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TQ tuning issue using M1 intake (SB stroker)

Posted By: Moparmal

TQ tuning issue using M1 intake (SB stroker) - 10/10/10 05:24 AM

Anyone had problems running a TQ on a M1 SB ?

Specifically, the low speed / idle circuit runs waaaay lean , and no amount jetting up or rod changes has an effect.

Anyone got any solutions so I can keep using this carb?
Posted By: ScottSmith_Harms

Re: TQ tuning issue using M1 intake (SB stroker) - 10/10/10 06:04 AM

Are you checking your engines vacuum with a vacuum gauge? That's where I'd start. It's possible you have a leak somewhere.
Posted By: Moparmal

Re: TQ tuning issue using M1 intake (SB stroker) - 10/10/10 07:00 AM

SSH - I just swapped the M1 in -

I had a vac guage on it this morning - its reading around 13 at 900 rpm, but it does waiver a little beween 10 and 13.

I did the leak test with fluid around the intake flange but it had no effect....

As soon as you blip the throttle, and as the rpms come down, the Vac drops to almost zero and the engine flutters and almost dies.

Because its been so badly behaved at low speed, I assumed it was the low speed circuit -

(I checked all the carb gaskets and this carb ran 12.6 at the track last weekend on an LD340)

Are you saying that the TQ shouldn't be effected by the M1 this badly?
Posted By: ademon

Re: TQ tuning issue using M1 intake (SB stroker) - 10/10/10 07:07 AM

is your M1 the spread bore? i'm running a t-quad on my warm 360 and have the pri jets drilled to .101 and have the piston set up at just one turn off bottom, make sure its bottomed and you note exactly when it starts to come up. also make sure you have the right piston spring on the rods, it should be about 1.5" tall and the spring dia should be .023. i have seen other springs that are not correct. i'm running without a choke and related hardware.

Attached picture 6242374-party046(640x480).jpg
Posted By: ademon

Re: TQ tuning issue using M1 intake (SB stroker) - 10/10/10 07:12 AM

i'm also running the older strip dominator intake with the plenum worked over, this is what the M1 was patterned off of.

Attached picture 6242378-082(640x480).jpg
Posted By: Moparmal

Re: TQ tuning issue using M1 intake (SB stroker) - 10/10/10 07:50 AM

ademon - in a round about way you've answered the problem.

I needed to know if these SP intakes caused issues with TQs - clearly as your running one on a non stock 360 , this tells me the TQ circuitry can work fine on an M1.

Obviously my problem is elsewhere - and I'm thinking SSH is right, and its a Vac leak.

I've had TQs a long time - there's no issue with the calibration - except that I knew something was up when I had to go so rich on the primaries and it still showed lean on the AF guage.

I just hope this intake is not porous - I bought it off a member here.
Posted By: ScottSmith_Harms

Re: TQ tuning issue using M1 intake (SB stroker) - 10/10/10 07:56 AM

Try using an unlit propane torch to detect vacuum leaks, if even a small amount of the gas finds it's way into the engine you should see an RPM increase. Works great and leaves no mess.
Posted By: ademon

Re: TQ tuning issue using M1 intake (SB stroker) - 10/10/10 08:01 AM

maybe the choke pulloff? but doubt it. try spraying around the intake to head and see what happens, maybe the intake was milled a bit, mine was loading up a bit and idling rough till i adjusted the piston/rod setup precisely. Not sure about idle circuit my engine is about 400hp and has run low 12's with a holley, Maybe someone that has run a t-quad would know what idle mods need to be done on a very hot big cam motor.
Posted By: Moparmal

Re: TQ tuning issue using M1 intake (SB stroker) - 10/10/10 08:08 AM

Thanks for the tips on leak checking - I reckon my workshop guy will be on to it.

ademon - My engine only makes 370 with the LD340 so its not crazy on the cam side.

Re the intake - it was new so its not milled.

This is why I find it so hard to believe its leaking - it was a flush fit using if Felpro gaskets.

What makes e think you're both right is that the AF gauge goes off the scale lean when I lift off.

Probably sucking air in no doubt.
Posted By: ademon

Re: TQ tuning issue using M1 intake (SB stroker) - 10/10/10 08:14 AM

I do like to run the 1/4" spacer with the thin gaskets on each side and not the cheap looking thick ones that are sometimes in the kit.
Posted By: ademon

Re: TQ tuning issue using M1 intake (SB stroker) - 10/10/10 08:24 AM

BTW what size jets you running? do you still have the choke setup on it? hate to drill jets when i don't know where i'm at, an AF meter is a big help i need to get one.
Posted By: Moparmal

Re: TQ tuning issue using M1 intake (SB stroker) - 10/10/10 08:46 AM

@ ademon - I realised I had a problem when I went to .107th primaries and it showed lean at 16 AF on the AF guage at 2100 rpm in top gear.

Please note: Last weekend I ran 12.6 with the LD340 - AF guage read 12.5 at idle, 14-15 at cruise, 12.4 at WOT in 3rd.

