Back fire when i turn the key? Now it wont idle

Questions about the Platinum Sprint series ECU settings or features? Ask here.
ap1234
Posts: 12
Joined: Sat Jul 20, 2013 3:08 pm

Back fire when i turn the key? Now it wont idle

Postby ap1234 » Wed Aug 14, 2013 12:34 am

Hi if any one could help or has any ideas it would be very helpful.
So ive been driving with haltech 500 for a bout 2 weeks now and it runs pretty well for my inexperienced DYI street tune.
Yesterday when i turned the key to the on position on my car i heard a strange back fire. I didnt turn the engine over or anything i just booted up the haltech. I checked the manifold and it had knocked out the hose for the pcv valve. I replace the hose. Checked all the vacuum hoses and started up the car and now it wont idle. Like its not getting enough air. I can hold the car on with my foot on the throttle but when i let it go the revs drop below the 500 mark on my dash.
I raised the raw idle adjustment on the throttle body and got it to idle at 600rpm.

I unplugged the egr valve just in case because it was making a weird noise. (but its always made this noise and it was running fine). Im going to make a block off plate for it today incase its stuck open or something.

I reuploaded the back up of the map. And no change. I raised the duty cycle on the idle control and made almost no noticeable difference. (from 50% to 100% made like 100rpm of difference) When before a 10% change would mean about a 600 rpm difference.

Im not sure what could of happen or why it back fired like it did, and why now it wont idle.
Other then that the car Drives fine, and gets into boost.
AFR look good, Vacuum pressure looks normal 21inHg now that i got it idling and about 24inHg under engine braking.

baselkwt
Posts: 132
Joined: Wed Mar 20, 2013 11:16 am

Re: Back fire when i turn the key? Now it wont idle

Postby baselkwt » Thu Aug 15, 2013 1:23 pm

dont know. but something similar happened to me once. check that your camshaft sprockets havent jumped a tooth on your timing belt

ap1234
Posts: 12
Joined: Sat Jul 20, 2013 3:08 pm

Re: Back fire when i turn the key? Now it wont idle

Postby ap1234 » Fri Aug 16, 2013 12:14 am

thanks for the reply
im going to check the timing today while i put in the block off plate.

i think the idle control valve may have crapped out.

JimKden
Posts: 370
Joined: Wed Jan 12, 2011 2:28 am

Re: Back fire when i turn the key? Now it wont idle

Postby JimKden » Fri Aug 16, 2013 1:18 am

Seems like Haltech likes to trigger the coil drivers on key on. It will blow stuff off the intake, it did for my two cars until I installed a relay and set an rpm switch to close the relay on cranking to avoid the blowback.

ap1234
Posts: 12
Joined: Sat Jul 20, 2013 3:08 pm

Re: Back fire when i turn the key? Now it wont idle

Postby ap1234 » Fri Aug 16, 2013 8:10 am

JimKden wrote:Seems like Haltech likes to trigger the coil drivers on key on. It will blow stuff off the intake, it did for my two cars until I installed a relay and set an rpm switch to close the relay on cranking to avoid the blowback.


Where did you buy this relay and how do you have it wired up? So the haltech only gets power once it engine is turning over?

JimKden
Posts: 370
Joined: Wed Jan 12, 2011 2:28 am

Re: Back fire when i turn the key? Now it wont idle

Postby JimKden » Tue Aug 20, 2013 12:33 am

Any 12V DC relay with Normally open output contacts will work. The switched side (output contacts) is wired into the +12V feed to the coil. The relay control side is wired with the same +12V feed (that was used for the output contacts). Set any unused DPO for a rpm switch and wire it's terminal to the relay control side. Set the rpm switch to turn on at some low rpm, say 100rpm and off at some number above your maximum expected rpm (above redline).
The relay will be open and no power to the coils until the rpm reaches the setpoint (say 100 rpm). The rpm switch then closes the relay at the DPO set to close rpm and will remain closed above the rpm switch setpoint up to the maximum setting for the rpm switch. This way the coi criver can be cycled at key on and the coils are unpowered at that time.

ap1234
Posts: 12
Joined: Sat Jul 20, 2013 3:08 pm

Re: Back fire when i turn the key? Now it wont idle

Postby ap1234 » Tue Aug 20, 2013 1:36 am

Oh i see thats very simple thanks, but both my general purpose DPOs are in use, idle control and boost control...
Ill just drive like this i guess it hasn't done it since.

It ended up it was the idle control valve, i went to junk yard picked up two(5 bucks each!) just incase, switched it. Now it idles fine


Also i was wondering if you could help me with one other issue im having. Its very hard to star when its cold. Its like the crank timing is retarted, but its set to 10BTC my base ignition timing. It sounds like its firing when the piston is on the way down i hear a pop out the exhaust. it only does this when its cold and only does it the first time i start it. I have the crank speed set to 300rpm im not sure if thats got anything to do with it.

User avatar
Peterson
Posts: 122
Joined: Mon Aug 17, 2015 2:35 am

Re: Back fire when i turn the key? Now it wont idle

Postby Peterson » Sat Mar 31, 2018 4:51 am

JimKden wrote:Seems like Haltech likes to trigger the coil drivers on key on. It will blow stuff off the intake, it did for my two cars until I installed a relay and set an rpm switch to close the relay on cranking to avoid the blowback.

I know that it is an old thread but for everyone that get that occasional backfire at "key on" you can do what jim wrote or if you don't want to sacrifice an output assigned as an "rpm switch" a "delay on" relay can be purchased and replace the traditional one.Wiring is the same.I used that one:https://www.altecautomotive.co.uk/timer-relays-fixed-duration-12v--24v-variants-3895-p.asp and called it a day.


Return to “Platinum Sprint Series”

Who is online

Users browsing this forum: No registered users and 2 guests