Studder/pop/hesitate/fail while in boost 1/2 to full throttle

[Firegst]

Ok, So first thing is first I will tell you every mod on the car the symptoms I am having, then what I have tried and or fixed so far. I just bought this car with the symptoms mentioned.

Car is a 1997 gst eclipse, has tdo5h 14b turbo with dnp turbo mani, and external wastegate, has a 2 1/2 down pipe into 2 3/4 exhuast pipe with no cat and or resignator all the way back to a can there is a secondary o2 about 3/4 back in the exhaust tho. Has a Greddy front mount with a Greddy type S BOV, all hard IC piping and a 4 inch filter coming off the MAF.

When driving the car under light to Grandma style driving it is fine, when you use 1/2 to full throttle or 1/4 throttle long enough to build boost the car studders, pops and then hesitates....If you keep your foot in it, it will keep poping and blowing off. In first gear you can almost reach 4k before this happens at WOT. The car is running a 94 ecu with a esm chip and no check engine lights, also have a 97 ecu that I have tried also with no CEL's but car studders faster, pops more drives like poop. The 94 ecu the car likes alot more, than the 97.

I have replaced the FPR solenoid, plugs, wires, test and fixed any boost leaks, waste gate actuator works properly etc....Even tried hooking the factory Boost solenoid back up with stock 97 ecu still drives like shit..I have tried oem spec plugs gap to .032 as well as one step colder plugs.

I have not yet checked timing or fuel pressure, thats on the list for tommorow.

I am wondering if this could be a timing issue? But why would it run worse with the stock ecu rather than the chiped one if its running factory psi via the wastegate?

Also the car runs rich as f**k I have pulled the plugs to find this out, the car doesn't have a wideband nor a a/f gauge which i ordered a day ago.

At first I thought that this was a simple boost leak, but the car doesn't seem to be hitting fuel cut more like ignition cut/shuddering. Then I thought it has to be plugs? NOPE wires? nope...car idles/loops with the 94 ecu but runs better than the 97 which has a better idle than the 94.

I am not getting any compressor surge if that matters, the spark from the wires to a ground source reaches over an inch and I can see the spark in the middle of the day, so I don't think it would be a coil but I have yet to test them. Also I thought maybe the issue could be a bad MAF, but again its not fuel cut, at least it doesn't feel like a brick wall ....also there is no CEL's on either ecu to say its a bad sensor i.e cam, knock, maf, map , etc....Could it be a TPS? also need to check that as well....

Any thoughts and or Ideas of what could be going on here? I would like to get the car running right and any help/advice would be awesome. Again like I said I will test the fuel pressure tommorow, but when I check timing should I run the stock ecu or the chiped one or does it matter? Also if I have a bad FPR would it cause this? And if both the fuel pressure and timing check out where should I go from there...I realize I could probably test every system but I would like to test the most likely ones first.

Sorry I have given you so much info at one time in short little burst, but this is all pretty new to me ( DSM's) so please be patient, and point me in the right direction. Thanks in advance for any help and or suggestions.



UPDATE: The car had a boost leak and a big one at that, when I first did the boost leak test, I had only found two leaks the BOV and BISS, with both of those fixed I still had the same problems. One coupler was hidden behind the bumper support, where I couldn't see, get to or hear. I had no clue it was there...I took the Front bumper off and did a proper boost leak test and found the coupler was blown in half!...I didn't catch this the first time because I had no regulator so I was using constant air flow not allowing the leaks to show.

 

[Dert]

Did you try NGK BPRE6 plugs gapped to .028? These cars are picky when it comes to brand of plugs and gap. Could be bad TPS or ISC but your idle would be odd if the ISC was bad. Does your throttle body have a lot of buildup in it? Might need a good cleaning. Do you still have the honeycombs in the MAF? Having them removed can cause a lot of issues also.

 

[andrewshowers]

Chipped ecu? What chip? Sounds like it is either too rich or too lean. Sounds too rich to me. Do you have a wideband you could install to check the afr? That would be my guess.

 

[GSTurbo1]

have u tried cleaning your maf?

