JPN_Garage Posted September 6, 2013 Share Posted September 6, 2013 Bought my 240Z a couple of months ago and since the first day I have not been able to pin point the issue Car is a 72 240Z L28et swap ( 11K Rebuilt ) Stock ECU 5 Speed R200. The issue is that after 20 to 30 min of driving the car once you stop at a light or stop sign and continue driving when the car gets close to 3000 RPM in every gear she starts pulling, loses power and shutting down but does not turn off so you have to let go of the gas pedal and shift to a higher gear. The longer you drive the car the worse it gets, I already checked all vacuum lines, replaced the maf sensor, installed a new MSD fuel pump, plugs and wires and other visual inspections but can not pin point the cause. Can it be the the Fuel pressure regulator it being stock or is there something else I am not checking. Any help would be greatly appreciated. Quote Link to comment Share on other sites More sharing options...
rejracer Posted September 6, 2013 Share Posted September 6, 2013 Download the FSM from Xenon S130. From there study the system, knowing what sensors do what. There is nothing wrong with a working stock FPR. I also start troubleshooting these cars by cleaning contacts on the ECU, Cylinder head temp sensor, AFM, throttle switch and injectors. The L28ET electronics are not complex or hard to understand, and work well for what it is. Quote Link to comment Share on other sites More sharing options...
spiff Posted September 6, 2013 Share Posted September 6, 2013 Well, is the engine stock or is it modified by any means(have you turned up the boost)? If it starts stumbling or hesitate that could be indicators of it not getting enough fuel, assuming it runs fine under a certain rpm. You could hook up a gauge and check fuel pressure to see if the FPR is working. If it isn't, replace it, if it is working then again I must ask you if you have turned up the boost and if you have done that turn it back down again untill you can figure out a way of supplying the extra fuel it needs... Quote Link to comment Share on other sites More sharing options...
JPN_Garage Posted September 6, 2013 Author Share Posted September 6, 2013 Rebuilt engine on stock boost not overboosting at all full 3 inch exhaust. I did notice that when i disconnect the vacuum line that goes to the factory FPR the car runs better but still has the same issue just slightly. Quote Link to comment Share on other sites More sharing options...
tooquick260 Posted September 6, 2013 Share Posted September 6, 2013 Mine did something similar... Would not pull 4000rpm on anything but stock boost. I figured mine was low voltage on the fuel pump! was fine on 5.5 lbs boost I could push to 6000rpm but anything different would cut out reaching 4000rpm. Actually pop, fart miss cut out. Quote Link to comment Share on other sites More sharing options...
spiff Posted September 6, 2013 Share Posted September 6, 2013 The fpr on my Z32 went bad after storing it through the winter, so it is possible for them to fail. You should hook up a gauge to check fuel pressure or try another known working one, maybe someone can lend you one? Quote Link to comment Share on other sites More sharing options...
cgsheen Posted September 6, 2013 Share Posted September 6, 2013 Download the FSM from Xenon S130. ... I also start troubleshooting these cars by cleaning contacts on the ECU, Cylinder head temp sensor, AFM, throttle switch and injectors. Bingo. Always start by checking & cleaning the electrical connectors & checking the wiring. Run through the ECCS component tests in the 1982 or 1983 Factory Service Manual. You'll be able to test the components and the wiring (harness) back to the ECU if you follow the troubleshooting tests. Another common problem on a high-milage AFM is a hesitation, bog, stumble at "cruising speed" - usually around 2500-3000 RPM. More than a few threads on the interweb discussing the issue. You might check to see if your AFM has been opened - BUT - don't "adjust" it yourself! Verify every other part first, check and clean all of your connectors, check the wire and wiring. Post your progress, put up some pictures. Quote Link to comment Share on other sites More sharing options...
JPN_Garage Posted September 6, 2013 Author Share Posted September 6, 2013 (edited) I opened the gas cap and drove the car around and it felt much better but the problem was still there, I changed the fuel filter, FPR and installed a vented gas cap and all problems are gone. Fuel filter was from 2009 by the way and was extremely dirty so I checked all feed and return lines and nothing was clogged, checked the fuel tank and all was clean. Car feels amazing, Thanks guys. Installed a Vibrant Manual Boost Controller and took it to 10lbs and It had no hesitation at all, it felt amazing. Edited September 6, 2013 by shakotan_culture Quote Link to comment Share on other sites More sharing options...
tooquick260 Posted September 7, 2013 Share Posted September 7, 2013 Great,,,, if you want to try my remanufactured afm let me know. Hope all works out well. Maybe see you next week at the UTI car show. Quote Link to comment Share on other sites More sharing options...
