turbo integ backfires

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sil180drifter

Junior Member
need help just got my turbo installed on my integ took it around the block to about 6 grand. it ran fined but when i was cooling the turbo down on idle i decided to just blip the throttle to hear the blow off valve and it happend a loud ass pop almost like a shotgun blast. i immediately stop the car. know im kinda of afraid to take the car to the limits. does anyone know how this problem got started. thanks
 
get better engine management. Backfires are from running stupid rich, or in any case where there is enough fuel left after combustion to re-ignite from the heat of the exhaust.
 
Is there a way to stop that? I dont have a turbo on my h22 but I notice some times when I let of the throttle while im actually moving it back fires!
 
Originally posted by pissedoffsol@Aug 19 2003, 10:45 AM
tune what? an FMU is non-tunable

Sure it is. You can change the disk in it. Oh yeah, it's not *TUNABLE* like a Hondata, but it's more tunable than you make it to be.

Also, B, you've never owned a turbo Honda, let alone one with an FMU. I have. I've also done the AFC hack. The FMU isn't really that bad Sure, it's the bottom of the barrel, but it's simple, cheap, and at lower boost levels, goddamnit, it does work.
 
Originally posted by liquid00meth@Aug 19 2003, 01:11 PM
define "works". heh. You mean, "makes the car run", or do you mean makes the car run for more than 10,000mi :p

I ran an FMU on my Civic at 10 PSI from 117K miles to 133K miles. Then got rid of it. As far as I know, the car has almost 140K on it, and it's still running strong. Most likely, it'll be at my get together in a few weeks, and you'll be able to see it there.

It was always rich as soon as boost came up. The *ONLY* thing wrong was that my turbo spooled so quickly, that when transitioning from vacuum to boost fast, it'd go lean for about a second, and I think that problem could have been solved by finding an alternate vacuum source than what I was using. I never got around to playing with it, though.
 
it would go lean because there was nothing that anticipates the boost coming (ie. and ECU). But if it runs that long, I mean, an FMU is crappy, but heck for low boost levels I guess it is the cheapest way out.
 
Actually, it was going lean because the vacuum line I had going to the FMU was taken from the OEM FPR source. Essentially, I had fuel lag. What I should have done, and would have tried if I had the car longer, was to mount the FMU near the turbo and take the boost signal driectly from the compressor housing. This would have allowed the FMU to see boost sooner than the intake manifold, and would have gotten rid of the lean spot.

Then again, the lean spot only showed itself if you were driving really hard.

An FMU isn't crappy. It's an ingenius device that was developed in the '70's to feed carbs more fuel under boost. It just happens that it'll work under limited conditions with fuel injection.
 
i have the calibration plates and a field vtec controller and will get the car dynoed soon hopefully this will solve the problem thanks for the reply. if anyone else got anymore 5 cent to add to this please do. would help out alot.
 
man, there is nothing crappier than an FMU. There is no "more" bottom of the barrel. they work for low boost and choppy fuel curves, but they are anything BUT not crappy.
 
i know its fucken crrapy but i bought it brand new for 75 bux and the plates cost me 50 bux and this was years ago before hondata became popular if i had to do it again i would've probably gone hondata
 
Than again with hondata you have to have a pro tune the system at a authrized hondata store! Well at least to be sure its going to be 100% right.. and keep costs down without have the stage 4 system.. or what ever one that always you to do it! Whats shitty about that is when you live in the middle of no where and the closest place is 2 states away!
 
Originally posted by Accordturbo94@Aug 23 2003, 11:32 AM
Than again with hondata you have to have a pro tune the system at a authrized hondata store! Well at least to be sure its going to be 100% right.. and keep costs down without have the stage 4 system.. or what ever one that always you to do it! Whats shitty about that is when you live in the middle of no where and the closest place is 2 states away!

not true. you are more than welcome to buy the tuning package.. rom editor and so forth. nothing is stopping you.

but do you trust yourself to tune?

that, and stage 4 stopped being made about 2 years ago. you need to do some more reading up on it :p
 
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