 

[Firegst]

Did you try NGK BPRE6 plugs gapped to .028? These cars are picky when it comes to brand of plugs and gap. Could be bad TPS or ISC but your idle would be odd if the ISC was bad. Does your throttle body have a lot of buildup in it? Might need a good cleaning. Do you still have the honeycombs in the MAF? Having them removed can cause a lot of issues also.

I have tried both the bpre6 and brpe7 plugs both run the car the exact same....Bad TPS would throw a code I would think on the stock ecu, and the 94...at least the 97 stock ecu.

Throttle body was cleaned, and MAF still has all the honeycombs.

Chipped ecu? What chip? Sounds like it is either too rich or too lean. Sounds too rich to me. Do you have a wideband you could install to check the afr? That would be my guess.

Its def rich, but with both ecu's the stock one should not be rich being that its stock with stock psi, I do not have a wideband yet but it has been ordered..

have u tried cleaning your maf?

I have not, kinda scared to as I know these things are picky...the whole situation is almost like the ecu doesnt know the car is getting boost, and or how much doesn't compensate with spark or puts to much fuel.

 

[Pameluxen]

I've got the same issue but at 4500-5000 rpm at 1/2 to WOT. Like you said grandma to light driving is okay for me aswell.

Idk if it will help much but, I hooked a scan tool up to mine and when the pop/shutter/fail starts ignition timing was cut directly in half.

 

[Colt4G63 also]

You're right not to want to clean the MAF. Cleaning it would probably destroy it.
It sounds like a spark issue to me. Since your ECU is chipped, I'm going to assume you are running more than the factory boost level. I'm running 30 psi right now, and I find that a set of NGKbpr7es plugs gapped to .025" last me about a month and a half with track use twice a week. In fact I had to change a set last night at the track. Any larger of a gap, and spark blows out. I also have had great luck with NGK wires, which seem to last for years,(although I cover them with flexible wire conduit) and only cost around $35 for a set.

 

[slayer450]

I've got the same issue but at 4500-5000 rpm at 1/2 to WOT. Like you said grandma to light driving is okay for me aswell.

Idk if it will help much but, I hooked a scan tool up to mine and when the pop/shutter/fail starts ignition timing was cut directly in half.

Sounds like you might gave a knock sensor problem. When a knock sensor acts up it retards timing. My car was doing that for about a month and before a got a cel.

 

[delta448]

The chipped ECU must be a 95 model year EPROM, like is needed for ECMLink, just with a build date in 94. You can't swap a 1G ECU into a 2G car easily, they don't even have the same number of harness plugs. So saying it's a 94 ECU is a bit misleading.

Have you done a boost leak test?
Are the injectors the ones the chip was burnt for? Nobody with any sense burns a custom chip set for stock injectors.

 

[Firegst]

I've got the same issue but at 4500-5000 rpm at 1/2 to WOT. Like you said grandma to light driving is okay for me aswell.

Idk if it will help much but, I hooked a scan tool up to mine and when the pop/shutter/fail starts ignition timing was cut directly in half.

Did you fix this issue? I cant hook a scan tool while using the 94 ecu only the 97 and I would have to go a shop for that...but your getting more rpm then I, the lower the gear the more rpm I can go, in fifth gear with 1/3 throttle it wont even make it to 3500 before it happens

You're right not to want to clean the MAF. Cleaning it would probably destroy it.
It sounds like a spark issue to me. Since your ECU is chipped, I'm going to assume you are running more than the factory boost level. I'm running 30 psi right now, and I find that a set of NGKbpr7es plugs gapped to .025" last me about a month and a half with track use twice a week. In fact I had to change a set last night at the track. Any larger of a gap, and spark blows out. I also have had great luck with NGK wires, which seem to last for years,(although I cover them with flexible wire conduit) and only cost around $35 for a set.

I have replaced the wires, with oem style and I have gap the brp7es plugs to .032 but I am running the 8 psi only I believe the stock wastegate on the tdo5h uses.

The chipped ECU must be a 95 model year EPROM, like is needed for ECMLink, just with a build date in 94. You can't swap a 1G ECU into a 2G car easily, they don't even have the same number of harness plugs. So saying it's a 94 ECU is a bit misleading.