JPN_Garage Posted September 7, 2013 Author Share Posted September 7, 2013 After the car worked great the whole day on my way home after a 45 min drive the car started cutting out again but this time I could here the fuel pump going in and out so the car would lose all power when the FP would go silent. Its an new MSD Fuel pump. What can it be? Quote Link to comment Share on other sites More sharing options...
Tony D Posted September 7, 2013 Share Posted September 7, 2013 (edited) "I can hear the pump going in and out...the car would lose all power when the FP would go silent" "It's a new MSD Pump, what could it be?" Power to the MSD Fuel Pump The MSD Fuel Pump Saying it loses power makes me assume you hear your pump while driving (and this is not stopped at a light at idle where the AFM Contacts could be opening shutting the pump off...) in which case....other than an FPR dumping pressure intermittently (first time for everything in Fantasyland I suppose...) this brings us to power to the pump, and the pump itself. New parts fail more regularly than proven running parts a year old... Edited September 7, 2013 by Tony D Quote Link to comment Share on other sites More sharing options...
spiff Posted September 7, 2013 Share Posted September 7, 2013 If you have recently changed the fuelpump chances are one of the wires have come loose, or the nut that holds the wires to the fuelpump. Happened on mine, 2 minute fix. Check connections first before tearing up your efi system Quote Link to comment Share on other sites More sharing options...
tooquick260 Posted September 7, 2013 Share Posted September 7, 2013 Hey, i have the same pump. Did you get that at the speed shop on OBT? American Motor SPorts? Where are you pulling power from for the Fuel pressure relay to feed the pump? I ended up going to ignition on hot and circumventing the fpr. Quote Link to comment Share on other sites More sharing options...
JPN_Garage Posted September 7, 2013 Author Share Posted September 7, 2013 (edited) Well the sound the pump makes is a up and down motion like a wave with 2 second intervals and that's after the car has been driven for more than 30 min Ant to correct myself the msd was slightly used but It was not used for the past year. Edited September 7, 2013 by shakotan_culture Quote Link to comment Share on other sites More sharing options...
Xnke Posted September 8, 2013 Share Posted September 8, 2013 Start with the pump...power it from a NON CAR source, just jump two wires to it from a spare battery, listen to it running with the car turned off. If it starts doing making the noise, it's NOT the wiring or the fuel pump relay. It could be a bad pump It could be a bad fuel pressure regulator (Happened to me, although mine would run and run and run then the pump would get louder and louder and louder and then the car would die) It could be a clogged fuel filter (yep, you just changed it, and it could be full of trash again!) Quote Link to comment Share on other sites More sharing options...
tooquick260 Posted September 9, 2013 Share Posted September 9, 2013 Did you figure anything out? Quote Link to comment Share on other sites More sharing options...
JPN_Garage Posted September 9, 2013 Author Share Posted September 9, 2013 Well installed a new pump and after 30 min of driving the same, pump goes in and out over and over till it completely turns off then I have to try to start it a couple of times till the pump starts working again. Ill be checking the new filter tomorrow and the wiring to see if its an electrical issue Quote Link to comment Share on other sites More sharing options...
HowlerMonkey Posted September 10, 2013 Share Posted September 10, 2013 (edited) Unplug the 02 sensor and see if it still does it. Easiest test to perform before you decide to clean all the terminals. I've had this happen, unplugged 02 sensor, drove it for a year because it was seized in the turbo elbow. When I plugged in the new sensor after doing some other work that required pulling the turbo elbow, it was fine. If you're driving on the highway with rpms over 3500 or so, the system ignores the sensor anyway. (throwback from 55mph speed limit when car was made) Edited September 10, 2013 by HowlerMonkey Quote Link to comment Share on other sites More sharing options...
JPN_Garage Posted September 11, 2013 Author Share Posted September 11, 2013 Checked my new fuel filter and it was a little dirty so after draining the tank this is what comes out. Its a bucket full of fuel and rust at the bottom, so i will be pulling the tank out and cleaning it. Quote Link to comment Share on other sites More sharing options...
tooquick260 Posted September 11, 2013 Share Posted September 11, 2013 That looks nasty..... Makes me wonder about mine? I think i will use dads scope and take a look! Quote Link to comment Share on other sites More sharing options...
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