2G sometimes it pulls, sometimes not

[Mike_GST]

Hello guys.

I looked around for threads like this, but none of them presents irregular working like mine.
I have now my '98 GST for one year and half and something is bothering me since ever.
My car sometimes pulls strong and sometimes not. No reason I can notice.
Same day, same temperature, same time, same conditions. I pull once, the acceleration presses my body to the sit. Then stop the car and pull again. The rpms goes up, the pressure gauge shows full boost, but the car has a very weak performance. In this same exactly pull, if I release and quick the accelerator, the car reacts full performance again! Pretty wird thing.

Everything in the car is stock. When I bought it, replace all the belts, spark plugs and fluids.
At first I was suspicious about the wastegate, that an erratic opening and closing could be doing that.
The car has VERY LOW MILEAGE, so being sitting could make some moving parts get sticky, I thought
Then I released that little rod that connects it to the actuador and moved with my hand right and left.
Very smooth movement! Is not the wastegate.

Well, I don't believe this problem is related to the air flow, neather from or to the engine. It couldn't be such a leackage on the lines, way to make the performance drop that much, without been noticeable in the gauge, which by the way, shows full boost.

Do you guys have any guess?
Thank you very much.

 

[Chumpaumpalumpa]

Start at 10 psi and if you have no/ fix all the leaks do it at 15 psi and that'll be good for you.
Also to clarify, starting in 3rd gear is not a bog, it would cause the engine to bog. Another way to explain it would be if you press the throttle and the engine starts to rev down.

If your hoses leak, tighten the clamps. If they still leak, they might need replacing. The chinese silicone couplers as we call them, are fine. Silicone is silicone, its muito difícil de bagunçar.

 

[Utz_3]

I would perform a boost leak test if I were you, make a boost leak tester like the one in those videos, it is a cheap, yet very useful tool. Since you are stock, test at 10-15 psi. Also try to get an aftermarket boost gauge for more accurate readings, the stock one is not all that great as it has been discussed on here. Even if you have vacuum/boost leaks the stock gauge will rise when going into boost.

 

[chrysler kid]

Splitting hairs the engine is part of the car, but I like your definition a little better

My car does not have any boost leaks and it's monitored by a boost gauge hooked to the fpr vac line. I still think bastarddsm had the best definition, the car bogs and knock sensor picks up the vibration and pulls all timing out of the motor and it just dumps fuel

 

[Mauispyder]

Replace BOV regardless, you'll be glad you did, 1g or metal EVO one.

 

[Mike_GST]

About replacing the BOV, if I need to, there ain't options besides the Tial. Looks like HKS and Greddy don't make recirculating BOVs. Junkyards have some 1st gen Eclipses, but only GS models, none of them turbos. Still, some of them I asked, already sold out. Evos didn't arrive here that early.

I use to run the heck out when someone offers me chinese stuff. Or they are really piece of junk or I have very bad luck with them. But again, no option besides those chinese couplers.

Well, i'm gonna need some time now to get all the parts togheter and build the leakeage tester device. One thing came to my mind. In the vídeo-tutorial posted by Chumpaumpalumpa (thanks man), they connect the device right to the compressor intake. What about take off the air box and connect it to the MAF inlet? I believe this way I could find out leakeages all the way since MAF, plus compare the devices gauge pressure to the dashs one (see if works ok).

I also took some time to read about how knock sensors work. If I understood right, it'd be a hell of a coincidence it "reading" knocks from boost vibration through leaks. I read somewhere there's a kind of resin that goes on the face of the knock sensor, to filter some vibration frequency range. And also that this resin use to melt off or loose its efficiency with time. Maybe the sum of boost leaks in a vibrating way (very possible) and a sensor knock without this filtering could result in a much more likely hypotesis. Interesting! I'm starting to feel that all of what you guys sayed until now are related and getting togheter to one single point.

 

[Utz_3]

With regards to the bov, I am sure you can find a 1g here on the classified for very cheap. Otherwise you can either find a used Greddy type S or RS here in the classifieds, or go with a new NGR Type S, which essentially is almost the same, but with a stronger, better designed diaphragm.

