Question about 1999 GMC Sonoma
Re:"truck try to start but,look like not caching all cylinders cause while
crank, if i puhs acelerator to the floor then try to start i remove
plugs they, are wet i clean then reinstall,"
If you are saying that the cylinders are flooding and there is misfire, check the coil packs. This get tested reading Ohms on primary and secondary coils, reading volts in. Ohms on primary coil terminal (B+) must be in range of 0.3-1Ohms, secondary resistance reads between 5K and 15K. There are different kind of coil packs for this engine. Their ratio is always about 90:1, to return 45K Volts. On this one impedances should be 0.2 ohm primary resistance; 6.7 KOhms secondary resistance.
Other way to test coil packs is swapping the two packs in this engine (not swapping spark cables, swapping the modules).
Also do a code scan. If there is misfire this is reported as P03xx OBDII code.
Reading codes you can also find out if there is any rich or lean code detected by the O2 sensor. If car is not starting at all there will be no mixture code reported from O2 sensors, as there is no ignition.
Regarding mixture, if ignition and distribution is OK, check the factors that determine mixture. Check MAP/MAF sensor and IAT sensor. Test starting with new air filter , test with no fuel cap and check the vacuum. If vacuum has a hole it will **** air in the mixture, mixture will be lean, you have pressure but the engine does not ignite even if there is spark.
To test vacuum use the fuel gauge in vacuum lines and spray carb cleaner on hoses, if there is a hole pressure will go up.
If still nothing check and eventually replace the AC delco EGR valve. Valve stuck open is a common failure, car will not start, engine will flood. In that case the mixture is rich.
PS:Please stop telling everybody "if you dont know dont answer" There are two kind of answers, the ones from people who does not have a clue and go for the few bucks, and the one from people that may help you. There is no way to filter them. Most of the answers are from experts but some idio t is also posting. Simply discard the bad ones and stick to the good ones.
You should stick with an expert and keep troubleshooting, not keep arguing.
I know you are discarding everything, and probably going for r., but who cares. I am out of here.
All the best, good luck with your GM engine.
Posted on Sep 16, 2010
Most likely problem is a dead injector driver(s)
you'll need to buy a "noid" light from the parts store
you will install this at the end of the injector harness where it is connected to each injector
then while cranking you will watch the noid light
flashing = good driver
bottom line is....
****, push, bang blow and IN TIME
compression might be good but if timing is off then NO BANG!
Posted on Sep 15, 2010
Check up the Crankshaft Position (CKP) sensor. Replace if necessary.
The best idea is to scan the Engine Control Module (ECM) using a diagnostic tool connected to the data link connector of the car, in order to pull out all diagnostic trouble codes (DTC) stocked.
Posted on Sep 15, 2010
Check to see if there is a crank shaft position sensor and make sure the plug is OK. Consider replacing it, since a faulty sensor/connection will prevent the engine from starting (computer's job).first remove rocker covers so you can see the rockers move.
To check if the distributor is fitted correctly.turn the engine over manually until you know you are the firing stroke on number 1 cylinder.
remove the distributor cap.and the rotor arm should be in line with number 1 cont tack in the cap.If not.. you will have to remove the distributor and line it up so that it is. also make sure that the plug leads are going to the cylinders in the correct firing order Then refit the distributor just place the rocker in place [ just to stop oil going all over the engine] and see if the engine starts.You will of course.have to readjust the ignition timing. Check out.Keep updated.Thanks.
Posted on Sep 15, 2010
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Posted on Jan 02, 2017
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