97 GS-T 6-bolt swap missfiring after 3200RPM

[Texastornado]

Hey guys!
I recently purchased a 97 GS-T with a 6-bolt swap. The car seems to start missfiring when you give it too much gas at high RPM's beginning around 3200. He explained that the car is running rich and needs a tune and that he took it into a DSM mechanic. The mechanic stated that he needed to chang the ignition coil out because it is missfiring. If you accelerate slowly into each gear, you can get up to 60MPH no problems. Its when you give it a considerable amount of gas that it starts missfiring. He has a wideband installed and it goes completely blank once it starts to missfire. It will climb quickly from 13.9 to 18 then missfire. Once it begins to missfire, I let off the clutch and gas and let the RPMs drop below 2000 and the Wideband pops right back up to 13 respectively and the car drives normal. This is my first DSM and have done a decent amount of research on this issue. Does this sound like a coil pack issue or could be more? Boost leak, etc... Any info would be greatly appreciated. I'm just now starting to get my feet wet and am looking at getting this car running good. Thanks

 

[FullMetalJack]

My car was misfiring throught the rpm band and my A/F gauge said it was running rich all the time. My problems were faulty spark plugs, plug wire resistance out of specs, and a bad coil pack. A weak or faulty ignition system would be the first thing I'd try. another cause could possibly be a faulty emissions system.
To test your coils you can connect an ohmmeter to both terminals on each coil (terminals on coil for cylinders 1 & 2, and coil for cylinders 3 & 4 respectively) and measure the Secondary resistance. if the resistance is not between 11,300 to 15,300 ohms then you should replace it.
You should also connect the ohmmeter to the coil plug terminals and test the Primary resistance. to do this, look at the plug with the clip piece up and connect one wire from your ohmmeter to the bottom terminal (terminal 3, ground), and then connect the other wire from your ohmmeter to the the terminal on the top right (terminal 2) and then the top left (terminal 1) and and record the resistance, if either of these measurements are not between 0.70 to 0.86 ohms then you should check the wiring going to coil pack plug for breaks and anything else.

Hope this helps.

The other thing that can cause misfiring and rich A/F ratios is the ignition timing being off.

sorry. I just realized you have a 6-bolt. everything is the same except the plug to the coil packs. it should have 4 wires, so when you check the primary resistance you need to look at the plug with the clip part up and terminal 4 is the bottom right terminal(ground, same as terminal 3 on the 7-bolt), terminal 1 is top left, and terminal 2 is top right. the wire on the bottom left you won't need to test the primary resistance.

if you're confused about anything just PM me or reply to this thread and i'll try to explain better

 

[flinguist]

The 1G CAS can also cause misfire problems because it doesn't have high enough resolution for the 2G ECU. You can fix that problem w/ DSM Link, which has a feature that disables the misfire detection. Magnus also has a trick to prevent it. See page 10 of this PDF. http://www.magnusmotorsports.com/tech/1gina2g.pdf

 

[wolfie359]

If the wideband keeps climbing like that doesn't that mean he's running out of fuel, Fuel pressure or Injectors? What octane fuel are you running? I would assume as the computer cut back timing due to knock you would actually get more gas into the exhaust causing your wideband to tell you its running rich, but then again knock happens when your a/f gets too lean... This is all to the best of my current understanding, food for thought

 

[Texastornado]

@FullMetalJack: Thanks for the advice! I work IT at a chemical plant and I have a multimeter at work. I'll run a test on it tomorrow and post the results

@flinguist: Thanks for the link and info on DSMlink. The guy I purchased the car had mentioned that. I spoke to his DSM mechanic and am trying to set up a date where i could take the vehicle in to get some work done to it.

@Wolfie359: I'm running 93 octane. You can definately smell the gas just idling.


Thanks guys for your input. It's greatly appreciated. Like I said, this is my first DSM, and i want to learn as much about it as possible. I'll be on this forum quite frequently .

 

[wolfie359]

What if you are in a high gear at low rpm (like 3rd gear at 30mph) and you just floor the pedal? Is there any variance in the RPM in which it starts to misfire, or any abnormal readings on your wideband?

