Last post on Feb 23, 2013 at 8:21 AM
You are in the GMC Safari & Chevy Astro
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GMC Safari, Chevrolet Astro, Van
Feb 27, 2012 (4:20 pm)
I have a 2004 Astro. It has 130xxx miles on it. Sometime ago it began throwing a check-engine light (a mass airflow sensor code, among others). I have gone through and changed plugs and wires (not cap and rotor). It still throws the mass airflow code although I have put in a good mass air flow sensor and I am not sure why. It may be related to the other issue I am having though.
In addition, it will run poorly until it warms up and even then it will still sometimes runs poorly. By poorly, I mean it has a real rough idle, surges while at stoplights and will even die at stoplights and stopsigns unless I feed it just a tad bit of fuel while holding the brake more firmly to keep the vehicle from rolling forward.
I have found that it while it is likely to act up first thing in the morning, there is no rhyme or reason to when it decides to act up although... I have also found that if it does act up, I can shut the entire thing off (not wise in an intersection) cycle the key to the off position, cycle it back on and wait for the fuel pump to pressurize and then start the vehicle. It will then start just fine and run with no issues whatsoever. No surging, no rough idle, no threat of dying in the while stopped at at stoplight.
I have also found that it is most likely to exhibit symptoms if I just jump in and crank. (Like we all probably do unless you own a diesel) However, if I get in and turn the key to "run" wait a few seconds for the vehicle to come to life, then crank, it is more likely to run with no issues. I have also found that at times, I will get in, it will be hard to start. It will crank and crank and crank with no fire, unless I floor the gas, then it will come to life and as long as I feed it fuel, it will run. If I let off the gas, I get my rough idle and sometimes it will even die before I get it into gear, or it will die as I put it into gear. If I start cranking and all it does is just crank with no fire, I can cycle the key completely off, then back on, waiting a few seconds and it will start and idle, run and drive with no issues.
So in short, there is a rhyme and reason to when it acts up. If I just jump in and start the vehicle, it is likely it will act up and have serious drive-ability issues. If I jump in, turn the key to run, wait a few seconds for the vehicle to "wake-up", then it is more likely to run with no issues (although this doesn't work 100% of the time. More like 80%).
Any ideas on what it could be? Fuel pressure is fine, plugs and wires are new. Mass airflow sensor is good.
#1963 of 1972 Re: '04 Surging Motor [the_big_al]
Feb 28, 2012 (10:33 am)
Sounds like a fuel pump/fuel issue. I have never had wait for a modern vehicles fuel pump to pressurize before starting. It may just be the wire harness going to the pump. GM had some issues with fuel pump wiring on pickups and vans from the 90s and the Astro was pretty much unchanged from 1995 until it's death in 2005.
#1964 of 1972 Re: '04 Surging Motor [cob]
Feb 28, 2012 (12:56 pm)
but why would a fuel pump cause surging? a rough idle I could understand, but this is a surge. It surges from almost dying to about 600 RPM at idle. It does not surge while at speed or while feeding it fuel. My statement about letting the fuel pump pressurize might be mis-leading a bit. That is generally the length of time I let it sit before firing it up. You're right though in that I too have never had to wait for a fuel pump to pressurize. I just generally get in and fire away no matter the vehicle aside from diesels.
One of the other things that it will do is that if is exhibiting issues, is that when I rev it then let off the gas, it will idle all the way down to almost dying and then usually it will die. Or sputter and come very very very close to dying and only by feathering the gas can I keep it alive. Again though, cycling the key off and then back on will generally cure all issues.
Could it be an idle control valve??
#1965 of 1972 Re: '04 Surging Motor [the_big_al]
Feb 29, 2012 (10:42 am)
Have you tried ready the codes from the computer to see if there is a problem with a sensor? Does the check engine light come on while it is running rough? You could also pull the neg. battery cable for 30 min to reset the system to see if it helps. Make sure to read the codes first because resetting the system will erase anything stored. I would try that before swapping out any parts.
#1966 of 1972 Re: '04 Surging Motor [the_big_al]
Feb 29, 2012 (11:09 am)
I had simlar issues with my 2001 safari, 4.3 l engine. It, surprisingly enough, turned out to be the fuel pump. I would take it to (I cannot believe what I am about to say) a Chevy dealer and have their mechanics check it out. The dealership was my last resort but this might have been the one case in my life where I should've gone there first. They did a pressure test on mine and I think a vacuum test and it was a fuel pump issue. I replaced it and the trouble corrected.
#1967 of 1972 Re: '04 Surging Motor [cob]
Feb 29, 2012 (3:13 pm)
The only code it will throw intermittently is a mass airflow sensor code. It comes and goes and does it while driving. Not sure why it is throwing that particular code. I have swapped out 2 different mass air flow sensors and it still throws the code. No other codes are present.
#1968 of 1972 astro running deep
Mar 04, 2012 (11:56 pm)
I am a owner of a 1994 Chevy Astro EXT CL version which i bought brand new no major problems almost 300,000 miles on it in still running deep.link title
#1970 of 1972 1995 GMC safari
Sep 24, 2012 (4:14 pm)
Driving my 1995 GMC safari home stopped at light it "chugged" and died now it will not start again. Sound like it wants to new battery and fairly new starter.
any help would be great
Sep 29, 2012 (3:55 am)
I also have stalling problems when restarting within 5-10 minutes of turning engine off. Am happy with the features of the van, but very concerned about the reliability. Have been in 4 times in under 20,000 miles for the injectors only. Would be curious to know how t2muchjam got to the arbitration point. I wrote a complaint letter to GM last fall and received a form letter extending the warranty on the injectors only to 100,000 miles. Haven't followed up again, and now this past Thursday, it happened again.
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