Poor idle when cold closed loop

[jaysz2893]

Car has new opti, wires, plugs, coil, IAC, TPS, FPR, Fuel Pump, battery, alternator, and temp sensor in water pump. Runs pretty well when hot but occasionally when braking hard and the clutch dumped, the rpms drop to almost stalling or it stalls. When it is cold and stalls it has to crank a lot to get it restarted. Seemed to be fine with my modified stock tune for emissions, so I'm leaning to the tune. It is a Solomon tune from way back. Are there any good chip tuners left? All the local people say to 24x the car. Any ideas?

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[jaysz2893]

running eye bleeding rich, even when up to temp. 30 - 900 mv O2 readings, hunting for idle, IAC stuck at 160, TPS set at .66 on a damn BBK 52 MM TB with the drill mod and the brass fitting for BLM issues.... bad injectors? They are Accell 26# and they sat for 4 years with fuel in the rails.....

[popo8]

Car has new opti, wires, plugs, coil, IAC, TPS, FPR, Fuel Pump, battery, alternator, and temp sensor in water pump. Runs pretty well when hot but occasionally when braking hard and the clutch dumped, the rpms drop to almost stalling or it stalls. When it is cold and stalls it has to crank a lot to get it restarted. Seemed to be fine with my modified stock tune for emissions, so I'm leaning to the tune. It is a Solomon tune from way back. Are there any good chip tuners left? All the local people say to 24x the car. Any ideas?

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Chip tuners are gonna be hard to find and Ive definitely not heard good things about the soloman tunes, but have no experience myself.

LTXtexh.com is my drug...

[jaysz2893]

Chip tuners are gonna be hard to find and Ive definitely not heard good things about the soloman tunes, but have no experience myself.

LTXtexh.com is my drug...

I fooled around more last night with a PCM for Less and my stock modified tune. Now the cranking is hard to start. I am smelling raw fuel now too. I'm going to get some fresh injectors and see how it goes.

[popo8]

U have a burnt chip from pcm4less? Or u burnt ur own based on pcm4less' tune?


If its pcm post bryan herter the kevin/keith dude sucks and makes everything super rich.

I fooled around more last night with a PCM for Less and my stock modified tune. Now the cranking is hard to start. I am smelling raw fuel now too. I'm going to get some fresh injectors and see how it goes.

LTXtexh.com is my drug...

[Injuneer]

“Cold closed loop” seems like an odd description. To clarify - do you mean it’s OK in open loop at cold start, but the instant it transitions from open loop to closed loop - coolant above ~140°F, O2 sensors hot enough to work (~600°F) and 206-seconds since cold start - it gets nasty?

What does the fuel pressure look like? What pressure does the pump prime to? How fast does the pressure drop when the pump shuts off? What is pressure at idle with the vacuum line off the fuel pressure regulator? How much does the pressure drop when you reattach the vacuum line? Can show up problems with the fuel pressure regulator, fuel in the vacuum line, leaking injectors, etc..

What are the engine mods?

PCM of NC (North Carolina) still does chip tunes, assuming he wasn’t wiped out in the hurricane. I have no idea how good his tunes are, but he was the chip guy for pcmforless many years ago.

Assuming you scanned it and no codes.

Have you considered running an ECM data log using GaryDoug's Scan9495 (also works on 93)?

[jaysz2893]

“Cold closed loop” seems like an odd description. To clarify - do you mean it’s OK in open loop at cold start, but the instant it transitions from open loop to closed loop - coolant above ~140°F, O2 sensors hot enough to work (~600°F) and 206-seconds since cold start - it gets nasty?

What does the fuel pressure look like? What pressure does the pump prime to? How fast does the pressure drop when the pump shuts off? What is pressure at idle with the vacuum line off the fuel pressure regulator? How much does the pressure drop when you reattach the vacuum line? Can show up problems with the fuel pressure regulator, fuel in the vacuum line, leaking injectors, etc..

What are the engine mods?

PCM of NC (North Carolina) still does chip tunes, assuming he wasn’t wiped out in the hurricane. I have no idea how good his tunes are, but he was the chip guy for pcmforless many years ago.

Assuming you scanned it and no codes.

Have you considered running an ECM data log using GaryDoug's Scan9495 (also works on 93)?

I think i have open/closed loop backwards in my mind. When cold it runs like crap. Once it gets warm it gets a bit better but it got worse last night when trying to get to the bottom of it. Now when warm it is seeking an Idle, running PIG rich, and stumbles when i try to move it. I def smell raw gas. Pump primes to 35ish. I didnt check to see what it drops to and how fast, but when I try to start it sometimes it takes a lot of cranking and the TB wide open to get it to fire over. Fuel Pressure is ~35 psi at idle , vac line on (new pump and FPR, pump is hot wired off the alt.) and goes above 40 under WOT/load. Ill double check the FPR with the line off. Mods are 52mm BBK, Longtubes/ORY (heated o2 conversion) LPE 211/219 cam, 1.6rrs, accell 26# injectors. I look into the Scan software asap.

[jaysz2893]

U have a burnt chip from pcm4less? Or u burnt ur own based on pcm4less' tune?


If its pcm post bryan herter the kevin/keith dude sucks and makes everything super rich.

LTXtexh.com is my drug...

It was a Bryan tune and now none of the tunes i have are working right lol

[popo8]

It was a Bryan tune and now none of the tunes i have are working right lol

Well if the tunes worked before, that just means something mechanical changed somewhere since the tunes are the same.

LTXtexh.com is my drug...

[Injuneer]

When it starts in open loop, it uses the stored long term fuel trims (LTFT) but not the short term fuel trims (STFT). Running poorly in open loop sometimes means the fuel needs more corrections than the LTFT's can provide. In the stock tune, the LTFT are limited to a range of +25% to -15%. When it enters closed loop, the STFT can add or subtract an almost unlimited amount of fuel.

If it's running rich, in open loop, putting the accel pedal on the floor puts the ECM into "clear flood" mode - that basically turns the injectors off.... something that could be required if the injectors are leaking, flooding the cylinders when the engine shuts down. That's why it's important to see how high the pressure gets when the fuel pump primes, and how fast it drops, indicating leaks.

Are you saying that you have the pump wired directly to the alternator, so that it runs all the time? That would really make leaking injectors worse, since that means leaking injectors would be pouring fuel into the cylinders as soon as you turn the key. Running the pump through the stock relay, with the ECM interlock prevents that from happening, since the pump only runs for two seconds, and doesn't start up again until the ECM sees the cam position signals from the Opti.

At this point, the easiest check might be to pull the fuel rails up with the injectors intact, turn the key to "run" to pressure the injectors (not to "start") and look for drips from the injectors. Best to do that with a cold engine, outside, putting cups under the injectors to avoid a fire. Keeping a fire extinguisher handy is also a good idea. If you have leaks from the dirty Accel's, the stock injectors might make a good temporary replacement, while you get the Accel's cleaned.

The other possibility could be a problem with the lifters or sticky valve(s), holding the valves open. The incoming air fuel blows right through the exhaust valve, the O2 sensors see the oxygen (air), tell the ECM it's running lean, and it starts pouring fuel into the engine it doesn't need. That can also be a problem with a high overlap cam, but yours wouldn't appear to be that issue, unless it's got a very narrow LSA.

I don't think Brian or Keith ever did chip tunes. I though that's what the guy in North Carolina did for them. He split off from pcmforless at least ten years ago. He's very close to Mooresville, NC in the center of Florence damage.

http://www.pcmofnc.com/

But I don't think it's a tune problem. Leaking injectors seems more likely at this point. I've never heard anyone say anything good about Accel injectors.