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GMC Safari/Chevy Astro Starting/Stalling/Idling Problems



  • Reply for the 1996 Safari with the spuuter and misfire. When I was originally troublshooting my no start problem I suspected the engine control computer... I think it's call the ECM on the wire diagram. Anyway I was referred to an experienced mechanic that did exactly what you did. (We're talking about the module below the brake master cylinder with 4 cannon plugs coming off towards the front of the vehicle...just making sure) The mechanic took a ball peen hammer and hit the ECM while I had the van running. Since the van didn't skip a beat we ruled out the ECM as my problem. He did however tell me that this was a problem for vehicles with your year model and what you did was the test for that defect. I guess what happens is that a crack develops in the circuit board inside the unit and then when it gets hot/cold, hot/cold etc etc it starts to cause issues like what you describe. You should be able to pick up an unprogrammed ECM at your local parts place. You'll have to take the little panel off the side of your old ECM so you can retrieve the knock sensor for your new computer. Of course you'll have to have the new one programmed which should cost around $80. Unless you know someone personally at the dealership to help you I wouldn't even go near there with this problem. Good luck. By the way, I'm told the van won't run without it being programmed.
  • started again today- this only is happening when it snows outside and the the streets become slushy - never when it rains and never when it's just cold outside- without snow--- this is driving me insane, I drove over to my GF's last night and started misfiring again , then I backed it into her driveway and it really got worse and then died- I was able to restart it after it died, let it run for a few minuits and then when I steped on the gas pedal it went to full throttle , but before this I would give it gas and start to misfire and buck off and on- I really need some help on this one - do any of you have or had the same problem- writing while i am trying to start the van,,,I stuch a hair dryer in the cavity near the coil--? guess what it started,could the moisture in the air from wet heavy snow be causing problems with the coil????need some help
    thank you
  • pinky6pinky6 Posts: 3
    We have a 1999 Astro Van and it stalls out/then won't start in wet weather. The distributor cap coilwire plug wires fuel pump and relay have all been replaced still stalling out, any ideas?
  • Hello, my 94 astro will just shut off as im driving or even stopped at a light. I replaced the ignition mod,coil,cap,rotor, plugs and wires but its still stalling. any help with this issue would help me greatly. thank you :sick:
  • Steve_01Steve_01 Posts: 42
    Any codes? OEM or aftermarket cap and wires? This engine uses a very high voltage coil/spark/ignition. Low quality ignition components will allow the spark to 'leak' or short out easily.

    You might also want to check the fuel pressure. Don't know about the 94, but on my 97 the fuel connector is just left of the distributor cap. Look up the spec's for 94. 97 fuel pressure is around 58-63 psi. You can probably rent a pressure gauge for little to no cost.

    I've seen posts in this forum indicating that the bulkhead connector (behind the battery) has 'melted' and/or folks have found corroded connections causing the symptom you described.
  • No codes, Im not sure about the cap and wires I've had the van for a month now. it will start right up aprox 2 min after stalling . Im thinking of replaceing the fuel pump assembly as my next step but I will check the fuel pressure before I dive in. thanx
  • alberta4alberta4 Posts: 4
    I have a 97 Safari RWD with 200K kilometers on it. I am having real problems with hesitation. It has been going on for about 3 years. At first it only happened in the spring but it has been getting consistently worse. The hesitation happens when I step on the accelerator the van seems to die and then lurch forward in a stuttering kind of jerky way. Once I get to higher speeds it is ok. If I do not drive the van for a few days it gets worse. After I drive around for 20 minutes or more the problem seems to resolve itself. If I drive everyday, it is not as bad. It is the at its worst in the spring (I do not have a heated garage and it gets really cold in Edmonton). It is not throwing any codes and I have brought the car in a number of times and my mechanic can't find anything wrong. I specifically asked him to check the distributor, coil and spark plug wires (because moisture seems to make it act up). I am starting to have doubts about my mechanic. I am thinking it may be a dirty throttle body or a bad TPS. I have doubts about an O2 sensor causing this type of problem with no codes (but I am not a mechanic). I would really appreciate any advice that anyone might have regarding this problem.
  • bwgmcvanbwgmcvan Posts: 10
    bulk head connector,, that sounds like that could be the problem- 2 months ago it was snowing out, slushy,, started sputtering and jerking then died- I pulled over , banged that area and it started up, also when I was driving home it started again, pulled over, sat for 5 minutes , pulled off and started on my way home- I had to pull off the road 5 times until it ironed itself out and ran smooth. This only happens when it's snowing?? any thoughts- also my service engine light goes on for a few days then shuts off- constantly- any thoughts
  • Steve_01Steve_01 Posts: 42
    edited March 2010
    Don't forget about the fuel filter, could be clogged.
    In case you don't have a repair manual here's some quick specs for you. According to my manual, the CMFI (Central Multiport Fuel Injection) system is used on all 4.3L V6 VIN W engines manufactured from 92 to 95. In 96 they switched over to the CSFI system. The CMFI system uses a single central fuel injector which feeds each cylinder through six separate tubes and poppit nozzles. The fuel pressure regulator is mounted directly on the fuel injection unit.

