Poor idle when cold closed loop

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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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.....

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Originally Posted by 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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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...

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Originally Posted by popo8

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...

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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.

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.

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Originally Posted by jaysz2893

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.

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LTXtexh.com is my drug...

“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)?

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Originally Posted by 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)?

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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.

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Originally Posted by 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.

LTXtexh.com is my drug...

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

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Originally Posted by jaysz2893

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

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

LTXtexh.com is my drug...

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.

Some quick clarification. Bryan never did the chip tunes. It was always Alvin who took care of those under the PCMForLess name. Alvin still is "PCM's of NC" to my knowledge.

Jay, your fuel pressure at prime should be higher than 35. I'd be curious to see if you have a leaking injector, or possibly a leaking regulator? Based off your symptoms, especially with the hard start, I'm leaning towards the injectors leaking. If my memory still serves me, Accel injectors back in the day were notorious for being leakers.

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Originally Posted by Fastbird

Some quick clarification. Bryan never did the chip tunes. It was always Alvin who took care of those under the PCMForLess name. Alvin still is "PCM's of NC" to my knowledge.

Jay, your fuel pressure at prime should be higher than 35. I'd be curious to see if you have a leaking injector, or possibly a leaking regulator? Based off your symptoms, especially with the hard start, I'm leaning towards the injectors leaking. If my memory still serves me, Accel injectors back in the day were notorious for being leakers.

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Yes! Alvin! I'm leaning on the injectors being the culprit too. The FPR was bad as was the pump from sitting all those years with old ethanol fuel in the system. Makes sense that the injectors would suffer too. Plus on my budget at the time , only the used and mediocre was all I could afford.. lol.

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Originally Posted by jaysz2893

Yes! Alvin! I'm leaning on the injectors being the culprit too. The FPR was bad as was the pump from sitting all those years with old ethanol fuel in the system. Makes sense that the injectors would suffer too. Plus on my budget at the time , only the used and mediocre was all I could afford.. lol.

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[gentle reminder] Pop that rail up and have a look. You'll know real quick once you key it on. [/gentle reminder since it's been so long for you]

well, that didnt totally fix it. It looked like 2 we leaking so i replaced the set with a new set of accels. I had some bosch but they wont fit the damn intake, too short. Now if i can get it to fire over it doesn't stick rich. problem is I cant get ti to fire over and run smooth, Seems like ignition now. I just put a delco opti and coil in before i got it inspected. Nothing is showing up in trunerpro, but I cant get it to run long enough. Still needs to crank a lot and the throttle body open to get it to fire over.

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Originally Posted by jaysz2893

well, that didnt totally fix it. It looked like 2 we leaking so i replaced the set with a new set of accels. I had some bosch but they wont fit the damn intake, too short. Now if i can get it to fire over it doesn't stick rich. problem is I cant get ti to fire over and run smooth, Seems like ignition now. I just put a delco opti and coil in before i got it inspected. Nothing is showing up in trunerpro, but I cant get it to run long enough. Still needs to crank a lot and the throttle body open to get it to fire over.

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Are you running it on the last good tune it ran on? If not, switch to that, take any variables out of the equation.

Yep, it is the one that ran the car last weekend for 80 miles.... even foot the floor of wont fire right. Really seems ignition to me now. When I took it to DMV I had big cats in the pipes and it got Hot under the hood. Enough to melt some wire loom. I'm gonna track down the wires and I have a spare ICM somewhere. I'll report back... lol

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Originally Posted by Fastbird

Are you running it on the last good tune it ran on? If not, switch to that, take any variables out of the equation.

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I doubt it's the ICM. That's a "works or it doesn't" type of thing.

If you want the service manual diagnosis chart, I still have my 93 service manual and can put some pics up.

Or download a copy for free, courses GaryDoug:

https://www.mediafire.com/?40mfgeoe4ctti

I have my manual and I am walking away from it now. I couldn't find my spare ICM. I took a video and I'll post it soon. I knew this damn car was going to do this to me.

