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LOUD Backfiring

So whenever the engine is winding down after revving, cruising or getting into the gas, it back fires A LOT. The higher i rev it up, the louder the backfire fir is and most of the time there is multiple backfire when winding down. It is REALLY loud. my car runs rich during those^^^ times too. Could that be the reason?
1987 turbo coupe 5speed: Boport stage 3 head/2.5 cam , Precision stage 3 50trim .63 turbo, Tial 38mm wastegate, Jangus gutted/ported intake manifolds, 60mm tb, Jangus open dumptube, Jangus 3" elbow, Perrin boost controller,Esslinger adjustable cam pulley, Esslinger small crank pulley, stinger FMI, RFL BOV, Spec stage 3 clutch, B&M short throw, 140 speedo, Walbo 255lph, BBK fpr, 3G alternator, ARP studs.  Be faster... :poke:

LOUD Backfiring

Reply #1 –
LOL give me your car NOW so I can go cruising around town scaring the  out of everyone.
 
I already do that in the summer with my '38 Buick by flipping the ignition off and back on, but I'd love to be able to do it in a thundercat. Yes you have a severe rich condition most likely. Maybe also valves sticking open...but more likely injectors not closing.
1987 20th Anniversary Cougar, 302 "5.0" GT-40 heads (F3ZE '93 Cobra) and TMoss Ported H.O. intake, H.O. camshaft
2.5" Duals, no cats, Flowmaster 40s, Richmond 3.73s w/ Trac-Lok, maxed out Baumann shift kit, 3000 RPM Dirty Dog non-lock TC
Aside from the Mustang crinkle headers, still looks like it's only 150 HP...
1988 Black XR7 Trick Flow top end, Tremec 3550
1988 Black XR7 Procharger P600B intercooled, Edelbrock Performer non-RPM heads, GT40 intake AOD, 13 PSI @5000 RPM. 93 octane

LOUD Backfiring

Reply #2 –
lol how loud it is backfiring, it would DEFINITELY scare someone! You know what, im thinking it might be one of my valves sticking open then! When i start my car up, a puff a blue smoke comes out. Ive been told it is a valve stem seal. I am hearing chatter from the valve train. And now this! Im thinking the shop i had build my cylinder head had a bunch of monkeys working on it!
1987 turbo coupe 5speed: Boport stage 3 head/2.5 cam , Precision stage 3 50trim .63 turbo, Tial 38mm wastegate, Jangus gutted/ported intake manifolds, 60mm tb, Jangus open dumptube, Jangus 3" elbow, Perrin boost controller,Esslinger adjustable cam pulley, Esslinger small crank pulley, stinger FMI, RFL BOV, Spec stage 3 clutch, B&M short throw, 140 speedo, Walbo 255lph, BBK fpr, 3G alternator, ARP studs.  Be faster... :poke:

LOUD Backfiring

Reply #3 –
Quote from: SR71blackbird;383287
lol how loud it is backfiring, it would DEFINITELY scare someone! You know what, im thinking it might be one of my valves sticking open then! When i start my car up, a puff a blue smoke comes out. Ive been told it is a valve stem seal. I am hearing chatter from the valve train. And now this! Im thinking the shop i had build my cylinder head had a bunch of monkeys working on it!

 
That's why I do my own work. I have one local shop I trust for my general machine work, and one guy I trust who does my valves and valve seat profiles. I just give them the specs I want to see, and do all the assembly work and parts sourcing myself.
88 TC 5speed, 168000+ miles, stock 2.3T long block, ported RFE6 exhaust, Evergreen T3 running 15#'s.
Up next: FMIC, fresh air intake, ported intakes, ported big valve head.

LOUD Backfiring

Reply #4 –
So do you think that my problem is because of the valve stem seal not being put in right so its is letting oil by and making the valve stick?
Im sending a different head off to boport to get it fixed up and i'll be selling my current head soon.
1987 turbo coupe 5speed: Boport stage 3 head/2.5 cam , Precision stage 3 50trim .63 turbo, Tial 38mm wastegate, Jangus gutted/ported intake manifolds, 60mm tb, Jangus open dumptube, Jangus 3" elbow, Perrin boost controller,Esslinger adjustable cam pulley, Esslinger small crank pulley, stinger FMI, RFL BOV, Spec stage 3 clutch, B&M short throw, 140 speedo, Walbo 255lph, BBK fpr, 3G alternator, ARP studs.  Be faster... :poke:

LOUD Backfiring

Reply #5 –
Does your vacuum/boost gauge bounce around at idle? A sticky valve will play heck with your vacuum reading. Sticking valves can be caused by burnt oil residue between the guide and stem (which can be caused by bad seals, but not usually), improper valve guide to stem clearance, or a bent valve stem. If you're running super rich when you close the throttle, try and figure out why. I know I'd much rather fix that issue and replace the valve stem seals than needlessly buy another head.
88 TC 5speed, 168000+ miles, stock 2.3T long block, ported RFE6 exhaust, Evergreen T3 running 15#'s.
Up next: FMIC, fresh air intake, ported intakes, ported big valve head.

