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GMC Safari/Chevy Astro Starting/Stalling/Idling Problems



  • I've been chasing this phantom for 4 months now. My Astro will start, run for a few seconds, then die. I finally got a TBI fuel tester, hooked it up to the left line right before the throttle body, and did not get any measurable pressure reading. This could be good news? My next step is to hook it up where the manual says to, which is right before the fuel filter. If I get good pressure there, then I know my tester is working, and that there is a problem between the fuel filter and the throttle body (blocked line?). If the pressure is not good before the filter, then I will know it's time to drop the tank. A few months back I had a dealer install a new OEM pump which I provided. That replacement did not solve the problem. Stay tuned.
  • Hmmm. I don't know how the fuel pressure regulator is set up in the 93 TBI or if it even has one but... if it does have a fuel pressure regulator (probably does), and it is malfunctioning, you could get the same low or no pressure reading. It might be worth blocking the fuel return line if you get low/no pressure before the filter just to make sure the fuel is not possibly recirculating back into the fuel tank without any resistance from the fuel pressure regulator. Just a thought. It might save you the trouble of dropping the tank. Unless the regulator is actually built into the fuel pump assembly.
  • bda54bda54 Posts: 8
    My 96 safari 4.3 vortec won't start when the temps get into the 20's or higher temps and it is humid. It will crank but then hesitate about every 3-4 seconds and then repeat this behavior, but will not start. If I hold down the accelerator, it will not do the hesitation but will backfire sometimes. It's almost like the distributor cap is wet inside and shorting accross to misfire on the wrong cylinder sometimes, when I try to start it. It's 36 degrees today and raining and I tried to start it and the same thing. Any suggestions. I don't want to start blindly replacing parts as I guess at the fix. It has about 135M miles on it.
    Thanks in advance for any suggestions!!
  • I have had alot of these 4.3 problems frustrating I know until I fiquired out the most common problem with this engine. It seems to be always the cap and rotor. no matter if its only 3 months old. I think it has to do with where it position on the engine they get hair line cracks and cause the miss fire affect when trying to start
    Replace cap and rotor.and plugs and wires if they haven't been changed in awhile. Let me know if this solves the problem
  • bda54,
    That sounds like the same issue a lot of us including me are having here. I have already replaced everything in the ignition system, checked the EGR valve, replaced the fuel pressure regulator, and checked the injectors for leakage but I'm still having this issue so even though it seems like some sort of ignition problem, I have to believe that it is something other than ignition. I rented a code reader from AutoZone for free. The current readings I'm getting are related to certain O2 sensors. I'm debating weather or not to replace them at this point but if I want to drive the van it seems that I don't really have much of a choice.