Have you done a boost leak test?
Are the injectors the ones the chip was burnt for? Nobody with any sense burns a custom chip set for stock injectors.

Must be a 95 then with 94 build date, because the plugs do infact match...I dont think anyone with any sense burns a custom chip without a a/f gauge and or boost gauge .....but I can't tell if the injectors are stock or not because I dont see a brand, however I do see numbers that read d1151ba

Wait! arent those rc 550's? if so that would explain the running rich with stock ecu, but as far as the chip ecu if its tuned for them shouldnt it be running right with them?

 

[delta448]

Gap the plugs to 0.028".
If you have a genuine MHI turbo, it's stock wastegate pressure is more than 8psi.

edit:

MHI?

MHI stands for Mitsubishi Heavy Industries

Need a picture to confirm if the wheel is a 14b, covers can be machined.

d1151ba

Wait! arent those rc 550's?

Lucas 550's, RC rebrands them. They flow almost 600 cc/min at 43.5psi.

 

[Firegst]

Gap the plugs to 0.028".
If you have a genuine MHI turbo, it's stock wastegate pressure is more than 8psi.

MHI? also the turbo numbers are td05h 48178-01 0 with an s above the numbers...that I thought was a 14b small little guy

 

[liquidsilver]

Come on man gap the plugs to .028 and report back

 

[Firegst]

Come on man gap the plugs to .028 and report back

Watching my son at the moment and the car turbo inlet etc is off at the moment from doing a boost leak test..if he passes out or something I will swap back in the 95 ecu change the firing order back, and re-install everything with the plugs re-gapd.

Update: mom watched my son, Gaped the plugs with no change, car still falls on its face, I did notice tho that with the factory boost solenoid hooked back up that the BOV is fluttering alot, which I thought was compressor surge? If so how can I stop this..and if I remove the boost solenoid vaccum lines and what not and still have compressor surge what then? I just put the car back together so the pic of the wheel we have to wait...if you show me the wheel of something else you think it might be then I can compare. I was thinking about taking the car to a firestone, having them replace the knock sensor, coil packs, and to see if the car is in time correctly, on top of my alingment, wheel balane rotate etc...the reason I want to go to firestone is because I have a line of credit through them. So should I have them test the tps, and maf while I am there? thanks for you help guys.

Thinking possibly the flutter is because it is under low boost? Cant tell because I dont have a boost gauge but just a thought.

I was wrong the BOV is not a type S but this one in the picture.

Google Image Result for http://www.maxpowermotorsports.com/product_images/z/425/blow-off-valve-01__30796_zoom.jpg

 

[delta448]

I just put the car back together so the pic of the wheel we have to wait...if you show me the wheel of something else you think it might be then I can compare.

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The compressor blades on a 14b are equally spaced, a 16g has paired blades.

I was thinking about taking the car to a firestone, having them replace the knock sensor, coil packs, and to see if the car is in time correctly, on top of my alignment, wheel balance rotate etc...the reason I want to go to firestone is because I have a line of credit through them. So should I have them test the tps, and maf while I am there? thanks for you help guys.

Thinking possibly the flutter is because it is under low boost? Cant tell because I dont have a boost gauge but just a thought.

Don't spend money on parts until you know those need replaced. Do you have a DMM?

You still need to do a boost leak test.

Flutter may be related, how stiff is your installed BOV spring?

 

[Firegst]

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The compressor blades on a 14b are equally spaced, a 16g has paired blades.


Don't spend money on parts until you know those need replaced. Do you have a DMM?

You still need to do a boost leak test.

Flutter may be related, how stiff is your installed BOV spring?

I have done the boost leak test with leaks found at the idle screw and bov, those have been fixed...my turbo has the pair blades like to the turbo to the right, but are still a tad bit different...It didnt flutter before I re hooked back up the boost solenoid. I dont know what a DMM is..

 

[Dert]

If its cutting timing it's probably knocking and retarding the timing. Also gap the BPR6ES plugs to .028 if you haven't already. You may have a clogged injector causing lean condition from lack of fuel.

 

[And_44]

You still using the 95 ECU in the 97? I'm not a 2g guy but arn't the firing order's differen't between the 2ga and 2gb ecu's? Maybe the wires are hooked up to the wrong plugs?

