Loud pop ,backfire mabye when going wot low rpm though low boost.
06-11-2009, 10:24 PM
#1
Loud pop ,backfire mabye when going wot low rpm though low boost. I fought a super frustrating cam sensor problem and won but now getting stumped. Car is making a loud pop /backfire type of thing when try to go wot now to have some fun with my kit. Last fall I couldn't dare go wot as had 60s but stock pump. Now have lonnies twin pumps ,we did test them and they seemed to be working at least off boost each pump was working.
I have hobbs switch on second pump. I have 60s in there.
I have new granatelli wires and new plugs. gapped at about .030 or .028 .
I have new fuel filter injectors. I have no fuel pressure gauge in cabin yet. Soon. I have hptuners and its been recently 3 bar tuned. Don't see anything too obvious in the tune but did go very low on timing like 12 max.
And have like 10 on low octane table but here it only reverts to that on stock operating system not hptuner 3 bar. I can't check misfires they don't work with 3 bar hptuners . Car seems to run fine idling ok. has been shutting off lately like out of the blue but restarts instantly and other than the pop/backfire at wot it seems fine. No check engine stuff either.
It does not do this at high rpm wot.I have not go up that far.If go more part throttle think can get to rev limit of 6500 out of it.
Its more quick stab of the peddle at even low rpm like 2000 or 3000 in say third or fourth that brings this on.
Other day too thought it soing somethihng when tried to go wot in sixth. It almost seems like hitting a rev limiter but have that set at 6500.
So any ideas fellow boosted guys.I doubt its plugs blowing out. Only running at gate boost of 8psi and so far haven't. Have seen 5psi going under wot .
I can't see it being fuel with the new pumps and all. I can see mabye something dumb was done in tune.I did some of it and local guy did other stuff on it. Someone said maybe the timing is just too low. Maybe too rich too .Have to log some stuff. As said can't log misfiires unless put maf back in and maybe rig up 1bar sensor.
I want to use my power. Whats up?
I have hobbs switch on second pump. I have 60s in there.
I have new granatelli wires and new plugs. gapped at about .030 or .028 .
I have new fuel filter injectors. I have no fuel pressure gauge in cabin yet. Soon. I have hptuners and its been recently 3 bar tuned. Don't see anything too obvious in the tune but did go very low on timing like 12 max.
And have like 10 on low octane table but here it only reverts to that on stock operating system not hptuner 3 bar. I can't check misfires they don't work with 3 bar hptuners . Car seems to run fine idling ok. has been shutting off lately like out of the blue but restarts instantly and other than the pop/backfire at wot it seems fine. No check engine stuff either.
It does not do this at high rpm wot.I have not go up that far.If go more part throttle think can get to rev limit of 6500 out of it.
Its more quick stab of the peddle at even low rpm like 2000 or 3000 in say third or fourth that brings this on.
Other day too thought it soing somethihng when tried to go wot in sixth. It almost seems like hitting a rev limiter but have that set at 6500.
So any ideas fellow boosted guys.I doubt its plugs blowing out. Only running at gate boost of 8psi and so far haven't. Have seen 5psi going under wot .
I can't see it being fuel with the new pumps and all. I can see mabye something dumb was done in tune.I did some of it and local guy did other stuff on it. Someone said maybe the timing is just too low. Maybe too rich too .Have to log some stuff. As said can't log misfiires unless put maf back in and maybe rig up 1bar sensor.
I want to use my power. Whats up?
06-12-2009, 11:06 AM
#3
I took hard look at my tune and last guy that helped on it did some really weird stuff. I went thru it and hoping its the problem. See how it goes when get back from trip in a few days and try it out.
If its not tune then have to double check things like fuel pressure,spark plug wires to make sure they are one, 02 sensor replacement maybe and check some plugs.
Will update in a few days.
If its not tune then have to double check things like fuel pressure,spark plug wires to make sure they are one, 02 sensor replacement maybe and check some plugs.
Will update in a few days.
