• From: Houston, TX
  • Registered: 2012-06-21
  • Posts: 1,608

Topic: Van Problems. Chevy Express 1500

Bob and I have been trying to get this van running so we can sell it from my mom's estate, but we're kind of at the end of our wits. New 350 crate motor was installed last year by someone who is a decent wrench but not good enough for this kind of work. Not sure if it was throwing any codes before, but ever since the swap there have been problems. We cleared a P0101 (MAF code) by eliminating some terrible vacuum leaks, replaced the melted and shorted plug wires that were resting on the exhaust, and when it kept throwing P0300 (random misfire) we replaced the coil as well. Also had the HEI module checked out at AutoZone and it was fine. It ran fine for a minute then started throwing an EGR code(P0404). Replaced the EGR and now it runs even worse and throws a different EGR code (P1404). That's currently the only code aside from P0300. Only thing we can think of is there may be a wiring harness issue, but nothing is obvious.

It's not California, so I'm considering figuring out how to tweak the tune with my HPTuner Pro and just get it to ignore the EGR so it'll run fine and stop throwing DTCs. I'm a total noob with tuning though, so any suggestions are welcome. Set it on fire and run away is already on the list.

Alternatively, ANYBODY IN SLIDELL LOUISIANA WANT TO BUY A CHEVY VAN WITH BRAND NEW GOOD RUNNING 350 MOTOR JUST NEEDS FUEL PUMP RAN WHEN PARKED

Escape Velocity Racing
  • From: Houston, TX
  • Registered: 2012-06-21
  • Posts: 1,608

Re: Van Problems. Chevy Express 1500

Sorry, run symptoms might be helpful as well. Starts up fine although it can be rough to start when warm. Idles fine. Put it in gear and head down the road and it lacks power. As soon as you get on the throttle hard, the CES light starts blinking and it throws random misfire code. With minor variations it has been doing the same thing since we started, just with different additional codes showing. Currently just random misfire and EGR. Although it does run much better with new properly routed plug wires.

Escape Velocity Racing
  • From: Shippensburg, PA
  • Registered: 2010-11-18
  • Posts: 1,963

Re: Van Problems. Chevy Express 1500

What year van?  OBDI or OBDII?

Any chance a critter may have made a nest somewhere that ended up in a bad place?

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  • Registered: 2011-10-14
  • Posts: 4,167

Re: Van Problems. Chevy Express 1500

racinrob wrote:

OBDI or OBDII?

Any chance a critter may have made a nest somewhere that ended up in a bad place?

Express replaced prior GM vans in 1996 so all are ODBII.

The critters both chewing wires and creating a nest in the airbox or intake tube were my first thoughts as well.

  • From: Houston, TX
  • Registered: 2012-06-21
  • Posts: 1,608

Re: Van Problems. Chevy Express 1500

2001, OBD-2. Intake and air box are clean. Could maybe use a new air filter, but I doubt it's bad enough to be causing rough running this badly. Also forgot to mention there is a random ticking coming from the top of the engine, almost sounds like an electrical spark. Seems to go with engine RPM but still fairly random. Maybe arcing under distributor cap? Still wouldn't explain the EGR code though.

Escape Velocity Racing
  • From: Mankato, MN
  • Registered: 2015-03-20
  • Posts: 354

Re: Van Problems. Chevy Express 1500

Maybe stating the obvious but, bad ground?

  • From: Houston, TX
  • Registered: 2012-06-21
  • Posts: 1,608

Re: Van Problems. Chevy Express 1500

Update: replaced cap and rotor since the contacts looked toasty. Needed to be done but no effect on the current problem.

On further test driving, the van is now throwing a code for lean condition on Bank 1 (P0171). Still throwing P0300 and P1404. Engine is also definitely knocking under load, verified by KR showing up on my HPTuner. I seriously doubt this is an O2 sensor problem. Beginning to think we have another big vacuum leak somewhere. I also suppose it could be a defective new EGR, which I'm not looking forward to having to replace again just on a whim. Any way to diagnose EGR valve in car?

Escape Velocity Racing
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  • From: Cocoa, FL
  • Registered: 2010-06-26
  • Posts: 4,055

Re: Van Problems. Chevy Express 1500

Knocking is a big clue for timing.  Tooth off?

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  • From: Pepperell MA
  • Registered: 2009-12-06
  • Posts: 536

Re: Van Problems. Chevy Express 1500

The EGR valve itself is not likely a problem if you replaced it.  They are connected to an EGR valve controller that might be an issue.

One test is to hook a hand vacuum pump to the valve and see if it opens and closes - that shows the diaphragm in the valve is good.  If you put a new one in it's not likely to be clogged yet which is another failure point.

Are the passages in the intake manifold clear?

The other thought:  what info does the computer use to determine a faulty EGR?  O2 sensor readings?  Amount of fuel used?  Sensor on the EGR valve itself?  Finding that info might lead you to the real issue.  Troubleshooting is one place the factory manuals are worth their weight in gold.

Nick
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  • From: Shippensburg, PA
  • Registered: 2010-11-18
  • Posts: 1,963

Re: Van Problems. Chevy Express 1500

I just re-read your original post.  You stated "just needs fuel pump, ran when parked"  Just trying to think of the easy stuff first, but did you put in fresh fuel?

"She's a brick house" 57th out of 121 and 5th in Class C, There Goes the Neighborhood 2013
"PA Posse" 21st out of 96 and 2nd in Class C, Capitol Offense 2013.
"PA Posse" 29th out of 133 and Class C WINNER, Halloween Hooptiefest 2013
"PA Posse" 33rd out of 151 and 2nd in Class C, The Real Hoopties 2013
  • From: Houston, TX
  • Registered: 2012-06-21
  • Posts: 1,608

Re: Van Problems. Chevy Express 1500

Sorry, the all caps bit was a joke. Craigslist ads and all.

Escape Velocity Racing
  • From: Houston, TX
  • Registered: 2012-06-21
  • Posts: 1,608

Re: Van Problems. Chevy Express 1500

Followed a procedure online for making the computer re-learn the new EGR's zero position voltage, apparently that's a common problem when showing P1404 on a new EGR valve. No change in behavior, code comes back on test drive. Was also briefly showing P0405, which strongly suggests wiring problems. Connector at EGR is clean and in good shape, what wiring is visible looks fine. Next I guess I'll go looking for the ECU connectors.

On the knocking front, my scanner shows it bouncing around 15 BTDC at idle. This sounds like way too much. This is also weird because I thought we set this properly with an OBDII reader when she was having issues with it earlier this year, but god knows what's changed since then. I don't remember how we did it last time and I'm having trouble finding exact specs for this vehicle, but most sources suggest around 0 at idle for 5.7L Chevys of this vintage. So it may be as much as a tooth off.

Escape Velocity Racing
  • From: WPB Fl.
  • Registered: 2010-10-27
  • Posts: 1,571

Re: Van Problems. Chevy Express 1500

If I remember the vortec 5.7 is +-2 deg, 0 is the goal, with 15deg it should actually have a "one tooth off"code
Doesn't sound like a EGR

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  • From: Mankato, MN
  • Registered: 2015-03-20
  • Posts: 354

Re: Van Problems. Chevy Express 1500

Are they anything like the older Chevy's where you disconnect the brown wire going to the distributor then set the timing?