Stumble under WOT

[93RS]

My Laser is stumbling under WOT... It doesn't do it if I ease into until about half throttle then go WOT... I have read into as much as I can find, which isn't much, but nothing seems to fit my symptoms. I don't have a lot done to my baby just a MBC set at 10psi, Hard UICP, and a hacked air box. Everything that I can find the OP's have a whole bunch of go fast goodies, and it usually ends up being something involving the go fast parts. It hasn't done it for a while but in the past after a hard pull the CEL will come on with a code 11 (power transitor? Correct me if I'm wrong) and it feels like its running on 2 cylinders, give her a little gas and the CEL goes away and so does the hard misfiring. I've read that the PT has a bad contact, or that its bad. I had it out when I replaced my coil pack and I tested it both cold and after heating it up with a heat gun and it checked out. It wasn't dirty either. Any advice would be greatly appreciated !!! Thank you in advance

 

[LarryJoe]

I'd try a new set of ngk bpr6es plugs gapped at .28.

 

[Afizzle]

Boost leak test it. Make sure you test at 5 lbs over what you run. Get everything that sees boost, including the lower injector seals (where the injectors meet the block), throttle body gaskets, BISS screw, FPR, and all other boost lines, couplers, ect ect. Find a leak, fix it, then retest. Air takes the path of least resistance so it will take many tests.

When you hold 15psi air tight, youve fixed all boost leaks and can rule that out.

After that, or during, swap in new plugs. If new BPR6ES help but dont completely fix the problem or only temporarily fix the problem, swap to NGK BPR7ES. Almost the same plug just run a little cooler.

 

[black97spyder]

Someone correct me If Im wrong but aren't the NGK BPR7ES' a step hotter than the BPR6ES'?

 

[Phantom DSM]

Someone correct me If Im wrong but aren't the NGK BPR7ES' a step hotter than the BPR6ES'?

Bpr7es are a step colder actually. even as you go to bpr8es, bpr9es.. The higher the number, the colder it is.


fresh plugs and boost leak should take you in the right direction as the guys mentioned

 

[93RS]

It's got new plugs (gasped at. 028), wires(Ngk), and injector seals... She holds 20 psi no problem. Someone mentioned to me to ground the engine to the body and make Sure the battery is grounded to the body I haven't tried it yet but does it sounds like a possibility?

 

[93RS]

Took the laser out for a short drive she ran fine, parked it, came out and drove it again and it feels like its only running on 3 cylinders... Im gonna pull the plugs out tomorrow. I was doing some reading and Im considering running some bpr7es. Im running 10-11psi with a 2g TB elbow, Hard UICP and a hacked air box... Think its a good idea?

 

[93RS]

Pulled the plugs out one was ### looked like melted away the other 3 looks like she's was running leanish... Put my new bpr7es in and it ran good for 5 miles went into a store came out and it started running shitty again.... Pulled out the logger shut each cylinder down 1 by 1 and they all seemed equaltive... I'm gonna ohm out the injectors and check the plugs when it's cooled off.

 

[PrimerPLus]

Do a Boost Leak test, do a Leak Down test, maybe bad tps, check your coil pack for resistances, plug wires could be bad, are your grounds all nice clean and tight,are you using stock injectors, maybe they are dirty, replace your fuel filter if it hasn't been.

 

[93RS]

Blt done, compression test done, new wires done, new coil pack done.... Checked the resistor box and they al read 6-8 checked the injectors 3 ohmed at 3, 1 was 6.5... Bad injector correct?

 

[Phantom DSM]

Im assuming you have the blue 450cc injectors which are low impedence. Generally around 3 ohms or so is the most you will see from low impedence. Test the resistance on them cold, then after they are hot.. If the 4th one read 6.5 then it is out of range..See if you can swap a different injector and if it will help..Is it still acting like its running on 2 cylinders/misfire ?

I also checked on code 11 you mentioned and thats actually an o2 sensor code, not power transistor...

 

[93RS]

It is still running shitty but only on a hot start after its been sitting for 20 min to 4 hours... I only tested the injectors cold and they were (4) 3 (3) 3 (2)6.5 (1) 3.... I then checked the resistor box and all checked out at 7 which is high according to the test but only by like .5ohms. When shes running good I can hear all the injectors with a screwdriver and my ear but hole 2 is quiet. Today when it was running poopy I did the screwdriver test again and I could hear them all about the same. Yes they are blue top 450's. I just ordered some Black top 450s So Im at a waiting point, once my injectors get here ill throw them in and hope for the best because the resistor box is being extremely hard to find anywhere. On a positive side note I got my FP intake on the way as well

 

[Phantom DSM]

still a nagging problem then huh, well try out the injector swap and then see if its reading any codes..02 sensor could still be crapping out. Hopefully that should do it.
Good buy on the fp intake, got one too

 

[93RS]

How big of an improvement are they? The for intake that is...

 

[WES_393]

I also checked on code 11 you mentioned and thats actually an o2 sensor code, not power transistor...

To my knowledge, this is correct. The Mitsu OBD1 code 11 means 'Oxygen Sensor Malfunction'. That could easily be part of your running issues, the O2 sensor is very important for the ECU's fuel control. So I would at least test the front O2 sensor, or even just replace it with a quality OEM replacement. It's not uncommon for them to become lazy or intermittent after a while.

 

[93RS]

Ordered, tested, and installed my black top 450s problem solved! Injector on hole 2 decided to go out completely on me Monday so She sat til Thursday night Now I got to modify my intake pipe I bought so my stock MAS can fit.... It's always something Thanks everyone!