1993 Chevy Van Running Rich trouble code 45

Tiny
KACZMO
  • MEMBER
  • 1993 CHEVROLET VAN
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 270,000 MILES
Hi,
A couple months ago, my fuel pump went out. I replaced it and also put in new plugs, plug wires, cap and rotor, fuel filter, air filter, and pcv valve. The van seems to run decently, but the "service engine soon" light came on. By jumping the a and b terminals on the diagnostic terminal, I was able to get trouble codes. They are code 44 - O2 sensor (lean exhaust), and 45 - O2 sensor (rich exhaust). I replace the O2 sensor near the cat converter and cleared the codes. The service engine soon light came on again (it doesn't always stay on, it will go off - intermittent). Code 44 no longer comes up so looks like thats taken care of, however code 45 still comes up and the van has a trottle body so there's no way of adjusting air/fuel mixture. It seems obvious that it must be a sensor. Where should I begin? I don't want to just keep throwing parts at it till its fixed. I was adivsed that the diagnostics is OBD1 so the problem can't be pin pointed and I'm afraid that if I take it to a shop for diagnostics they're going to, like I said, throw parts at it till its fixed, handing me the bill. Thanks so much for any help, Steve
Tuesday, November 18th, 2008 AT 3:01 PM

7 Replies

Tiny
JAMES W.
  • MECHANIC
  • 2,394 POSTS
Not knowing how long this has been going on, I can only guess. My first thought is, with 270K on the motor, you could have an injector or 2 that are spraying fuel like a garden hose. The ECM will try its best to maintain the 14 to 1 fuel ratio unless the fuel input is out of range, then you get a code 45. How do your plugs look when you pull them out? This could be an indication. Hope this helps.
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Tuesday, November 18th, 2008 AT 6:10 PM
Tiny
KACZMO
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Hi,
as I stated before, it all began a couple months ago when the fuel pump went out. I had no problems and the service engine soon light never came on until after the new fuel pump. Since then it seems to have been getting progressively worse. As of lately, when I start it sometimes it doesn't fiire up right away, then on the second try, it has to crank over a few times before it catches. Seems to be idling a bit rough too. I'm wondering if the timing may be off a little. Also, I noticed that sometimes when I first start going, it kinda boggs down like it might stall but then doesn't, then its fine. Thanks, Steve
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Wednesday, November 19th, 2008 AT 7:47 PM
Tiny
JAMES W.
  • MECHANIC
  • 2,394 POSTS
Re-reading your previous postings The engine timing is controlled strictly by the ECM. There is no adjustment. I'm thinging your temp sensor may be out of range. It could be telling the ECM the engine is colder than it is. This would create a rich exhaust condition which will trip the "O2 rich" condition. It could be a cheap fix. Try it and let me know.
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Saturday, November 22nd, 2008 AT 12:14 PM
Tiny
KACZMO
  • MEMBER
  • 5 POSTS
Hi,
thanks for your reply. I took the air cleaner assembly off as I wanted to visually inspect the performance of the injectors. The injectors are fine, however I discovered that the fuel pressure regulator is leaking pretty bad, sending excess fuel into the throttle body. Its obvious that this is causing the problem. The part will be in tomorrow. I'll let you know how it goes. Thanks, Steve
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Monday, November 24th, 2008 AT 8:04 PM
Tiny
JAMES W.
  • MECHANIC
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'ATTA BOY, I knew you could do it.
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Tuesday, November 25th, 2008 AT 2:28 PM
Tiny
KACZMO
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Hi,
Hope you had a nice Thanksgiving.
So far so good, no trouble code.
Looks like the fuel pressure regulator did the trick.
Thanks again for your help (and encouragement),
Steve
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Saturday, November 29th, 2008 AT 3:47 PM
Tiny
KACZMO
  • MEMBER
  • 5 POSTS
Hi,
well I thought all was well after putting in a new fuel pressure regulator, but it wasn't very long till the dreaded SES light came on again, same code. I have noticed that it comes on mainly when I'm driving up a somewhat long incline, so when the engine is under a heavier load. Also, in the driveway, when I'm warming it up, it will sometimes blow some black carbon in the exhaust, leaving black splatter markes on the house. Definitely unburned fuel here. The light seems to be intermittent. I'm wondering if, when I installed the fuel pump, maybe I didn't get something sealed properly, causing a fuel system pressure leak. Could this be my problem? Or do you have any other suggestions? Any help is greatly appreciated. Thanks, Steve
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Monday, March 16th, 2009 AT 7:07 PM

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