Just a quick search in the classifieds and i found these:

http://www.dsmtuners.com/threads/updated-my-list-again.500012/#post-153566241 (Greddy type rs)
http://www.dsmtuners.com/threads/garage-sale-dsm-parts.499762/#post-153564616 (1g bov with hard pipe)

I am sure if you look a little more you can find some cheaper ones.

 

[Mauispyder]

I got a new in box EVO blow off valve from extreme psi for about 150.
I've never pressurized the maf inlet during a leak test, but I have hooked up to the beginning of the lower intercooler pipe so I wouldn't be distracted by the bubbling from the turbo seals into the oil pan.

 

[Chumpaumpalumpa]

About replacing the BOV, if I need to, there ain't options besides the Tial. Looks like HKS and Greddy don't make recirculating BOVs. Junkyards have some 1st gen Eclipses, but only GS models, none of them turbos. Still, some of them I asked, already sold out. Evos didn't arrive here that early.

I use to run the heck out when someone offers me chinese stuff. Or they are really piece of junk or I have very bad luck with them. But again, no option besides those chinese couplers.

Well, i'm gonna need some time now to get all the parts togheter and build the leakeage tester device. One thing came to my mind. In the vídeo-tutorial posted by Chumpaumpalumpa (thanks man), they connect the device right to the compressor intake. What about take off the air box and connect it to the MAF inlet? I believe this way I could find out leakeages all the way since MAF, plus compare the devices gauge pressure to the dashs one (see if works ok).

I also took some time to read about how knock sensors work. If I understood right, it'd be a hell of a coincidence it "reading" knocks from boost vibration through leaks. I read somewhere there's a kind of resin that goes on the face of the knock sensor, to filter some vibration frequency range. And also that this resin use to melt off or loose its efficiency with time. Maybe the sum of boost leaks in a vibrating way (very possible) and a sensor knock without this filtering could result in a much more likely hypotesis. Interesting! I'm starting to feel that all of what you guys sayed until now are related and getting togheter to one single point.

HKS and Greddy do make recirculating BOVs. A standard 1G BOV would more than meet your needs. Just get one off the classifieds here or post a want to buy ad (WTB) on the classifieds saying you want one and someone will get back to you.

Ok just to make sure I know what you're talking about, when you say Chinese couplers you mean the round piece of silicone that goes between 2 pipes and you clamp it on to the pipe? If yes, don't worry about buying those. Not ALL chinese stuff is garbage. You can buy those couplers worry free. They will be fine, everyone uses those.

Just do it on the compressor inlet. That's how it's always been done. There's not much that can leak on the intake pipe. Just tighten the clamps down tight and you will be fine. Its a BOOST leak test. All the boost is after the compressor.

The knock sensor can be falsely triggered. It's a common issue for these cars. It's called phantom knock. I'm not sure abut the 420a, but the 4G63 sensors are susceptible to phantom knock. Do some reading on that.



This is what I mean by couplers:
http://www.streettunedmotorsports.com/parts/b/stm_silicone_reducer_couplers.jpg
or
http://www.stinger-performance.com/...KHXj0Av0Q_AUIBygC&dpr=1#imgrc=f7Fv4bKSmOk7KM:

 

[chrysler kid]

It's great to see some one reading up on their car, great work sir

I'm going to slowly raise my hand, every part I have is from ebay. They technically aren't performance parts. My intercooler pipes were really mushy under the mesh pieces so I needed some replacements. I weighed my options, it was either piece together piping from random radiator hoses or get what is really a great designed ebay kit

So anyways
Cx racing intercooler piping kit, $119 shipped great fitment
Fake greddy type S blow off valve $19 shipped (holds stock t25 boost no problem)
Ebay intake, $89 shipped
Hks clear timing cover $19 shipped from Hong Kong
Ebay 9 piece silicon radiator hose kit $54 shipped

