM
Post #2 of 24
(3063 views)
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Re: NEED HELP 2000 K3500 dually 7.4l
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CA standards are just higher for less emissions and shouldn't destroy all power. If cats were designed for the truck and not that old I'm not ready to blame them but will say nothing will beat OE for max performance that I know of.
Your O2 sensors may not be sending the right signals. Cat performance is one thing, the reason why is where to concentrate. I suggest a full code reading again and post the #s not the maybe of what's wrong. If this already has too much back pressure from cats you can test for that.
I think a 7.4 should pull a boat like nothing CA emissions or not. I'm on the other ocean in MA with similar regulations. If somehow the parts were not compatible with computer controls that certainly would be a problem.
You have the check engine light on so again, get a better code reading as I think there' s more to it than just cat efficiency so far,
T
(edit - typo fixed. 1st sentence, "should changed to shouldn't which is what I meant)
(This post was edited by Tom Greenleaf on Sep 24, 2013, 2:22 PM)
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Formula242
User
Sep 23, 2013, 3:13 PM
Post #3 of 24
(3059 views)
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Re: NEED HELP 2000 K3500 dually 7.4l
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yeah i was thinking the same thing.. im a tech at honda and trying to pull strings to get a tech2 to go more in depth with it.. but i have a generic scanner i will take home with me and run the codes.. and post them up on here.. i was just gonna run through data stream and check injector pulse and cam offset to make sure im within the 0 +-2 degrees since the dealer who installed engine had to send it out to another dealer to set distributor.. i didnt realize it was a cali truck till changing o2 sensors cuz i ordered 2 upstreams and 2 downstreams well the upstreams worked but down streams where different connectors so i ordered another set of upstreams since they had say connectors...so now the next question is there a difference between 49 state o2 and cali o2 sensors..this is my first cali truck and i can say they are different cuz when i did fuel pump i had to get it for cali emissions.
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Tom Greenleaf
Ultimate Carjunky
/ Moderator
Sep 23, 2013, 3:43 PM
Post #4 of 24
(3050 views)
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Re: NEED HELP 2000 K3500 dually 7.4l
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I couldn't say any exact info CA standards vs the others. No doubts though that things as critical as upstream sensors which can and will alter performance if not communicating with the powertrain computer properly is going to be trouble. Downstream is or should just tell that all WAS fine and off goes the exhaust out the back.
Again - get the better code reading knowing that the parts may be the issue. BTW whatever the claims on those converters said I'm not so sure of. A good cat isn't a restriction so I don't know what to say on that. OE specs should have been just fine.
I simply do not know how much the CA standards change the whole set up but would bet it does big time,
T
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Hammer Time
Ultimate Carjunky
/ Moderator
Sep 23, 2013, 3:59 PM
Post #5 of 24
(3043 views)
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Re: NEED HELP 2000 K3500 dually 7.4l
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If your offset is off it will set a P1345
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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Discretesignals
Ultimate Carjunky
/ Moderator
Sep 23, 2013, 4:52 PM
Post #6 of 24
(3036 views)
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Re: NEED HELP 2000 K3500 dually 7.4l
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GM performance engine...wonder what mods it has and if the programming in the VCM has to be altered?
Not sure on this, but I do believe those had torque management systems to keep from blowing the transmission up, so it might be reducing more torque in tow/haul mode.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
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Formula242
User
Sep 23, 2013, 5:37 PM
Post #7 of 24
(3030 views)
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Re: NEED HELP 2000 K3500 dually 7.4l
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the offset is within specs and i cleared codes last friday when i was in it with a generic scanner i will drive it to work tom. the light usually comes back on within 20 miles of driving.. as far as the engine it was a direct replacement and i dont hae the tow/haul mode. remember this is still the old body style truck.. i know wat codes were in was cat efficiency bank 1 sensor 2 and cat efficency bank 2 sensor 2 just dont remember the dtc number
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nickwarner
Veteran
/ Moderator
Sep 24, 2013, 1:20 PM
Post #8 of 24
(3016 views)
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Re: NEED HELP 2000 K3500 dually 7.4l
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Those would be P0420 and P0430. When you are towing with this, are you leaving it in overdrive?
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Formula242
User
Sep 24, 2013, 1:23 PM
Post #9 of 24
(3015 views)
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Re: NEED HELP 2000 K3500 dually 7.4l
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no its in 3rd
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Formula242
User
Sep 25, 2013, 11:10 AM
Post #10 of 24
(3007 views)
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Re: NEED HELP 2000 K3500 dually 7.4l
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finally brought it to work with me today just ran through the data stream and printed off a scan tool data list from identifix.. as a rough guide to reference too.. found that the baro normal is suppose to rear 1.94 volts i have 4.64 volts, the injector pwm b1 suppose to be 4.5 m/s and injector bank 2 is 4.5 m/s also both banks im reading 3.7 m/s mass air flow sensor normal 7.05 g/s and im getting 8.36 g/s map sensor normal is .71 volts and im getting 1.1 volts the cat effieciency codes did not come back just had a code in it for p0440a never have seen that code before.. but noticed in the misfire graph that sittin at idle i was getting a misfire from 4 mostly but then it would misfire on 3 and then 8.. not all the time tho
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Formula242
User
Sep 26, 2013, 8:39 AM
Post #11 of 24
(2997 views)
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Re: NEED HELP 2000 K3500 dually 7.4l
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i was thinking about changing the map sensor out and seeing wat readings i get if it changes??????