When you see that the WB AF guage shows pretty accurate readings - I start to worry when I have 16s AF and I'm running .107 primaries with the tree on 5 turns (1996 rods too) !!!

The car drives like a pig as well -fluttering off idle and other issues.

To run it that rich and still show a lean - ish mixture - there's something not right.
Posted By: HotRodDave

Re: TQ tuning issue using M1 intake (SB stroker) - 10/10/10 03:56 PM

It is possible to be rich and show lean if the mix is not being ignited. The sensor reads the oxygen not the fuel and if the mix does not burn it will read that unburned oxygen as a lean condition.

I think it would be worthwhile to throw a set of new plugs in, mabey one got fouled out then you started throwing fuel at it to cure the lean condition and wreaked all kinds of havok on it.

The single plane intake will give less signal to the carb and require a touch more fuel. I would try putting a piece of wire in the idle air bleed and see if that helps, if it does then you need to shrink the air bleeds. It sounds like your problems are with the idle circuit and since it is not makeing the proper air fuel mix then when you open the throttle there is not enough signal to get the other circuits pulling fuel properly. But again before I changed the carb any more I would check the ign system and throw in some new plugs.
Posted By: ademon

Re: TQ tuning issue using M1 intake (SB stroker) - 10/10/10 05:01 PM

That is some large jets, i was told by demonsizzler that my setup with the choke removed should be about .101 primary, i too was using the 1966 rods but went to another # to lean out low speed. 5 turns on the tree seems like a lot.
Posted By: ademon

Re: TQ tuning issue using M1 intake (SB stroker) - 10/10/10 05:03 PM

when did you change the jets? after you had it at the track when it was running good, with good AF readings?
Posted By: dOOc

Re: TQ tuning issue using M1 intake (SB stroker) - 10/10/10 05:09 PM

Hay Guys - members of the ThermoSquad ....

DID YOU HEAR that TODAY is the BIRTHDATE of the one-and-only Plastic Fantastic ?

Someone PLEASE ...post a pic of a cake ....with some flaming Berri Crabs on-top !
Posted By: Moparmal

Re: TQ tuning issue using M1 intake (SB stroker) - 10/10/10 08:50 PM

I changed the jets out after I went racing and when i swapped the intake.

I was running .101s with three turns on the tree, and .138 secondaries.

I'll try limiting the idle air bleeds and see if that makes any difference -
Posted By: DEMONSIZZLER

Re: TQ tuning issue using M1 intake (SB stroker) - 10/10/10 09:02 PM

Mal, what base gasket are you using under the carb?
I ask this because the wrong base gasket can make the carb loose the idle circuit. Also if you have a lean condition caused by an intake manifold leak, the cylinder next to the cylinder with the intake intake leak will show that the plugs are different in color or inconsistent in color.

I have done a lot of testing with the MP single plane intake and T.Q. carbs and it is a very good match and works well. Your jet size on the primaries would normally be too big, David.
Posted By: Moparmal

Re: TQ tuning issue using M1 intake (SB stroker) - 10/11/10 09:46 AM

Hi all

Well I swapped in a borrowed 650 AVS and the car purred like a kitten

- no surging,
- no variation of vacuum (held steady at 14 and didn't sag after blipping the throttle)
- Even the idle mixture was perfect and no variation on the AF guage.

Seems its clearly the TQ and not an intake Vac leak.

So -

This means I have to get the TQ working.

Dave - thanks for chiming in - what sort of base gasket should I be using?

(I know the jets are too big - that was a desperate attempt by me to try to get the idle/low speed circuit driveable)

Any tricks to get the idle circuit flowing a little better?

I guess I could elongate the idle slots a little - anything else?
Posted By: Diplomat360

Re: TQ tuning issue using M1 intake (SB stroker) - 10/11/10 03:04 PM

Take a look at this old post of mine...similar issue maybe? I have tried a number of things so far, some with greater success, others going the wrong way LOL.

https://board.moparts.org/ubbthreads/show...rt=all&vc=1
Posted By: Moparmal

Re: TQ tuning issue using M1 intake (SB stroker) - 10/11/10 09:00 PM

Thanks D360 - I'm not sure I want to go through all that agony

I've done the holes in the butterfly thing a long time back - but this is a case of lean running well off the idle and into the low speed circuit.

I might try reducing the air bleed hole size and see if anything improves -

Like you - I still can't figure if you are meant to enlarge the idle jets as well as reduce the air bleed size - hopefully Demon Sizzler will chime in again.

Id also like to know what the correct base gasket is to use.
Posted By: DEMONSIZZLER

Re: TQ tuning issue using M1 intake (SB stroker) - 10/11/10 11:12 PM

Mal, you need to use an open center base gasket. All of the oem T.Q. base gaskets were open center. A 4 hole gasket will cause sever idle issues.

Also I would not suggest any bleed mods yet, David.
Posted By: Rug_Trucker

Re: TQ tuning issue using M1 intake (SB stroker) - 10/12/10 02:40 AM

Quote:

Hay Guys - members of the ThermoSquad ....

DID YOU HEAR that TODAY is the BIRTHDATE of the one-and-only Plastic Fantastic ?

