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I’m new to this forum and also to tuning. I have a Mazda RX3 with a 4 port 13b street port. The intake system is a TBI with 750cc on the primary and 1600cc on the secondary (both high impedance) on top of a Racing Beat intake manifold. The fuel system I have is a MSD high pressure fuel pump, 4 MSD ls1 coils, Aero motive fuel pressure regulator and 3/8 fuel return. The computer system I’m using is a Haltech PS1000 and I used Haltech’s terminated end wiring harness. I’m using the onboard MAP sensor.
A week ago I was able to get the engine started and the car was idling nice and the temperature was cool. I took the car for spin around the block, it drove nice for a lit bit, but after the second spin, the car started to idle really rough and then stalled. I tried to start the car back and it will only start if I give it a lit throttle. I screwed the throttle up a lit bit to bring up the RPMS, the car will start and stall. Car will not idle on its own. I tried to bring the idle up on the ECU, but that also does not work. I changed the spark plug thinking that was the problem, but nothing. I have good fuel pressure and spark to all the plugs. I need a little help diagnosing my problem. The car does smell like it is running little rich, but the plugs are not wet. I’m stuck and need some help. I’m using Haltech’s base map that was installed on the computer.
Are you monitoring your AFRs?
yes, readings is about 12.5
Try leaning it out, that is very rich for idle if your on pump fuel, if it's E85 it's very lean.
If leaning the mixture out does not help, I'd suggest trying to add some fuel. Rotary engines tend to need rich mixtures to idle at low RPM. My 13B-REW with stock ports idled smoothly around 12.0 AFR (on gasoline), but unhappy idling much leaner than 13.0 AFR even when warmed up. With TBI injectors mounted so far from the ports, you might need to run an even richer mixture to avoid stalling when you open the throttle. Do you know what AFR and RPM the engine was idling at when cold? Perhaps try to start by using that same idle RPM and AFR at warm temperatures, then try leaning the mixture or decreasing idle RPM if you are able.
Have you seen the webinar on fuel tuning for rotary engines?
increased the fuel still having bad idle to no idle. To keep the car running, I have to give it a little throttle to keep it running.
Try changing a new set of sparkplugs, if the idle recover maybe there is something that is fouling the plugs for example to much acceleration enrichment fueling on the ecu program. (you have big inyectors so a little exes on acceleration enrichment could wet the spark plugs too much plus the mix of two stroke oil you have to use and with the spark plugs cold heat range that rotaries use it is posible that the spark plugs are bad now. Try that like a diagnostic and then look for the cause, just an idea.
I was able to get my car to idle and it will start with no problem. At idle I was able to get my AFR at 13.5 to 14.0. The problem I'm having now is that when I hit the throttle from 0 to full throttle, the engine goes lean on the AFR and the engine hesitates. Does anybody have Haltech PS1000 map for a rotary to help me out plugging in my numbers. I played with the transient throttle and it did not help.
What did you play with, with regards to the transient throttle?
What did you change to get the engine to start and idle properly again?
Have you correctly set the base ignition timing?
There's little point worrying about your transient response until the complete fuel and ignition tables are correctly tuned as the transient enrichment needs the base fuelling to be correct first.
My timing is on zero. I was able to get some numbers from a friend for the base fuel map and the injection timing. The Haltech base map I got from the website was off, I was unable to get my car to start and/or to idle. I played with the numbers on the fuel map and the injectors. The base map: injector timing, coolant enrichment. If anybody had a map from a running rotary engine using a haltech ps1000 would be very helpful. Thank you guys for the information I have been receiving, it has been assisting me to get my vehicle running.
Any port work done? I find my street ported 13b-rew likes to idle with around 12 degrees timing, and around 8 degrees split
Basically, you need to get it dialled in and get on a dyno. There are no magic numbers that are going to make your engine run properly. Work on getting your idle around 13:1AFR on pump gas, with the timing i mentioned, it should be close. Once youve done that, you can kind of see a trend going. I would enter your injector data (dead times, size, impedence, fuel pressure) and then tweak the map, rather than playing with both. I like to do that, just to get it ldling nice. Then, to make sure your dead times are right, choose an afr to stick to at idle (ie 13:1) and then unplug the alternator (if possible) and observe the changes as the battery starts to die,and the voltages change. As the voltages change, watch the AFR, and if it changes, change the dead time until its back to the afr you started with. (i usually go down to 10v and then interpolate the rest) I hope that makes sense. After that, you can free rev it a bit, and see the trend thats emerging regarding fueling. Once you see that, you can get a rough estimate of what the part throttle fueling will be like, and can kind of fill that area of the map to get it driveable.
Thanks for the information, I will try it on my day off.