Passed HC, Failed CO

Brad Bartilson

New Member
Feb 2, 2002
Gettin closer but no tamale! After failing the IM240 test 4 times previously (extremely high HC and CO), I've managed to pass HC but still quite high on CO. So far I've:
-Swapped high temp thermostat back in, running 190F.
-installed an emissions chip
-used CRC emissions additive to fuel
-adjusted my T+ to leanest setting, BLMs/INTs move around 128

Could it be that my Kirban high flow CAT is the issue?

-Brad 87TR
Readings Most Recent TEst:
HC (gpm) 2.5 [limit 3.0]-pass
CO 40.13 [limit 20.0]-fail
CO2 500 [no limit]
Nox 1.94 [6.0 limit]-pass

Previous test:
HC 3.3 (fail)
CO 25.0 (fail)
Nox 1.149 (pass)
Okay, what chip is installed? What injectors? Is the chip for those injector? I noticed that as the HC dropped, the CO went up and the NOx went up. How warmed up was the engine? Was the engine management system in closed loop for a long period of time?
Injectors are 009s. Chip was Joe Lubrant's emissions chip. Joe has cut me several chips for these injectors, mostly to try to make it run leaner. Car was warm, in closed loop (10 mile drive). At the end of the test I was seeing 200F. This run the fuel pressure was 35psi. When I've tried to run less, I stall frequently. Seems that I can make the BLM and INT values run (average) above or below 128 by varying the fuel pressure, however, I get stalling when I go too low.
If it stalls when you drop FP, what are the IAC numbers and the TPS settings? Those should be set pretty close to factory 15-20 for IAC and 0.42v for the TPS. Are they set that way? How low are you trying to adjust the FP to?
0.42 TPS, I had IAC as low as 15 with low fuel pressure (25psi), but I when I adjusted the fuel pressure back up to 35 psi to avoid stalling, IAC went up to 50.
I was also seeing intermittent "burps" on Turbolink (~1 per 25 frames) that indicated low battery (down to 0 volts). Couldn't catch it (verify it) with a DVM, so I installed WinALDL which uses the COM port (and a different cable) instead of the parallel port used by Turbolink. Still get the same single frame "burp". While the other frame readings are normal, I'm wondering that since all the readings are hosed up during this burp, perhaps it is affecting the fueling enough to cause a problem. My next step is to obtain a max/min hold DVM and try to catch it on the supply line to the ECM.
Maybe instead of using a DVM, you may try a graphing multimiter or a digital storage oscilloscope(DSO). Like a Fluke 98, MAC wave or SnapON LS2000. The refresh rate of a DSO is in milliseconds.