small tuning problem, need advice, suggestions

[Koenigturbo]

Car: mkiii

Mods: Lexus,550's, ct 26 with 57 wheel, Aeromotive set at 40 p.s.i. timming 10ish degrees

Problem: car's idle is low (after it's warmed up) and the car stalls when I let off the gas, but not every time. Also, I can hear it popping and back firing when I let off the gas. Idle's fine when cold.

I think the problem is: timings is to retarded, to lean, vaccum leak, bad v.s.v? or all four.

To solve the problem: besides retimming, if it's to lean how do I fix that?? raise the fuel pressure? And of course check vaccum leak. Anything else that you guys/ gals can think of?

"Thanks ahead of time"

 

[kotu100]

do you have an safc? my vote is for the AFM sensor or plug.

 

[grimreaper]

40 psi is a LOT of fuel. That with the vac off? what are your vf's?

 

[mdr40z]

I say rich also, do you have anything to tell you a/f?

 

[Koenigturbo]

do you have an safc? my vote is for the AFM sensor or plug.

I don't have a S.A.F.C.

 

[Koenigturbo]

40 psi is a LOT of fuel. That with the vac off? what are your vf's?

VF'S? Please explain that to a Newbie,...like me.

 

[Koenigturbo]

I say rich also, do you have anything to tell you a/f?

besides plugs??
No.

 

[mdr40z]

besides plugs??
No.

you need something, if not a wideband use a cheapy a/f ratio gauge so you at least know if you are in the ballpark.
safc only adjusts your idle and wot, a must but probably not causing this problem

 

[Koenigturbo]

40 psi is a LOT of fuel. That with the vac off? what are your vf's?

Come to think of it, I think your right it could be the vaccum line, I think I need to check that.

 

[jdub]

Do you have a BOV vented to the atmosphere?

Are there any ECU codes?

You need to drop your FP to ~30 psi vac on.

 

[Koenigturbo]

Do you have a BOV vented to the atmosphere?

Are there any ECU codes?

You need to drop your FP to ~30 psi vac on.

B.O.V....stock
codes: No

40 P.S.I. is at fast idle, when the car is cold, it runs at about 30, when warm.

It that possible/

 

[jdub]

A 10 psi FP rise is a lot for fast idle, what is the rpm at fast idle?

What kind of plugs are you using?

Have you checked plug wire resistance per the TSRM?

 

[Koenigturbo]

A 10 psi FP rise is a lot for fast idle, what is the rpm at fast idle?

What kind of plugs are you using?

Have you checked plug wire resistance per the TSRM?

Resistance: I don't know, is because these are new M.S.D. 8 mm wires, so I figure, Why check them.

Plugs: N.G.K. platumins

R.P.M. Well,.. good call, I need to check that. My suppossive "High" idle (when cold) is around where my "normal" (warm) idle should be.. around 850ish and my warm idle is around 400ish Which is low.
I need to double check that.
I though "popping through the exhaust is because it's lean.
P.S. I need to hook up a tach in order to give you a good answer.

 

[jdub]

Take a look at this troubleshoot chart and use it as a guide:
http://www.cygnusx1.net/supra/Library/TSRM/MK3/manual.aspx?S=FI&P=14

Popping in the exhaust is more often a rich after-fire.

 

[kotu100]

Resistance: I don't know, is because these are new M.S.D. 8 mm wires, so I figure, Why check them.

Plugs: N.G.K. platumins

R.P.M. Well,.. good call, I need to check that. My suppossive "High" idle (when cold) is around where my "normal" (warm) idle should be.. around 850ish and my warm idle is around 400ish Which is low.
I need to double check that.
I though "popping through the exhaust is because it's lean.
P.S. I need to hook up a tach in order to give you a good answer.

if you dont have a tach how do you know the idle?
850 is still high idle, 7mgte idle spec is 650rpm. the 7mge is higher (800 i think)

you need to check your Vf's this is the signal the AFM is sending to the ECU. i bet u this number will be bouncing all over the place, commonly caused by a bad AFM sensor, or plug.

i have this problem in my car, popping from exhaust, low idle, dying sometimes. i can fix it by having the AFM plug in the perfect position. chances are the AFM is your problem.

unless incorrect timing is the cause of the low idle.

 

[jdub]

My bet is on a vac leak or the ISCV/it's air path.

BTW - your plug wires should be good.

 

[Koenigturbo]

if you dont have a tach how do you know the idle?
850 is still high idle, 7mgte idle spec is 650rpm. the 7mge is higher (800 i think)

you need to check your Vf's this is the signal the AFM is sending to the ECU. i bet u this number will be bouncing all over the place, commonly caused by a bad AFM sensor, or plug.

i have this problem in my car, popping from exhaust, low idle, dying sometimes. i can fix it by having the AFM plug in the perfect position. chances are the AFM is your problem.

unless incorrect timing is the cause of the low idle.

How do i know where my idle is? I don't, I guessed "Yep" I know, it's getto, I guessed at the idle, by ear and experience, yes your right, I gotta hook up my tach.
"Plug" you mean the one that is swedged in with a plug? The one that your not suppose the adjust? If's that's the one then does it need to go in or out? if's that not what you meant, then I'm lost, You mean the electrical plug that goes in the AF.M. Sorry I'm just a "Newb".
Even though, I didn't check any of your suggestions, your answers is real helpfull, I bet your right, also I now what "vf's is.
Thanks, I'll consider these, since we have the same identical problem.

 

[Koenigturbo]

Do you have a BOV vented to the atmosphere?

Are there any ECU codes?

You need to drop your FP to ~30 psi vac on.

No, S**&T ?? My PSI is 40 with vacuum on. "WOW" Thanks JDub" I need to readjust that,

Thank you!!!!

 

[jdub]

No, S**&T ?? My PSI is 40 with vacuum on. "WOW" Thanks JDub" I need to readjust that,

Thank you!!!!

Pardon me?
(not sure how to interpret this, since I posted that comment on the previous page...3 posts ago)

 

[Koenigturbo]

Pardon me?
(not sure how to interpret this, since I posted that comment on the previous page...3 posts ago)

"Oh no, no, don't take my comment as negative, I shouldn't have said that. I really apreciate your help. Just to let you and every know, I do not ever say bad things to anyone EVER. I keep my comments to myself, childish comments are NOT what I'm about, they do not get me anywhere or results. "Jdub" I really apprecieate your help, your smart guy. Why would I be a smart ass when I'm need help, so, please, do not take it as a smart ass comment.
What I meant was, I'm really surprized that I have mine set so high, I need to readjust it, that's why I said "No Shit" and not what you think I said. "No shit" was not address to you, it was address to my mistake on the f.p.

as I've said, "JDub", I apprecieate your/ everyones help and would not jepordize it (see, I can't spell).

Thanks!!! I mean it!!