    Fuel pressure:
    Key ON, engine OFF - 58-64 psi
    Engine running at idle - Pressure should DECREASE by 3 to 10 psi

    Remember that low fuel pressure, does not necessarily indicate a bad fuel pump. It could indicate a bad fuel pressure regulator. In the 96 and up (CSFI) systems, it's not uncommon for the regulator to leak inside the intake manifold. A leaky regulator could lower your fuel pressure and make the engine run crappy, not to mention fuel could leak down the inside of the engine into the oil pan. Not good.
  • Steve_01Steve_01 Posts: 42
    The only way to know for sure is to pull the battery out and disassemble the bulkhead connector. I haven't had to do that on mine but I did pop the cover off while I was replacing a dead battery a few months ago. It looks like there's a bolt (maybe 10mm?) in the middle of the connector holding it tightly in place. It's worth a look.

    If you go to your local large chain auto parts store, they will usually check the codes for you for no charge. The check engine light doesn't necessarily have to be on. The computer will store the code(s) for a while but it would probably be better to have it checked while the light is on just in case.

    My Astro has had the light come on once or twice and go away on its own. I know for a fact that it has intermittently low compression in cylinder #1. Probably a sticky valve. The only time the light has come on is when it's sat for a week or so without driving.

    If you have a P0300 code, that's a random misfire. P0301 = cylinder 1 misfire, P0302 = cylinder 2 misfire. And so on, you get the idea.

    Hope that helps.
  • I had a similar problem with a 94 Bravada. Turned out the CMFI connector on the plentum had a slightly bent pin. I had to replace the harness inside the plentum. If you touched the connecter with the car running, it would cause it to stop.
  • I have been chasing this problem for a while now and thought I had it solved. The van has a rough idle and wants to hunt for the correct idle speed. The main symptom is on accelerating from a stop where if feels like half the cylinders cut out. Today, sitting in the driveway with the van in park, I accelerated to about half throttle when it started cutting out. With my scan tool hooked up, I see the S-T fuel trim drop to the mid 80s. I can also see IPW fluctuate from 7 to 0. At times it is steady at 2 with the van running smoothly. Since there are so many input that can control the IPW, I am at a loss as to where to look.

