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GMC Safari/Chevy Astro Starting/Stalling/Idling Problems

I have a 1998 Chevy Astro, 156,000m this is a recent issue where if it rains heavily during the night my van will not start at all the next morning, I dont seem to be able to hear the fuel pump engaging @ Key on position, I have checked and replaced the fuel pump relay, but still the same problem persists. I am not sure what the culprit could be as the only time i have trouble is when it is very wet out, this has happenned once before after getting to work and trying to leave to go to a jobsite.
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Comments

  • My Astro just started doing this last night. Does anybody have any ideas?
  • I have a 1994 Gmc Safari and I have replace the fuel pump and the fuel filter as well as the fuel pressure regulator I get fuel all the way up into the injector and into the fuel pressure regulator but it still wont start I spray starter fluid into the throttle body it starts until it evaporates then dies DOES ANYBODY HAVE ANY SUGGESTIONS ? :confuse: :mad:
  • I have a 1995 gmc safari... they recently change water pump, gas pump and filter but now its leaking gas down the exhaust.... does any one know why this is happening .... my van its been parked on my drive way for too long now and i miss it very much i need to get it running again before starts snowing please if anyone knows i will appreciate any recomendations.... i heard it could be the fuel presure regulator... what u think??? :cry:
  • Ok, people. I am new @ this. I am in dire need and I need help. I need a fuel pump for my 1998 GMC SAFARI. Problem is...they are prohibitively expensive and I am a poor parent of 3 children with 1 in college. Anyone has any idea on how to fix/replace the fuel pump in a fashion affordable to me? Thanx so much. Bye.
  • My 93 Astro 4.3L quit running one day and won't restart. It has 60 psi of fuel pressure and plenty of spark. It also shows a code 43 which is the electronic spark control system faulty. Replaced the ignition module to no aveil. Anybody have the same problem? :sick:
  • I have the same problem with my 2000 astro when it rains the fuel pump doesn't get any voltage. Please if anyone knows why please post it . Thank you
  • SO this test is to place a piece of wire or metal(something that will stay in place on it on...like an alligator clip and then hold the boot with a well insulated screwdriver (as in drapped over it ) and gradually move the tip away from the grounded metal surface.(Would insulated pliers help me hold/control it better?---If this is not a good result should I look at new wires or plugs(different brand or premium platinum) that give a better spark or what would help this? Or is there another part which provides this spark. I replaced the ignition coil already.

    If the fuel presssure leaks down before a couple of minutes does that mean the injectors are not providing enough fuel long enough? Could their signal be dropping out too soon or are they bad. Could this be the fuel pump. I heard from another mechanic that this system had lots of problems and has been updated. He was lobbying for work but did say as you that if I am going to do the work myself that to make sure I check everything out before I invest in the updated injectors system. Last time I checked it was about $520.00 and I think its a dealer only item. This current system is CMFI on the 1995 I have. In 1996 they went to CSFI and if it retrofits (and this is the solution maybe I could find a slavage one . The bad news would be if they just changedthe CMFI and only new will work.
    Thanks again...

    On the Explorer I was checking the IAC valve. Since I cleaned it out(carbon buildup) the idle is doing as you describe. It does go to about 1100 before settling down to about 600rpm. It actually was racing up before. I will continue to observe this and if it continues or reoccurs I will clean it again. It may need to be replaced. The TPS (throttle position sensor also had inconsistent voltage but with this improvement it may have nothing to do with the surging/racing idle at this point.
  • "If the fuel presssure leaks down before a couple of minutes does that mean the injectors are not providing enough fuel long enough? Could their signal be dropping out too soon or are they bad. Could this be the fuel pump."

    The fuel pressure leaking down means that the fuel injectors are leaking or their is a leak somewhere in the system. The leaking injectors can cause some flooding of the cylinders, depending on how bad it leaks, because the leaking fuel injector never completely closes and squirts some fuel when it supposed to be closed. The Fuel pressure should NOT leak down, but hold the same pressure for several minutes if the system is "tight" and not leaking. Most common leakage is through the injectors, there could be one or more that is not sealing closed due to dirt in the injector or a sticking injector. In these cases, inspection and cleaning of the injectors is recommended. Other sources of leakage (not common) can be leaking backpressure through the fuel pump or and an external leak. Sometimes the injectors short out and don't open, then it makes that cylinder run lean. I'm glad I drive a Ford, you may notice that the Fords seldom, if ever, have any fuel injection problems.