    The thing about getting information on the O2 sensors is that the vehicle has to run for about 5 minutes or so before you start getting feedback on the sensors. You said that if you hold down the accelerator, then you could keep it running although it backfires. My advice is to rent a code reader before you replace anything. You will probably get what I'm getting, "Multiple misfires in random cylinders" and it should narrow down which O2 sensor(s) is malfunctioning if any. Maybe that's the cause of the symptoms. Please let us know what you find either way. Thanks.
  • when did you replace the cap and rotor? the car will start with a bad o2 sensor
    replace the cap and rotor..!! I dont care if it is 1 month old or 5 months old or 1 year old they go bad because of the place they are located on the engine
  • Brand spankin' new OEM. Actually I bought two because the first one was not OEM. I thought maybe the aftermarket cap might be causing a problem but as it turned out, that wasn't the case. All the parts I have replaced have zero miles on them because the piece of crap is undrivable. The engine will start and run, it's just that it idles extremely rough, and if you give it gas it chokes and pukes. If I try putting it in gear and give it a little throttle forget it, it sounds like the engine is going to self destruct.
  • bda54bda54 Posts: 8
    I just replace the cap and rotor yesterday afternoon and she runs great. I suspected that that might be the problem, but it seemed too straight forward. I bought the NAPA upgraded cap and rotor made by Ecklin. Thanks for the advice. Also I noted that your user name is dakota4x4. I have a 03 dakota quadcab. I love the truck. I just wish I could get the city driving mileage up a little. I get 18.2 mpg on the road loaded with camping and hunting gear, but I only get 12.5-13.0 mpg around town, even combined with freeway around the cities. Anyways, thanks again for the info regarding my Safari. Have a great day.
  • Thanks Steve. Your problem description matches mine. My Haynes manual has a pretty good trouble shooting section for the fuel system. The fuel pressure regulator is on the 1993 Z-motor TBI assembly. When I get more time to work on it, I will verify that the left line is the fuel supply line, and the right line is the tank return. Another thing to check, if you have a later model (i.e. Vortec) Astro, is whether your fuel gauge is bad. My wife's 1999 (Vortec intake) Suburban died in traffic the other day with the fuel gauge indicating completely full. After we had it towed home, we figured out that the fuel tank was absolutely empty. Now we rely on the trip meter instead of the gauge. My Astro does not seem to be out of fuel, since it primes every time. It will probably be a few weeks before I get to the bottom of this.
  • For those who have been following my posts, I have tinkered with my 1993 Astro for almost 5 months now, could not get it to run. It would start, run rough for about 5 seconds, then die. I replaced the cap, rotor, plugwires, plugs, and fuel filter. Which was okay, they needed it anyway. Then I made the mistake of cutting off the catalytic converter, big mistake. At this point I got the dealer involved, hoping he could help guide me to a solution. He "installed" a new cat for me. His first foray was to replace the fuel pressure regulator. That did not fix it. Then he convinced me to authorize a fuel pump replacement. But that did not fix it. Then he wanted to replace the injectors, I said no. I could not afford his $90/hour rate. I paid him $500 for nothing, had it towed home. I replaced the injector pod, per the dealer's recommendation, still did not fix it. I noticed he simply clamped the new cat up, did not bother to weld it, big air gaps near the O2 sensor! Over time I also replaced the IAC valve, the fuel oil pressure switch, the coil, and the ECM/PCM; all unnecessary. Then it sat through another hard winter here in Ohio. I finally decided to look at the fuel pump work that was done by the dealer today. When I got the fuel sender assembly out of the tank, I noticed that the dealer had shoved the old torn clogged fuel screen onto the new fuel pump. Pretty shoddy work. Then I noticed that the dealer did not use the short section of fuel hose that comes in the kit, but instead used the original hose, which connects the pump to the main fuel line. When I touched it I noticed it was crumbly, most likely the source of the black specks that I found in the first fuel filter I changed. When I pulled it (the crumbly short foam fuel hose) off the dealer installed fuel pump, I noticed it had a big hole in it!! Actually it looked like a slit. I bought a new pump, a new fuel screen, some fuel hoses, and reinstalled the fuel pump assembly correctly, tank, etc...I added some gas, charged the battery, put the dog house back on, installed the computer and trim panels, dejacked the Astro. She started right up, purred like a kitten. Problem solved! So the original problem was a hole in the short section of fuel hose between the fuel pump and the fuel line. I also replaced the fuel relay connector since it was melted, probably from a fuel pump that was working itself to death. I'll have to have a local welder seal the cat forward of the O2 sensor. I may write a letter to the dealer complaining about the shoddy work of the service department, but in this economy, I don't want to get anyone fired. I hope the Astro returns to its trustworthy self.
  • NOT!! I drove this beast to town, it died after about 50 miles! When the tow truck operator picked it up the next day, it started right up. When he dropped it at our house he demonstrated that it would start right up. I changed the fuel filter again this morning, thinking the fuel tank work had stirred up a lot of dirt. The van started and ran fine for a few minutes, then died. Now it won't start. The tow truck guy thought the crank sensor could be losing it, giving good signal when cold, and then going bad when hot. I suppose I could blindly replace another perfectly good part? I can't believe this van.
  • We all feel your pain brother. These vans are fricken unbelievable. I'm tired of throwing good money after bad on mine, not to mention the time involved. If I hadn't lost my job back in January, I think I'd finally give up on mine. About the only thing I haven't replaced are the O2 sensors and catalytic converter. Oh ya, and the fuel injector unit, although I tried one of the new style multiport fuel injector "upgrades" but there's no way it fits. The hoses kink when you try to fit them into the intake manifold. Anyway, I guess we all just keep plugging away. Maybe Obama will provide us all with new Astros! Uhhh...yaaaa....
  • Well,
    I went another round with the Astro today, and lost. I could not get it to start, no spark. I re-investigated a relay next to the fuel relay that looked like it might have cooked in the past, replaced it with a new one I had sitting around, and the damn van started. While it was running I wiggled the wire harness to this unnamed relay, it might be for the ac/heater blower, and the van stumbled a little. Then I closed the passenger door and it died. It would not start after that. It's too cold to work on it any more today, but I suspect the computer is not properly grounded? It is right there next to the passenger door hinge. I checked the resistance(s) of the coil, all 3 tests were nominal. I suppose I'll need to pull the computer out and see if there is some ground strap that I did not reinstall the last time I pulled it out. This van does not want to serve. The good news is that I think I have fixed all the fuel issues I was having. Now I just need to find this electrical bug.
  • I finally vanquished the Astro's problems. After fixing the fuel issues, which you can see from my previous posts, I went after the sudden loss of spark. I took the ignition module to the auto parts store, had it tested. It failed. I replaced it yesterday, and the van is running just fine.