 

[Texastornado]

What if you are in a high gear at low rpm (like 3rd gear at 30mph) and you just floor the pedal? Is there any variance in the RPM in which it starts to misfire, or any abnormal readings on your wideband?

In 3rd gear@30mph my wideband fluctuates from 13 to 14. Its when i give it alot of gas that it starts to missfire. Same thing with accelerating from a stop.
1st gear fine, but when i get to 2nd, and i accelerate up to 4000rpms the wideband goes blank and it starts missfiring. The only way to stop it is to let off the gas and clutch, and wait for the RPMS to come back down below 2000. Then after a few seconds, the wideband come back on to around 12 or 13, then i put it into 3rd gear and it runs fine. I hope this helps

It also doesn't do it if the car hasn't been running for a while. It seems to accelerate fine the first 10minutes of driving. Its when the vehicle gets into normal running temperate it seems to start happening more. To me it feels as though when i give it alot of gas, the engine sometimes seems to not be able to take in enough air to match it. Hence why i think when u left off the gas and cluth and let the RPMS come back down under 2000, that it burns up that excess gas and the missfiring stops. I'm thinking about driving 2hrs to an autozone that has the coil pack in stock. Only thing is, i want to plug it in, and see if thats the case before i drop $180 on it. Do you think they would let me do that before purchasing it?

I'm going to take it into a DSM shop sometime this week, (hopefully friday) in order to get the coil installed and get a tune. I don't want to get my eyes poked so i was wondering around how much would a shop charge to get the vehicle tuned?

 

[FullMetalJack]

If the wideband keeps climbing like that doesn't that mean he's running out of fuel, Fuel pressure or Injectors? What octane fuel are you running? I would assume as the computer cut back timing due to knock you would actually get more gas into the exhaust causing your wideband to tell you its running rich, but then again knock happens when your a/f gets too lean... This is all to the best of my current understanding, food for thought

that does sound like you could be running out of fuel since the wideband goes to 18, that's like stupid lean for any motor. Theoretically, if the computer detects knock and retards the timing then there would be extra fuel.checking the fuel pressure isn't too easy unless you have a gauge to connect to the fuel line and a vacuum pump. if you do then let me know and I'll give you step by step instructions on it. you can also run a couple quick tests on the injectors to make sure they're functioning properly, you can get a mechanic's stethescope (or a screwdriver with your ear pressed to the handle works too) and with the car running put the metal rod (or screwdriver) to the injectors and listen closely to the clicking sound and if one sounds different then you should probably replace it. and you can test the resistance of the injectors by unplugging the harness and checking the resistance through the injector and the resistance should be between 2.0 and 3.0 ohms. and you can test the harness by connecting a "noid" light (sold at autozone for cheap) to the harness and try to crank the engine and the light should flash, if not then the ECM, Injector resistor, or the circuit is faulty.

I don't know if autozone would let you do that, you may want to try calling first and asking then just to be on the safe side.

Exactly how much boost are you pushing? Do you have a boost gauge?

 

[Texastornado]

Yeah its only set to 10psi. I took it to a shop in San Antonio called JMS Performance. They specialize in DSMs and Evos. Should get a diagnosis by this afternoon and ill keep y'all updated. The guys have a great shop and have a good rep.

 

[PieEyedPiper]

You don't have any fuel mods.. You're gonna be lean, hopefully nothing has been damaged.

 

[Texastornado]

You don't have any fuel mods.. You're gonna be lean, hopefully nothing has been damaged.

It's got an EvoVIII Fuel Pump. I called the shop today and the CEL code they were getting is missfire on Cylinder #3. The guy said it could be either the ignitor or the injector. Tomorrow he said he'd be able to take a look at it more and get to the root of the problem. About how much would it be for injector replacement or ignitor including parts and labor? I asked him and he said he'd get an estimate tomorrow.

