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chevy vortex hard starting


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Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Aug 22, 2012, 6:39 PM

Post #26 of 46 (1573 views)
  post locked   Re: chevy vortex hard starting  

All I asked for was the fuel adaptives mainly long term, which appear to be negative, assuming you cleared it first. I want to to clear the computer first, then start it up and monitor which way the long term trends.



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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.



toolman0007
User

Aug 22, 2012, 7:09 PM

Post #27 of 46 (1565 views)
  post locked   Re: chevy vortex hard starting  

ok went back out cleared the computer again live data longft1 neg1.6 longft2 0.0 ran for 5 min nothing changed


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Aug 22, 2012, 7:11 PM

Post #28 of 46 (1562 views)
  post locked   Re: chevy vortex hard starting  

You need to run it longer than 5 minutes, hence the name "long term"



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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.



Discretesignals
Ultimate Carjunky / Moderator
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Aug 22, 2012, 7:45 PM

Post #29 of 46 (1556 views)
  post locked   Re: chevy vortex hard starting  

ECT -8? F or C? Was this taken at start up or operating temp?

When did you record this information. Was the engine idling and at operating temperature?

Really that is only one frame of information which isn't much.

B1 STFT -10.2
B1 LTFT -1.6
B2 STFT -8.6

What is B2 LTFT?

B1 looks fine whatever load cell it was in

What is the value for the MAF? Which unit is the value in? grams/sec or a frequency?

I'd be wondering more about the 20 psi fuel pressure leak down in less than 5 mins.





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toolman0007
User

Aug 22, 2012, 7:49 PM

Post #30 of 46 (1553 views)
  post locked   Re: chevy vortex hard starting  

ok cleared it again at an idle for 20 min longft1 remained at neg 1.6 longft2 at 0.0 idle is running at 980 for the hell of it took rpm to 1150 kept it there for another 10 min ft1 went to 2.3 and ft2 was at 3.1 and did not change in the ten min of maintaining 1150 rpm


toolman0007
User

Aug 22, 2012, 9:15 PM

Post #31 of 46 (1550 views)
  post locked   Re: chevy vortex hard starting  

the ect was at operating temp maf this is what was on the screen lb... 1.234 as for units of measure in my settings I have a choice English or metric that's it . I can read a live graft in live data it's kind jumping all over. nothing real constant with it it dose spike when the gas is hit and levels back to a more even line but with in sec it's back all over the place.


toolman0007
User

Aug 22, 2012, 9:26 PM

Post #32 of 46 (1548 views)
  post locked   Re: chevy vortex hard starting  

oh and the terms u mentioned longft1 Long term fuel trim that's what the book says, the purpose and function is something i'm still trying to find out


toolman0007
User

Aug 25, 2012, 8:52 PM

Post #33 of 46 (1496 views)
  post locked   Re: chevy vortex hard starting  

  ok I spent the last part of today taking the upper half of the plenum off. the fuel reg dose not show any signs of leaking. put a vacuum pull on it and it's holding although I did find some other issues. a lot of grim and oil and carbon under the plenum. the throttle plate had a good eighth of an inch of carbon built up on the back side enough where it plugged the small weep hole in it. it seems like the fuel distribution block may have some seepage where the lines go in. not sure how they come out or weather anything is serviceable. I did take the hold down plate for those lines and tweaked it a bit and the lines seem to have snugged up a bit I did replace the fuel reg seeing how i'm going this far . I also took the throttle body off the plenum quite a bit of corrosion on the seating surface and i think it may have been leaking and pulling air. just have to clean up the belly pan under the upper part of the plenum and put it back together. will let you know what the out come is. again thanks for your help


Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Aug 26, 2012, 6:54 AM

Post #34 of 46 (1487 views)
  post locked   Re: chevy vortex hard starting  

Those do get really nasty underneath the upper intake. You can thank the EGR system for that. I can't remember if they have the newer style injector on it with the injectors on the ends of the hoses. If you don't mind spending the extra money, you can install the upgraded injector assembly that solves a lot of problems the older poppet valve injectors had.

