r0BB Posted April 30, 2022 Report Share Posted April 30, 2022 Hi, I need some help figuring some things out. Engine is an EVO9 engine -fuel pressure on the ecu is showing around 55 psi however, on the FPR gauge showing around 80psi on idle -AFRs are not consistent, on the AEM gauge it goes past 17 but on the ecu stays around 13 on idle -I unplugged the front O2 sensor and it did nothing, there are 2x O2 sensors (pre and post cat) and the 1x at the front, ECU was reading AFR so was the gauge when the front O2 was unplugged. Took the car for a drive yesterday and 1st, 2nd and 3rd gear seem fine (only running 21psi) but when I tried to do a 4th gear run it backfired around 4000 rpm (log included) Any help would be greatly appreciated Log 2022-04-29 6;03;41 pm.llg Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 30, 2022 Report Share Posted April 30, 2022 There is no lambda working at all in your log. The backfire at 4000RPM is whatever you have set up on GP Limit 2. Quote Link to comment Share on other sites More sharing options...
r0BB Posted April 30, 2022 Author Report Share Posted April 30, 2022 Lambda Avg shows it i think Quote Link to comment Share on other sites More sharing options...
r0BB Posted April 30, 2022 Author Report Share Posted April 30, 2022 Quote Link to comment Share on other sites More sharing options...
Adamw Posted April 30, 2022 Report Share Posted April 30, 2022 The log screen you show above shows 20.5psi MGP @ 4000RPM and the lambda is 1.007, hence GP limit is correctly limiting you to 4000RPM. Quote Link to comment Share on other sites More sharing options...
r0BB Posted May 1, 2022 Author Report Share Posted May 1, 2022 Really appreciated your replies. That's good becuase it's leaning out right? I can only see lambda 2 on the ecu, does that that mean the front O2 is not working and will it be throwing a code if its not working or unplugged? As I mentioned I unplugged it and it did nothing Quote Link to comment Share on other sites More sharing options...
Adamw Posted May 1, 2022 Report Share Posted May 1, 2022 The factory narrow band O2 sensors are generally not used at all. I dont know why someone has set up your only lambda as "Lambda 2", seems illogical but it will still work ok. Quote Link to comment Share on other sites More sharing options...
r0BB Posted May 2, 2022 Author Report Share Posted May 2, 2022 Thanks for that I tested the plug to the front O2 and it was getting 14v not sure why. Is there a way for me to check that it's not setup? I also ordered a smoke machine to do a leak test as I'm pretty sure I have a leak somewhere, taking off one of the vacuum hoses did nothing to MGP and taking out the PCV did nothing too (just unplugged them to see if anything would change on the ecu) Quote Link to comment Share on other sites More sharing options...
Adamw Posted May 2, 2022 Report Share Posted May 2, 2022 What is the actual problem you are trying to solve? Quote Link to comment Share on other sites More sharing options...
r0BB Posted May 3, 2022 Author Report Share Posted May 3, 2022 Honestly I'm trying to figure out the problem, I may have more than one. So far my FPR is only going up to 68psi under 20psi of boost FPR show the following: ECU sensor at idle 54psi The gauge on the FPR is showing over 70psi on idle Then I have the vaccum issue (I think) where unplugging one of the vacuum hoses does nothing to the idle and doesn't show any change on the MGP (on the ecu) I will be doing a smoke test this weekend hopefully to check for any leaks but other than that not sure what to look for / test. I should also mention that the car was fine about 6 months ago before taking out the gearbox. Thanks for your help Adamw. Quote Link to comment Share on other sites More sharing options...