My car had been sitting for 3 years and needed these parts, while it was stored in a garage during that time most rubber pieces in the engine bay and suspension were very decayed. Basically after fixing the clutch my radiator neck broke and other rubber parts just fell apart as I took them off

No regrets, extremely happy with my cx racing upper and lower intercooler piping

From what I can tell with hks parts, they manufactured them in china. After the factory filled the initial order quantity given by hks they kept making them as branded "knock offs". Atleast that's all I can guess, a new hks bov in box on ebay is $50 shipped and my real hks branded timing cover was $20

For a real deal type s greddy blow off valve, I had a car with the name brand one back in the day and the adjustment screw popped out of the top of the blow off valve. There is actually one used on ebay right now with a round headed screw on top which is exactly what I had to do on my real $250 greddy whistle

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[Mike_GST]

Ok I made a mess with that question about the silicon hoses kit. Actually they are for water lines, not for air lines. Sorry about that, I just saw 11 hoses and didn't think there were so many just for the radiator, thought they were for both systems. The stock ones look to be made by rubber too. Anyways, if you guys have any experience with those, are they worry free too?
That's what I was talking about. Same thing can be found eather USA or Brazil:
http://www.ebay.com/itm/Silicone-Radiator-Coolant-Hose-Kit-MITSUBISHI-Eclipse-DSM-95-99-Turbo-4G63-Red-/281732705717?hash=item419893edb5:g:uh8AAOxyzqdTegnb&vxp=mtr
http://produto.mercadolivre.com.br/MLB-667856552-mangueiras-de-silicone-vermelha-eclipse-9599-samco-11-pcs-_JM
Took the car for a test ride this weekend. Did a lot of pulls, full throthle from zero and moving from 1.5k, 2k, 2.5k, 3k, 3.5k and 4k rpms all the way to redline, in first, second and third gears.
First notice: doesn't make difference in which gear or rpms range I floor the throtle. My cars performance sometimes goes nice, but mostly weak. Only when pulling from zero the car has a trustful behave when full throtle and actually don't remember once it failing under this circunstance.
Second notice: when in a higher gear, lets say third, flooring all the way from 2k rpms, in a good performance pull, I feel the engine very smoothly growing its power delivery by steps: definitely its not a continuos thing. It's hard to explain, but if you could picture this on a dyno chart, the power line would grow "squarely", looking like a stair. Could be timing smoothly getting retarded a bit, and a bit, and a bit. It tends to stop as higher the rpms go. Could be the vibration of the air through leaks scaping the frequency range that affects the knock sensor working, as higher the air flow goes in. That could also explain why I do not feel it happening when pulling from zero, since the gear shiftings are made in very high rpms.
Third notice (ain't something new): I've got to be realistic, no stock turbocharged car sounds that cool as mine does. Pulling hard through high buildings, I can hear a loud echo from the turbo spooling and also the BOV "sneezing" when shifting. I was hardly avoinding to consider that, but finally my critical sense took place and reminded me that a healthy stock car never suppouse to sound like a dragraces.
Got to be a leak, big one, BOV very included.
Chupaumpalumpa, when I mentioned about test leaks all the way from the MAF, my worry was not releated about boost, but the negative manometric pressure from the compressor inlet, if you know what I mean. Lets say there's a leak into the intake hose of the compressor. The compressor is gonna throw to the engine some amount of air that didn't pass throw MAF and this overload of air will appear in the O2 data, telling the ECU that the air-gas mix is too poor, making it throw more gas to the engine. That's just a though, really don't know if this controversial informations (from MAF and O2) would make the ECU confuse and adjusting with no consistence the stoichiometric mix over and over, causing the car this wierd behave.
To buy on Ebay or even private deals from US now is too expensive, brazilian money is pretty worthless, so I got to work with what I can find in here. Probably is cheaper to buy a brand new HKS BOV here than a second hand in USA plus shipping and taxes. Thanks for the research my friend (Utz_3). Will keep those models in mind. Also Chrysler Kid and Mauispyder thank you for the hints.

