This problem is driving me crazy. My signature will tell you what I have however I know I have the DIST. on TDC and I have replaced the IAC...TPS...MAP...and dist controll module..it has a new fuel pump. When we go for a drive it will idle beautifully then when you drive it put it under load it will backfire in the TBI...I can put my timing light with the wire for the dist. unpluged and set it at 6* BTDC where fastchip calls for then I can see it JUMP past 12* BTDC me doing nothing but watching.

Help me its killing me

Brian

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1989 Camaro RS

305 .030 over Hydro Pistons
Vortech heads milled to 58cc...Performer RPM intake....LT4 cam..Crane Gold rockers...FastChip custom chip...ALum. Driveshaft...3.73 gears with Posi...underdrive pullys...Rebuilt 700R4 with Vette Servo and B&M shift Kit...MSD ignition...A/C Delete No SMOG junk....1997 SS leather interior...B&M Shifter... Ultimate TBI mods...14X3 K&N open Element Non-Drop...Hooker headers....3" exhaust with Flowmaster Cross flow 16X8 Wheels from 97 RS Spohn LCA's Spohn Panhard Bar..LETS PLAY FORD!!

 

are you setting the timing with the EST disconnecteD?

that's the single brown wire with the black stripe located on your heater box under your hood on the passenger side..

disconnect it, start your car, set your baes timing (6 BTDC) then turn off your car and start it.. it will throw a Code 42 (EST, Electronic Spark Timing)

here are two tech articlels on wrote on timing... hope this helps

http://www.iroc-z.org/tech/distribut...ngdistrib.html
http://www.iroc-z.org/tech/distributor/settingtiming

ttyl man,
Colin

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Webmaster: www.IROC-Z.org

 

Yes the wire is unpluged. I just can't figure it out.......Idles like a dream but put under load it will backfire in the TBI....

OH GOD OF COMPUTERS SHINE ON ME!!
Brian

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1989 Camaro RS

305 .030 over Hydro Pistons
Vortech heads milled to 58cc...Performer RPM intake....LT4 cam..Crane Gold rockers...FastChip custom chip...ALum. Driveshaft...3.73 gears with Posi...underdrive pullys...Rebuilt 700R4 with Vette Servo and B&M shift Kit...MSD ignition...A/C Delete No SMOG junk....1997 SS leather interior...B&M Shifter... Ultimate TBI mods...14X3 K&N open Element Non-Drop...Hooker headers....3" exhaust with Flowmaster Cross flow 16X8 Wheels from 97 RS Spohn LCA's Spohn Panhard Bar..LETS PLAY FORD!!

 

did you put a new timing chain on the engine?

if you did, did you use your old crankshaft camgear or did you replace it with a new one?



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Webmaster: www.IROC-Z.org

 

The cam is from a LT4 and its all new timing chain but I did not change the gear on the DIST. Do I have to have a gasket between the Dist and the intake because I don't think it does. Could any of these things make this happen.

Brian

------------------
1989 Camaro RS

305 .030 over Hydro Pistons
Vortech heads milled to 58cc...Performer RPM intake....LT4 cam..Crane Gold rockers...FastChip custom chip...ALum. Driveshaft...3.73 gears with Posi...underdrive pullys...Rebuilt 700R4 with Vette Servo and B&M shift Kit...MSD ignition...A/C Delete No SMOG junk....1997 SS leather interior...B&M Shifter... Ultimate TBI mods...14X3 K&N open Element Non-Drop...Hooker headers....3" exhaust with Flowmaster Cross flow 16X8 Wheels from 97 RS Spohn LCA's Spohn Panhard Bar..LETS PLAY FORD!!

 

did you change the gear on the crankshaft..

the gear on the distributor doesn't usually wear much, there's not much stress on the gears there..

no, timing wouldn't be affected by not having a gasket but you should have on there anyway..



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Webmaster: www.IROC-Z.org

 

i just wanted to note that backfiring through the distributor usually means you are running too mcuh timing..

the cylinders are firing while the intake valve is still open.

back off the timing a few degrees and see how it takes it.

 

Ok what timing setting would be good? Any other ideas.

Brian

------------------
1989 Camaro RS

305 .030 over Hydro Pistons
Vortech heads milled to 58cc...Performer RPM intake....LT4 cam..Crane Gold rockers...FastChip custom chip...ALum. Driveshaft...3.73 gears with Posi...underdrive pullys...Rebuilt 700R4 with Vette Servo and B&M shift Kit...MSD ignition...A/C Delete No SMOG junk....1997 SS leather interior...B&M Shifter... Ultimate TBI mods...14X3 K&N open Element Non-Drop...Hooker headers....3" exhaust with Flowmaster Cross flow 16X8 Wheels from 97 RS Spohn LCA's Spohn Panhard Bar..LETS PLAY FORD!!

 

btt

------------------
1989 Camaro RS

305 .030 over Hydro Pistons
Vortech heads milled to 58cc...Performer RPM intake....LT4 cam..Crane Gold rockers...FastChip custom chip...ALum. Driveshaft...3.73 gears with Posi...underdrive pullys...Rebuilt 700R4 with Vette Servo and B&M shift Kit...MSD ignition...A/C Delete No SMOG junk....1997 SS leather interior...B&M Shifter... Ultimate TBI mods...14X3 K&N open Element Non-Drop...Hooker headers....3" exhaust with Flowmaster Cross flow 16X8 Wheels from 97 RS Spohn LCA's Spohn Panhard Bar..LETS PLAY FORD!!

