2002 Chevy Venture hesitates upon acceleration really bad f

Tiny
LCDOUCE
  • 2002 CHEVROLET VENTURE

Engine Performance problem
2002 Chevy Venture 6 cyl Front Wheel Drive Automatic 89000 miles

spits and sputters while you press on the gas. Idles fine. When sitting parked, if you press the throttle, it runs choppy. Only does this for a little while when driving after the van has been sitting overnight. Once running a while, it runs good. All O2 sensors and catlytic convertor have been changed. Is this fuel pump Problem?

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Friday, August 1st, 2008 AT 4:45 PM

16 Replies

Tiny
RASMATAZ
  • MEMBER

Could be fuel pressure, throttle position/MAF/MAP sensors and the EGR valve opening too soon-problem

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Friday, August 1st, 2008 AT 4:51 PM
Tiny
AMBRYATIM
  • MEMBER

Not to "thread jack" But, I too am faced with the same problem. My friends van is doing the exact same thing. 2003 Chevy Venture 4.3 V6 roughly 163,000 miles. But, everytime hers hesitated it would log a DTC of P0420 (Cataylist Effiency Below Threshold Bank 1)

She could let it warm up for about 20min and it would drive fine all day.

So, I changed the Cat Conv and the O2 sensor behind the cat. It was fine for about 3 weeks, then hesitated again and logged the same DTC P0420, but went away. I did notice that she has a small exhaust leak and it is getting worse. Could this also cause the P0420 code?

We then it alsmost died on her, the battery light came on for a second and then went out. She revved the van and then drove home. Tested the battery and found it to be bad installed a new battery and will wait and see if she has anymore problems.

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Monday, August 4th, 2008 AT 12:04 AM
Tiny
RASMATAZ
  • MEMBER

I did notice that she has a small exhaust leak and it is getting worse

False" air can enter the exhaust through leaks and upset the O2 sensor readings

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Monday, August 4th, 2008 AT 2:56 AM
Tiny
AMBRYATIM
  • MEMBER

Would the exhaust leak cause it to hesitate?

She drove the van this morning and it gave her troubles for about the first 20min of driving. (But, also during the hesitation period it never logged a code and the light MIL never came on). After that it drove perfectly fine all day with no hesistation.

I dont think it is the fuel pump due to the fact that if she lets the van warm up for about 15mins then dirves it, the van works flawlessly. So, I am still a little frustrated and any help is greatly appreiated.

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Monday, August 4th, 2008 AT 9:50 PM
Tiny
AMBRYATIM
  • MEMBER

Wouldn't all of these set a DTC? I have worked on one vehicle (99 Dodge Stratus) that had an issue with the EGR valve, but it was with "Insufficent Flow" P0401. But, now on this Chevy Venture I get no codes?

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Monday, August 4th, 2008 AT 10:01 PM
Tiny
RASMATAZ
  • MEMBER

Would the exhaust leak cause it to hesitate? The extra air will cause the oxygen sensor to read lean condition and send this to the computer.

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Tuesday, August 5th, 2008 AT 3:28 PM
Tiny
AMBRYATIM
  • MEMBER

Ok, the exhaust leak is right after the first O2 sensor in the flex joint I will have this repaired and reset the computer and try that out. What about the egr valve would I be able to test it with a vacuum gauge and at what vacuum should it open fully?

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Tuesday, August 5th, 2008 AT 6:54 PM
Tiny
AMBRYATIM
  • MEMBER

So, in essence it would cause the van to run richer than normal right? If it was sensing it was too lean it would logg a DTC correct? Well if so then it is not doing it. As for the MAP/MAF sensors what are there values (vacuum/air flow) at idle? Thank you for all the info.

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Tuesday, August 5th, 2008 AT 7:47 PM
Tiny
RASMATAZ
  • MEMBER

The EGR valve apply vacuum to it-it should stall or idle erratically. MAP voltage

Idle 1.0-1.5volts

WOT 4.0-4.9 volts

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Tuesday, August 5th, 2008 AT 11:37 PM
Tiny
AMBRYATIM
  • MEMBER

Ok, do you know what year GM came out with the "Electronic EGR Valve?

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Wednesday, August 6th, 2008 AT 9:17 AM
Tiny
RASMATAZ
  • MEMBER

I've seen it back then on a 92 GM Truck and 93 Olds Bravada- carbon might be preventing the pintle from closing-open it up and investigate

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Wednesday, August 6th, 2008 AT 4:36 PM
Tiny
AMBRYATIM
  • MEMBER

OK, thanks. I will check it later as of now I installed new spark plugs, hers were all carbon fouled and also they had been hot (nice white color on the electrodes) expecially the ones by the exhaust leak.

I got the exhaust leak repaired and she will be using it tomorrow so I will hopefully know something in the next 24hr. Man, each time I drive it, it works perfect.

Are you familiar with ScanXL?

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Wednesday, August 6th, 2008 AT 8:16 PM
Tiny
RASMATAZ
  • MEMBER

Are you familiar with ScanXL? No sir-you sure the curse is not for you lol-its hard to duplicate a problem at times and patient is not the key word-its something else.

I have a 1994 Bravada-The EGR valve gets plugged top easily with carbon -when you open it is noticeable -recommended fix is to use a screen similar to the faucet sink screen to catch the carbon so it won't plug the hole-

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Wednesday, August 6th, 2008 AT 9:51 PM
Tiny
AMBRYATIM
  • MEMBER

Scan XL is a diagnostic tool made by Palmer Performance. Allows you to data-log and read live data from the ECM.

