psu_Crash Posted July 26, 2008 Report Share Posted July 26, 2008 (edited) So everything has been running great except my idle was pretty high. About 1500 ... far too high. So I did a TPS and ISC reset today and set my idle screw. TPS was reading about 0.9 volts so I adjusted that to .48 according to the FAQ and the FSM. Now it really idles like crap. I got the idle to about 850 but it sputters like a have some monster cam with a stroker engine and it is running pig rich around 10.5. Give it a little gas and all is well until RPMs drop to about 1k. It also idles just fine at fast idle while it's cold. As soon as it warms up all goes to hell. Took it for about a 30 mile drive and it is fine anytime I stay above idle, A/F looks good then too. Base fuel pressure is currently 38psi on stock injectors. Mods in the sig line. All seemed well until I did the reset and adjustment. For all I know this issue was just hidden before by the high ide. Very stumped. What am I missing?? Any ideas? Edited July 29, 2008 by psu_Crash Link to comment Share on other sites More sharing options...
psu_Crash Posted July 26, 2008 Author Report Share Posted July 26, 2008 (edited) On a suggestion I checked all the vacum lines .. I can't find any leaks and the lines are all new. Someone ... anyone ... ideas.. ?? I am really bummed about this With the TPS is seems that the higher voltage = more throttle = more fuel... right? So why is it that when i dropped the voltage on the tps is runs soo much richer at idle ... really idling like crap .. and puffing black smoke at idle Edited July 26, 2008 by psu_Crash Link to comment Share on other sites More sharing options...
mikec Posted July 26, 2008 Report Share Posted July 26, 2008 The ECU doesn't look at the TPS voltage per-se, it watches for CHANGES in voltage - i.e. are you mashing the gas or lifting? The ECU uses that changing signal to know "driver wants to accel, dump in extra fuel" (like a carb's accelerator pump) or "driver wants to slow down. We can cut off fuel flow for that." Only if other sensors are busted does the ECU look at the steady-state TPS output in "limp home" mode. I recently posted on lousy idle, use the SEARCH button. In a nutshell though, some tests you'll have to do: 1: ECU error code test. Simple procedure, described in the FAQ depending on early or late model year cars. 2: test engine compression. A low cylinder will lead to lumpy idle yet the car will drive fairly normally. For a while... 3: fuel pressure test. Too much fuel pressure = rich. Too rich = lumpy. Your 36psi is correct though so you've already done this step. 4: injector leaking test. And having the right injectors installed in the car. Too many folks try to "get more fuel for a bigger turbo" and end up clobbering the off-boost and idle characteristics of the engine by swapping in a larger injector. On the 87-later cars, the ECU uses only the black plastic banded injector to idle and putt-putt drive... if you unplug the electrical leads on the blue/green one the engine should still idle. If it dies, the injector connectors are reversed. Also... for many years now Mitsu dealers have been selling THE WRONG INJECTOR to replace that black plastic one - Japan ships them one designed for earlier model year cars/other Mitsu cars (also black topped) that flows way too much. The right injector will have "L" stamped faintly on it just under the plastic. You mentioned your air/fuel ratios "look good." What does that mean - that you think the number is okay? What does the air/fuel actually do while driving at a steady 30 to 40 mph? It should bounce back and forth, about once or twice per second, between rich and lean. If it sits at a steady value, the ECU is NOT going into closed loop for some reason - usually because of a dead O2 sensor or a fuel injector that leaks. mike c. Link to comment Share on other sites More sharing options...
psu_Crash Posted July 26, 2008 Author Report Share Posted July 26, 2008 Thanks for the reply. Injectors were cleaned and flow tested at a local shop. I am 99.99% sure compression is fine as i checked it a couple weeks ago before and after retorquing the head. A/F at cruise jumps around between high 13's to low 15's but usually stays in the mid 14 range. Did the ECU error code test and it isn't throwing any codes ... that seems a bit suspect to me. I figured there would be something. I noticed this morning that I am getting some pretty good surging at idle too. about 250 RPM worth. Working on the rest of the afternoon/night to see what I can come up with. Hope I find something ... Link to comment Share on other sites More sharing options...
psu_Crash Posted July 26, 2008 Author Report Share Posted July 26, 2008 After several hours today of not much progress I decided it is time to finish the megasquirt install. At least for monitoring purposes so that maybe I can see where the problem is coming from. It's all in now and about 80% completely wired. Should be able to finish it up tomorrow. Link to comment Share on other sites More sharing options...
Komeuppance Posted July 26, 2008 Report Share Posted July 26, 2008 You're running dual 950's?? That sounds like it's causing you trouble right there... -Robert Link to comment Share on other sites More sharing options...
psu_Crash Posted July 27, 2008 Author Report Share Posted July 27, 2008 No the 950's aren't in right now. Currently has the stock 850's in it. I am putting them in this afternoon though and hoping to finish up the megasquirt to control them. I noticed that my fuel pressure is good when I crank the car but as soon as it starts the pressure drops to zero so I believe my injectors are leaking badly ... I will find out for sure in an hour or 2 Link to comment Share on other sites More sharing options...
Indiana Posted July 28, 2008 Report Share Posted July 28, 2008 We tried a "local" shop to have some injectors cleaned its not a new shop its been here 20+ years and we put them in and they were still as crappy flowing as they were before it was just wasted money they had no such flow testing and cleaning equipment they must have just sprayed some crap in the ends and printed out an invoice. Took them to a diesel injection shop I've used in the past and they came back cleaned and the problem was solved. Unless they cleaning injectors for their business and they know what they are doing you can hook these up and look at them spray and if they don't really leak they will call them cleaned and they are far from it. Those place have no clue what they spray patterns are supposed to be all they care about is if they do spray and they don't leak. Link to comment Share on other sites More sharing options...
psu_Crash Posted July 28, 2008 Author Report Share Posted July 28, 2008 Thanks for the info Indy I decided to just finish the megasquirt install today with new 950cc trilogy injectors. But now it won't run at all ... check the MPI forum for that post. Link to comment Share on other sites More sharing options...
psu_Crash Posted July 29, 2008 Author Report Share Posted July 29, 2008 Ok Robert here is how it all started. I am here to tell ya that it's not a lot of fun to run all those wires through the firewall and make it look good. http://img356.imageshack.us/img356/6532/msinstall006ac2.jpg But .. Alas it worked out nicely http://img292.imageshack.us/img292/5325/msinstall008cu3.jpg Untill you look under the hood ... It will be all tidy in the very near future. http://img294.imageshack.us/img294/3334/msinstall010db8.jpg This a 12V 10 amp relay that I installed to supply power to MS, JAW (thanks again .. works great now), Coil, and supplies +12V to the injectors. I used the wire from the positive side of the coil to activate the relay. http://img145.imageshack.us/img145/9836/msinstall011nq5.jpg And for a tach signal to the MS I spliced into the wire white off my MSD 8920 tach adapter that connects to the tach output on the 6AL MSD unit. no pics of that ... but you get the idea I will post another of the finished product very soon ... I hope Link to comment Share on other sites More sharing options...
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