1G 1990 GSX won't stay running all of a sudden

[Gumbob3]

1990 Eclipse GSX with mods on my profile.

Car was running great when I shut it off, I came back out a few minutes later to it failing to start. After some time and many attempts, it runs but it won't stay running. It will run OK for about 5 seconds if I get it to a point where I can hold the throttle to keep it around 3k rpm, then it will just fall flat on it's face out of nowhere. I have confirmed spark across all 4 cylinders and fuel injectors are working properly.

Changed MAP sensor. Has fresh fuel and a fully charged battery. Any ideas are very much appreciated. Thank you!

 

[steve]

Any idea what causing these short spikes where your sensors go wild?

 

[ctrenks]

Timing belt jump? lifters all intact? Gas + Spark should run. Also can you see fuel pres? I didnt look at the log but if there are short spikes i would say a bad ground or somthing shorting out to ground.

 

[Vegas Smith]

I can't view the log at work but I'm wondering about fuel pump losing pressure/not able to keep up.

 

[AWD-Tony]

First thing I would do is set the correct inj battery offset. Car is running at 11-12v with the values that are close to stock. Looks like op is running 1700-2100cc injectors??? TPS scaling is 180 which I've never seen. You’re on SD so you can zero out the maf slider.

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[1990TSIAWDTALON]

Check the CTS and its wiring.

 

[#95GS-EX]

Maybe a voltage drop from alternator? have you checked your volts when car is at idle? I had a similar issue where my car would lose voltage and turn off.

 

[steve]

First thing I would do is set the correct inj battery offset. Car is running at 11-12v with the values that are close to stock. Looks like op is running 1700-2100cc injectors??? TPS scaling is 180 which I've never seen. You’re on SD so you can zero out the maf slider.

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If I remember correctly he's done that and set deadtime adjustment in the basic fuel tab. It should be one or the other, not both.

 

[AWD-Tony]

If I remember correctly he's done that and set deadtime adjustment in the basic fuel tab. It should be one or the other, not both.

He has 1200’s in his profile. In his log, global is calculated at 1700. Maf slider was all over the place.

 

[steve]

Yes, but he also has added 540us of Global Deadtime on top of his lowering InjBatteryAdj values in the direct maps. So again use one or the other but not both.

I'm not sure how or if the MAF Comp sliders apply if you select the Disable MAF comp w/SD operation checkbox and are running SD.

 

[AWD-Tony]

I'm not sure how or if the MAF Comp sliders apply if you select the Disable MAF comp w/SD operation checkbox and are running SD.

I see. I’m not sure either. I’m going to try when mine is back together.

For deadtime vs injbattery, the scaling on the data sheet doesn’t increase/decrease with voltage proportionately so just adding more deadtime and leaving injbatteryadj is going to be off. I personally rather enter the info given by the manufacturer so there’s no guessing.

 

[steve]

For deadtime vs injbattery, the scaling on the data sheet doesn’t increase/decrease with voltage proportionately so just adding more deadtime and leaving injbatteryadj is going to be off. I personally rather enter the info given by the manufacturer so there’s no guessing.

Back in the dark ages (Pre-V3) all one had in DSMLink was the Global Deadtime to work with. (No direct maps)

Unless the manufacturer used a DSM ECU to come up with their info it's just a suggestion and you're still guessing. Better than nothing but not gospel. I'm sure there was a Mitsubishi or ND engineer that spent a bunch of time characterizing the factory maps for each configuration to account for ECU Drivers, Injector Inductance, Snubbers, Fuel Pressures, etc to pass emissions.

 

[Vegas Smith]

You have a discrepancy in how your wideband is setup. Under the datalogging pin assignment it's listed as egr but under the ecu side assignment it's front o2. Make sure these selections are accurate. This is the likely culprit.