Lean issue

Wildwomper · Mar 31, 2018

Hello all, I am a new proud owner of a 1990 eclipse gs turbo. I’ve had the car about a month now and have encountered a fair share of problems but with one persisting that I can’t seem to fix. I bought the car with a rebuilt head, and low miles considering it’s age. To cut the BS I’ll get to it. Essentially the car is running lean all throughout the power band, from idol, cruise, partial throttle and WOT. I will list my applied solutions that haven’t worked thus far. I got the car with a cracked manifold so I threw in one from an Evo 3, that didn’t fix the issue. I then routed my own custom hard intercooler piping kit using stock diameter piping being that the stock stuff was aged and dry and cracking, this didn’t solve the issue either. Next I did a BLT to find out my intake manifold gasket, throttle body shaft seals, BISS oring, and injector seals were all leaking. I replaced all of them and swapped in a 1gb throttle body. And as you guessed it, none of this solved my problem. When I BLT from the turbo a higher than normal flush of air comes out of the breather port on the valve cover. So then did a BLT from the throttle body and it was fine so I know it’s not my rings, pcv, or valves being partially open. I’m thinking it may be leaky turbo seals but even then I would think that that’s already pre-metered air so it shouldn’t affect my lean issue. So now I’m sitting stumped thinking it’s possibly a fueling issue but I don’t know exactly which is why I’m coming here. Current up to date symptoms of the car are:
•lean (16.3 to - - -) on the UEGO during cold starts
•warm idol around 15.3-16.8 and sometimes off the guage lean.
•slight small putts during idol out of the exhaust spaced at one about every 3-4 seconds.
•under cruising vacuum afr reads 15.5-16.3 then sudden spikes to off the charts lean and feels like it’s powerless and falls on its face. Can be resolved by applying hard throttle and letting off then it will resume back to as stated. And repeats this about every 5-10 minutes while cruising, depending on throttle position variation.
•under boost in first and second gear it hangs around 13-12 afr until redline where I might see 11.5 if I’m lucky, and all other gears never exceeding 12.5 at wot.
•random episodes of low rpm super lean warm starts and will resume to idol around 15.3-16.8 as stated earlier after driving a little.

I am new to the forum so I figured I should post this in the newbies section but any help would be greatly appreciated. Thanks in advance.

EDIT
I should also mention that when I first got the car it ran perfectly and the problem has proceeded to get progressively worse. But after all my efforts it is better but still not good.

linksys42 · Apr 1, 2018

Double check for exhaust leaks, at the manifold to head, manifold to turbine housing, turbine housing to o2 housing, and o2 housing to down pipe. Best way to do it is with a smoke machine. But you can half ass it by having a friend block tail pipe temporarily and listen at the junctions I stated above. Or another half ass way is to use seafoam and find them that way by looking for the white thick smoke created by the seafoam burning at the junctions I stated above. Another question, do you have a logger of some kind? What are you sensors reading? O2, TPS, MAFS, CTS, STFT, LTFT, BATT (could be as simple as a bad o2 sensor). After checking all of that I would move on to fuel supply problem, filter, pump, injectors, FPR. Also because you just got this car check ignition timing and mech timing. Good luck!

Vegas Smith · Apr 1, 2018

Could be super-old clogged fuel filter or fuel pump sock.

Wildwomper · Apr 1, 2018

linksys42 said:
Double check for exhaust leaks, at the manifold to head, manifold to turbine housing, turbine housing to o2 housing, and o2 housing to down pipe. Best way to do it is with a smoke machine. But you can half ass it by having a friend block tail pipe temporarily and listen at the junctions I stated above. Or another half ass way is to use seafoam and find them that way by looking for the white thick smoke created by the seafoam burning at the junctions I stated above. Another question, do you have a logger of some kind? What are you sensors reading? O2, TPS, MAFS, CTS, STFT, LTFT, BATT (could be as simple as a bad o2 sensor). After checking all of that I would move on to fuel supply problem, filter, pump, injectors, FPR. Also because you just got this car check ignition timing and mech timing. Good luck!

Thanks a lot for the suggestions, but I don’t have any logger of any kind, just an AEM UEGO I’m going off of. I am having an issue with dialing in the 1gb tps on the 90. The check engine light is on only at idle and at the moment any sort of throttle is pressed it goes away and comes back again at idle. I do have some super minimal exhaust leaks, but I will test them with the tail pipe block method and see if any others show up under pressurized circumstances. But they’re mainly just pin hole sized leaks under the soapy water test. But how would I check ignition timing and mech timing? Would I need a logger?

Vegas Smith · Apr 1, 2018

Oh, you have Tim Oawster's old car. If that is Tim's car then I'm sure the timing is on point as he does that for a living.

Wildwomper · Apr 1, 2018

Vegas smith said:
Could be super-old clogged fuel filter or fuel pump sock.

It has a Walbro 190 in it that was replaced at the same time as the head was rebuilt along with a new fuel sock, which was about two to maybe three years ago. The fuel filter was also replaced at the same time, and since that time the car has only had about 35,000 miles put on it so I haven’t quite reached the 60,000 mile maintenance interval for it yet. But it might be maybe my pump is dying, but it sounds to be running smooth.

Wildwomper · Apr 1, 2018

Vegas smith said:
Oh, you have Tim Oawster's old car. If that is Tim's car then I'm sure the timing is on point as he does that for a living.

You are exactly right LOL

, that’s why I have doubts about it being anything mechanical that’s being problematic or anything done wrong.

Vegas Smith · Apr 1, 2018

You're sure you don't have dsmlink? You may try and re-calibrate the wideband as they can read incorrectly after a while. I would just contact Tim on Facebook and ask if he has any suggestions.

