Holley hp efi computer and obd2 inspection
01-04-2016, 12:07 PM
#1
Holley dominator efi computer and obd2 inspection What do people do that are running the Holley computers in a street car than need to pass inspection? Are there provisions in the Holley for setting monitors or do you need the stock computer
Last edited by lmt0705; 03-19-2019 at 06:31 AM.
01-05-2016, 01:39 AM
#3
I would be willing to bet you could put the obdII port in the car and hook it to a "momentarily mounted" ecu. Then wire it up with a "bench harness" with just enough **** to keep it "happy". Have the other ends of this "bench harness" go out to the few things it needs to show a happily running car. Get the car inspected and then Go home and disconnect it all.
It would be well worth the effort in my mind if it was something that could be installed and spliced in with connectors in about an hour or two and then taken back off in and hour or two. Doing that once a year would not be that bad.
It would be well worth the effort in my mind if it was something that could be installed and spliced in with connectors in about an hour or two and then taken back off in and hour or two. Doing that once a year would not be that bad.
01-05-2016, 06:25 AM
#4
9 Second Club
Some of the new Haltech and Link ecu's offer OBD data and comms.
Other than that, for ecu's that dont offer it, but you need to retain comms with the OEM ecu then you'd need to piggyback the aftermarket ecu install leaving the OEM ecu in place, and if need be placing resistors etc on some loads to keep the OEM ecu happy, or else disabling any fault codes within the ecu itself.
Other than that, for ecu's that dont offer it, but you need to retain comms with the OEM ecu then you'd need to piggyback the aftermarket ecu install leaving the OEM ecu in place, and if need be placing resistors etc on some loads to keep the OEM ecu happy, or else disabling any fault codes within the ecu itself.
01-05-2016, 09:54 AM
#5
On The Tree
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woof that sounds like serious PIA. So are late model street cars just not running holley systems? Piggy backing ECUs with resistors to fool the stock computer sounds like a serious undertaking... is this something people are doing in their garage?
Do any of the micro or mega squirt products support OBD2?
Do any of the micro or mega squirt products support OBD2?
01-05-2016, 10:18 AM
#6
9 Second Club
woof that sounds like serious PIA. So are late model street cars just not running holley systems? Piggy backing ECUs with resistors to fool the stock computer sounds like a serious undertaking... is this something people are doing in their garage?
Do any of the micro or mega squirt products support OBD2?
Do any of the micro or mega squirt products support OBD2?
No more difficult than wiring in any system really. Piggybacking ecu's isnt uncommon these days because often the "engine" ecu is no longer limited to just the engine and can often be required for some car/chassis functions so the ecu must be retained, even if you want better engine control options for the tuner.
Whether it's DIY or not is simply down to ability, patience and having the correct information to make it happen
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01-05-2016, 11:04 AM
#8
TECH Resident
As stated, I would wire a factory ECM as simply as possible and have someone with HPT or EFIlive reflash it to eliminate codes and have all the monitors ready. I imagine NY is a lot like PA as far as emissions testing goes and this would satisfy "most" of us inspectors. I'm sure a google search would probably net some results for the simplest way to wrap it up.
01-05-2016, 11:29 AM
#9
9 Second Club
"Simple" really....although perhaps not always that simple
Decide what things you need the OEM ecu to and then the aftermarket, and wire accordingly.
generally speaking 2 wire resistive sensors cannot be shared with 2 ecu's or gauges so for coolant temp you'd need a sensor for each ecu.
Some ecu's can be configured though where pairing up wont affect readings, but not all.
3 wire powered sensors eg crank, can, MAP etc can be shared no problem.
So the install could be as simple as the Holley taking over fuel/spark duties leaving the OEM to control everything as it had been or you could give the Holley more control.
So it can be as simple or difficult as you want to make it.
01-05-2016, 11:39 AM
#11
9 Second Club
Piggy back you wouldnt be disconnecting any sensors from the OEM ecu. You would have no need to, except if you got rid of the MAF for example.
01-05-2016, 11:39 AM
#12
12 Second Club
You could make this work by running Holley or some other PCM with a stock PCM just feed the stock PCM a couple sensors with all the codes set to do not report and be fine.
01-05-2016, 12:42 PM
#14
12 Second Club
But you could easily build a harness to feed the stock RPM crank sensor, ECT, and a few other data sources.
01-05-2016, 01:53 PM
#17
9 Second Club
01-06-2016, 09:19 AM
#18
12 Second Club
Right but if you're running Holley or another system you're going to run their harness and then feed stock PCM some specific inputs.
Last edited by mshadow; 01-06-2016 at 09:25 AM.
01-06-2016, 09:20 AM
#19
12 Second Club
Actually they are the issue
The way you get a factory PCM to pass readiness without AIR/EGR/O2s/EVAP is setting all the codes to Do Not Report which then causes all those readiness monitors to pass when you key on.
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