 

[crash]

Do you have the bov venting to atmosphere? Is there a hose going from your bov to intake tube?

Look at Chrysler kid's picture for reference.

 

[Chumpaumpalumpa]

I understand what you were saying. There is vacuum on that side of the turbo when under boost. There is not much to leak there. Just tighten it up real good and don't worry about it. Replace any rubber parts that are cracked, stiff, or dry. All silicone kits are very similar in quality, whether water or air, they are fine for 99% of us. Did you do that boost leak test yet? That will tell you a lot.

 

[rough]

Maybe the fuel pump's hose has cracked or slipped off causing inconsistent performance issues.

 

[Mike_GST]

Do you have the bov venting to atmosphere? Is there a hose going from your bov to intake tube?
Look at Chrysler kid's picture for reference.

No, BOV is not venting to atmosphere. That little hose is where it supposed to be. Maybe it's cracked, can't see without removing it because there's another hose covering it.

I understand what you were saying. There is vacuum on that side of the turbo when under boost. There is not much to leak there. Just tighten it up real good and don't worry about it. Replace any rubber parts that are cracked, stiff, or dry. All silicone kits are very similar in quality, whether water or air, they are fine for 99% of us. Did you do that boost leak test yet? That will tell you a lot.

Still couldn't find a gauge 0-30psi or something close to this around. Will go to a larger city this saturday. Meanwhile I removed all the hoses (except that one from intercooler to anywhere else), checked insides integrity and mounted it again tightening the clamps little stronger. Didn't test it since then, but everything was looking fine. I'm more and more suspicions about the BOV. But still, just gonna be sure when testing boost leak.

Maybe the fuel pump's hose has cracked or slipped off causing inconsistent performance issues.

If that's right, wouldn't I see gas leaking also when the car on idle?

 

[bastarddsm]

It's not a boost leak, you have a phantom knock issue.

 

[bastarddsm]

If it had enough of a boost leak to cause his described performance loss, it would be constant, AND it would show up as fuel cut, and/or the stock boost gauge reading artificially high.

 

[bastarddsm]

Could also be a fuel issue.

 

[Mike_GST]

If it had enough of a boost leak to cause his described performance loss, it would be constant, AND it would show up as fuel cut, and/or the stock boost gauge reading artificially high.

To get a pressure gauge 0-20 or 0-30psi is going to take a while. The only place that can get one for me, I´ll have to wait until middle of February.
Besides that, I did some tests yesterday again and i'm starting to feel the car is getting worse and worse. More and more weak performance episodes are happening. The good pools happened just the few minutes I left home (even though I never drive it cold, always wait until the dashes temperature gauge is in the middle).
In a moment a was cruising an uphill, smoothly throttle it a bit, heared the turbo spooling, dashes pressure gauge on 3/4 of boost, noise of air flowing (probably somewhere not inside the engine) and no power at all.
Well, meanwhile I wait for the aftermarket pressure gauge to build the leak test, I could try working with the knock sensor fail hypothesis. Is there any way I could test it without replacing? Is there an easy way to take it off?

 

[chrysler kid]

When my car was 100% stock it wouldn't even spin the tires in first gear so performance feel really isn't much to go on right now. I did notice after I installed my new blow off valve the car boosted much more predictably, and after I did the intercooler piping the car had nearly immediate throttle response. I'm not saying you need to upgrade parts but the factory plastic blow off valve is really a weak point and could cause some of the problems you're describing

Make sure you're always filling up with 93 octane, the spark plugs are fresh and you may want to start planning to purchase a replacement blow off valve and a boost gauge.

 

[ThunderChild]

If you need a 1g bov I have 2 or 3 in good condition. I'd be willing to donate one too you for the cost of shipping (or even free if it's under $10-15).
I may also have an air pressure gauge laying around. Pm me an address and I can ship you a bov at least, and if I find a gauge I'll throw it in.

edit: didnt see you were in brazil till now (been using my phone) so it might not be practical to ship, but ive got a good 1g valve in hand, and have a pressure gauge but its a 0-300 psi gauge off a compressor. never used, just been bouncing between totes for the past couple years.