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https://m.facebook.com/story.php?sto...00001030488068


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I pulled the rails and primed the pump. No leaks with the new injectors .. primes up to 40 psi. It just doesn't seem to be getting strong ignition. Raw gas smell at the exhaust pipe if in keep it running with the throttle open.

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Pulled the valve covers and the valvetrian seems fine too

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@jaysz2893 any update on this?

None yet. I'm in Detroit all week. I'll be able to mess with it this weekend. I got a new coil and ICM as well as a IAC and MAP pigtail to fix the broken crap. I should do that anyway. I do have a line on a complete ls1 engine / harness/ PCM in a 4th gen k member for cheap......

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UPDATE!

New ICM and Coil and the car fires over... now i have low TPS voltage (and running rough) I tried 3 TPS sensors i had laying around and i have 0.4 closed and I cant adjust it anywhere. BBK TB. Even if i take it off and turn the TPS by hand I never get over 1 volt. I am stumped

UPDATE AGAIN

I followed the procedure and I get 4.96 when probing the blue wire to the battery. I think the harness could be messed up I tired 2 PCM and same thing.

Are you clearing DTC 22? It's going to stay in the ECM as a stored code until you clear it, or drive the car a significant number of "drive cycles" without the problem recurring, and it auto-clears.

In a 1993, DTC 22 (signal voltage low) sets when the TPS signal voltage is less than ~0.23 volts. 0.40 volts should not set a code. And of course there is no adjustment, because the ECM reads the voltage at key on, and as long as the voltage is between 0.30- 0.90 volts, sets the key on voltage as 0% throttle position.

You should have ~5.0 volts between the Black ground wire and the Gray 5 volt reference wire. Blue wire is the variable signal wire. Black wire goes to pin B on the connector, Blue wire goes to pin C on the connector, Gray wire goes to pin A. Signal voltage is read between the Blue wire and the Black wire.

ok, i found the ground was messed up and fixed it. i have the right voltage everywhere now. Cleared the DTC. now it fires over but wont stay running. The IAC is still at 160. I tried resetting it a bunch of times now. It is relatively new. I get a big sucking noise at the air intake and when i do give it gas to run, i hear a weird whirring noise....

What air box are you using, the one from SLP that came with the hood?

Test IAC electronics:

From Shoebox

http://shbox.com/1/iac2.jpg

Passages could be plugged. I remember one we sorted out where the coolant in the bottom plate had leaked into the air passage.

i pulled a spark plug and man does it look bad. Black, oily, smelly... I know it is running rich AF but it still seems like it is not getting enough fire. I put the opti on about 1+ years ago. It is a Delco. It sat for over a year before i messed with the car to get it to DMV. I really would love to to the TorqueHead 24x link. I know the 1992/3 kit was "coming soon" so I emailed them.. no reply ...

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Originally Posted by Injuneer

What air box are you using, the one from SLP that came with the hood?

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yes, the SLP one

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Originally Posted by Injuneer

Test IAC electronics:

From Shoebox

http://shbox.com/1/iac2.jpg

Passages could be plugged. I remember one we sorted out where the coolant in the bottom plate had leaked into the air passage.

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I tested the IAC and it tested good. I bypassed the coolant to the TB. I also cleaned the passages.. I've been out here in the shop since 5 AM reading my service manual and trying everything I can think of.. LOL I am thinking low spark energy could be the problem?

I had an IAC that was reading fine from a datalog standpoint but when I removed it from the TB, it was caked in carbon and the spring was completely stuck. As it was stuck open, the PCM was just dumping fuel. Not sure if it is relatable, but worth checking.

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Originally Posted by Z28pr0jekt

I had an IAC that was reading fine from a datalog standpoint but when I removed it from the TB, it was caked in carbon and the spring was completely stuck. As it was stuck open, the PCM was just dumping fuel. Not sure if it is relatable, but worth checking.

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the IAC was clean and i tried a new in box one too. This car hates me... I have a spare opti module. The plugs i took out so far look pretty bad. Ill pull this MF opti one more time and fix it. If it does not solve the problem, LSX here i come! :-P

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Originally Posted by jaysz2893

.... If it does not solve the problem, LSX here i come! :-P

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Blasphemy

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