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completly stumped

M

MJ1990buildup

NAXJA Forum User
Location
Chesapeake Beach
i have good gas in it, fuel filter, fuel pressure is great, new ignition coil, plugs, wires, cap, rotor, cps, rechecked compression is way up around 130ish, cleaned throttle body

still backfiring, noticed a little more power now, but no where near where it should be

i am completely stumped and thinking about going to get it scanned

not sure about the tps, o2 but they are fairly new they might of just got wet and wouldnt think of them to cause backfiring anyways

still have a slight exhaust leak from where i welded my cat on but i am almost positive that is not the problem

the only new gauge i havent bought yet is the vacuum tester but i wouldnt know where to begin, what the hell can be the problem?????
 
More than likely the CPS!
 
Mine wasnt backfiring but got real crappy gas mileage messed with it for about a week finally took it to the dealer. they said what the problem was is that i had a bad o2 after cat but I was like no I replaced it so we put a new on there then the front was bad so we put a new one on there. then the back was bad again. turns out the infamouse leak in the headder was the source of the prob it was sucking in cold air telling the o2's it was running lean causing it to throw more fuel in that combined with a bad o2 sensor just caused a big cycle one bad after the other. replaced the manifold and has been fine since.
hope it helps if it makes sence
 
MJ1990buildup said:
i have good gas in it, fuel filter, fuel pressure is great, new ignition coil, plugs, wires, cap, rotor, cps, rechecked compression is way up around 130ish, cleaned throttle body

still backfiring, noticed a little more power now, but no where near where it should be

i am completely stumped and thinking about going to get it scanned

not sure about the tps, o2 but they are fairly new they might of just got wet and wouldnt think of them to cause backfiring anyways

still have a slight exhaust leak from where i welded my cat on but i am almost positive that is not the problem

the only new gauge i havent bought yet is the vacuum tester but i wouldnt know where to begin, what the hell can be the problem?????
Click to expand...

Is all you ignitions stuff stock???? This is VERY important!!!!!!!! Your never know with any thing else....................
 
yes, all ignition is stock

i started it up and thought it was running alright, took it around the block with minimal backfiring

got back and realaized my map sensor vacuum line wasnt connected

hooked it back up and idle went to crap again and started backfiring

funny thing is the map sensor voltage test fine


keep them coming guys
 
Sounds like you either have a vacuum leak somewhere or timing is off.

Have you had the distributor out or messed with the throttle body or intake?

You say you have a vac gauge, whats your reading at idle?

Have you replace the pickup unit in the bottom of the distributor?
 
just tightend up my manifolds

still checking vacuum, not sure if i have a leak somewhere or not,
i do not have a vacuum gauge, looks like i might have to buy one

have not replaced the pickup on the distributor, but i havent had it out, havent messed with the timing, i think i'm goin go pull my valve cover and see if i can set my timing

can a distributor pick up get messed up from water, or would water not get to it, i didnt have any water in my oil

and i did pull off my throttle body and cleaned it thoughorly
 
distributor with water in it will kill you!

had many a time in which preasure washing the engine and filled distrubutor with water, ran for sh|t. drove it home, pulled distributor cap off, sat there with hair dryer and paper towels, runs good now.

check distributor cap, maybe a contact is worn and you are dumping gas out on the exaust stroke for a cyl right in to the hot exaust, causing a backfire? I know this seems simple, but did you look at the wires to make sure they were in the right order?

dont know after that....

shouldnt this be in oem tech? jsut a though, no problems though...
 
Last edited:
Just an idea ... you may have a worn out distributor (bad bearings). If you have a timing light, check to see if it's advancing too far when you rev the engine. You may be able to feel the slop in the shaft if it's real bad.

Good luck ...

Les
 
ok guys, tps checked out alright, and i am positive there is no water left in my distributor

it backfires at idle, less when throttled up
yes my wires are in the right order, i'm positive

i'm starting to think timimng simply because i have pretty much checked or replaced everything else

and again, it ran perfect before i took it for a swim, i would be really suprised if it is timing because these stupid things arent supposed to slip, but its getting narrowed down to it at this point

i'm also starting to think about egr, btw its brand new as well
 
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