 

[Mike_GST]

When my car was 100% stock it wouldn't even spin the tires in first gear so performance feel really isn't much to go on right now. I did notice after I installed my new blow off valve the car boosted much more predictably, and after I did the intercooler piping the car had nearly immediate throttle response. I'm not saying you need to upgrade parts but the factory plastic blow off valve is really a weak point and could cause some of the problems you're describing

Make sure you're always filling up with 93 octane, the spark plugs are fresh and you may want to start planning to purchase a replacement blow off valve and a boost gauge.

Could also be a fuel issue.

How about that! I made a research about brazilian fuel and turns out 2014, when gas types were renamed, also the intermediate quality gas had its octane rating reduced from AKI 91 to the same as the lowest quality, AKI 87. The highest quality has AKI 95 octanes, although it's ridiculously expensive and can't be found in my place. Since brazilian gas has 25-27% of ethanol (100-110 octanes) on its formula, never got worried about this. But AKI 87 WTF! That's one nasty waste slurry, Jesus! Now that's the first hypotesis to bust, as soon I get out of town. I work in a hydro plant in the middle of nowhere, so special things I have to drive 60-100 miles away from where I live.

If you need a 1g bov I have 2 or 3 in good condition. I'd be willing to donate one too you for the cost of shipping (or even free if it's under $10-15).
I may also have an air pressure gauge laying around. Pm me an address and I can ship you a bov at least, and if I find a gauge I'll throw it in.

edit: didnt see you were in brazil till now (been using my phone) so it might not be practical to ship, but ive got a good 1g valve in hand, and have a pressure gauge but its a 0-300 psi gauge off a compressor. never used, just been bouncing between totes for the past couple years.

Thank you so much for that tametalon92. I could be almost sure shipping this BOV is gonna cost more than 10-15 bucks. And still, it's gonna take forever (30-45 days) to arive here. Anyways, if you really don't mind of getting a quotiation, I live in Salto do Jacuí (city), Rio Grande do Sul (state), 99440-000 (postal code).

A friend of mine has an auto-part store and surprisingly has a 0-2kgf/cm² pressure gauge for a good price. It is gonna fit. Awesome! Again, as soon as I get out of town.

 

[Chumpaumpalumpa]

THe numbers to test at on the gauge you're getting are 0.7kgf/cm² (10psi) and then 1.05kgf/cm² (15psi)

 

[ThunderChild]

I checked shipping, and it's ridiculous as I expected haha. About 180 for a 2 lb package, youch!

Sorry man, if it weren't the case I'd hands down ship them too you.

 

[chrysler kid]

The quality of the gasoline also can effect performance. Try to fill at newer gasoline stations where they usually have good filtering systems incase any dirt or debris are inside the huge fuel tank undergound.

25% ethanol blend is terrible for cars, so I'm not sure you would see much benefit from premium fuel. Is e85 ethanol gas available in your area

 

[Mike_GST]

I got this weekend 25 liters of the AKI 95 octanes gas. It's not that expensive, by the way. Chrysler kid, this type of gas is the only one still with 25% of ethanol on its coposition. The other two regular types are 27%, on provation period. There are videos on youtube people spliting ethanol from gas, adding water in big bottles and than by decantation draining the water/ethanol combining. Not sure this is a safe method.

Anyways, to burn the left overs from the tank, before feeding it with the premium gas, went for a smooth ride today, but as soon as I got the highway had to go back home. My car is running bad, really bad. I just can't force not even a bit the throtle, it starts to choke or just don't rev up.

A friend of mine told me to check the plugs and the ignition wires. Pull them off today. Well, at least now I know what type of plugs are there and what's the wires resistance. The plugs are ACDelco 041LR6XB with gap of 0,8-0,9mm and the ignition wires gave me, from cylinder 1 to 4: 4.6 - 5.8 - 5.8 - 8.7 kilo OHMS. Do you guys notice anything beyond the usual here?