I recently bought a 2000 Sonoma 2.2 litre 5 speed. It has been running perfectly for a month or so. Today suddenly it began running rough missing and huffing black fuel smoke. It threw a service engine light which is sometimes steady, sometimes flashing. If I wind up the motor to about 4K if will take off and rev on with full power. At anything below 4K it misses and has no power. I took it to Advance Auto Parts to read the code and they said misfire cylinder 4 and open circuit fuel injection system. They did not know what this all mean't, anybody got a clue? I'm on a really tight budget right now and hate to put it in the shop and be robbed.
Help rough running Sonoma
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Molson02536
New member
Please post back your DTC codes, be glad to help you address your issues. There is just to many things that can cause this.
Please post back your DTC codes, be glad to help you address your issues. There is just to many things that can cause this.
Sorry but I don't have the codes as the handheld scanner used was at an Auto parts store. They only gave me the code definitions not the actual codes: 1. Misfire cylinder 4. 2. Open circuit fuel injection system.
I started it today, it is dumping so much fuel it is spewing liquid fuel out of the tailpipe. I'm guessing maybe it's a fuel pressure regulator gone haywire.
Molson02536
New member
Don't think it's the fuel pressure regulator, the fuel in the 2.2 liter is external on the fuel rail to the fuel injector. The injector pulse is to long causing your injectors to dump to much fuel in to the engine. Here is a link to your fuel system on your 2.2 liter vortec. number 535 is your cacuum line to your regulator. http://www.compnine.com/index.php?u...delid=7078&capuid=1&majorgroup=03&grouptype=B
Number 2 is your fuel pressure regulator http://www.compnine.com/index.php?u...delid=7078&capuid=1&majorgroup=03&grouptype=B
Auto Zone scan free of charge also.
Does anyone have a exploded view of the intake manifold plenum. You absolutely can not see where it bolts onto the head. I have removed 5 bolts, the nuts off 3 studs, and an alternator support. It still won't come loose I have looked and felt all over it and can not find any other fastener. Would like to see a diagram to make sure I haven't overlook one somewhere, my manual doesn't show this.
Molson02536
New member
Here you go and good luck.
http://www.compnine.com/index.php?t...=S&makecode=LG&grouptype=B&modelid=7078&uid=1
Thank you Molson
Ok, an update. I acted on advise via a certified GM tech on ask.com. I replaced the #4 injector, the fuel pressure regulator, and the intake gasket because it looked rough. It changed nothing, $150. and lots of time and effort for nothing. A new developement I noticed, the oil level is a quart high, thinned, and smells like gasoline. I'm clueless and wheeless now, guess I'll call a wrecker and take it to the dealer.
Molson02536
New member
Don't call it quit just yet, yes it sounds like you have fuel dumping in to your engine, pull the plugs out one by one and let me know the condition of each plugs from cylinder 1 to 4 and post me back. Did you try cleaning the EGR valve and MAF sensor??? Also would not hurt ti try giving your Sonoma a Seafoam treatment with two cans.
http://www.seafoamsales.com/
http://www.youtube.com/watch?v=NI9pNtUxXy0&feature=related
At wost I'll buy the Sonoma from yha
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Sorry but I'm fed up. I just took it to the GMC dealer, I hated to but it's costing me money not having a work truck. I already cleaned all the sensors and connectors(contact cleaner)except the O2 sensor in the exhaust. I also cleaned the whole intake system and throttle body, while everything was all apart.
Molson02536
New member
Keep us posted on your new toy and sorry you had to get rid of the Sonoma.
Oh no, I didn't sell it. I took it to have a diagnostic evaluation done.
Molson02536
New member
Cool keep me posted on what they have found and hpe it was something simple we missed that will not cost to much to repair.
Cool keep me posted on what they have found and hpe it was something simple we missed that will not cost to much to repair.
I will. Me and you both, pennies are tight right now.
Ok, I got the news over 1400 frick'in dollars. Bad ECM sending a bad pulse??? Bad injector, what another one, they all ohmed out the same. Bad O2 sensor.
I don't buy it, I'll go get it and pay the diagnostic fee. I can believe the ECM is bad maybe causing the fuel injectors to go W.O.T. then all the raw fuel freaking out the O2 sensor. The reason this seems probable is it runs good at full throttle above 3 to 4 K.. Anyone know where to get a cheap rebuilt ECM that can be properly flashed for my truck????
I don't buy it, I'll go get it and pay the diagnostic fee. I can believe the ECM is bad maybe causing the fuel injectors to go W.O.T. then all the raw fuel freaking out the O2 sensor. The reason this seems probable is it runs good at full throttle above 3 to 4 K.. Anyone know where to get a cheap rebuilt ECM that can be properly flashed for my truck????
Molson02536
New member
A way too reset the PCM is open the engine fuse box and remove the ecm/ecu fuse with the ignition key to the on position "engine not running" for 2 min and reinstalling it. After resetting start car/truck and let idle only do not touch anything during a 10 minute idle period.