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Formula242
User
Sep 28, 2013, 11:38 AM
Post #12 of 24
(2980 views)
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Re: NEED HELP 2000 K3500 dually 7.4l
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any of u guys would happen to know how much inches of vacuum i should have at idle??i unplugged map sensor last night and drove and didnt run like Sh!t just turned check engine light on but thats it.. i was gonna put a vacuum gauge on it monday and see wat i have and compare it to the readings on the scan tool with map plugged back in
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Hammer Time
Ultimate Carjunky
/ Moderator
Sep 28, 2013, 12:02 PM
Post #13 of 24
(2977 views)
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Re: NEED HELP 2000 K3500 dually 7.4l
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A healthy engine will give you steady 18 to 20 inches at idle. Anything under 15 and it's time to look for a problem.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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Tom Greenleaf
Ultimate Carjunky
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Sep 28, 2013, 12:02 PM
Post #14 of 24
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Re: NEED HELP 2000 K3500 dually 7.4l
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General and do this with a known actual manifold vacuum source. Put a "T" in line so item still gets vacuum and read your gauge. At sea level (matters if high altitude) if all is well about 18 Hg holding steady. If you snap idle up to like 2,000 it should go higher when you let go.
If you hold idle at about 2,000 it should be the same as at idle or indicative of exhaust restriction or you aren't doing it right,
T
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Formula242
User
Sep 28, 2013, 1:11 PM
Post #15 of 24
(2965 views)
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Re: NEED HELP 2000 K3500 dually 7.4l
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from wat scanner is telling me the map is reading 9 inches of vacuum
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Hammer Time
Ultimate Carjunky
/ Moderator
Sep 28, 2013, 1:27 PM
Post #16 of 24
(2964 views)
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Re: NEED HELP 2000 K3500 dually 7.4l
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You don't read off a MAP sensor. You use a vacuum gauge.
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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Discretesignals
Ultimate Carjunky
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Sep 28, 2013, 8:39 PM
Post #17 of 24
(2928 views)
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Re: NEED HELP 2000 K3500 dually 7.4l
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To figure out the pressure in the intake manifold you have to subtract the reading on the scan tool from whatever your atmospheric pressure is at your location. Remember the MAP sensor is a pressure differential sensor. It is comparing the pressure outside the manifold to the pressure inside the manifold. Your seeing the difference of those readings on your scan tool.
In your case if you got a reading of 9 inches and you were at sea level( 29.9 inches) that would be 20.9 inches in the manifold.
You stated that you have a MAP voltage of 1.1 volts. That is close to 20 inches.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
(This post was edited by Discretesignals on Sep 28, 2013, 8:58 PM)
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Hammer Time
Ultimate Carjunky
/ Moderator
Sep 29, 2013, 5:22 AM
Post #18 of 24
(2880 views)
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Re: NEED HELP 2000 K3500 dually 7.4l
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Yeah, the Einstein method will work.................. or you could just plug a vacuum gauge into is and look at it.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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Formula242
User
Oct 1, 2013, 8:21 AM
Post #19 of 24
(2859 views)
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Re: NEED HELP 2000 K3500 dually 7.4l
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hooked vacuum gauge up last night i have 19.5 inches of vacuum at manifold.. so if that chart is right then my map is reading correctly.. cuz my baro is 29.3... hm so that just eliminated faulty map sensor..should i perform a cylinder leak down test and see if i have a valve not seating or am i pissing in the wind on that due to being new engine??? could it posibly be an injector not firing right?
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Formula242
User
Oct 3, 2013, 9:24 AM
Post #20 of 24
(2840 views)
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Re: NEED HELP 2000 K3500 dually 7.4l
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did these have any injector issues?
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Discretesignals
Ultimate Carjunky
/ Moderator
Oct 3, 2013, 10:16 AM
Post #21 of 24
(2837 views)
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Re: NEED HELP 2000 K3500 dually 7.4l
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Our shop today and when I worked at the dealer didn't see any with injector problems. The multecs in those engines were better design than the older multecs that were prone to having shorted windings. Rare to find them plugged up on the ends.
I've read a few cases where they leak, but you would have hard starting issues and you would possibly smell raw fuel. If you think you have a injector flow issues, you can do a injector balance test. You need the injector timer tool though. You can also send them out and have them flow tested.
Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.
(This post was edited by Discretesignals on Oct 3, 2013, 10:17 AM)
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Formula242
User
Oct 3, 2013, 10:26 AM
Post #22 of 24
(2828 views)
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Re: NEED HELP 2000 K3500 dually 7.4l
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some days it starts fine but others it acts funny when starting like very slow to start as far as before it revs up or it acts like it started and then poof and die and retry and starts fine.. just hard to explain it doesnt do it often but have noticed it more and more lately... as far as the injector balance test.. i was just gonna break down and spend 50 bucks and take it to a gm dealer and have them do it.. was gonna do a cylinder leak down test tonight and just do a compression check tonight also and try to eliminate the internals of engine. just trying to do as much as i can to figure it out without a tech II
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Formula242
User
Oct 21, 2013, 8:00 AM
Post #23 of 24
(2776 views)
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Re: NEED HELP 2000 K3500 dually 7.4l
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just wanted to give a heads up on wat fixed the truck.. put all new injectors and she starts and run like she has never ran before
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Hammer Time
Ultimate Carjunky
/ Moderator
Oct 21, 2013, 4:53 PM
Post #24 of 24
(2774 views)
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Re: NEED HELP 2000 K3500 dually 7.4l
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Thanks for the follow up
Closed now as solved
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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.
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