Is your TPS working correctly?

 

[Diamond Star Werks]

sounds like your getting to much fuel to me. deff check fuel pressure.,

 

[Firegst]

sounds like your getting to much fuel to me. deff check fuel pressure.,

I have gapped the plugs to .025 28 and 32 with no difference, yes I am still using the 95 ecu in the 97 and yes I know the firing order is different I have to change it everytime I swap ecu's..there is no knock sensor CEL's or CEL's at all for that matter, on either ecu. So I don't know why timing would be being pulled, there is also no boost leak....when I bought the car, the 95 ecu had a CEL i removed the MBC and it went away, the guy I bought the car from also said the 97 ecu had a code but I couldn't get it to show up, I believe he said the code was for fuel trim or something and thats why the FPR solenoid was replaced.Maybe the timing belt jumped timing or something, the ecu couldnt correct that could it? Also I dono about the TPS or if it needs to be recalibrated or what have you..car is at the shop getting new tires at the moment.

 

[And_44]

Oh. Have you driven it long enough for a CEL to register?

 

[Firegst]

Oh. Have you driven it long enough for a CEL to register?

Ive gone about 15 miles, don't know how far I have to go to reset the monitors or whatever tho. Its scary driving on the stock ecu knowing I have the mods I do with a bigger turbo and injectors, please it runs like dog poop even under grandma driving.

 

[liquidsilver]

Now that you mention injectors again...can you get your hands on a set of stock injectors? Maybe give that a try with your factory ECU.

 

[delta448]

Now that you mention injectors again...can you get your hands on a set of stock injectors? Maybe give that a try with your factory ECU.

This is good advice.

Until you have a known good ECU with a known good injector calibration coded into it you'll be chasing your tail and all we can do is speculate on any other problems.

The stock 97 ECU doesn't automatically know the injectors it's controlling are 550's, which are 18% larger than stock, and once the long term fuel trims max out at -12.5% and you still have another 5.5% too much fuel, you'll get that p0170 code the PO told you about. I'd be concerned that the 95 ECU is also coded for a different set of injectors than the ones installed. It sounds like the PO either didn't care or just wasn't too bright.

How did he have the MBC installed that it would have caused a DTC? It should be installed on it's own vac line between a nipple on the charge piping and the wastegate actuator with nothing else "T'd" into it, especially the BOV.

Is your BOV a genuine Greddy or a knockoff? What about the turbo?

 

[Firegst]

This is good advice.

Until you have a known good ECU with a known good injector calibration coded into it you'll be chasing your tail and all we can do is speculate on any other problems.

The stock 97 ECU doesn't automatically know the injectors it's controlling are 550's, which are 18% larger than stock, and once the long term fuel trims max out at -12.5% and you still have another 5.5% too much fuel, you'll get that p0170 code the PO told you about. I'd be concerned that the 95 ECU is also coded for a different set of injectors than the ones installed. It sounds like the PO either didn't care or just wasn't too bright.

How did he have the MBC installed that it would have caused a DTC? It should be installed on it's own vac line between a nipple on the charge piping and the wastegate actuator with nothing else "T'd" into it, especially the BOV.

Is your BOV a genuine Greddy or a knockoff? What about the turbo?

Its a real greddy BOV not knock off, the turbo is a twin blade 16g not a 14b like I once thought, the PO got the car from a dealership that was traded in...he is a wholesale dealer...he has no knowledge of the car besides to buy and sell. I dont have anyone around to swap ecu's with and or injectors...My thing is if I am running the 95 ecu, have 550cc injectors and 16g how and I still running rich? and or ignition cutting? Do coil packs go out slowly or all at once? I havent looked at the fuel pump to see if there is a re-wire mod but its a quiet pump so I dont think it is aftermarket.


Also the MBC was T'd off of the BOV and then back to the wastegate with a 1/4 when the wastegate is a 3/16 line so it didnt even open the wastegate I would assume, now the mbc is gone and I have to share a boost source with the BOV for the WG because there is no nipple or other boost source on the compressor houseing/j pipe/ or IC piping...I have to tap the j pipe still.