Wildwomper · Apr 1, 2018

Vegas smith said:
You're sure you don't have dsmlink? You may try and re-calibrate the wideband as they can read incorrectly after a while. I would just contact Tim on Facebook and ask if he has any suggestions.

I’ve already milked Tim for all the answers I can, now he just wants me to bring it by fist. I don’t want to burden him with anymore questions. And fist is about $250 for their dsm checkup and that’s kind of steep for me. But if it comes down to it and I can’t seem to find the issue I may not have a choice. But as for link I wish because it’s still on back order for 90’s and from Tim himself he told me no it doesn’t have link. He sold it before he did anything major because he found his current gsx he’s built. I bought it from the guy who purchased it from Tim, which seemed like a fine gentleman who knew what he was doing also. So now I’m trying to do what I can to save this thing.

Wildwomper · Apr 1, 2018

Vegas smith said:
You're sure you don't have dsmlink? You may try and re-calibrate the wideband as they can read incorrectly after a while. I would just contact Tim on Facebook and ask if he has any suggestions.

But how would I recalibrate the wide band? The manual says nothing about how to do it without an ems.

Vegas Smith · Apr 1, 2018

Hmm, maybe the AEMs don't recalibrate.

Wildwomper · Apr 1, 2018

Vegas smith said:
Hmm, maybe the AEMs don't recalibrate.

From what I’ve seen I don’t think so.

linksys42 · Apr 1, 2018

Wildwomper said:
Thanks a lot for the suggestions, but I don’t have any logger of any kind, just an AEM UEGO I’m going off of. I am having an issue with dialing in the 1gb tps on the 90. The check engine light is on only at idle and at the moment any sort of throttle is pressed it goes away and comes back again at idle. I do have some super minimal exhaust leaks, but I will test them with the tail pipe block method and see if any others show up under pressurized circumstances. But they’re mainly just pin hole sized leaks under the soapy water test. But how would I check ignition timing and mech timing? Would I need a logger?

.

The very first thing you need to do is get some kind of logger. At least mmcd. Sounds to me like your TPS is way out of adjustment. Start there and I bet the problem will clear up. A quick search for TPS adjustment and how to check ignition timing and mechanical timing will give you a ton of information on this site. And to your other question no you do not need a logger to check ignition timing or mechanical timing (but you need a logger of some sort it will make your life 10 times easier in troubleshooting). Read the post in these thread below. And check-out the VFAQ site. Tons of info.

http://www.dsmtuners.com/threads/tps-in-but-wont-adjust-help-please.392810/#post-152472604

http://www.vfaq.com/index-main.html

linksys42 · Apr 1, 2018

Wildwomper said:
But how would I recalibrate the wide band? The manual says nothing about how to do it without an ems.

(From the manual.)

Each AEM UEGO sensor is individually calibrated and a resistor integral at the
connector body is laser trimmed with this value. This process replaces the traditional
“free air” calibration procedure when changing sensors and implements a sensor
specific calibration for unparalleled accuracy.

Wildwomper · Apr 1, 2018

linksys42 said:
.

The very first thing you need to do is get some kind of logger. At least mmcd. Sounds to me like your TPS is way out of adjustment. Start there and I bet the problem will clear up. A quick search for TPS adjustment and how to check ignition timing and mechanical timing will give you a ton of information on this site. And to your other question no you do not need a logger to check ignition timing or mechanical timing (but you need a logger of some sort it will make your life 10 times easier in troubleshooting). Read the post in these thread below. And check-out the VFAQ site. Tons of info.

http://www.dsmtuners.com/threads/tps-in-but-wont-adjust-help-please.392810/#post-152472604

http://www.vfaq.com/index-main.html

I’ve tried searching for how to adjust the tps but there are no cases, that I can find at least, of anyone giving a walk through on how to adjust a 1gb tps on a 90. Being the ecu’s are different and such and put out different voltages to the tps. And also I am using a 3g tps connector so the wires don’t match up color wise or else I know from what I read it would be easy to link up. I’ll try the link instructions you provided to me and see if that works. But I did replace the fuel filter today and it helped slightly, and I’m noticing now that every time I step on the break at idol the afr will drop from 16.5 to 17.2-4.

Wildwomper · Apr 1, 2018

Update: today I replaced the fuel filter and adjusted the tps so that the check engine light is gone. I also tightened all manifold and turbo bolts and solved all exhaust leaks. It helped a slight bit but it’s still idling lean and enacting most of the same symptoms as I stated earlier, but one I find weird is after cruising for a small period the car totally falls off the chart lean and loses all power, and as I stated above it can only be solved by letting off the throttle and applying hard throttle a couple of times to “wake it up” if you will, then it resumes cruising around 14.9-15.7 afr. I would really appreciate anyone’s help because I really want to get back to enjoying this car.

Mauispyder · Apr 1, 2018

Vacuum leaks? Try spraying the vacuum lines and connectors to see if this temporarily fixes the lean condition. Some cracks are like one way valves.

Wildwomper · Apr 2, 2018

Mauispyder said:
Vacuum leaks? Try spraying the vacuum lines and connectors to see if this temporarily fixes the lean condition. Some cracks are like one way valves.

I’ve got all boost leaks sorted, but just for the extra reassurance I’ll try another time to see. I may try the carbourater cleaner method to see if idle changes. Because it seems like a vacuum leak but nothing shows under boost leak tests.

Vegas Smith · Apr 2, 2018

Your narrowband o2 sensor may be going back as well.

Wildwomper · Apr 2, 2018

Update: alright so today I had time to do a propane vacuum leak test. Another failure. I checked all the couplers and lines and even put some propane directly into the intake to get a jist of what to expect. No where I placed the propane except the intake gave any sort of idol change. So it’s definitely not a boost leak at this point.

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