Adamw Posted May 3, 2022 Report Share Posted May 3, 2022 7 hours ago, r0BB said: Honestly I'm trying to figure out the problem, I may have more than one. Yeah but you havent even mentioned what are the symptoms of the problem you are trying to diagnose? Is it misfiring?,blowing black smoke? or something else? What makes you think you have a "fuel issue"? If your mechanical gauge reads different to the electronic sensor then you really need to determine which one is wrong with a 3rd known good device. If you attach your tune and give some detail about what fuel pressure sensor has been used I will at least check the calibration matches. For the "vacuum leak" I wouldnt expect disconnecting a small vacuum hose to have much noticeable effect. Are you using the factory MAP sensor in the manifold or the Link one in the ECU? Quote Link to comment Share on other sites More sharing options...
r0BB Posted May 4, 2022 Author Report Share Posted May 4, 2022 The main problem is that its cutting out / hitting "GP RPM Limit2" because its running lean Its using the MAP sensor on the ecu I'm pretty sure thanks evo6-29-04-2022.pclr Quote Link to comment Share on other sites More sharing options...
Adamw Posted May 4, 2022 Report Share Posted May 4, 2022 You can see in the log below, from around time 0:50.600 to 0:51.600 the injector PW (light blue) is quite flat - ie the ECU is commanding the same amount of fuel to be injected through that range. But around 0:51.200 the lambda (green) starts to drift away from target (dark blue). By 0:51.600 where the limiter kicks in the lambda is miles off target - about 1.78 vs 0.79 for the target. When the ECU is commanding a similar amount of fuel to be injected and the air flow doesnt change much (RPM x MAP) the resulting lambda should stay similar. So there is something external affecting fuel flow. I suspect your fuel pressure sensor is calibrated wrong but I still think it is most likely a fuel pressure problem. Quote Link to comment Share on other sites More sharing options...
r0BB Posted May 4, 2022 Author Report Share Posted May 4, 2022 Thank you so much for that I will start with the fuel filter first and report back. Quote Link to comment Share on other sites More sharing options...
r0BB Posted May 6, 2022 Author Report Share Posted May 6, 2022 fuel filter was clean the gauge on the FPR was busted, had 3 screws loose and the face was moving all over that's why it was reading very high pressure got a new gauge to replace the old one but not sure how that will fix the problem when the pressure sensor is seeing 68psi on load which is close to the max the fpr is rated to. I will connect the new gauge and see what it reads Quote Link to comment Share on other sites More sharing options...
Adamw Posted May 6, 2022 Report Share Posted May 6, 2022 We can probably assume the fuel press shown in the ecu is correct then. Fuel pressure should raise 1:1 with boost. You can see below at 0psi boost you had 55psi fuel press, then at 20.5psi boost you had 68.5psi fuel press. So for a 20psi increase in boost, your fuel pressure only increased by 13.5psi. This is likely some of your problem. Quote Link to comment Share on other sites More sharing options...
r0BB Posted May 6, 2022 Author Report Share Posted May 6, 2022 The car is tuned to run 31psi on high boost if the base fuel pressure is 54 (was 51 in October when i looked at old logs) plus 31 thats 85 psi, my fuel reg is rated at 70psi so it doesn’t really make sense Possibly i have some sort of blockage in the fuel lines ? Quote Link to comment Share on other sites More sharing options...
Adamw Posted May 7, 2022 Report Share Posted May 7, 2022 8 hours ago, r0BB said: my fuel reg is rated at 70psi so it doesn’t really make sense That would be max base pressure, not the max the fuel rail can reach when there is boost in the top of the fuel reg. 8 hours ago, r0BB said: Possibly i have some sort of blockage in the fuel lines ? More likely pump voltage drop due to wiring or pump not keeping up. Quote Link to comment Share on other sites More sharing options...
r0BB Posted May 11, 2022 Author Report Share Posted May 11, 2022 Fuel pump filter was very dirty so I ordered a new one new fuel reg and gauge being installed in the next few days I tried to put some air through the fuel lines but don't have an air compressor so the bicycle pump will do it for now I hope I will also be doing a smoke test to see if I have any vacuum leaks or exhaust leaks Quote Link to comment Share on other sites More sharing options...
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