HoustonZ Posted August 10, 2008 Share Posted August 10, 2008 I've been chasing this annoying problem ever since installing megasquirt v3/EDIS/holset. At approximately 4500rpm in any gear, the engine appears to hit a rev limiter and refuses to rev any higher. It sounds like it is losing spark or not igniting properly. My AFR is 10.5 under WOT. My plugs are at .035. I thought it was my VR sesnor cable, so I replaced it with a brand new shielded unit, no difference. You can see a good example of this in my datalog at 286 seconds in. In 2nd gear it just flatlines at 4300. boost.zip Quote Link to comment Share on other sites More sharing options...
Noddle Posted August 11, 2008 Share Posted August 11, 2008 I've been chasing this annoying problem ever since installing megasquirt v3/EDIS/holset. At approximately 4500rpm in any gear, the engine appears to hit a rev limiter and refuses to rev any higher. It sounds like it is losing spark or not igniting properly. My AFR is 10.5 under WOT. My plugs are at .035. I thought it was my VR sesnor cable, so I replaced it with a brand new shielded unit, no difference. You can see a good example of this in my datalog at 286 seconds in. In 2nd gear it just flatlines at 4300. Stupid question, but you do have your "Rev Limiter" set to be over 4500rpm ? Fuel Set-up / Rev Limiter Nigel Quote Link to comment Share on other sites More sharing options...
HoustonZ Posted August 11, 2008 Author Share Posted August 11, 2008 Yes, I have it at 6500 right now for both the hard and soft limit. Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted August 11, 2008 Share Posted August 11, 2008 What are you doing for an O2 sensor? It looks like the sensor is either disconnected or you are running pig rich the whole time. Quote Link to comment Share on other sites More sharing options...
HoustonZ Posted August 11, 2008 Author Share Posted August 11, 2008 I have an innovate LC1 with the wonderful defective DAC circuit so the output to megasquirt isn't working. I monitor the realtime AFR through Innovate Logworks software. It works nicely, minus the ability to autotune. My AFR is 14:1 at cruise, 12.5 under light throttle, and 11:1 at WOT. Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted August 11, 2008 Share Posted August 11, 2008 What are you using for an air filter and intake tubing? When I was using the factory turbo rubber boot, it would collapse under vacuum if the steel liner was taken out of it. Maybe the ignition moduled is defective. Is your VR sensor bracket or 36-1 wheel vibrating at 4500 rpms? Quote Link to comment Share on other sites More sharing options...
HoustonZ Posted August 11, 2008 Author Share Posted August 11, 2008 Running a holset hy35w with a 24x12x3 intercooler and 3" pipes. Screen mesh on the turbo inlet. Right now I'm running with the wastegate open while I tune. I have 45psi of fuel pressure, good looking plugs, no pinging or detonation, a steady 13v under load. Yesterday I reduced the spark plug gap to .025 thinking it might have been the spark blowing out, no difference. I should note that even in neutral it flat lines at 4500, so this isn't a load related problem. Quote Link to comment Share on other sites More sharing options...
mobythevan Posted August 11, 2008 Share Posted August 11, 2008 I should note that even in neutral it flat lines at 4500, so this isn't a load related problem. That is a good detail to point out, it should eliminate several things. Are you using the ford module to run the EDIS or the MS box? Quote Link to comment Share on other sites More sharing options...
HoustonZ Posted August 11, 2008 Author Share Posted August 11, 2008 I'm running through the ford module and simply using the PIP and SAW signals with megasquirt. I verified that my timing is actually changing with a timing light, and there doesn't seem to be anything crazy happening. It pulls pretty hard up to about 4300, then starts to trail off. When I get home from work I'm going to try to run a ground wire straight from the module to my battery terminal. Right now it runs back to my under-dash master ground strip. Quote Link to comment Share on other sites More sharing options...
WizardBlack Posted August 12, 2008 Share Posted August 12, 2008 If you are running 10.5 AFR during WOT in lower revs and it drops even half a point (10.0:1) then you are probably choking your motor with fuel. You are already on the border of doing it now. Lean it out some and see if that isn't why it won't get into the next load cell. Back off the timing a tad if you are worried about knock, but you should be able to hit 11.5:1 at WOT on pump gas. Quote Link to comment Share on other sites More sharing options...
Bernardd Posted August 12, 2008 Share Posted August 12, 2008 Have you checked to see if you're getting the timing advance at 4300 that your commanding? Quote Link to comment Share on other sites More sharing options...
HoustonZ Posted August 15, 2008 Author Share Posted August 15, 2008 Edited the values to bring my WOT AFR to about 11.8. It pulled stronger, but still has the same problem. My timing is advancing fine, I'm running 30 degrees at 2800rpm+ Quote Link to comment Share on other sites More sharing options...
cygnusx1 Posted August 15, 2008 Share Posted August 15, 2008 bad ignition module or coilpack? Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted August 15, 2008 Share Posted August 15, 2008 We had a ford edis-6 car at the shop once. It was an auto car, and it had a "safety" on it so that it wouldn't rev over 4500 rpms in park or neutral. I'm not sure if it's controlled by the coil pack or the ECU though, but it sounds so much like this problem. Mario Quote Link to comment Share on other sites More sharing options...
HoustonZ Posted August 23, 2008 Author Share Posted August 23, 2008 Hmmmmm, sounds like a possibility. I haven't seen any documentation about a feature like that built into EDIS though. I still need to try changing the c31 and c32 capacitors to a lower value though. Quote Link to comment Share on other sites More sharing options...
Matt Cramer Posted August 25, 2008 Share Posted August 25, 2008 C31 and C32 are part of the Megasquirt's VR sensor circuit and only come into play when the MS is reading the crank trigger directly instead of the PIP signal from an EDIS module. The usual symptom of the wrong value there is a drop in the RPM reading. Quote Link to comment Share on other sites More sharing options...
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