mahoney944

I just fully rebuilt my engine. After it's first start up, I noticed the car idles rich in the 12s even after it's fully warm. I have a rogue logger and my tps and dme temp sensor appear fine. I am also fairly confident I have no vac leaks and my idle is reset properly and my fuel pressure is set (adjustable fpr). My idle stabilizer seems to be working as it should. I notice in the logger that it's not going into closed loop once warm at idle. I ordered a new O2 sensor and should get it soon. But is there any other things that might cause the car to stay in open loop constantly that I can check in the mean time? The car is running m tune, LR version. While in open loop at warm idle I can adjust the fqs to - 11% fuel and get the car closer to 13.5 - 14.0. shouldn't my open loop be a little closer to 14.7 at idle without pulling so much fuel? I know closed loop would bring it in but the transition from open to closed would have to compensate more to do so?

Tom M'Guinn

Do you have multiple maps on your m tune set up? I know with my Vitesse chipboard, I have the choice between pump gas, race gas, e85, more timing/fuel, less, etc. One of my E85 maps, for example, adds about 30% extra fuel and disables closed loop operation. If I ran that map on pump gas, it would behave much like you describe...

mahoney944

It does have many map options but I'm running the pump gas #80 injectors map with no jumper installed ... So the primary map. I did remove the O2 sensor and there's some white chalk like stuff loose inside. I assume part of the sensor so perhaps that's all it is. I'll confirm my map selection again though.....edit confirmed the correct map.

fejjj

mahoney944

I have a new klr with only about 10 miles on it so I'll look past that for now. I have an extra map sensor I can try, which I will. The logger shows what position the tps is in and its spot on from what I can tell.

mahoney944

Jumping the diagnostic port bypasses the isv as it should. Unplugging the O2 sensor I see no real change. The only time I can get the DME to read anything but rich is when I crack the throttle quickly and it flashes lean for about a fraction of a second then back to rich. I read somewhere that it should read lean when you do that. I guess it's the DMEs way of detecting a wot faster enriching the mixture for open loop.

Droops83

There seems to be a common perception on Internet forums that "open loop" automatically means "rich mixture." This is not 100% the case. Open loop means that the DME is ignoring the signal from the oxygen sensor and running solely off the base map in the DME. During cold-start enrichment and in the WOT map (>66% throttle), this happens to be a richer mixture for obvious reasons. But at idle and cruise, a perfectly running 951 with no vacuum leaks or other defects should be running right around 14:1, even in open loop. If your 951's idle changes drastically when the O2 sensor is unplugged, your base mixture is not correct.

Something is making Mahoney's DME stay in open loop, but that doesn't automatically mean that the same issue is causing the rich mixture. You have 80# fuel injectors---I have the 80# Deka injectors in my otherwise stock engine running VEMS, and the injector duty cycle is only 2% at idle with a Bosch 3 bar fuel pressure regulator and 044 fuel pump. What did you set your fuel pressure to? Have you verified the setting with a gauge? What about your MAF/MAP readings?

mahoney944

Fuel is set to 43psi. I tried two different ways of setting it with no difference. First way, I jumped the fuel pump to stay on and disconnected the vac line, then set it. I also tried removing the vac line with the engine idling then set it. Both methods we're fairly similar settings. want to say the voltage was around 0.88 going off memory. I'd have to double check though.

mahoney944

What functions does the klr chip serve? I can't remember what chip is in there now.... I'm thinking its a LR 951 max chip. Not sure what chip m tune needs or if it matters on the klr side of things. That might be a question for Josh.

Tom M'Guinn

It's also possible that your car is just running so rich that it is outside the range of what your closed-loop system can make up for. .88v at idle is high for other systems, though don't know about m-tune. MAF Grounds good? I'd be temped to check the WOT signal by confirming there is 5v at terminal B (1 o'clock) on the diagnostic port under the hood when idling. The WOT maps are ON if terminal B shows ground (zero volts). Also, might as well check blink codes while you're there. Did all of the same components work well and give you a good AFR before the rebuild, or is it possible you've mixed and matched parts that don't like each other?