    On your Explorer, the IAC are common to need cleaning or replacement, poor idle is usually IAC or EGR system or vacuum leak.

    On my Explorer, my 2000 V8 5.0L is starting to give me a P0401 DTC, EGR insuffient flow, so I'll be having to clean the EGR and passages, maybe have to replace the Dpfe.

    Good Luck,
    E.D. ISF
  • The plan is to continue with the spark quality and further investigate the "leaking " of the fuel injector system after doing a leak down test on the Safari. This van was a freebie out of my father-in-laws shuttle service fleet and with the money I spent on getting it up to speeed I'll have just about bought it. Its probably going on the sale block as soon as I get it running...getting to the diminishing returns level.

    Its been a couple of days since I cleaned the Explorers IAC valve and the idle has been consistent so thats a good sign.

    We also have a 1998 V8 5.0L and I got that code and and it was the Fuel vapor management hose that was damaged. The unit itself broke while changing the hoses.They and the valve attachments are plastic and this truck has over 200K. It would be nice if I can help you with this information.
  • "We also have a 1998 V8 5.0L and I got that code and and it was the Fuel vapor management hose that was damaged. The unit itself broke while changing the hoses.They and the valve attachments are plastic and this truck has over 200K. It would be nice if I can help you with this information."

    That' nice but it's not a problem right now, it can wait a month or so until I have time to get to it. Right now we have all this Christmas stuff going on, and I just don't have time for anything, unless it's an emergency.

    Keep me posted on the GMC cause Im curious at to what you find, since we've been through almost everything so far.

    Good Luck,
    E.D. ISF
  • I pulled the intale manifold tunung valve off and as Lindertech suggested it should show carbon buildup inside the manifold but any wetspots would indicate a leak;I see some wetness.
    The leakdown of the fuel pressure was evident. The psi would rise up to 64 and fall back immediately to 58. It would fall to about 56-57 over the next several minutes. It is said that this system needs 60-61psi at a minimum for proper operation. After I rule out the spark as discussed I am going to pull the manifold and have a look at this fuel injection to be sure of the dampness I see. Its so cramped in the engine bay I am only able to view with a mirror.
    On our 98 V8 explorer by the way which is my wifes daily driver she has complained of a "whistling noise" for several weeks. I changed the chain tensioner and idler arm pullys, cleaned the MAF, throttle body and EGR valve, replaced all hoses and lubricated the drive belt. What else could be causing this annoying sound...fan cluth????
  • When does it make the whistling sound? At Idle? While standing still? While driving down the road? Does it come and go or change pitch or volume with a change in engine speed or with road speed? I am trying to rule out wind noises, as they have been a common complaint in the past.

    What is steering me away from the fuel injectors not being the reason for the NO START is the fact that you sprayed fuel in the intake and the engine still won't start, even with good cylinder compressions, This leads me to think that the ignition is the reason for the no start. The ignition needs to be confirmed before you tear into that fuel injection.
    If the injectors were not working, the engne would still fire and run for a second by spraying fuel in the intake.
    Good Luck,
    E.D. ISF
  • Tested the spark length and consistently less than 1/2 inch some oblue mostly orange not pale. Interesting enough this is with new wires, ignition coil, distributor cap and rotor, So what does this tell me. Has it ever been better or is there a way to improve on this. I was particularly looking at no.1 cylinder since that was the one that was wet.

    Again there is a leakdown going on as the fuel pressure is not holding and an outside vlsual(not the most conclusive at this time)showed some dampness where it should be dry carbon buildup. So I am in the process of removing the intake plenum to get a better look. I will be looking closely at the fuel injection "spider"...one injector feeds six poppets. I am awaiting feedback from a supplier of refurbished unit to see if the regulator could just be replaced or does the entire unit. They sell a kit that includes all pieces. I really don't see any other direction to go unless you think the spark results are significant.(Please see above question...what can be done to improve a weak spark?)
    Taking a while due to the holidays and the stress of moving into a new home and boy do I need this vans space. To be continued....
  • Your spark is too weak. I checked the spark on my 2000 Explorer at terminal #1 of the coil pack, and it threw hot blue/orange sparks up to 1 1/2 inches long. I think your less than 1/2 inch sparks is only good for a lawn mower. You had better check your manual to see how to check and test the ignition system.
    If you can't find the problem, you can pull the cap and rotor, or maybe just pull the whole distributor out and take it down to the Autozone Store and let them test it. They can test the module, the pickup coil and the coil output. Does yours have the coil in the distributor cap?
    Here is the link to the Autozone repair info for the HEI ignition, it has a lot of information:

    http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/1- 1/7d/1e/0900823d80117d1e.jsp

