Hey All:
Been getting 1171 (lean) and 1174 (Lamda) codes in a pair for the past four days. Can clear and it will return about once or twice a day. Truck runs fine...no different.
I sprayed some starter fluid around intake and vacuum lines. The only place I could reproduce an engine stutter was spraying it directly at the brake servo in the intake manifold. Is this piece supposed to be totally air tight or is known to leak a little.
I saw one post where a guy used liquid electrical tape on the red ring to fix some codes from a vacuum leak.

Have new 02 sensors (within6 months) and a new MAF (2 weeks ago). New air filter as well.

thanks for any ideas!

 

Ive been getting a p1171 recently with a pending p1174. This motor was fully rebuilt, all new components. Fuel mileage has always sucked (average 13-15mpg, mostly 13 or less).
The CEL appeared just the other day with those codes. I cleared and the p1171 returned after two drive cycles.
The 02 sensors are of unknown age and the MAF was cleaned during the rebuild.
I looked over all the hoses and connections and all are tight, no cracks, but I didn't gas any -yet.
I ordered both front 02 sensors and a MAF as they are all original and approaching 100K miles (sad, because on our Audi's, nearly everything lasts 2-4x longer than on the Rover).

 

You have a vac leak and yes the broken brake servo could be your problem. When I smoke test my engine no smoke comes out of the brake servo so yes, it is suppposed to be air tight. If the vac line is the part broken then you just need the vac line. If it's the connector in the intake then you will need it also.

Hose - Brake Servo To Intake Manifold - Without Secondary Air Injection (Genuine Part # SQB103300 ) - Land Rover hoses from Atlantic British


Intake Manifold Brake Servo Vacuum (Genuine Part # LZN100220L ) - Land Rover hydraulics from Atlantic British


I have had both these codes twice now. The first time was the intake tube not tight enough and the throttle body. The second time was bad lower injector orings.

In both cases I used my smoke test with a cigar trick to find the leak. Here is the thread I made to show people how to do it.
https://landroverforums.com/forum/di...s-cigar-54235/

 

I had a broken servo ring when I got the truck....got a new red ring and new brake vacuum hose when I installed a new brake booster. So their not "broken" but still leaking air (smoke). I did some RTV around the ring yesterday and it threw same codes today. I taped up the air intake real tight and did the smoke test, fully inflating the glove. Smoke did not come out but I could hear air leaking. Did some soapy water around servo and it was leaking from out the RTV....even though smoke would not come out. I've done a bigger, better bead around the servo again to see if I can stop the leak. Not too sure about using liquid electrical tape (as I've seen on a couple posts) as it's very flammable. We'll see if this stops the air leak. (BTW, tube and red ring hold tight when pulling on it, after installing, but it was still leaking air....?)

 

For smaller leaks I had to put a zip tie over the glove to hold it on the intake so I good blow really hard into the hose. After I did this I was able to get the smoke to come out of the smaller leak. Also, Keep blowing more and more smoke in, even after the glove is inflated.

When you say you replaced the red ring do you mean that whole piece I pictured above, right? If not then that is more then likely why it's not sealing all the way.
When I replaced the same part on my truck I had to hold the throttle full open and hammer it out of the intake from the inside with a long extension. When installing the new piece they send a temporary 1" vac tube that clips in where the vac line goes. You are supposed to keep that vac tube in and use it to tap the new part back into the intake. It is easy to damage the new part on install if you are not careful.

I hope this helps

 

yea...threw codes again tonight. I'll try blowing more smoke in harder tomorrow and see if I can find a small leak. Weird that those codes didn't show up until I changed the MAF and was running the same servo the whole time.

I still have the rest of the servo part I can install if I don't find a definitive answer. thanks

 

update.....did a new smoke test. Everything very tight, glove stayed inflated and got plenty of smoke in system. No leaks visible. Thought I might have seem a fractional leak at joint of throttle body to intake....tightened up bolts. Brake servo not leaking smoke....no smoke could be seen and glove stayed filled with air.

Threw same codes again. Wondering what my next steps should be?

 

I really expected you to find a leak somewhere. I'm kind of at a loss.

Did this problem start before or after the new o2's and MAF?

Are you leaving the MAF on for the test?

Did you buy a bosch MAF?

Is the filter clean and pressed in all the way and the air box sealed correctly?

Do you have SAI?

 

Here's the history of the issue:
1. Offroaded and got in some minor water, probably to top of tires briefly.
2. Got misfire code that stopped after it dried, but then got bank 1 sensor 1 code over and over. I had replaced o2 sensors this past year (NTKs)
3. I cleaned o2 connector and dielectric'd it....still got code. So I replaced bank 1 sensor 1 figured the misfire or something else ruined it.
4. That fixed Bank/Sensor code but then it was still idling rough and threw two other codes that pointed to MAF, so I installed a new MAF (not sure if it's BOSCH....got from O'rielly which usually goes to Bosch most of the time.) I figured with new 02s and a new MAF, I should be good.
5. Then I started getting this 1171 and 1174 issue. Found leak in red servo ring, fixed that, tightened bolts, etc...still throws codes 2 or 3 times a day. Truck runs ok....has lack of a lot of pickup and go speed, but it's always been that way since I got it.
6. Other questions: ran test without MAF on...have brand new Wick paper filter seated well in tray...I do have SAI (it runs kind of loud like many do).

* I understood from some other posts that if it's the MAF, I'd see other codes along with these two? I do have some oil leakage (minor) around valve covers, but no smoke came out. Ordered gaskets to fix that.

 

The reason I ask if the MAF is Bosch is because I have heard of people having problems with the cheap MAF's. How much did you pay for it? A Bosch should be around $100 and the cheap ones go for for around $35. Partsgeek has a genuine bosch for $101.63/free shipping. It's the best price I've found (it's the second MAF on the list) 01 2001 Land Rover Discovery Air Mass Sensor - Air Intake - A1 Cardone, Bosch, Dorman - PartsGeek

Do you have a buddy with a know good MAF that you can swap in and clear the codes to test a bad MAF?

I do the smoke test with the intake tube and MAF on. I put the glove on the intake side of the MAF. The only part I remove is the filter box. You may have a leak where the MAF connects to the intake tube. Basically you are looking for air entering somewhere after the MAF.