    In summary, I had the following failures in order of appearance. The first thing that happened in September (5 months ago) was I jump started the van, and melted the 4 prong connector behind the battery. I fixed it, then went on a long road trip. When I got back the van died. Basically no fuel pressure. I replaced the fuel filter, which was jammed with black flecks, and but that was not the problem. I had the dealer replace the fuel pump, but he did it incorrectly. I discovered later that the short (2" long) section of hose between the pump and the steel line had a hole in it. The dealer had reused the original hose on the new pump, and thus the new pump delivered fuel right back into the tank! It was also the source of the black flecks which jammed my fuel filter. I found that the electrical connector to the fuel relay was badly melted, and replaced it. It may have overheated from a fuel pump that was overworked. The last problem was an intermittent ignition control module which finally failed hard. None of these problems were detected by the computer, which is probably why so many shade tree mechanics like myself have such difficulty finding them. I do hope the Astro will ride for many more miles.
  • keicokeico Posts: 4
    Ok so after many months of using carb cleaner to start the car, It finally gave out in the McDonalds Drive Thru.

    It just stalled and wouldn't start.

    After towing it home, I couldn't hear the fuel pump engage at all.

    So I dropped the tank, and rebuilt the pump. Low and behold she fired right up

    As far as the the fuel filter, I cut the lines and used a fuel line repair kit, so i could install the the new filter.

    I will say this much. This was no easy job. The bolts that the secure the fuel tank straps were rusted and would not bulge. Two of them would not budge. So I had to cut the straps.

    Anyway I ordered new straps and am in the process now of cutting into the floor to install some new bolts.

    Removing the fuel lines that run from the tank (Which are suppose to be quick connect) was very time consuming. There was a lot of rust buildup.

    I am just happy there were no fuel leaks.

    Anyway by tomorrow i will finally be finished and back on the road
  • steverstever Posts: 52,683
    I haven't been following this thread, but sometimes you can get a balky fuel pump working temporarily by banging on the fuel tank with a rubber mallet or chunk of wood. It helps to know the "right spot" to bang on.

    But that trick saved my neighbor a tow with his Aerostar last summer.

    Steve, visiting host
  • Steve_01Steve_01 Posts: 42
    I replaced the crankshaft position sensor and now the engine seems to run better, but still not good. Now instead of all the misfiring, choking, and puking, it just seems to be a bit underpowered. Before replacing the crank angle sensor, if I would give the engine a little throttle, it would sound like it was about to self destruct. Now it runs much better but it has a stumble and/or hesitation and runs smooth at a constant RPM. I believe the crank angle sensor was definitely part of the overall problem. I just ordered 6 new separate injectors and am going to rebuild the injector unit myself. About $150 for a set of brand new, not rebuilt, injectors. I'll let you know how it goes...
  • Dear shortline,
    Did you find the answer to why your astro dous not have lights or fuel pump? Please reply, thanks.
  • Steve_01Steve_01 Posts: 42
    A quick update...
    The injectors made a huge difference. I'm definitely headed in the right direction. The issue I'm having now is that the catalytic converter and at least two O2 sensors are bad. The engine is running rich due to the inaccurate information being sent from the bad O2 sensors. You can actually hear the fuel-rich exhaust combust in the catalytic converter. It sounds like a loud one time knock (not engine ping) intermittently. I have a new catalytic converter and four new O2 sensors on order from AutoZone, a little over $300 total. I'm praying that this will be the final piece of the puzzle. I'll have another update after I get the new parts installed.
  • mochajavamochajava Posts: 2
    I have a 03 GMC Safari. When I try to start it it acts as though it is flooded and won't start? There is fuel and the pump is working. Help
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