cmp1516 said:

Alright update, the multimeter came but the new TPS is still being delivered, however I can't resist and did the tune Waltah posted in this thread.

Adjusted the IPS just enough for the switch to touch the throttle whlist not adding tension that can cause the throttle to open and also not stick when closed. (Note that the screw on the IPS wasn't fiddled since I got this from a junkyard so I didn't messed with it). IPS has continuity on closed throttle, moving on to the TPS I turned the key to "ON" and adjusted the TPS the best I could. The lowest I got was 85+ ohms, any other adjustments goes higher on closed throttle so I left it with that since a new TPS is on the way. Next up was the BISS which was turned all the way in then backed out 2 turns, I unplugged the battery then left it for a while then plugged it to reset the codes.

Car stalls on cold start so I upped the BISS by 2 more turns then it idled around 700-750, let it sit for about 5 mins then tried the AC which still bogs the idle to 600-650. Took it for a test drive and the chugging was almost minimal, accel was more smoother albeit a little chugging same goes for decel but it only occurs below 1k. I haven't driven it a lot since I was in the middle of replacing my shifter cable bushings for skateboard bearings and it's a long story, but once the TPS arrives I'll throw another update.

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Scratch that, here's a more important update

But before that here's a little backstory, when my car was being overhauled in the shop the power transistor shorted and broke the ECU, both the power transistor and ECU was repaired for an extra cost.

My power transistor does not have a socket, it only has wires from the harness with some silicone to hold it in, luckily since I went back to a 1G MAF I now have a spare 8 pin socket that came from my old 2G MAF that fits the power transistor so I did just that. Little did I know the "repair" that the shop did cracked the power transistor housing so when I inserted the socket, 1/4 of the power transistor broke off. Silver lining is the car still runs, so I did some test runs and oh boy did it acted funny. The chugging got worse, speedometer is going crazy all the while the car felt slow then stalls when idling, thankfully I reached home before it died completely.

In short, it seems it's the power transistor all along. Luckily the ECU wasn't harmed as there's a blistering red CEL on the gauge. I'll update again once all the parts needed are installed.

cmp1516 said:

Car stalls on cold start so I upped the BISS by 2 more turns then it idled around 700-750, let it sit for about 5 mins then tried the AC which still bogs the idle to 600-650.

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This translates as "ECU is not taking charge of idle RPM." Which is to say "ECU does not see a closed TPS." I don't know what the maximum resistance to be recognized as 'closed' is; I've seen them work okay with 40 ohms but maybe 85 is too high.

Are you absolutely sure you're measuring on the right pins? If so, I'd say let's wait and see what happens with a new TPS.

waltah said:

This translates as "ECU is not taking charge of idle RPM." Which is to say "ECU does not see a closed TPS." I don't know what the maximum resistance to be recognized as 'closed' is; I've seen them work okay with 40 ohms but maybe 85 is too high.

Are you absolutely sure you're measuring on the right pins? If so, I'd say let's wait and see what happens with a new TPS.

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I thought on a 1g throttle closed was solely the idle position switch. I know ecu cuts fuel above 1500rpm at throttle closed. It's the same system that causes idle surge if outside air comes in and rpms exceed 1500.

pauleyman said:

I thought on a 1g throttle closed was solely the idle position switch. I know ecu cuts fuel above 1500rpm at throttle closed. It's the same system that causes idle surge if outside air comes in and rpms exceed 1500.

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I'm pretty sure it is solely the IPS. But on my Expos -- which are pretty much like 1g Eclipses -- I've seen those switches show 20-40 ohms when closed (due, I suppose, to dirty contacts) and still work okay. It's probably better to replace an IPS that doesn't show close to zero but if it works okay I will often leave the used part that doesn't quite meet specs alone.

But 85 ohms seems high and the comment that the resistance goes up regardless of which way he turns the TPS makes me wonder if EMP is measuring on the right pins. Unfortunately I 'don't have either a real 1g Eclipse or the manual so I can't look up just which pins are right.

My wife's car had that fuel cut chug on idle way back when. It was due to the Idle Speed Control Valve having busted off its stop lug and jammed full open.

Final update (maybe) power transistor arrived so I got to work, readjusted everything Waltah mentioned from IPS, TPS to BISS, throttle cable and even CAS. replaced fuel pump, plugs and wires, TPS and PTU.

Runs great, pulls hard, great response, but still low-end chugging. I'm beginning to think the ECU might be the culprit here, if the shop f'ed up the PTU repair the ECU might as well have been too.

For the last attempt I tried to unplug the coolant temp sensor (it was replaced by the shop with a crap local brand) then set the BISS to 1k RPM since it has crappy motor mounts and anything below that vibrates the cabin, originally I was going to do the proper 1G BISS adjustment by grounding both timing plug and diagnostic plug however the diagnostic plug is missing so scratch that.

And by some dumb luck the car doesn't idle lower when AC is on, it maintains 1k idle as if there's no accessory load at operating temp, I stared at the RPM gauge for 5 minutes while turning the AC on and off, RPM doesn't bog at all. Is this a win?

I'll get a proper coolant temp sensor, while the ECU can wait since there's no budget yet and the chugging is more manageable now.

Edit: Got a proper coolant temp sensor car runs properly now, it was this all along.

Gigantic hilarious update!

I was going to let this thread die but I worry that some DSMers might stumble across this thread to find answers for a related symptom.

Ladies and Gents, I present you the problem... The whole goddamn engine was "rebuilt" in the worst possible way of rebuilding engines ever, no wonder it runs like total crap!

keep in mind, the following photos are said to be "general overhaul" job but I hysterically digress.



Starting from the valve cover, for a general overhaul job why would they cheap out on fixing a broken bolt by covering it with RTV?


These valves look pretty worn for a recently built engine (3 months old that was barely even used)


Another cheaped out area, the idiots honed the piston wall via sandpaper and elbow grease, I could feel the roughness just by slightly touching it


No way a newly rebuilt engine could have this much mineral deposits


Wow... just wow, how much of an ass would someone cheap out on replacing core plugs!? Yeah sure just jam as much as RTV possible in there, that'll work (rust below the core plug says otherwise)


Spot something different? Dumb monkeys installed a bearing upside down, what happens when a bearing is upside down? No oil passage, and no oil passage means?


Voila, friction! so all bearings of the crankshaft are shredded to bits



So in short, I'm rebuilding the engine from the ground up AGAIN with a help from a trusted mechanic who finally knows what he's doing. The earlier shop that did this? Well ain't sure if we're gonna sue them but sure as hell want a refund from their expensive joke.

All in all, at least I get to delete my balance shafts and paint some stuff up, hoping for the best!