new setup backfire while cranking!!!

[gold98Z28]

just put the LQ4 in my 98 camaro. the only problem it has is popping/backfire while cranking. sometimes it will crank right up but most of the time it requires very slight opening of the throttle,and sometime it cranks it butt off, backfires and caries on like the distributer is 180 out.lol. it is internally stock except has the stock truck heads milled .045, and a 224/228,.581.588, 114LSA cam. other than that it is stock 98 computer and wiring. i thru together a base tune for starting it up from bits of my tune from the stock LS1, a stock truck tune and a tune from the repository with a similar cam. absolutly no driving or idle problems with the small cam. runs and drives as good or better than ever.
ANY suggestions on what to look at/change.here is my current tune.

[kindaslo]

I've had this problem with mroe than one ls1 computer ocntrolling an ls2 motor.

I'll be interested in what the fix is.

I've played with cranking ve, spark dwell, low frq maf. Nothing seems to have a definite effect on this.

[ls1itldo]

may be mechanical... reluctor wheel perhaps????

[kindaslo]

good point, which reluctor wheel are you using the ls1 (24 tooth) or the ls2 (58 tooth)

[Hauss]

may be mechanical... reluctor wheel perhaps????

could be but he said it ran well after startup..... does it backfire out the the exhaust? scan and see what your timing is while cranking, you could try to increase the numbers in Idle Flare Up table... also try adding some values to engine/idle/adaptive airflow/ low p/n... that table is completely zeroed out. good luck!

[Hauss]

where did the VE cranking numbers come from? just curious if those were a guess or something you tried with a similar combination....

[gold98Z28]

good point, which reluctor wheel are you using the ls1 (24 tooth) or the ls2 (58 tooth)

this is not a LS2 as my tune file says. it is a LQ4 steel block6.0 out of a 05 truck. i was under the impression it had the same reluctor wheel as the ls1. im not 100% on this tho. maybe george(12secSS)can chime in on this since he seems to have a LQ4 in everything he owens.lol the cranking VE numbers are stock for the 98 ls1. it also sets a cam sensor low input code when this happens? BUT runs,drives,idles perfect

[ls1itldo]

you just answered your question.... if the cam sensor is messed up, or the wiring is wrong, it will only happend on start up...after the car is started, it will not resort back to the cam sensor for timing, it only looks at the cam sensor on start up... Something is a miss with the cam sensor

[gold98Z28]

you just answered your question.... if the cam sensor is messed up, or the wiring is wrong, it will only happend on start up...after the car is started, it will not resort back to the cam sensor for timing, it only looks at the cam sensor on start up... Something is a miss with the cam sensor

then i will yank the one out of the stock ls1 and set all the crape ive been messin with to do with cranking back to stock and see what happens.

[Hauss]

the cranking VE numbers are stock for the 98 ls1

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shouldn't that matter? doesnt' the lq4 have different requirements? you did say that if you crack the throttle then it works fine right? what about the timing during cranking is it very low or even negative?

[gold98Z28]

nope quess not.lol it was definatly the cam sensor. thanks to ls1itldo for letting me in on its only used during startup. was unaware of that. I thought the backfire was setting the code but its all good now. much thanks.

[kindaslo]

wow, so a new cam sensor fixed your problem? or the 98 cam sensor fixed your problem?

[ls1itldo]

Cam sensor are the same for 98+ f-body. It was just a bad sensor, or bad wiring..... Glad you got it fixed

[gold98Z28]

somehow it got pulled loose during install. I would have thought it would effect it all the time but now i know why it only messed up on starting. clear the code and it would stay off forever till you started it again.lol all good now starts everytime. thanks to ls1itldo for making me check the sensor. now for the next problem. out of injector.lol stockers not cuttin it. 99% duty cycle