    Good Luck,
    E.D. ISF
  • Oh I forgot the other "great way" to test your ignition output voltage is one I found on that fuel injector site that you pointed me to at Linder Technical Services. Look under Bubbas Teknikal Tips, "Ignition Voltage Output Test"! I think if you throw the wrench over 30 feet, the ignition will be OK! The trick is to be sure that you use the Sears wrench!

    Here's the link!

    http://www.lindertech.com/bubba.htm
  • OK, so the sparks do not appear to be as strong as you describe they should be. SO what would make them weak? All the reading I have done on spark plug wires speaks to the resistence determination of spark. The new set vs. the old set was very close with the new set having slightly more. I changed them since they were the original set on the car when I received it and I did not know their age(GM uses AC Delco and that name was on them.) The only difference was the distributor to coil lead was significantly higher in resistence. Could the ignition switch have an influence even though I am getting a spark

    What should I be looking at now then concerning ignition. There was no mention of advice in your last post...
  • On the V8 Explorer the sound is standing still. When the truck was in for a recall the dealer said it was the belt tensioner and idler pulley. Another mechanic listened to it and said the alternator bearings were bad. After having the alternator bearings refurbished at the auto electric outfit I used the whistle remained. After changing the belt tensioner pulley a nd the idler pulley the noise remains. I wonder if the tensioner itself is the culprit...that I did not change?
  • My post was full of advice on what to do.
    Please read it again:
    "Your spark is too weak. I checked the spark on my 2000 Explorer at terminal #1 of the coil pack, and it threw hot blue/orange sparks up to 1 1/2 inches long. I think your less than 1/2 inch sparks is only good for a lawn mower. You had better check your manual to see how to check and test the ignition system.
    If you can't find the problem, you can pull the cap and rotor, or maybe just pull the whole distributor out and take it down to the Autozone Store and let them test it. They can test the module, the pickup coil and the coil output. Does yours have the coil in the distributor cap?
    Here is the link to the Autozone repair info for the HEI ignition, it has a lot of information:

    http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/1- - 1/7d/1e/0900823d80117d1e.jsp "

    #1 I said to Check the information at the Autozone website link that I posted, it has ALL the information that you need to check and diagnose the problem.
    #2 I said to Take the distributor down to the Autozone Store and let them check it, because they have the testing tools to check the PICKUP COIL, check the MODULE, and to check the IGNITION COIL.
    #3 You are checking the resistance of the wires and such, but you need to make sure the system components are working correctly to be sure the coil is putting out the Hot Spark that it is supposed to put out, over 40,000 volts. The specific components that need to be indivually tested are:
    A. The PICKUP COIL.
    B. The MODULE.
    C. The IGNITION COIL.
    The components can be tested with an ohm meter to see if they are in spec, but they need to also be tested with the proper electronic testers to be sure that they are performing properly. Then, the assembly all put together needs to be tested for total output. The Total Output Volts should be over 40,000 volts, there is a tool # J-26792 for testing the coil output.

    The best thing to do with it is to pull the distributor out and take it down to the Autozone and let them check the whole assembly. Just be sure you have it properly in time when you reinstall it.

    Good Luck,
    E.D. ISF
  • Did they put a new serpentine belt on it?
  • I think I responded before I got your last post which as you say was chunk full of good info. Three autozones I called do not test distributors and one mechanic I was referred to says he needs the van..imagine that.

    I tested the pickup coil by (fig 12 on the auto zone site) and according to fig. 13 it needs replacing. I gave a spark with the 4terminal connector dosconnected and as well I found the new rotor I had put on after the no start problems started was also cracked...hmmm.