    The van has new fuel filter, plugs, wires, cap, rotor, EGR valve (repeated DTC 32) and O2 Sensor. The van has 186k on the odometer with 150k on the engine. Fuel pressure also checks out, the spider is not that old and holds pressure well. There are no other codes.
  • ok, so I took off the engine cover so that I might be able to diagnose the problem when it happens. it didn't shut off for two days so I thought that the cover might have something to do with it. I re routed the ignition wires so that they are away from the heat shield of the cover and put the cover back on. this was three days ago and still going strong without a problem.
  • Steve_01Steve_01 Posts: 42
    On that note, years ago I had a similar problem with my 97 Astro running rough and not starting. It turned out to be the coil wire shorting out against the transmission fluid dipstick tube. If I look closely at the tube, I can see where the high voltage arcing has slightly eaten away at the metal. I wrapped the tube with the same type of foam insulation used to insulate the hot water pipes in the basement. That took care of the problem.
  • irish_johnirish_john Posts: 2
    Hi all, I'm a new kid on the block, Just joined today............. What I would like to know is if any you guys out there be so kind as to give me some advice about my 1995 GMC Safari?
    I found her running very bad with regards power, she would take off ok but after she change into top gear she seems to lack in power, and also I have notice like a rattle or a kinda chain type noise when I go to excelerate with my foot right down on throttle ? As a result I am scared to push her to hard in case I cause more problems. I have just change the oil on her and put new oil filter on and also changed the trans fluid and put new air filter in, but till she is not running well at all, So at the weekend I got me mate to fit a new fuel filter on her hopeing that this will sort it out, but again she is just the same lacking in power???...............
    So do any you guys have any idea as to what could be my problem with her?
    I live in Belfast, Northern Ireland, and I get all my parts from a dealer in England, so I hope its not going to cost me the earth to fix :cry:
    Thanks so much for you time in reading this :cry: for help!
    John, Belfast, Ireland.
  • bwgmcvanbwgmcvan Posts: 10
    DId you check to see if your catalitic converter is clogged?
  • irish_johnirish_john Posts: 2
    Hi mate, thanks for ur reply, Ihave not checked the cat converter? how do i go about doing this???
    Please help!
    Johnny. :sick:
  • bwgmcvanbwgmcvan Posts: 10
    Check it night, see if it is glowing "red hot" this is an indication that you have a clogged Cat converter,, builds up with carbon, that is one way, look on the net and see if you can't come up with some way of deciphering how to check the cat converter

    keep us posted mate,
  • russ75707russ75707 Posts: 7
    edited June 2010
    I have a 1995 Astro,4.3l z ,cmfi.I have had a problem with the van idling rough at stoplights,but when shifted into Park or Neutral the damn thing runs smooth as can be.In an ongoing attempt to find and fix this problem,(i have 250,000 +)I have never eliminated problem by cleaning egr,iac,etc,fuel pump went amid all this,of course,I caught this one b4 I got stranded yessss,replaced pump,filter,thorough carbon cleaning,tune up,ran sea foam through everything,nothing has made a difference.I wonder if the torque converter really is sticking?Thedistributor shaft feels sturdy,but whadda I know,how can I rule that out?Is the best way to rule out sensors is to unplug them one byone?I have yet to get a code other than 12 from pins on obdm-wan (whatever its called) connector.i'm starting to get pissed now,I broke knock sensor and temp sensor thing trying to reach through beside motor,had to rig those back after I identified them.Now what?Anyone.....anyone......anyone at all.....No,I will not burn it!!Shameful thoughts,does anyone have any ideas that might help me locate and stomp the s**t out of this meddlesome problem for good?Cat converter is cleaned out too
  • bwgmcvanbwgmcvan Posts: 10
    Check you wires/coil/plugs- there could be carbon build up in the cap,, or wires that are not shielding the spark and arcing.
  • GuildmanGuildman Posts: 6
    I know this issue has been addressed but I don't know what to try next.94 Astro 162k starts to idle rough at stops and stalls with more frequency at stop lites,only after car is warmed up.Have removed and cleaned egr,Noticed egr valve was not moving freely,after cleaning problem still there.Valve did not stick when fully depressed to solinoid in egr.Is that a sign it needs to be replaced?Whats the most likely next problem to check? No check engine lite comes on.Mechanic checked dist cap, plugs,wires,and said they were all good.He didn't want to start throwing parts and money at it cause there are are to many possible causes.Saw someone had a fix with vacuum hose & elbow at pcv.Could it also be the IAC?Have new tires and so many new parts I hate to give up,everything else is running great.Any help is greatly appreciated
  • GuildmanGuildman Posts: 6
    Can't edit message so I'll add to it.As with Russ post previously,when I shift to neutral or park at a light problem problem dissipates or mostly gone.4.3 llter cmfi w engine.No hesitation or misfire when driving,only at idle after engine heats,and problem is intermittent.
  • graylinergrayliner Posts: 39
    Not sure, but since you're ok when out of gear I'm wondering about the mysterious Throttle Valve cable -maybe line pressure is off due to electrical/solenoid? It connects the throttle body to the tranny and is full of voodoo. Might want to track down an experienced/trained GM transmission shop to road test diagnose it. There's a science to it. Check the lockup torque converter clutch solenoid. They can stick when hot.

