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Part throttle surging http://www.ladsm.com/forum/viewtopic.php?f=26&t=15410 |
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Author: | CAFIFTY [ Sun Sep 15, 2013 9:23 pm ] |
Post subject: | Part throttle surging |
My galant VR4 has been giving me some troubles for awhile. Drive fine at WOT but at low throttle inputs it bucks and surges. On cold starts is idles at like 2000 RPM and surges but once it gets warm it idles nicely at 1000 RPM. So far I have: Checked for leaks. Gets to 20psi on the leak tester and then leaks down slowly. Replaced the plugs Replaced the plug wires Replaced the throttle body and IAC Adjusted the BISS Replaced the Coil Replaced the knock sensor Pinned out the TPS and it was okay Replaced the CAS Went to another 1g MAF Pinned out the MAF connector Rewired the Idle Switch Checked compression (its good) Checked Fuel Pressure (its good) Then I found rust in my fuel tank so I: Got the tank blasted/cleaned Replaced the fuel filter Replaced the Injectors because this were full of rust(2G 550s) Replaced the fuel pump Replaced the fuel pressure regulator I am running out of ideas. I have never taken any of my cars to a shop before but I am considering dropping it off at Road///Race Engineering at this point My gut feelings are: 1. My replacement 1g MAF was also bad 2. Fucking 02 sensor is bad. Last time I had TMO logging it looked like it was stuck lean BUT I figured it was because the sampling rate was slow. BUT the fuel trims looked all in place and this doesnt make sense 3. The IAC is bad even though i pinned it out and it reads okay.... I am a fucking Mechanical Engineer, I calibrate cars for a fucking living, and I can't fucking figure this out. I am super aggravated. I just want to fucking drive and race this car. |
Author: | Synthetek [ Sun Sep 15, 2013 9:26 pm ] |
Post subject: | Re: Part throttle surging |
Check the coolant temp sensor. |
Author: | CAFIFTY [ Sun Sep 15, 2013 9:29 pm ] |
Post subject: | Re: Part throttle surging |
Yeah i was thinking about that today also. Last time I logged stuff. ECT was reading correctly in TMO but was reading 120 degrees higher when viewing it TunerPro RT. Seems to be reading correctly in the dash though and the fans kick on and off. Thanks for the quick response. Still highly considering paying someone to figure this out. Is Road///Race Engineering my best bet? PSS the car is stock |
Author: | LOLVTEC [ Mon Sep 16, 2013 8:13 am ] |
Post subject: | Re: Part throttle surging |
Remove all your emission crap. Block of egr Sent from my SGH-M919 using Tapatalk 2 |
Author: | -red97rum- [ Mon Sep 16, 2013 5:17 pm ] |
Post subject: | Re: Part throttle surging |
I second checking the coolant temp sensor, it can make the car hard to start and do other weird things. The ecu uses a different sensor than the temp gauge in the cluster. The fans run off a thermo switch that's plumbed into the radiator, below the passenger fan (for a 1G). Good luck and let us know what it was when you figure it out; it's gotta be something simple! |
Author: | CAFIFTY [ Tue Oct 08, 2013 2:41 pm ] |
Post subject: | Re: Part throttle surging |
I replaced the coolant temp sensor with a brand new one and its still surging. I also replaced the 02 sensor and the TPS sensor. Still doing it. Ordered a logger cable from http://www.dsmcables.com/ and waiting to get that. Turned out my new laptop doesnt have the com port my old toughbook did so i cant use the cable i made awhile back Another note. I noticed the when the TPS sensor is unplugged the car runs exactly the same as when its plugged in (shitty)...Thinking this might be the issue. Need to figure out the pin out of the TPS sensor. I guess pin 1 (green) should read 5v. To top it all off when troubleshooting my engine just died and smoke started to come out of the ECU. Took it out and turns out the legendary caps decided to take a shit. I have another ECU but was so disgusted with everything that i decided to take a break. I am really kicking myself for buying this thing. |
Author: | CAFIFTY [ Wed Oct 09, 2013 11:27 am ] |
Post subject: | Re: Part throttle surging |
Starting to think its the MAF even though i replaced it. Anyone have a known good maf |
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