951and944S

How are you defining "Warmed up"...?

What is the trigger, 180F coolant temp...?

T

mahoney944

Got the new O2 sensor and started the car up. As soon as I hit 150 degrees the car went into closed loop and idled 14.7. So that's sorted now. I do however think it's odd that the open loop seems too rich all around, if I jump the isv on the diagnostic port my fuel ratios go into the 12s at idle. I can lean it out with the fqs but that seems like a band aid to possibly another issue. Everything was just replaced on the engine, funny enough besides the oxygen sensor since I bought it slightly before tear down. It was a complete bare block up rebuild and I replaced all the rubber hoses and clamps, fixed any connectors that showed any wear etc. I'm fairly confident there's no vac leaks unless there is a brake booster issue I'm unaware of...any good tests for that?

mahoney944

Well its been a long process. I had a used motor put in my car shortly after the time I got the car... this being many moons ago. I didn't know much about the engine except it seemed to run ok, though I noticed it seemed a bit less powerful than I remembered the car being. Fast forward years later after a few upgrades and repairs the car was sitting pretty and I was happy with the car overall. I decided to take the car a step further and invested in Rogues LR m tune kit. On initial install the car did not run real well. I replaced every seal I could get to reasonably. I invested in Rogues ecu, which has a port for the map sensor hook up, and logger, worked with josh through email and I was able to get the car running decent but not great. Well here I ended up pushing boost past the rings on a particularly cold day and blew out the rear balance shaft seals. The next step was just to do a complete rebuild to roll out any issues being related to the engine, making sure that everything was installed and fitted correctly. New everything. One interesting thing I found on tear down was the rings were either gaped way to big by someone or worn I think I remember measuring over .075" gaps on most of the rings which would explain the blow by. Any who, I just got the engine fully assembled and installed and it seems to be running pretty well, I noticed maybe a droplet of oil on the cam box corners at the seal but nothing actively dripping. There is a few things I need to do yet, my fuel pressure drops after I shut the car off within maybe 10 -15 minutes, which I believe to be the check valve at the pump since the fpr is new and the damper seems ok. My dme relay died over the rebuild (only about 2 years old) so I decided to try one of those solid state ones with pump prime should be arriving soon. In the mean time I've been bypassing the relay with a 3 wire jumper. Now that the new O2 sensor is on the car goes into closed loop. My only issue I believe is the richness of open loop all around. Jumping the isv will force the car into open loop and afr in the 12s. closed loop returns it to 14.7, jumper removed. not sure what the next logical step is. The grounds on the rear of the engine are good and my battery and alternator cabled were just replaced, also new battery. I do have a brand new DME harness stored away but I'm not going to use it until I deem the harness absolutely needed. New ones don't pop up too often. The one in the car seems to be working. I get a fairly good sense of the harness going through the live logger.

Droops83

OK, the "open loop" that you mention at the beginning of the post refers to the DME ignoring the O2 sensor signal. When you jumper the pins under the hood, that simply bypasses the idle control valve---that would be a form of "open loop," but I wouldn't refer to it as that because it causes confusion. When you bypass the ICV, the idle speed/mixture is solely based on the idle adjustment screw in the throttle body and the mixture adjustment in the stock AFM (or in the case of the Rogue setup, whatever the MAF/chipset is calibrated to at that airflow setting).

It seems that your tune/configuration results in a rich mixture at idle. This might not be too much of an issue, so before pulling your hair out trying to figure out what is causing it, check out your general tune in open loop (disconnect O2 sensor) at light load and cruise conditions and see where the mixture is. If it is in the 13.5-14:1 range, then it should be good and the closed-loop feedback will take care of the rest. If it is in the 12s at this range, then it is too rich all around and might not run very well with the O2 sensor feedback constantly making large corrections to the injector pulsewidth. In that case I would work on figuring out what is causing the rich running, whether it is a sensor out of calibration or simply the tune itself.

mahoney944

when I jumper the isv the logger shows that it goes out of closed loop, so I presume it's in open loop. That's why I referred to it that way. Idk the fine details of it by any means it's just what I noticed. Maybe it shouldn't do that. Not sure.