    The testing of the voltage of the ignition module has me confused No 4"Check volts at "+" and "C" and should I probe both together or probe one and apply the other lead to ground. When I did both methods I got less than 1 volt with the KOEO which indicates to repair wire from module. These two wire swhich connect the Ignition module and the new ignition coil showed .001ohms continuity. Does this appear too low?)but they are not open. I need to do step 5 in fig 13(hopefully my spark plug testor can suffice as a test light?)

    I did not change the serpentine belt when I changed the pulleys ...think I need to?
  • I'm surprised by the Autozone, I apologize for recommending them, I had ignition checked on an HEI distributor years ago, but it may have been another store, they have changed names of the stores around here. Discount is now Advanced and One-Stop is now Bumper to Bumper. I called the Autozone here in St Pete and they said they can only test the module, it has two screws, you take out the module and take it to them and they can test it. I would do that, and then test the magnet at the pickup coil. If the magnet gets weak, it can make the fire weak. You can lightly touch a small metal screwdriver blade to the poles pieces and feel for magnetisum. As far as testing the spark output voltage, the easiest way to do that is by "drawing an arc" like I desctibed before. The longer the arc, the higher the voltage, but be sure to have the battery charger on the battery when you are cranking the engine, because low battery volts will make low spark volts. I would think that if you can draw out an arc an inch or longer while cranking the engine, that should be good. A rough rule of thumb is the voltage is about 10,000 volts for every quarter inch. So a one inch arc should be about 40,000 volts.

    About your question: "The testing of the voltage of the ignition module has me confused No 4"Check volts at "+" and "C" and should I probe both together or probe one and apply the other lead to ground?"

    Your question is about Figure 12 steps 3 and 4. If you look in FIGURE 11, it gives you the answer. Those + and C wires go from the module to each side of the coil. The coil is fed "Hot" from the ignition switch and that same connection goes to one side of the coil and also to the "+" wire. Therefore the "Hot" wire from the switch feeds one side of the ignition coil and also the "+" wire, which feeds power into the module. This means the "+" wire should always show power when the ignition is on, I would assume it should be near battery voltage. The test says it should read above 10 volts, with the connector unpluged, measure from the "+" to ground with the key on for your reading.
    The "C" wire goes from the module to the other side of the coil from the power connection. This tells me that this is the wire that "Fires" the coil, by electronicly grounding at the instant the coil is suppose to fire. Everytime this wire grounds and then opens, it lets current flow through the primary of the coil, the coil builds up a magnetic field, then the instant the wire is opened (switched) by the module, the magnetic field around the coil collapses and creates the high voltage in the secondary coil. The module is an electronic switch that switches the "C" wire to ground On and Off. So to test the "C" wire, with the ignition on and the connector unpluged measure from the "C" wire to ground with the key on for your reading. The test says it should be over 10 volts. The voltage you are reading is what is coming through the primary winding of the coil. With no load on the circuit, the voltage you read should be the same or very close to the voltage you read on the "+" wire.

    What you are calling in fig 13, step 5 is step 4. Connect a 12 volt test light between the Tach Terminal and ground. The Tach terminal is exactly the same connection as the "C" wire, the "load" side of the coil. They call for the light to be steady when you crank the engine, to verify that there is no votlage drop across the primary coil as it is firing. If there IS blinking of the light, that means the primary has voltage drop everytime it has load placed on it, which means the coil is bad. An ordinary 12 volt test light will work for this, the most common electrical tool that there is.

    About the serpentine belt, the belt on my 97 used to make noise and would slip a little when it got wet, yet it looked ok. I put on a new belt, the the difference was like night and day, it's been perfect now for 4 years, no noise, no slip.