NOTE: I am not saying this is the only way to reset the ECU. I understand there are many other ways but I have found this way to be easiest and, most importantly, the safest. consult your manual for proper fuse locations.
Start up the car and let it idle for about 10 minutes. Don't hit the gas pedal during this time. The engine may stall but let it and just start the engine again, this time allows your ECU to make new data based on how much air it sees coming into. Use this time to reset your radio stations and clock. After 10 minutes is up, turn the car off.
That's it, you're done. Once you start the car up again, the ECU should be aware of the changes to the motor and good luck. Worth a try at this point and here is a link to where you can get a ECM for your Sonoma or you can try the local salvage yard, average price there is $50.00 with warranty.
http://www.autoecmecu.com/gmc-ecu-ecm.html
I will try that reset, thanks. Also I talked to a guy with a remanufactured ECU company who said you cannot just swap with any ECU. He said the ECU must be reflashed with very specific vehicle info that pertains to many certain things including your exact odometer reading etc. He said if you hook one up that gets contradictory info it will go into a "limp mode". Does this sound true to you?
Molson02536
New member
That is correct, but does not apply to your Sonoma. There is a part number on your ECM which you have to match up to ensure the ECM is for a 2.2 Liter engine and not the 4.3 liter V6. The only thing is that when a Scanner is hooked up to your ECM, the Vin identification and PRO code burned in the used ECM will not match up to your Vin number and PRO code on your Sonoma unless you have it flashed with your information. As for the odometer reading, it will not change. The odometer reading is held on the odometer it self, the newer vehicle with electronic dash are the vehicle that need the new ECM flashed to rematch the odometer reading.
I have a 1996 Jimmy and the HP tuner i have don't support the 1996 ECM, i had to get creative and use a 1998 ECM with the 2001 binary program to have the ECM run my Jimmy and to be able to use my HP tuner to do a custom tune.
Have the Sonoma rescanned at Auto Zone for the DTC codes, Auto Zone scan free of charge and see if there are any new codes after you reset the ECM by pulling the fuse. Keep me posted.
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That is correct, but does not apply to your Sonoma. There is a part number on your ECM which you have to match up to ensure the ECM is for a 2.2 Liter engine and not the 4.3 liter V6. The only thing is that when a Scanner is hooked up to your ECM, the Vin identification and PRO code burned in the used ECM will not match up to your Vin number and PRO code on your Sonoma unless you have it flashed with your information. As for the odometer reading, it will not change. The odometer reading is held on the odometer it self, the newer vehicle with electronic dash are the vehicle that need the new ECM flashed to rematch the odometer reading.
I have a 1996 Jimmy and the HP tuner i have don't support the 1996 ECM, i had to get creative and use a 1998 ECM with the 2001 binary program to have the ECM run my Jimmy and to be able to use my HP tuner to do a custom tune.
Have the Sonoma rescanned at Auto Zone for the DTC codes, Auto Zone scan free of charge and see if there are any new codes after you reset the ECM by pulling the fuse. Keep me posted.
Oh, I haven't done anything yet, just unhooked the battery. The service dept. said #4 injector was bad again. What thu_____, I put a brand new injector on at #4 position. I think the ECU is messing it all up. I looked under my glove box and found what I guess is the ECU, it just looks like a massive electrical junction with a bazillion wires to each side. I'm going to try the reset before I go any further with anything.,,
Molson02536
New member
Your ECM/PCM is located in your engine bay on the passenger side fender for the 2000 Sonoma. Inspect your wire leads to the fuel injector, ensure that the ground wire is not grounding out on the #4 injector. Try running the engine with out the #4 fuel injector lead wire, not connected and see if there is any changes to the engine's Idle.
There should be a change in the idle and, we may get luck to find that it's just a simple ground wire that is grounding out causing your #4 injector to run rich which should mean your ECM is good.
http://www.compnine.com/index.php?u...delid=7078&capuid=1&majorgroup=03&grouptype=BRemove the injector electrical connector, turn the key to the on position without starting the engine. This test will tell you if the computer has proper system voltage and injector trigger signal. Remove an electrical connector from a fuel injector. Probe both sides of the connector with a grounded test light or multimeter (voltmeter). Set the voltmeter to DC voltage. Have a helper turn the key to the "on" position without cranking the engine and observe.
The test light/voltmeter should illuminate/read one side of the connector. The multimeter should read about 12 volts. Next, switch the test light or multimeter (voltmeter) lead (black) or to the positive side of the battery to test the system ground injector trigger. Disable the ignition system so the engine will not start (disconnect ignition coil or remove the ignition fuse). Probe the side of the connector that did not light up in the previous step, have a helper crank the engine over and observe the test light, it should blink on and off or the multimeter (voltmeter) should bounce from 0 to 12 volts. (Note: if no injector pulse and there is a constant 12 volt, there is a short in the ground injector trigger) Moisture can cause the injector connection to short circuit. Always inspect and clean all electrical connections at the fuel injector.
Keep me posted
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