Our 1999 Chevy Truck looses power after the engine warms up. We have changed the knock sensors, o2 sensors, catalitic converters, and the fuel pump relay? What are we missing?
Have you had the s10 scanned for the DTC codes. Auto Zone scan free of charge and this should help figure out why your loosing power when the engine warms up. You could have a faulty MAP sensor or a weak fuel pump, dirty fuel filter.
Not knowing what has been done, here is a few things you can do and check.
You may be weak on fuel pressure, even a couple of lbs low on fuel pressure can cause low performance.
Double check cold start cranking fuel pressure. If under 63-62 lbs you have problems. Run the full fuel pressure test and post back pressures.
Here is the guide lines on testing.
Check cold start fuel pressure.
Check engine running fuel pressure.
Check engine running on the road fuel pressure.
Then shut it off and watch for fast leak down.
Pinch off at rubber part or block off return line and check full pressure.
Later V6 and V8 gm engines should have 60-66 fuel pressure.
Cold start should be 64-65 lbs of pressure.
If you do not have full fuel pressure on a cold start the injectors will not squirt fuel.
Engine running should be 60-66 lbs pressure depending on engine load.
Full pressure with return pinched off should be 75-85 or more.
And if it has a fast leak down after shut off you have a leak.
Post back fuel pressure readings.
The 75-85 is only a check on the capable full pressure of fuel pump.
If you can not find the rubber return line check full pressure by
plugging return line or just or the true full pressure can be taken
direct at the end fuel filter.What are the pressure readings that you have done.
What are your cold start pressure readings?
You need 3 things.
Good hot blue spark to all plugs.
Good gasoline and proper fuel pressure. 63-64 lbs.
If you have all 3 then move on to injector pulse to all injectors.
I think each injector is on a separate driver on that one.
Check for pulse to all of them.
The next thing you can look at is the Cap and Rotor, inspect for any damages and corrosion which is common to accumulate in the distributor due the a clogged vent screen at the bottom of the distributor. That is where is ICM is located also and my be on it's way out and needs to be replace.
Best thing to do is check for any DTC codes at Auto Zone and that should help determine what is causing your loose or power. A bad fuel pump and dirty fuel filter will not trip any DTC codes.
Start with the simple and check all the fuses, the wire leads to the MAP sensor, it's located on the passenger side on the intake manifold by the throttle body. Check then check the distributor Cap and Rotor and replace, check the fuel pressure reading, and almost forgot to check the MAF sensor.
Try this in the mean time, turn you ignition to the run position "engine not running" and pull the fuse to your ECM for 1 min and place back in. Turn your ignition off for 5 sec and turn on again for 10 sec and then start the engine. It may stall out, let it. just start it again and let idle for 2 min and go for a test drive. This will reset your ECM to default and relearn all the sensors on the engine and transmission. Any DTC codes will have been erased and any DTC codes will be new to the issues your engine is having. Good luck and keep me posted, be glad to help you get your S10 running 100% again soon.
Jan 26, 2010 |
1999 Chevrolet S-10 Pickup