1G Car still backfires after like 4500

[BigRb247]

OK well you can read my setup in my profile, but heres the problem.

When I go to 100% throttle, it backfires like a mother at like 4500 till whenever. The weird thing is, it only does it certain times. Like the last couple nights its been cool here, and it doesn't do it, but like this morning/afternoon it was like 70 out, it did it. I don't get it and I'm getting really annoyed.

Could this be a vacuum leak or something else? I have my big 16g ported, and the 34mm flapper mod. Any input would help. Thanks.

PS I also have NGK plugs and wires, and I just changed the plugs AGAIN last week.

 

[1993eclipseGS]

Does it loose all it's power as soon as it starts to break up?

 

[CanadianTSi]

Whats the gap on the Plugs?

 

[Maglin]

Also how much Boost are you running?? Usually a backfire is ignition related. Maybe you have a CAS that is going out or possibly a bunch of crud on your intake valves. Also make sure that your Base Timing is set properly.

 

[BigRb247]

To answer your questions, no it doesnt lose power. There gapped at .28 IM running 20 PSI. Whats a CAS. Sorry im not that advance, and i have no idea how to cheack my base timing, could someone fill me in?? Thanks

 

[gsxtacy]

.028" gap is good for under 18 psi.

If your touching 20 psi AT ALL...you definetly need to decrease the gap to .024-.026"

The compressed air is blowing the flame out.

You good to go after a gap change!!!

Good luck.

gsxtacy

 

[BigRb247]

Alright thanks il try it out and let u guys know

 

[gsxtacy]

any updates?

 

[BigRb247]

yea, ive been so busy latley i forgot to post back sorry, but anyways yea that was the problem, it hasnt done it secnce u told me to do that, it pulls with them gapped at .26 thanks gsxtacy!!!!! But im goin to the track next week, u think i should turn up the boost a couple lbs or no? remember im at 20?

 

[gsxtacy]

if you have access to 110 octane or better, sure turn up the boost as much as you feel comfortable with. Your intercooler is the wink link. Any boost over 23 is useless if your on a SMIC, and don't have H2O injection.

good luck, glad to know I nailed it!!

gsxtacy

 

[BigRb247]

OK well my car still backfires after liek 4500. I was suggested to gap my plugs at .24-.26 since im running 20 psi. That seemed to work for a day or to and now it still does it. I have ngk plugs and wires. I have the bpr6es's. Do i need to get the Bpr7es's? I had them on before but this was when i thought they burnt out, and the only thing they had at the local car quest was the 6es's. I never gapped the 7es's at .24-.26. DO you think i need the 7es's? Or is there another problem? I dont want to buy them if its not gana do anything. It just gets really annoying!!! thanks

 

[gsxtacy]

List your recent (within 1yr) maintanence:

Everything. Air filter cleaning, 4 oil changes....ect.

If your fuel filter hasn't been changed or cleaned......As extrememotorsports says....and I quote "changing the fuel filter cures a host of problems on DSMs", it can cause studdering and bucking.

But tell me everything.

gsxtacy

 

[92awddsm]

Well, a set of ngk 7's are only $8 so its not like they are a lot of $. I switched to the 7's after 18psi and I think a lot of people would recomend it. Do you have a NAPA close to you? Last time I got mine, they had 108 ngk bpr7es in stock. I have to order them from any other place. You might also want to try a shop that sells/repairs atv's. The 7's were stock is some honda atv from what a local cycle shop told me.

 

[BigRb247]

Had 5 oil changes since I owned it about a year ago. Had a new air filter for about 3 months but still backfired before that. I haven't changed the fuel filter. Timing belt done about 4 months ago. And I think that's about it.

 

[gsxtacy]

1. Unbolt fuel feed at fuel rail.
2. Disconnect main fuel line in front of Pass. Rear wheel.
3. Have a friend hold 44 oz. Coca Cola cup on fuel rail feed line in engine bay.
4. Use 35-55 psi compressed air and blow from rear of car to fuel rail feed line
5. Get some clean gasoline and small funnel and re-fill fuel filter line with clean fuel.
6. Have friend put 44 oz cup on rear fuel line.
7. Blow (now clean) fuel from front to rear.

Repeat until clean fuel is obtained.

You'll be surprised how dirty the fuel filter is. After this process, run some fuel injector cleaner in the tank and let me know how it runs afterwards.

Then again, you could buy a filter and attempt the swap., I still recommend the FI cleaner afterwards though.

gsxtacy