Intermediate hard start problem
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Intermediate hard start problem
01-31-2004, 11:25 AM
I have a 97 Jimmy with 120,000 miles on it. Recently it began to have starting problems where you would have to turn the engine over 2-3 tims befoer it would start. I have run high octain 93 fuel (mobil, chevron or Amoco) only since new. The ignition system has new plugs, wires, cap, rotor and coil (all delco). There are no codes or check engine lights.
The vehicle runs fine once started with a small % of the time a rough idle will show up while at a stop light (engine cold or hot).
After the hard start proble I cleaned the throttle body with no improvement in starting, however the vehicle did feel as the acceleration was improved. I have also replaced the fuel filter. When I removed the filter I noticed the fuel that remain was almost black in color when I poured it out. I did not see any other obstructions on the screen. Any though as to what created this dark color to the gas? Could the fuel pump be the problem with some part of it breaking down? When I spoke with the dealer I was told they have seen this on ocassions but I need to bring the vehicle in. The problem is I am a retired and disabled police officer with very limited funds. If I take my time I can do a lot of the work myself. I hate to drop $60.00 or more for a check out unless I have reached a total dead end.
I have reasearched replacing the fuel pump and found after market units at Discount and auto zone for $300.00 with lifetime warrantys versus the delco unit for $500.00. I know someone makes them for delco for the GM techs what is you opnion? I believe I can accomplish this job with help from my neighbor and son in lieu of the $1000.00 est I received.
I have not checked the pump pressure yet and will hopefully try to do so this weekend.
Any suggestion or thoughs would greatly be appreciated.
PS I dont know if it matters or not but the intake manifold gasket was leaking and since has been replaced by the dealer
01-31-2004, 02:33 PM
With Black stuff running out of the filter, I would tend to believe that you have some contaminated fuel..I would suggest removing the tank and cleaning it out, replacing the pump and filters and running some detergent (I suggest GM #12345104
Port Fuel Injector Cleaner )
Also, that truck was designed to run on 87 octane fuel...higher octane fuels can cause driveability issues,especially in cold weather.
10-27-2004, 12:03 PM
BTC it sounds like you have the two main systemic problems in the GM class of vehicles with 5.7l engine; CfSI poppet clogging and intake manifold leaking antifreeze.
My 1997 Tahoe has had both (112K now).
I'm in California and GM has agreed to clean and if necessary replace the CFSI with a MFI system up to 200,000 miles.
My problem is only occasional hard starting. I have been using Techron which I understand to be GM P/N 12345104 injector cleaner with some success. Four tank fulls.
I have not completely solved it though. Called dealer and they asked "Is check engine light on? (no) How many miles?" They don't want to do anything without "Check Engine" light on.
Is there a way to remove the poppets and take them someplace to be cleaned ? Or should I just raise a stink at the Dealer ?
The problem is occsional "firecracker" pop at cold start. I would ignore but it's my wife's car and she says it's ready to 'explode' & needs new car !
10-27-2004, 11:03 PM
1.) Get the computer codes scanned at your local Autozone.
2.) Black colored fuel coming out of a fuel filter is normal, that is just the trapped contaminants coming out the inlet.
3.) 1997 is a bad year for the black ignition switch in the steering column. I suggest you go over to the Blazer section and do a search for it. All the 1997's are plagued with this problem. A $25 switch and all is well.
4.) Remove your MAF sensor and spray brake cleaner through it so you can dissolve the crap that collect on the sensor filaments. Again, this is a problem with the 1996+ 4.3Ls.
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