    I had trouble with my distributor, timing on a '97. I replaced the timing chain, while in there checked to see that my crankshaft sprocket dot was lined up with my camshaft sprocket dot so my timing could be set. The #4 cyl will be at Top Dead Center now. And the rotor in the distributor will need to be facing the #4 terminal in the distributor cap.

    Put a new crank position sensor on (if yours has one) because this can cause issues. The timing chain is a good thing to do just as wise general maintenance anyway. Don't want mine to grenade on me anyway. But I don't really think it's a timing/distributor issue. I suspect a tranny-electrical issue.

    Hmmm... let us know what you find please.
  • russ75707russ75707 Posts: 7
    The clutch lockup solenoid idea sounds entirely plausible,anybody know where it's at on Astro's? I can test a solenoid,all they are is a contact that becomes magnetized when energized,and creates a circuit.I have a two wire connection @ the rear driver's side of tranny that I thought was speed sensor.The connection has been badly fouled w oil for a while and I cleaned it thoroughly several times appears to be clean and dry at last look though
  • GuildmanGuildman Posts: 6
    With further checks on other forums,I think you're right about it being the TCC solenoid.Other symptoms-after exiting freeway to a stop I hear a clunk almost like I've been rear ended-maybe thats the lockup not releasing from overdrive.The engine misses intermittently at idle in park as well,but that could be another problem.Trouble is,all these things are inconsistent so I can't reproduce them at the shop.The solenoid fix looks like it might be beyond the average diyer.Is it? Thanks for the help
  • russ75707russ75707 Posts: 7
    Where is it?Anyone tell me where it is I'd like to take a look at it,maybe i'll check autozone repair manuals
  • GuildmanGuildman Posts: 6
    Unbelievably,all my rough idle, stalling at lights and after coming to stops at freeway exits,seems to be solved by one treatment of Techron fuel system cleaner!Hard to believe cause all symptoms were pointing towards Tcc solenoid.I'm reading ethanol mix in California gas,especially cheaper brands, will clog fuel injectors over time.If this fix holds its the best $9.00 I've ever spent.I'll throw in another bottle for good measure on the next fill up.
  • russ75707russ75707 Posts: 7
    edited August 2011
    I have read exhaustively night after night,scouring the automotive forums,picking up some pretty impressive viruses from some of them,cleaned egr 5 times,changed fuel pump #4 for me,broke knock sensor and cts sensor on drivers side btwn #3 and #2,tuned up,changed rear end,rear u-joint twice,changed oil a coupla eimes,fixed ac,then broke it ***** w it like a *******. All while trying to find out if spyder needs replacing or not,and why rough idle when stopped but clears immediatly when put in
    park or nuetral,damnit i even went to clean out cat converter and found out it had all blown back into my late model muffler and ruined it.UR NOT GETTING OFF THAT EASY!! LOL another cause I've investigated is possible loose/worn distributer shaft bearings
  • GuildmanGuildman Posts: 6
    Believe me,I know its to good to be true.I feel your pain,& I'm gonna assume you did the fuel additive (twice?) with no results.I also did a couple of small things for what its worth.Sprayed carb cleaner around all the vacuum lines,making sure they were all intact,especially at the ends and where they lie close to engine block& get to much heat.Also cleaned pcv and checked elbow at pcv valve.Let you know if my fix holds,or maybe I'll just park it so I can claim victory over this beast,ha,ha
  • russ75707russ75707 Posts: 7
    I hear u about parking it,wanna quit on a high note!I only know of maybe 4 vacumn lines all good,I visually inspected pcv elbow,half assed,maybe that warrents a second look,I try to schedule doghouse/engine cover removal when I have a whole day of work there,cause inevitably i get done and am too tired to put it back right,and @ 260,000 miles and 15 yrs of age,if u dont stay on top of the little things,it turns into a junky piece of crap pretty fast.I guess tcc solonoids are inside housing of tranny,so I will need to plan that in advance,A lot of cursing,tool throwing,and etc. goes on then...
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