 

Move it back in increments of 2*. See if that stops it.
bsa

 

i would start a 0 BTDC and go from there.

just because you have a cam that says "go with 10 degrees" or whatever, doesn't mean that is what your engine will want. Set it where the engine wants it best

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Webmaster: www.IROC-Z.org

 

Well the thing is that if I set the timing at 6*btdc where the chip asks for the idle is wonderful but when you get on the road is the problem. I think the advance is not advancing when speed comes up......Any ideas...this is killing me No matter where the timing is with the wire pluged in there is a backfire and no power


Brian

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1989 Camaro RS

305 .030 over Hydro Pistons
Vortech heads milled to 58cc...Performer RPM intake....LT4 cam..Crane Gold rockers...FastChip custom chip...ALum. Driveshaft...3.73 gears with Posi...underdrive pullys...Rebuilt 700R4 with Vette Servo and B&M shift Kit...MSD ignition...A/C Delete No SMOG junk....1997 SS leather interior...B&M Shifter... Ultimate TBI mods...14X3 K&N open Element Non-Drop...Hooker headers....3" exhaust with Flowmaster Cross flow 16X8 Wheels from 97 RS Spohn LCA's Spohn Panhard Bar..LETS PLAY FORD!!

[This message has been edited by Brian Felts (edited June 14, 2001).]

 

What sort of backfiring is this? Is it one big pop when you press the gas and then it's sort of OK, or does it go pop-pop-pop-pop in time with the engine speed (i.e. as the engine speeds up the popping does too), or does it just randomly pop during acceleration with no particular direct correlation to engine RPM? All 3 of these things would indicate different possible causes.

You do need a gasket between the dist and the intake, otherwise it will leak oil as I'm sure you have discovered by now. That has nothing to do with the other problem.

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"So many Mustangs, so little time..."
ICON Motorsports

 

Its one big POP when I hit the gas....Then it will pick up speed then if you hit the gas again One big POP.


Brian

------------------
1989 Camaro RS

305 .030 over Hydro Pistons
Vortech heads milled to 58cc...Performer RPM intake....LT4 cam..Crane Gold rockers...FastChip custom chip...ALum. Driveshaft...3.73 gears with Posi...underdrive pullys...Rebuilt 700R4 with Vette Servo and B&M shift Kit...MSD ignition...A/C Delete No SMOG junk....1997 SS leather interior...B&M Shifter... Ultimate TBI mods...14X3 K&N open Element Non-Drop...Hooker headers....3" exhaust with Flowmaster Cross flow 16X8 Wheels from 97 RS Spohn LCA's Spohn Panhard Bar..LETS PLAY FORD!!

 

Too Much advance, WAY to much advance.




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60 Ranchero - Project ( Money Hole )
85 Sport Coupe LG4 - Daily Driver 15.26 @ 87.0
Reader's ride -> My Ride

Just another Hot Rod kid, or thats what they all tell me.
Livin' the Stereotype

 

my 74 used to do that.. im almost positive it hasnt happened to you, but look under the distributor cap.. my button got melted into the plastic around it, wierd. anyhow, it would idle fine, rev fine, put it in gear and it would crap on itself. also, start over with the timing. take your distributor out.. check everything to make sure its all hooked up right, put the distributor back in. Put the #1 at TDC, check timing, and try again. it could be an electrical problem like i had, or it could be something mechanical that isnt working together(like timing).

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• 83 Z28-- not a pretty site to look at, 200k miles and im sure it was treated like a rental car every day of its sad life(before i got it).. sold, thank the lord
• 74 Z28-- 383/400, green on black. pretty clean. FOR SALE!!!

 

Did you hook the EST wire back up before you drove it? If not you need to.

 

Big pop when you hit the gas is a lean condition... not enough fuel being fed. Sounds like you need chip work and/or an AFPR. Specifically, in your chip's programming, you need to increase the function that correspnds to the accelerator pump in a carb.

Continuous popping that sounds like once each engine cycle is a valve that leaks pr whatever reason, or a bad head gasket in certain places. A random contnuous popping not correlated to engine speed would be very early ignition timing.

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"So many Mustangs, so little time..."
ICON Motorsports

 

What fuel Pressure is good for stock. I have a Meter on it but don't know whats NORMAL.


Brian

------------------
1989 Camaro RS

305 .030 over Hydro Pistons
Vortech heads milled to 58cc...Performer RPM intake....LT4 cam..Crane Gold rockers...FastChip custom chip...ALum. Driveshaft...3.73 gears with Posi...underdrive pullys...Rebuilt 700R4 with Vette Servo and B&M shift Kit...MSD ignition...A/C Delete No SMOG junk....1997 SS leather interior...B&M Shifter... Ultimate TBI mods...14X3 K&N open Element Non-Drop...Hooker headers....3" exhaust with Flowmaster Cross flow 16X8 Wheels from 97 RS Spohn LCA's Spohn Panhard Bar..LETS PLAY FORD!!

 

I don't know for sure, but I believe somewhere around 11 or 12 psi is normal. I don't fool around with TBI though, so I don't really know.

------------------
"So many Mustangs, so little time..."
ICON Motorsports

 

i am having kind of the same problem . i have taken a old 350 block an put vortec heads with new crank, timing chain, voodo lunati cam, all new from top end to bottom end. when i start it the motor idles fine but when i hit the gas just a lil bit it will pop backfire an sometimes come back up thru the carb, it is also running way to rich. took all the plugs out an bought new ones changed the factory coil an wires to accel. i also changed the power valve on my holley carb. did all of that seemed to idle better gave it some gas an pop backfire pop... etc can any body tell me what i'm doin wrong, an how to fix my prediciment...

 

I'm getting sorta the same problem after we changed the fuel pump. We'll find out if it's the timing tomorrow. Though, mine only pops when it's in park(or neutral) and I rev it up a bit. I don't rev it up too high but it still pops a bit. My problem is probably a little different from yours..but most of the symptoms are the same(no power, etc.)