Upgrade:







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toolman0007
User

Aug 26, 2012, 6:54 PM

Post #35 of 46 (1466 views)
  post locked   Re: chevy vortex hard starting  

  well the pic you showed is what I have. other than having to put it to the floor to start it the truck runs like a champ . it was mentioned after a few tests that there was concern with drop in resting pressure with the fuel. and with out removal of the plenum one never knows. so while I was in there I put a new fuel regulator. I also took the time and once the injector assembly was in and mounted. I reconnected the fuel lines and and hit the key 53 psi and no leaks. my scanner has live data with a graph for the maf comparing it to what I have seen online nothing looks like mine . hit the throttle she spikes well then levels out and then it's all over the place it's my understanding just at an idle the pastern should have some consistency. it also gives me a numeric scale and it will go from 1233 with swings as high as 1340 and those numbers change fairly rapid. anyways did all the work and still have the same problem. A direct answer will the maf cause this kind of issue, that being going full flood mode to get it to start


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Aug 26, 2012, 7:06 PM

Post #36 of 46 (1462 views)
  post locked   Re: chevy vortex hard starting  

No, the MAF will not cause the starting problem. Check the temp sensors for accuracy.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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.



Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Aug 26, 2012, 7:18 PM

Post #37 of 46 (1458 views)
  post locked   Re: chevy vortex hard starting  

I'm going to be honest. MAF sensor testing is difficult. It's almost impossible to test MAF sensor performance with a scan tool because most scan tools don't have a high enough sample rate. You have latency in the PCM when it calculates the signal, latency between communication from the PCM to the scan tool, and latency of the scan tool itself to process the data into a graphical display. Just about everything concerning air flow can affect how the MAF sensor responds, so values aren't really consistent vehicle to vehicle.

I have seen MAF sensors that were slow to respond to air flow changes even after they were cleaned that you would never see on a scan tool. You really need to know what a good MAF signal looks like on that vehicle for the amount of air flowing though it. Just a small change in frequency makes a huge difference in the way the computer adds and takes away fuel to the engine. A digital storage oscilloscope really is the only way to see the true MAF sensor signal.

Clear flood mode the PCM disable injector pulse, so it may still be getting MAF information, but it isn't doing anything with it.

If you have no leaks under the intake, but still have the pressure bleed off problem that can cause delayed starting. The PCM may still be running the fuel pump in clear flood mode. Have you tried cycling the ignition on and off a few times before starting the engine to see if it starts faster?

edit: Another thing I have run into with most MAF sensor performance issues is that you usually get 02 sensor codes because it affects fuel trim, but not always. Depends on the severity of the MAF's performance problem.





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(This post was edited by Discretesignals on Aug 26, 2012, 7:32 PM)


toolman0007
User

Aug 26, 2012, 7:33 PM

Post #38 of 46 (1452 views)
  post locked   Re: chevy vortex hard starting  

an what range am I looking ... volts ?


toolman0007
User

Aug 26, 2012, 7:40 PM

Post #39 of 46 (1449 views)
  post locked   Re: chevy vortex hard starting  

 well I finding it hard that the system has not set the check engine off again since this started


Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Aug 26, 2012, 7:41 PM

Post #40 of 46 (1449 views)
  post locked   Re: chevy vortex hard starting  


Quote
an what range am I looking ... volts ?



For the MAF?





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 Aug 26, 2012, 7:42 PM)


toolman0007
User

Aug 26, 2012, 9:06 PM

Post #41 of 46 (1441 views)
  post locked   Re: chevy vortex hard starting  

what am I checking volts and what range for temp sense


toolman0007
User

Aug 26, 2012, 9:08 PM

Post #42 of 46 (1439 views)
  post locked   Re: chevy vortex hard starting  

sorry replied to wrong post .... temp censer


toolman0007
User

Aug 29, 2012, 6:56 PM

Post #43 of 46 (1392 views)
  post locked   Re: chevy vortex hard starting  

I have yet to check the temp sensor truck will be cold in the am will check it then. most would not be happy about this but the check engine light came on on the way home. this is what came up code P0101 mass or volume air flow A circuit range performance. with technology as is is today you would think these systems would just say hey dude this is the problem fix me


toolman0007
User

Sep 1, 2012, 8:35 PM

Post #44 of 46 (1353 views)
  post locked   Re: chevy vortex hard starting  

just letting you know the issue with my hard starting has been resolved . temp sensor plug and head of the sensor was all corroded in stalled new sensor and plug end and all is back to normal


toolman0007
User

Sep 1, 2012, 8:43 PM

Post #45 of 46 (1352 views)
  post locked   Re: chevy vortex hard starting  

trucks back to running normal again temp sensor was all corroded new sensor and harness end now things are fine


Discretesignals
Ultimate Carjunky / Moderator
Discretesignals profile image

Sep 21, 2012, 5:11 AM

Post #46 of 46 (1277 views)
  post locked   Re: chevy vortex hard starting  

See this thread for continuation of problem and solution:


http://autoforums.carjunky.com/...6757;t=search_engine





Since we volunteer our time and knowledge, we ask for you to please follow up when a problem is resolved.






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