    Good Luck,
    E.D. ISF
  • Well: I went through the guidelines in fig 13(fig 11 is for the 4cylinder) and approached from a "no spark" as oppossed to low spark because in box No.1 it says..."a few sparks and then nothing is considered no spark." Got a big spark from the ignition coil even with insulated tools. Reolaced rotor that was cracked. Got more than 10 volts from "c" and "+" but got 1-10 with tach lead to ground which indicates to replace module. Well I took your advice and had mine checked and it passed so I'm thinking maybe passing still does not mean able to do its job fully but I regreased mine...frustratted at this point and thinking of just getting a new distributor but I continued to put the parts back to gether and redo some of the tests. Specifically the crank test in step 4 fig 13 and the engine sounded like it wanted to turn over. I hooked all the wires back up and doggone if it didn't start. Purring like a kitten. God only knows cause I don't.
    Now mind you I had started pulling wires off to take off the intake plenum so it ran with the TPS and MAP sensors disconnected and I think it caused some codes; the Chk engine light is on now so I hooked them back up but the light is still on. I'll watch this. I did have a couple of plug wires crossed and after rearranging them the engine smoothed out. The saga continues but for now I see a bit of light....Thanks so much to you my friend. Oh; got a drive belt for the wifes' V8 Explorer.
  • Figure 11 is for the 4 cylinder engine, but the electrical drawing is the same, the pickup, module and coil and wiring is basicly the same for all of them.
    I know why the engine started, it's because of one of two things:
    1. either because you replaced the cracked rotor (it could have been leaking off the high voltage)
    2. or removing the module and replacing it could have cleaned and refreshed it's connections (it could have had resistance or corrosion in the connections to the module).
    Wow, So ends the Saga of the GMC Safari Van that wouldn't start! That was quite a lot to go through to find that problem, as we have been at this for over a week it seems? I'm glad the effort paid off, I was sure it would start, I was just hoping it would start before Christmas, So let this be a Christmas present to you! Stay in touch.
    Merry Christmas & Happy New Year,
    from Electric Designer In Sunny Florida
  • I would agree that refreshing the connections make sense because out of habit a cleaned them a little with a screwdriver before putting it back together. The cracked rotor also as well possible.
    Wow is right but I sure learned a lot and goes to show two heads are better than one. I need to do a top end clean of this van but I am glad you suggested I hold off on the fuel investigation. I am hoping that by having the intake and throttle body extension off while running the engine is what gave those TPS and MAP sensor codes and that once I get everything put back together they should reset. I'll check those circuits anywaay just to be sure.
    Hows your residential electrical? I get the idea you're an electrician. I need to install a couple of outlets in the new basement. Do they have a forum for that? I amrodslack@mindspring.com if not.
    Happy Holidays to you and yours!!
  • Your Welcome and Merry Christmas
  • i have a 95 safari that just quit. it will turn over but wont start. replaced the feul pump and steering column checked the fuses and pump relay. now for the funny part everything works execpt for the fuel pump head lights and interior lights. did a test on the wiring at the back of the fuse block and found that a fuseable link wire was testing as grounded. if i jump power to the fuel pump fuse it will start any ideas would be nice as it is my grandparents van and they are handicapped thanx
  • That fuseasble link is testing as grounded because it IS connected to GROUND THROUGH THE LOAD. The problem is you have lost your SOURCE of POWER to that FUSEABEL LINK. Go back to THAT point and toubleshoot from THAT point, UPSTREAM towards the BATTERY and you WILL find your problem. Being that all the lights are out and the fuel pump is out, the problem must be at a major connection towards the battery, and because this fuseable link carries so much load, it must be electrically near the battery, drawingwise. In other words, the fuseable link is usually connected very close to the battery, so you must be close to finding the problem.
    Good Luck,
    E.D. In Sunny and Warm Florida
  • i'm having the same problem, and i replaced the fuel pump and fuel relay and fuel filter, but when i replaced the fuel pump it ran for 1 day and now won't start any suggestions?
  • I have a 1990 astro with the exact same problem I have carbon cleaned,changed the fuel filter,fuel relay,temp.control valve,injector cleaner I can't figure it out have recieved any advice? :confuse:
  • Happy New Year! well the van came in handy moving and as such I am still in the mode of unpacking . The van broke again on the last mode. I thought it was "skipping" and my first thought was the distributor was somehow not aligned properly(I removed it to check it during the last diagnostic...wish I hadn't now. It was marked and seemed to align back up to the marks I had for guidance and it crank? ) but if so it would not have crank at all...am I correct? Nevertheless the OBD1 showed TPC(throttle position sensor), MAP and IAC sensor codes. Both the MAP and IAC sensors have been manually cleaned and were chunk full of deposits and thus it still broke again. Does it appear as I should start changing out these sensors or does it appear that something in the timing may be the culprit..your thoughts as always appreciated.
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