Someone PLEASE ...post a pic of a cake ....with some flaming Berri Crabs on-top !



What year was that Doc?
Posted By: Moparmal

Re: TQ tuning issue using M1 intake (SB stroker) - 10/12/10 10:23 AM

Well I'd like to say its better news -


Just to recap, here's how the carb behaved on the DP intake before the swap -

    Mixture screws 4 turns out
    AF - idle was 12.2, Cruise was 14.5 and WOT was 12.5
    Vac was 13
    Jets were .101 / .138


I had it running pretty darn good.

On Sunday after the swap - I had

    Mixture screws all the way out
    13- 16 AFs bouncing around like crazy at idle
    Off the scale lean at cruise
    Vac bouncing between 9-13 and dropping to zero on deceleration.


I swapped on a buddies AVS 650 and all the bad symptoms went away!

    - it idled at 12.5 and I had steady Vac at 15.


This told me it was def a carb issue - not an intake leak.

- so here's how I spent my Tuesday evening -

Testing of TQ,

    Replaced the carb flange gasket - improved slightly but still a vacuum variation and running pretty ordinary (Sorry its bad news Dave) - AF was between 13 and 14.5 at idle

    Took the holes in the butterflies out to .094th - slightly more even idle but a still way lean and a big Vac drop after blipping the throttle.

    Blocked off the air bleeds completely, and the idle settled - it stayed around 12-13 AF and the Vac settled at 14.


So.......I thought I had it licked - till I went for a drive , and -

    AF dropped to zero when i let off the pedal

    AF went to 9s under light acceleration and I blew black smoke.


Conclusions

    - Blocking the air bleeds richened the mixture so it idled better

    - but the low speed circuit needs the air from the bleeds to maintain a decent cruise/light accelration mixture

    In which case - blocking the bleeds is not going to work.


Next step

Would I be right in thinking its not getting enough fuel through the idle circuit?

Is this common?

In which case, how do I fix it?
Posted By: joedust451

Re: TQ tuning issue using M1 intake (SB stroker) - 10/12/10 02:17 PM

Quote:

Well I'd like to say its better news -


Just to recap, here's how the carb behaved on the DP intake before the swap -

    Mixture screws 4 turns out
    AF - idle was 12.2, Cruise was 14.5 and WOT was 12.5
    Vac was 13
    Jets were .101 / .138


I had it running pretty darn good.

On Sunday after the swap - I had

    Mixture screws all the way out
    13- 16 AFs bouncing around like crazy at idle
    Off the scale lean at cruise
    Vac bouncing between 9-13 and dropping to zero on deceleration.


I swapped on a buddies AVS 650 and all the bad symptoms went away!

    - it idled at 12.5 and I had steady Vac at 15.


This told me it was def a carb issue - not an intake leak.

- so here's how I spent my Tuesday evening -

Testing of TQ,

    Replaced the carb flange gasket - improved slightly but still a vacuum variation and running pretty ordinary (Sorry its bad news Dave) - AF was between 13 and 14.5 at idle

    Took the holes in the butterflies out to .094th - slightly more even idle but a still way lean and a big Vac drop after blipping the throttle.

    Blocked off the air bleeds completely, and the idle settled - it stayed around 12-13 AF and the Vac settled at 14.


So.......I thought I had it licked - till I went for a drive , and -

    AF dropped to zero when i let off the pedal

    AF went to 9s under light acceleration and I blew black smoke.


Conclusions

    - Blocking the air bleeds richened the mixture so it idled better

    - but the low speed circuit needs the air from the bleeds to maintain a decent cruise/light accelration mixture

    In which case - blocking the bleeds is not going to work.


Next step

Would I be right in thinking its not getting enough fuel through the idle circuit?

Is this common?

In which case, how do I fix it?



Hey, i think you should "listen" to what demonsizzler advised you to do, that might solve your issues .
Posted By: ademon

Re: TQ tuning issue using M1 intake (SB stroker) - 10/12/10 03:18 PM

need to go back to the small jets and get those.107 out, also drop the tree to 1 or two turns, you may have knocked a float or something out of wack when you installed the .107's in.
Posted By: Rug_Trucker

Re: TQ tuning issue using M1 intake (SB stroker) - 10/12/10 08:35 PM

Float height is measured from the gasket.
Posted By: Moparmal

Re: TQ tuning issue using M1 intake (SB stroker) - 10/12/10 08:48 PM

Quote:


Hey, i think you should "listen" to what demonsizzler advised you to do, that might solve your issues .



Joedust - Maybe you missed it - here it is......

Quote:

Replaced the carb flange gasket - improved slightly but still a vacuum variation and running pretty ordinary (Sorry its bad news Dave)



ademon - I went back to .101 jets as soon as I swapped the flange gasket - I've had a fair bit of experience with these carbs, but never hit this type of issue before....

I really think its not getting enough fuel, even with the air bleeds fully blocked, I can't get the AF below 12.5 AF

FWIW, if I'd had the mixture screws set like this on the old intake it would have been reading 9s!

.....so I'm wondering what my options are to fatten the idle circuit?

MM
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