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1171&1174 Helpme Oprah, helpme Tom Cruz

1656 Views 12 Replies 3 Participants Last post by  symuasi
2001 Disco 2 se, 230,000 miles. This car failed emissions for a check engine light going on two years ago, so I made it a project car. Hadn't really done much to it until now. It was running a little rough so I gave it a tune-up. I replaced the spark plugs (E3s), wires, coil pack, intake gasket, air filter, oil filter, and renewed the oil. I also replaced the radiator, four O2 sensors, the MAF, and purge valve. I am ready to put my lift kit on and a fancy new bull bar to replace the front bumper, but I would like it to pass emissions first. The check engine light now comes on at about 40 to 50 miles, I've burned a couple tanks of fuel and I'm driving around with a bogus license plate trying to get this thing to finish it's testing sequence. I did the cigar smoke test and I couldn't find any leeks, no smoke. I am running out of options. Says it is running lean on bank 2 1174 and 1171. I put new O2 sensors on though. I had these same codes before I did all this stuff. Setting up for the cigar test I did find one hose disconnected from the throttle body to the valve cover, I thought that was it so I didn't do the smoke test at that time, I connected the hose and felt victory to soon, 75 miles in the light came on again. That is when I did the smoke test and found no leaks.
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Have you checked injectors on bank 2?
Negative on the injector check.
I would have to tear down the whole thing to get to the injectors though right? The truck is running perfect right now, I am just getting the codes. No knocks, no noises, no hesitations, and the motor is running very smooth. I have no reason to believe that it is an injector issue, I hope.
Just tried seafoam. I used seafoam to clean the injectors through the vacuum tube. I put another can in the g-tank just for kicks. I then reset the computer and drove 45 miles, stopped to let her cool down about twenty mins, then I drove back 45 miles. The chk eng light is not on, but I checked the computer and it still hasn't run the evap, O2, and catalytic tests. It is showing a P1590 error, but that one doesn't make the chk eng light come on. I will let her cool down for an hour and then take it out again, if I can get to ninety miles or so without a code then maybe it is over. No way it will be that easy though.
Just food for thoughts, here are two long shots:

Gasket leak on right downpipe maybe? When I was tracking a lean code on my Disco, I was told by a fuel injection specialist that air can get IN the exhaust system through such a leak with the right conditions, and cause a lean code. That may have been a contributing factor in my case because we could hear a leak using a hose near the flange.

Also if your engine didn't run smooth, I'd suggest a cylinder not firing could cause a lean code, because I had some misfiring that new spark plug wires took care of, and my lean code got away after that.

Sorry I can't help more than that, and good luck!
Lowest bidder might be on to something. I used seafoam on my last post. I poured it into the vacuum of the intake and it sucked it in nicely revving the engine each time. Now, as the smoke pressure increased inside the engine, sometimes with a heavy pour during the application of seafoam, I would see smoke bellowing from under the engine on the passenger side (right side) of the engine. It would only happen during a heavy pour of seafoam through the vacuum tube and I only let that happen two or three times(not on purpose). After the application, I reattached the vacuum hose and revved the engine a couple times. If thick white smoke bellowed from the exhaust pipe, then I would get some smoke (exhaust) coming from underneath as well, but only during thick white smoke from the actual exhaust pipe. The update is though that after the seafoam treatment I made it to 150 miles before the light came on with only one code 1174. I monitored the voltage graph on the upstream O2 sensors and it did show that bank 2 was spiking slightly higher than bank one. Bank one was pretty steady with a flat line. The computer was just taking its time in completing the three remaining tests and that's why I got to 150 miles. It never completed them on this run. I think the seafoam is working, so I re-administered an additional bottle through the vacuum and then checked the voltage graph again. The graph showed Bank one and two are now tracking evenly. Tomorrow she is going on a long journey, the chk eng light is currently off (reset) and the tests are going to run tomorrow.(I hope) Fingers crossed that this fixed the current issue, but I will check the exhaust for leaks if this fails. I'll slap some hooker headers on that baby with some glass packs and a hurst stick shift, oh wait that was so thirty years ago, got carried away with a red neck turret, sorry.
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Seafoam did not do the trick. I am now going to look into exhaust leak. I am back at square one . 1171 & 1174 I will check out the exhaust leak and re post this tomorrow.
Update: Well I lifted up the truck, got underneath it look'n for exhaust leaks. Revved it, turned it off and on, blah, blah, blah. Tight as a blahbady blah on a blah blah. No leaks, but there is a development. Three kids and wife in the car waiting for chic-fil-a order sitting in drive through I may have caught a break. I heard a new noise, a whistling coming from under the hood. I was praying for it to keep whistling long enough to get the food and go park so I could pop the hood. Sure enough and whistle of unknown origin, a vacuum leak. I couldn't find it though. I got home, pulled into the driveway and put it in park. I jumped out and called my neighbor over to help me find it. I grabbed a length of tubing and started looking and bam, it disappeared. Can you believe that, gone and unknown. I know I have a leek though. We turned it off to cool down, turned it back on and a few revs later it was back. Still very hard to find, I fed the hose under the intake manifold and I found it about three quarters of the way in. So tomorrow I have to tear it back down, but I did find a leak. I don't know if it is "the" leak, but I have a feeling that it is. It could be a valve cover gasket leak or intake gasket leak. I did just replace the intake gasket though.
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Update: Well I took her back apart again and found that the valve cover gaskets were leaking, falling apart, and you could basically unscrew the screws by hand. I even painted the valve covers a nice shade of blue and they look awesome. The new gaskets went in great. One thing is that you have to watch out for those pesky spacers that are built into the valve cover gaskets. When you take the old gaskets off those spacers can fall into the rocker assembly and disappear. You can lose sleep over it when that happens, I know I did. Also I took apart the valve covers (protector plates on the inside) and I pressure washed them until they were new looking. I can't really figure out why one is a different color than the other one. After everything is back together and everything is hooked back up correctly I can tell she is running even better.
Now I have narrowed the problem down to the O2 sensors. One of them is reading higher voltage than the rest and I am perplexed. The bank 2 sensor 1 is reading say .335 to roughly .775 all the time. The rest of the sensors are reading a steady .010 to roughly .080. If I rev the engine I get them all up to around .800, but then they all correct back down. bk 2 sen 1 does correct down with the rest, but then quickly goes back up to the higher readings. Now, the one that is trouble has spliced wires. I didn't do it, some jack leg mechanic did it. Question is, will this effect the voltage reading? Moral, don't let them work on your rover just because they have an English accent. 1171 and 1174 are still rock'n my rover.
As I was trying to get rid of a code, I spliced an old rear O² sensor with a front O² connector. I did a clean soldered splice and that sensor worked as well as the 3 other sensors that were brand new. I personally don't like crimped splices because you never know it the joint offers resistance or not. Problem with soldered splices is the wire can fail right next to the joint because it can't flex.
Good Bye 1174 & 1171. I will not miss you. Well, it is over. In addition to everything I just tore down the engine again, it gets easier every time, and rebuilt the injectors and replaced the lower "valley pan" gasket. Once in there, it was totally toast. The two rubber seals at the front and back were basically gone. In hind sight I should have just replaced all the intake seals&gaskets the first time. The head gaskets are just going to have to wait, but I will keep an eye on them. Also, the spliced O2 wires did not make a difference. After I fired her up after the rebuild I had no codes, the computer did all it's tests within twenty miles, using the idol for 30 mins, 35 MPH for 5, 45 MPH for 5, then 55+MPH technique. So the 1174&1171 problem, Vacuum Leak, for sure. The o rings on the injectors were hard as a rock. Here are some after pics:


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