SYTY will not idle.

[v12powers]

New to SYTY's have 3 Buick GN's so I am kinda familiar with how gm does fuel injection.

I bought a 93 typhoon that had blown headgaskets and was apart. got it all back togeather, (surfaced heads, checked bores for wear in crosshatching, ect) I also purchased a Turbo tweak chip with adjustability, 3bar map that the chip is calibrated for, new 60lb injectors and full tuneup. I cannot get it to idle worth a crap. I have smoked it with a smoke machine, no vac leaks, swapped TPS, IAC, and IAT sensors, and still no change. unplugged coolant temp sensor, still idles like crap. I have a wide band on it, and the afr is like 10.0 at idle, even with lowering fuel pressure on the chip, (has its own potentiometer on the chip board for idle) it still is rich, then lean, what do I check next? any ideas would greatly be appreciated.

 

[denny]

Re: SYTY will not idle.

Check that the dist is not off by 180*

 

[v12powers]

Re: SYTY will not idle.

I installed it from the #1 spark plug just coming off compression, with the rotor facing forward, but I can def check it again.

 

[dgoodhue]

Re: SYTY will not idle.

What is your fuel pressure set to?

 

[v12powers]

Re: SYTY will not idle.

43 psi static with vacuum line unhooked and caped

 

[SEL777]

Re: SYTY will not idle.

I just read on here somewhere that another SyTyer had idle issue due to the throttle blades not fully closing.I can't seem to find it tho.

 

[v12powers]

Re: SYTY will not idle.

I looked at that. its an aftermarket professional products 58mm throttle body. and when I smoke it, nothing comes out of the blades with the intercooler off. so I think its sealing up right.

 

[SY-1193]

Re: SYTY will not idle.

New to SYTY's have 3 Buick GN's so I am kinda familiar with how gm does fuel injection.

I bought a 93 typhoon that had blown headgaskets and was apart. got it all back togeather, (surfaced heads, checked bores for wear in crosshatching, ect) I also purchased a Turbo tweak chip with adjustability, 3bar map that the chip is calibrated for, new 60lb injectors and full tuneup. I cannot get it to idle worth a crap. I have smoked it with a smoke machine, no vac leaks, swapped TPS, IAC, and IAT sensors, and still no change. unplugged coolant temp sensor, still idles like crap. I have a wide band on it, and the afr is like 10.0 at idle, even with lowering fuel pressure on the chip, (has its own potentiometer on the chip board for idle) it still is rich, then lean, what do I check next? any ideas would greatly be appreciated.

...all good things to check listed above.

I have some questions for you:
1. When you installed the TurboTweak Chip did you piggy back the stock chip onto the TurboTweak carrier?
2. If you did follow directions and the chip is piggy backed: have you checked if it is loose or not seated correctly since you installed it? Both the TT Chip and the piggy backed chip?
3. Is your WideBand o2 pinned into the ECU correctly? Did you change the right DIP switch on the TurboTweak Chip to enable WideBand?
4. IAC plugged in (idle air control 4 pin connector on bottom of throttle body).

 

[v12powers]

Re: SYTY will not idle.

I re pulled it all apart and looked. Chips are seated correctly. Pin F14 on the ecm is where the wideband pins into. and I can see it logging and emulating on my OTC 0bd1 scanner. those are good ideas. I also replaced the IAC and it is plugged in. I can watch it on the scanner going from 49 to 60 which is high I know. I also have a FPR gauge in the truck and the FPR stays around 38 to 39 at 10psi vacuum at idle. then raises under boost. to 7psi where it wont run.

 

[SY-1193]

Re: SYTY will not idle.

I re pulled it all apart and looked. Chips are seated correctly. Pin F14 on the ecm is where the wideband pins into. and I can see it logging and emulating on my OTC 0bd1 scanner. those are good ideas. I also replaced the IAC and it is plugged in. I can watch it on the scanner going from 49 to 60 which is high I know. I also have a FPR gauge in the truck and the FPR stays around 38 to 39 at 10psi vacuum at idle. then raises under boost. to 7psi where it wont run.

So you are loosing fuel above idle? Sounds like fuel pump. Typically when they go bad they will work until you go to drive them and may act crazy at idle too. They don't all just die some just act crazy.Check Fuel Pump relay and all connections to the pump first. Still this doesn't explain why you are so rich. But you said in your first post it was rich then lean...so that falls under crazy right?

What rpm can you rev it to? I saw a pump that acted fine 'til 2500 rpm then would make the truck die.

 

[v12powers]

Re: SYTY will not idle.

