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View Full Version : could it be my timing chain? backfiring through intake/detonating


Squishy
08-31-2006, 11:05 PM
well after all the work ive done to the mustang(aluminum heads, cam, intake, fuel system, exhaust....) its still running like a pile, it will backfire through the intake once in a while when i give it a little gas, it doesnt always happen, but im running out of things that could be wrong

the reason i figure timing chain is it happened all of a sudden, i used to be able to run on 90 octane at 14* timing, im at 8-10* now and it detonates sometimes, and the backfiring. thought it was bent pushrod, checked those, fine, i figured it may be a headgasket, but theres no oil in the water or water in the oil, and it doesnt billow out white smoke.

im running out of things to check, and thats all i can come up with, but it needs fixin. what do you all think?

gordwould
08-31-2006, 11:13 PM
do a compression check that might give you a better idea i know last weekend i lost power and it started farting out the intake under acceleration so there is no compression in 1 and 3 and no water in oil or vise vursa but im sure it is head gasket and try turning the crank back and forth by hand feeling for chain slap or slack

barracuda
09-01-2006, 01:25 AM
did you do the chain when you did the cam? Sounds like it could be the chain.

Squishy
09-01-2006, 02:20 AM
i didnt, but when i checked it it looked allright, but then again ive never seen a worn one to tell the difference. ive got a new one in the box i may as well swap it out anyhow and eliminate the possibility of that problem

gordwould
09-02-2006, 12:29 AM
you might want to check out the fireing order i know there are two different fireing orders on 5.0L and 5.8L they both have two that is but that is if there is good compression

Squishy
09-09-2006, 03:32 AM
you might want to check out the fireing order i know there are two different fireing orders on 5.0L and 5.8L they both have two that is but that is if there is good compression

firing order is correct. ill check for play in the timing chain, and probably replace it asap

In The Zone
09-09-2006, 07:00 AM
i didnt, but when i checked it it looked allright, but then again ive never seen a worn one to tell the difference. ive got a new one in the box i may as well swap it out anyhow and eliminate the possibility of that problem

if it is worn u can tell by deflection on the slack side there should be a maximum deflection if it is close or exceds it time for chain

i typically replace items of this nature every time they are exposed....

chain &cam
clutch R&R including rear main and slave as well as front input shaft seal on trans if possible
gears inner seals (where appicable) outers
u name it if it can be done and means not having to open that can o worms for another couple years all the better
rather spend xtra on the other things that may fail in the future

just my .02[cheers]

lizard
09-09-2006, 09:22 AM
may be a small headgasket leak

u fuel inj?

also sounds maybe running lean , whats the plugs look like

OldEnuff
09-09-2006, 10:21 AM
My '87 Bronco was doing that after some ignition work I did.

Turns out that even though I checked and rechecked I had somehow got the dizzy in one tooth out :o [27]

gordwould
09-09-2006, 01:24 PM
do a compression check it will tell you if it is a head gasket or a valve issue if the compression is good im sticking with fireing order and ill post both fireing orders up for you to try if its got good compression(150 lbs and higher)

gordwould
09-09-2006, 01:35 PM
also if you pulled the distributor while doing all this work i would go with jim and the distributor could be set wrong but do a compression test before ripping it apart again[cheers]

230
09-09-2006, 02:26 PM
A friend of mine is real gooder with mustangs if ya like i can bring him over.

Squishy
09-09-2006, 02:26 PM
firing order is correct, 302ho&351 firing order, i had checked it and checked it again, and when i put in the new fms "high performance" 9mm wires, it came with diagrams also. its not running lean, it is running rich(fuel pressure is set to 36lbs, fuel system consists of 190lph pump, sdjustable regulator, 30lb injectors. the fuel system at the stock 39-41lbs on paper is capable of handeling 450hp no problem, im no where near that, guys with the same motor and fuel system run them as low as 30lbs with NO problems

the only thing i cant verify is that it isnt a head gasket, but, there is no white smoke coming out of the ehxaust, and no water in the oil or other way around. and i dont have a compression tester(allthough its not hard to borrow)

B
09-09-2006, 02:36 PM
got a leaky injector not misting properly just puddling ?

Squishy
09-09-2006, 02:48 PM
got a leaky injector not misting properly just puddling ?

shouldnt, just put these fuckers in not half a year ago

B
09-09-2006, 02:50 PM
it only does it when u are playing or happens when just driving normal...?....:D as if [wako]...

Squishy
09-09-2006, 02:51 PM
it only does it when u are playing or happens when just driving normal...?....:D as if [wako]...

it will just randomly do it, sometimes when im just pulling out of a driveway

78f150
09-09-2006, 06:56 PM
Just because their is no oil in the coolant or coolant in the oil does'nt mean it's not a headgasket it could be burnt between two cylinders by doing a compression test you could rule out if you have a head gasket or valve issue.

Squishy
09-09-2006, 07:16 PM
Just because their is no oil in the coolant or coolant in the oil does'nt mean it's not a headgasket it could be burnt between two cylinders by doing a compression test you could rule out if you have a head gasket or valve issue.

gonna pull all the plugs then check compression tomorrah most likely

Melvin
09-09-2006, 11:09 PM
what mass air meter u running? Also what brand of fuel pressure regulator. C&L mass air meters are notorious for being shitty. Pm for my number, we can discuss it over the phone.

BeerBaron Sr.
09-12-2006, 07:47 PM
Asuming this is fuel injecteted with a computer , change the
paramiters of the computer,because you have changed the paramiters
of the motor!!!!!!!!!!!!!!!!

jakerngr
09-12-2006, 08:02 PM
oil pump drive off the bottom of the distributor i had one twist before and it would backfire like crazy then the thing broke and no runny

WagoneerXJ
09-12-2006, 10:55 PM
oil pump drive off the bottom of the distributor i had one twist before and it would backfire like crazy then the thing broke and no runny

I've had an oil pump driveshaft break in a 302 of mine once. Twisted like a licorice and then snapped... Hell, half of it is still in there :eek:

Squishy
09-13-2006, 02:02 AM
ive broke 2 oil pump ds\s on this one, its not that problem right now