96' Discovery with two codes

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Manofspacebob

Active member
Aug 11, 2009
35
0
North East
Hello everyone,

I recently purchased Stu454's 1996 Discovery 1 from slowfiveo. Long story short to get this vehicle inspected in Rhode Island I need to have NO check engine lights on. The code the that is being thrown is P1176, P1179. I have done some research on this forum and pirate.

Initially, I had believed it to be the MAF, 02 sensors and vacuum lines. I purchased an aftermarket MAF and installed it but the vehicle ran worse and threw the same two codes. Cleaned the original MAF, reinstalled it and the vehicle ran smoother but still threw the same two codes. Checked the vacuum lines and everything appeared to be connected. According to stu454 and his paper work he had replaced the front two 02 sensors a couple years back. (atlantic british has no MAF's remanned or otherwise in stock either...)

What am I missing? This is my first discovery and a very maintained one at that. Could this be the charcoal canister or perhaps the fuel injectors? Or are both of my MAF's not functioning as I have read some of you post before.

Any guidance would be awesome...and as is expected feel free to insult my overall newness at this lol.

Kind Regards,
C
 
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Manofspacebob

Active member
Aug 11, 2009
35
0
North East
*Update: Early yesterday morning started the car up and I could smell gas. The smell was pretty over powering. I checked everywhere and could not find gas leaking out of any of the fuel lines. The check engine light came back on and the codes were same as before. (p1176, p1179)

In the afternoon, with help, replaced the exhaust from "Y" pipe back. The old exhaust clamps were loose right behind the muffler. Upon inspecting the old muffler it turned out to blocked up with debris. Surprisingly, it was the original muffler lol. The car runs significantly cooler now but still reeks of gas. I have a charcoal canister/purge valve on its way and dropped it off at a local shop to have them check out the vacuum lines.
 
p m

p m

Administrator
Staff member
Apr 19, 2004
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La Jolla, CA
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The debris were likely from one or both of your catalytic converters.

The gas smell upon a cold start-up is either a massive misfire or rinning very rich.
There are multiple possibilities for the engine running rich; a simple check is to connect a fuel pressure sensor to Schrader valve on the fuel rail. When you turn the ignition on (before starting the truck), the fuel pump should come up, and the pressure should increase to about 35-37psi. In a few seconds, if you have not started the engine, the fuel pump should turn off - but the pressure should hold. If it drops like a rock, you may have a leaky injector.
The codes tell a different story, however.

Running rich has been discussed here a lot, so some fingerwork could take you pretty far.
 
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Manofspacebob

Active member
Aug 11, 2009
35
0
North East
I did some deep searching of the forum thank you.

Small update:

Took the vehicle to an independent repair shop. Had all of the vacuum lines checked and smoke tested. No leaks. They have a proper obd2 that reported a misfire in both banks and now only a lean code. They reported that the O2 sensors were switching and were different front from back. In the process of replacing the fuel pressure regulator but before that checking the fuel pressure at the rail.
 
edthediscoman

edthediscoman

Well-known member
Nov 4, 2005
1,377
0
53
Rivertucky, Ca
My money might be on clogged catalytic converter. If the muffler was full, it can only come from upstream. Having similar issues and when it clogs I drive up a curb to bang out the stuff for a little while, or hit a bump at speed. Works for a little while till it gets more crap in the pipe. Working on replacing them but in Cali that's some cabbage.
 
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Manofspacebob

Active member
Aug 11, 2009
35
0
North East
Checked the fuel pressure to see if dropped as stated below and it didn't plummet at all. However, the readings on the gauge were double what the pressure should be. Perhaps the misfire readings on both banks? Blew out the return fuel line and replaced the fuel pressure regulator with a new one. The pressure was ever so slightly below what they should be.

Is the fuel pump on its way out?
 
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