It raises like its supposed to. but the afr is 10 no matter what so It boggs at about 7psi of boost.

 

[SY-1193]

Re: SYTY will not idle.

It raises like its supposed to. but the afr is 10 no matter what so It boggs at about 7psi of boost.

Ok. Are you just reving it or driving it to get these readings?

Also what brand of WideBand? If it is a type that is calibrated is your calibration done correctly? (thinking if cal is off and computer thinks it is rich and pulls fuel out making it actually lean).

 

[dgoodhue]

Re: SYTY will not idle.

10" of vacuum is really low even for aftermarket cams.

 

[v12powers]

Re: SYTY will not idle.

AEM wideband, Is calibrated for the chip. (by Turbo Tweak) If I rev it to 1200 or 1500 it will run okay. and I can drive it. that's how I can get 7pis of boost. but its not making power.... I agree on the 10 in vac being low. I am starting to wonder if its compression. could be I have a killed ring or two that I couldn't see...

 

[v12powers]

Re: SYTY will not idle.

I really appreciate all of your guys time trying to go through this with me too. sincerely

 

[dgoodhue]

Re: SYTY will not idle.

What kind of mods does your truck have?

 

[SY-1193]

Re: SYTY will not idle.

I re pulled it all apart and looked. Chips are seated correctly. Pin F14 on the ecm is where the wideband pins into. and I can see it logging and emulating on my OTC 0bd1 scanner. those are good ideas. I also replaced the IAC and it is plugged in. I can watch it on the scanner going from 49 to 60 which is high I know. I also have a FPR gauge in the truck and the FPR stays around 38 to 39 at 10psi vacuum at idle. then raises under boost. to 7psi where it wont run.

is your vacuum/boost gauge in PSI or in/Hg. on the vacuum side? You said 10psi vacuum? 10 PSI is roughly 20"/hg which is about normal

 

[jeepruby04]

Re: SYTY will not idle.

Have you verified TDC is correct on the balancer? The outer ring can slip. I lost a fresh rebuild to this.

 

[Don W.]

Re: SYTY will not idle.

With all due respect, having the dist "180 out" means nothing. 180 out and it wouldn't even run.:rant:

Check that timing is set to -0- with brown wire under pas side, disconnected. MUST CHECK this. Reconnect brn wire when timing is set. If the ck eng light is still on disconnect bat for 30sec to clear. Just based on what you've said it sounds like timing is late.

Fuel pres sounds correct. But 7psi under boost? Must be a misprint. I doubt it would even run with 7 psi fuel pres. Must be talking about boost not FP. Fuel pres should follow boost pressure, pound for pound under boost.

AFR 10-1 at idle is way rich. Adjusting IAC count (see below) will help some. Late timing might be part of this as well.

IAC counts need to be high 20s low 30s at idle. 28-33 if pos. Adjust with throttle butterfly stop.

The "idle fuel trim" can't control fuel pres. Eric can correct me but I'd bet it controls pulse width.

My truck idles fine with 10" vac. with a race cam. Not smooth but quite satisfactory.

Timing at -0- with brown wire disconnected first, then IAC count, then post back.

Can you post some logs?

HTH

 

[Don W.]

Re: SYTY will not idle.

is your vacuum/boost gauge in PSI or in/Hg. on the vacuum side? You said 10psi vacuum? 10 PSI is roughly 20"/hg which is about normal

Ya, this is a very common rant:again) mistake. It can't be in/hg and psi at the same time. Two different scales. Combo gauges, which I suspect he has, read in/Hg on the vac side and PSI (pounds per sq in) on the boost side. Two different measurements in the same ga.

1" of mercury (1 in/Hg) is equal to about 0.5 psi. So 10 in/Hg vac at idle is about a NEGATIVE 5 psi. Not commonly used.

FWIW the other method, common in piston aircraft with constant speed propellers, is absolute manifold pressure. The entire ga reads in in/Hg. 0 would be a perfect vac all the way to, for example, 70 in/Hg at 20 lbs boost. 20 lbs boost = 40 in/Hg + 30 in/Hg at seal level = 70 inches of manifold pressure. A LOT in an airplane BTW unless you're in a WWII fighter. Some turbo aircraft engines are "turbo-normalized" meaning the turbo is only used to bring manifold pres "back" sea level. No actual boost is applied.

Look at a DM run. 15 lbs boost will equal about 60 in/Hg. DM is giving you absolute manifold pres in in/Hg. As the engine idles (vac increasing) DM reads less and less in/Hg.

Fun