Last post on Apr 30, 2013 at 10:37 AM
You are in the GMC Safari & Chevy Astro
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Chevrolet Astro, Fuel System, Van
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#131 of 210 chevy astro 1993 tbi z motor won't run
Feb 07, 2009 (7:04 pm)
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.
#132 of 210 Re: chevy astro 1993 tbi z motor won't run [blackpacific1]
Feb 08, 2009 (2:41 pm)
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.
#133 of 210 96 safari 4.3 vortec, won't start when it's humid
Feb 09, 2009 (2:57 pm)
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!!
#134 of 210 Re: 96 safari 4.3 vortec, won't start when it's humid [bda54]
Feb 09, 2009 (7:31 pm)
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
#135 of 210 Re: 96 safari 4.3 vortec, won't start when it's humid [bda54]
Feb 10, 2009 (10:22 am)
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.
#136 of 210 Re: 96 safari 4.3 vortec, won't start when it's humid [Steve_01]
Feb 10, 2009 (7:43 pm)
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
#137 of 210 Re: 96 safari 4.3 vortec, won't start when it's humid [dakota4x4]
Feb 11, 2009 (9:24 am)
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.
#138 of 210 Re: 96 safari 4.3 vortec, won't start when it's humid [dakota4x4]
Feb 11, 2009 (10:47 am)
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.
#139 of 210 Re: chevy astro 1993 tbi z motor won't run [Steve_01]
Feb 14, 2009 (3:14 pm)
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.
#140 of 210 Astro fuel stall problem solved
Feb 21, 2009 (8:27 pm)
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.