Now, as for the curse on me, you might have something there.
But, I dont have a problem with patients, my patients depends on how often she calls me and tells me it is cutting out.

So, was your Bravada cutting out/hesistating before you cleaned out the EGR valve?

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Wednesday, August 6th, 2008 AT 11:17 PM
Tiny
RASMATAZ
  • MEMBER

Was your Bravada cutting out/hesistating before you cleaned out the EGR valve??? Yes sir-idles erracticaly big time/stalling/hesitates-Give it a shot

EGR TROUBLESHOOTING PROCEDURE
The following "generic" procedure may help you troubleshoot EGR problems.

1. Does the engine have a detonation (spark knock) problem when accelerating under load? Refer to the timing specs for the engine and check ignition timing. The timing may be overadvanced. If the timing is within specs, check the engine's operating temperature. A cooling problem may be causing the engine to detonate. If the temperature is within its normal range and there are no apparent cooling problems, other possibilities to investigate include a spark plugs that are too hot for the engine application, a lean air/fuel mixture, low octane fuel or too much compression (due to a buildup of carbon in the combustion chambers or because of pistons or heads that have too much compression for the fuel you're using). Be sure you've ruled out all the other possibilities before focusing on the EGR system.

2. Use a vacuum gauge to check the EGR valve vacuum supply hose for vacuum at 2000-2500 rpm. There should be vacuum if the engine is at normal operating temperature. No vacuum would indicate a problem such as a loose or misrouted hose, a blocked or inoperative ported vacuum switch or solenoid, or a faulty vacuum amplifier (or vacuum pump in the case of a diesel engine).

Sometimes loss of EGR can be caused by a failed vacuum solenoid in the EGR's vacuum supply line. Refer to a vacuum hose routing diagram in a service manual or the hose routing information on the vehicle's emission decal for the location of the solenoid. If the solenoid fails to open when energized, jams shut or open, or fails to function because of a corroded electrical connection, loose wire, bad ground, or other electrical problem, it will obviously affect the operation of the EGR valve. Depending on the nature of the problem, the engine may have no EGR, EGR all the time, or insufficient EGR. If bypassing the suspicious solenoid with a section of vacuum tubing causes the EGR valve to operate, find out why the solenoid isn't responding before you replace it. The problem may be nothing more than a loose or corroded wiring connector.

3. Inspect the EGR valve itself. Because of the valve's location, it may be difficult to see whether or not the valve stem moves when the engine is revved to 1500 to 2000 rpm by slowing opening and closing the throttle. The EGR valve stem should move if the valve is functioning correctly. A hand mirror may make it easier to watch the valve stem. Be careful not to touch the valve because it will be hot! If the valve stem doesn't move when the engine is revved (and the valve is receiving vacuum), there's probably something wrong with the EGR valve.

Another way to "test" the EGR valve on some engines is to apply vacuum directly to the EGR valve. Note; This only works on ported vacuum EGR valves, not backpressure EGR valves or electronic EGR valves. Vacuum should pull the valve open creating the equivalent of a large vacuum leak. This should cause a momentary drop in idle speed and a noticeable increase in idle roughness.

Backpressure type EGR valves are more difficult to check because there must be sufficient backpressure in the exhaust before the valve will open when vacuum is applied. One trick that's sometimes used is to create an artificial restriction by inserting a large socket into the tailpipe, then applying vacuum to the valve to see if it opens. Don't forget to remove the restriction afterwards.

4. Remove and inspect the EGR valve if you suspect a problem. Most failures are caused by a rupture or leak in the valve diaphragm. If the valve is not a backpressure type, it should hold vacuum when vacuum is applied with a hand-help pump. If it can't hold vacuum, it needs to be replaced. Note: This test does not work on backpressure EGR valves.

Backpressure EGR valves sometimes fail if the hollow valve stem becomes clogged with carbon or debris. This you can see for yourself. It's almost impossible to remove such a clog, so replace the EGR valve.

Carbon accumulations around the base of the EGR valve can sometimes interfere with the opening or closing of the valve. These can be removed by careful brushing or by soaking the tip of the valve in solvent. Do not soak the entire valve in solvent or allow solvent to get anywhere near the diaphragm. The solvent will attack and ruin the diaphragm.

5. Inspect the EGR passageway in the manifold for clogging. Use a pipe cleaner or small piece of wire to explore the opening for a blockage. Sometimes you can dislodge material that's clogging the opening by carefully poking at it. Other times, it may be necessary to remove the manifold and have it professionally cleaned


http://www.2carpros.com/forum/automotive_pictures/12900_egr_gm_1.jpg

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Thursday, August 7th, 2008 AT 12:09 AM
Tiny
JAHJAHBINKS1
  • MEMBER

After months of saving to buy a new tranny because of the jerking and stalling, backfiring my problem was solved for the mere cost of $ 10.00 the items included 1 can of throttle cleaner and 2 spark plug wires however my total repair cost due to shop fees and people guessing at what the problem might be the cost was $400+ not to mention I cut out my converter and had to have it re installed, after reading countless threads and watching countless youtube videos and noticing alot of the same complaints but with alot of different answers I decided to take this on myself

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Wednesday, September 24th, 2014 AT 11:19 AM

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