Supra sounds like a chopper!

[EverythingFallsApart]

Just finished the bhg repair. Timing is good. no visible vacum leaks. egr system was removed and all blocked up. all plug wires are firing. It drives pretty decent except for a little shaking and just sounds horrible. It's super loud and sounds exactly like one of those annoying harleys. The exhaust has that tapping rumble and very shaky. NOt the smooth flow I used to have. Can anyone help me out to see what the problem might be? NO codes either. thanks

 

[Supra Blues]

If it sounds like a chopper, you have got to have an exhaust leak somewhere.

Get that fixed first.

 

[88SupraTurbo]

check your egr plate on the back of the engine... if the seal is blown u will be able to feel exhaust coming from behind the left cam cover (when looking at the enging from the front of the car)... thats the exact same thing my car was doing and thats what it turned out to be.

 

[EverythingFallsApart]

check your egr plate on the back of the engine... if the seal is blown u will be able to feel exhaust coming from behind the left cam cover (when looking at the enging from the front of the car)... thats the exact same thing my car was doing and thats what it turned out to be.

I plugged the exhaust side on the back of the head cause i removed the whole egr system. ALso put a block off plate on the intake manifold. Everything there should be fine.

 

[EverythingFallsApart]

If it sounds like a chopper, you have got to have an exhaust leak somewhere.

Get that fixed first.

A rear exhaust leak would definetly be noticable but air is definetly getting threw the muffler. The only thing I can think of is something with the header but everything in the engine sounds pretty normal. It shakes a bit(that choppy sound) but I don't notice anything. I don't know what a header leak sounds like though. COuld a small leak cause this much issues?

 

[Supra Blues]

Small leaks can be loud simply because of the volume of air going through the engine.

 

[EverythingFallsApart]

does anyone know the size of tap for the header bolts? I might need to re-tap them and see if the header will fit better.

 

[chevyeater]

M10x1.25 if I remember correctly, it has been a while. Take one of the studs out and bring it to a hardware store to be sure. You'll probably end up needing to helicoil all of the stud holes in the head.

 

[EverythingFallsApart]

M10x1.25 if I remember correctly, it has been a while. Take one of the studs out and bring it to a hardware store to be sure. You'll probably end up needing to helicoil all of the stud holes in the head.

You sure it's not 12x 1.25? any second opinions?

 

[CassMori]

mine was doing a similar thing, found the problem this evening -- #4 injector clip wasn't on all the way.

 

[mk3forme]

no its definitely 10x1.25 as i just had a time with mine. And Chevy is right, you will most likely have to helicoil the holes as they will probably strip out when you bring them up to torque. Go ahead and call around locally before you take the header off and see who carries the helicoil kit so if you need it you can get it. I know my autozone and Advance doesnt carry anything bigger than an 8. if you have a kwickset fastener store in your area they should have it. And good luck on the far rear hole if that one gives out. There is no room for a drill and I have to drill by hand with a pair of Vise Grips and alot of patience. I believe the drill bit size needed was 13/32 so make sure you have that to as my kit came with tap but no bit and I had to buy a bit set just to get that size Good luck

 

[Xtreme]

mine is doing that right now. It's loud (open 3 in. downpipe) but it's missing a cylinder. I finally narrowed it down to #2 exhaust valve is not seating correctly. Check if all of your cylinders are firing by removing each plug wire off the coil in succession to see if it makes a difference in the way your car runs. If the car stumbles and runs real rough, put that one back and move to the next, until you find the dead cylinder (if you have one).
-X


on that tough to get to hole, try a right angle air drill (with the pressure turned down) they take up ALOT less space than a conventional drill, and are very handy to have. I got my bit from a place called Fastenal for about 5 bucks. Pretty good bit, too. You might also try a dremel tool with the flex shaft to drill that hole.

 

[mrnickleye]

Check that there is no exhaust leak at the EGR cooler on the back of the head. Also, the exhaust manifold could be slightly warped, thus not seating 'flat' on the head. Just had to send one out to the machine shop for a resurface. Went back on real nice, and no more problem.
Also, when I was at the toy dealer in the 80's, I had to have several intake and exhaust manifolds machined. Avoid problems and check them when they're off. TSRM gives specs.

 

[EverythingFallsApart]

well I don't think I have a exhuast manifold leak. I put some bubble liquid on the header and then started it up and nothing. Egr is plugged and don't feel or see any issues there. Timing seems to be ok as all the marks line up but somethings up and I can't figure it out. The exhuast does that put put sound.

 

[IJ.]

Worst case scenario for the "putt putt" sound is a burnt exhaust valve .

 

[mk3forme]

putt putt sound? What like a missing cylinder sound?

 

[EverythingFallsApart]

it's hard to describe. Can anyone host a video for me?

 

[mrnickleye]

Do a compression test on the engine to check all cylinders. If you have one that is very low (ie: 75 lbs) then that would likely be a burnt valve in that cylinder. A burnt valve can give a putt putt putt sound out the exhaust pipe. If the sound is coming from the engine compartment, then it is likely an exhaust leak in the compartment.
-Manifold Gasket
-Header pipe to manifold gasket
-cracked manifold
-EGR tubing
-Egr cooler
-EGR valve

Get a mechanics stethoscope from the auto parts store (or tool dealer), take off the rod/diaphram assy, and use just the hose to listen around for a leak. NOTE: I added some length of vacuum hose onto it so I would not burn the original one, and to reach further.

 

[miggles]

when i rebuilt my engine i put in new ngkr plugs.one had dies straight out the box.took me 1 week to find it after checkin and recheckin cam belt timing,ignition leads,coils,ignitors,everything but removin sparkplugs.after 1 week i pulled them out and there was one nice n shiny.changed it to a new one and no more missing/putting.

 

[EverythingFallsApart]

I adjusted my timing a bit and it quiet it down a little and it runs a lot better but the exhuast still does that put put. I pulled my plugs. I had ngk iridiums in there for about 2 years. One seemed a little messed up so I threw in a orgininal ngk copper that appeared to be fine. It made no difference. The rest of the plugs appear to be fine. I did a compression check on cylinders 1, 2, 5, 6. I didn't get to 3 and 4 cause I didn't feel like taking the throttle body off. But those cylinders I did check all compression was fine and shot up quick within 2 cranks. I will be checking the other cylinders soon but i'am pretty sure they should be fine. I had the head off and the valves appeared to be fine also. I'am just wondering if there's some tiny exhaust leak somewhere. wow this one is annoying..