LOUD Backfiring

Reply #6 –
OMG ALOT!!!! its vibrates really badly until 2000rpm.  so that's the problem...... The guy that build my head is going to get an hear full!! Thank you for the help Jangus. I appreciate it.
1987 turbo coupe 5speed: Boport stage 3 head/2.5 cam , Precision stage 3 50trim .63 turbo, Tial 38mm wastegate, Jangus gutted/ported intake manifolds, 60mm tb, Jangus open dumptube, Jangus 3" elbow, Perrin boost controller,Esslinger adjustable cam pulley, Esslinger small crank pulley, stinger FMI, RFL BOV, Spec stage 3 clutch, B&M short throw, 140 speedo, Walbo 255lph, BBK fpr, 3G alternator, ARP studs.  Be faster... :poke:

LOUD Backfiring

Reply #7 –
Sounds like you HLA'S may be to tight. But you said it makes valve train noise . So that is not the issue unless one is real tight. I have seen countless engines with loose guides run perfectly. Just start any Porsche and watch the blue smoke come from the exhaust. And they all do it. Their guides and seals are designed very loose. They do that for a reason. But if your engine is not smooth until 2 grand you have other issues than valve seals. The 2.3 Ford seals are basically pretty good and it takes a lot to mess them up. Unless one is missing. Also if you have a cam bigger than 470 Lift the retainers must be modified or the guides cut down. I dont know what the lift is on the 2.5 BO-PORT CAM??  But a compression test or leak down will set you free.

Also Bo-port cams are reduced base circle cams. So shimming is critical. Was it done correctly???

Also the 2.5 needs the guides reduced. I think nything bigger than the 1.9 needs guides reduced. Was it dun???
I spend money I don't have, To build  cars I don't need, To impress people I don't know

HAVE YOU DRIVEN A FORD LATELY!!

LOUD Backfiring

Reply #8 –
Quote from: SR71blackbird;383308
OMG ALOT!!!! its vibrates really badly until 2000rpm.  so that's the problem...... The guy that build my head is going to get an hear full!! Thank you for the help Jangus. I appreciate it.

 
Hold on. Before you go tearing someone a new one, you need to start checking things over. Tom did hit on a very good point on the HLA clearance. You should check it. Also, if you have a weak valvespring or two, that could cause havoc also. Now, combine a weak spring with HLA problems, and you've got a major headache. The point I'm trying to make is: Start checking things first. As for the valve guide clearance issue, it could be a problem if it's to tight. If it is, when they get hot they'll start to grab the valvestem and cause the valve to hang open.
88 TC 5speed, 168000+ miles, stock 2.3T long block, ported RFE6 exhaust, Evergreen T3 running 15#'s.
Up next: FMIC, fresh air intake, ported intakes, ported big valve head.

LOUD Backfiring

Reply #9 –
The 2.5 would need double springs at the least. BO would not recommend a stock spring. Stock springs are JUNK and cant even tolerate a stock cam. I have changed many valve springs on the 2.3 even in daily drivers. The springs SUCK. As far as a tight guide it is very possible. But then the motor would not smoke. Just saying. But everything is a possibility if the clearances are UN KNOWN. When building an engine a build sheet is mandatory.
I spend money I don't have, To build  cars I don't need, To impress people I don't know

HAVE YOU DRIVEN A FORD LATELY!!

LOUD Backfiring

Reply #10 –
Couldn't agree more on the build sheet Tom. Without knowing what the clearances were, it could possibly have a tight guide on one valve, and loose one on another. Depends on how much pride the machinist had in his work.
88 TC 5speed, 168000+ miles, stock 2.3T long block, ported RFE6 exhaust, Evergreen T3 running 15#'s.
Up next: FMIC, fresh air intake, ported intakes, ported big valve head.

LOUD Backfiring

Reply #11 –
True very true. I think at this point a leak down or compression test might be in order. I would also check the HLA clearance just for giggles.
I spend money I don't have, To build  cars I don't need, To impress people I don't know

HAVE YOU DRIVEN A FORD LATELY!!

LOUD Backfiring

Reply #12 –
OR...it still could be a tuning issue.  I know you kind of half-assed attached that O2 ground wire (the orange one that's supposed to attach to the turbo), and you're still running stock engine management with a bunch of mods done to the car.
Long live the 4-eyes!  - '83 Tbird Turbo

LOUD Backfiring

Reply #13 –
Well i have a full boport roller assembly. i have the springs down below. Bo said they would work with my setup. I guess it would make sense if it was the HLA's because they are wider then stock ones. I gave the shop a build sheet. The guy that built it has built 3 2.3 circle track winning cars so he has worked with 2.3's before. I did a compression check 2 weeks ago and 3 of my cylinders had 130 and one had 125.
Chuck, I got a good ground on that wire about 2 weeks ago thanks to Toms help. So that shouldnt be the problem. However i do have a pigger back tuner that comes with a computer, tune, filter and wiring in my garage that might be going in soon.
http://www.bo-port.com/index.php?act=viewProd&productId=37
1987 turbo coupe 5speed: Boport stage 3 head/2.5 cam , Precision stage 3 50trim .63 turbo, Tial 38mm wastegate, Jangus gutted/ported intake manifolds, 60mm tb, Jangus open dumptube, Jangus 3" elbow, Perrin boost controller,Esslinger adjustable cam pulley, Esslinger small crank pulley, stinger FMI, RFL BOV, Spec stage 3 clutch, B&M short throw, 140 speedo, Walbo 255lph, BBK fpr, 3G alternator, ARP studs.  Be faster... :poke:

LOUD Backfiring

Reply #14 –
I had a valve guide installed pen 15eyed that caused backfiring occasionally.  Ended up being an intake valve and it finally stuck, not once but twice.  Mangled the pushrod both times and the last time it stuck in the head/guide.  Ferrara valves are not cheap!