 

[bmx77802]

not to hijack your thread, but im having this exact same problem. ill be driving, and everything is fine then all of a sudden, the motor will miss horribly, shaking the entire car. i push the clutch in for about 3 seconds and its fine when i let the clutch back out. i got a cel and it came up as po300 which is multiple/random missfire. im guessing its the coil pack because i wouldnt think all my injectors are messed up. when you listen to the injectors though, what would be a normal ticking noise to hear? would it be consistant sort of like a heartbeat or would it have a delay between the ticks? if you could explain to me how to test the coil pack a little better that would be great as well

 

[flinguist]

not to hijack your thread, but im having this exact same problem. ill be driving, and everything is fine then all of a sudden, the motor will miss horribly, shaking the entire car. i push the clutch in for about 3 seconds and its fine when i let the clutch back out. i got a cel and it came up as po300 which is multiple/random missfire. im guessing its the coil pack because i wouldnt think all my injectors are messed up. when you listen to the injectors though, what would be a normal ticking noise to hear? would it be consistant sort of like a heartbeat or would it have a delay between the ticks? if you could explain to me how to test the coil pack a little better that would be great as well

Read post #3.

 

[bmx77802]

i have the 6 bolt swap but im not sure if its the 1g cas or a late 2g cas. its up on the left side of the intake cam, and you can see where the previous owner did the modification to the wiring. is there a way to tell the difference between the 1g and the 2g cas?

never mind i did some reading, and im going to do the potentiometer mod and see if that helps. thanks for that link flinguist.

 

[Texastornado]

I am also looking at upgrading my BOV to a greddy type-s. I've read there are 2 ways to have it. 1 is recirc with oem MAS, or vented to atmosphere with GM MAFT. Can anyone tell me what, if any big differences there are? Non recirc spool lag? What if I'm gonna boost 15psi average? Just FYI, I don't care if its loud or not. What's more reliable, beneficial?

 

[Ilikespeed]

I also have a freind that I did the swap to. His is a 98 talon awd, and hes got the stock ecu.
When I finished the car it ran like it had cams, and rich as hell, and wont build boost after 10psi, just spits and studers. He took it to a shop and they told him it was a dead cylinder #4. I messed w it for a bit checked timing and fuel pressure, plugs, wires... took it for a quik ride and it boosted to 20 before exploding a intercooler elbow, ran great for that 1 min of thrill. after that was back to square 1 w/ the issues.
maybe theres a pin in the ecu that has to be switched around. Im gonna run a compression check and keep u guys updated if it the prob w mine. If I can fix the compressoin leak long enough to confirm that its the prob, the it mite help u out w ## problems as well.

Just tryin to help others help me help each other.

I am also looking at upgrading my BOV to a greddy type-s. I've read there are 2 ways to have it. 1 is recirc with oem MAS, or vented to atmosphere with GM MAFT. Can anyone tell me what, if any big differences there are? Non recirc spool lag? What if I'm gonna boost 15psi average? Just FYI, I don't care if its loud or not. What's more reliable, beneficial?

The forums have alot of info on just the maft, Ive done alot of looking into using maft just cause i hate the mess that sits there before turbo. Im gonna get one when my pocket decides to give it up.. Which is empty.

The forums have alot of info on just the maft, Ive done alot of looking into using maft just cause i hate the mess that sits there before turbo. Im gonna get one when my pocket decides to give it up.. Which is empty.

 

[bmx77802]

so what did the shop say was it fuel realted or ignition?

 

[Texastornado]

I called yesterday and he hadn't gotten to it yet, he was still working on this one galant. I called today and he said that he was actually working on my vehicle now, and he thinks it might be a boost leak. He was in the process of doing a boost leak test and said its possible that it could be getting too much boost. He'll work on it tonight and tomorrow and call me as soon as he's narrowed it down from boost leak, ignition, or injector. Would a boost leak cause cylinder #3 to missfire? I still think the previous owner's mechanic was right about the coil needing to be replaced. With a 6-bolt swap and a 16g turbo, whats a decent boost setting i could run? 14/15psi? How about with a GM MAFT installed?

UPDATE!!!!11 XD

The mechanic at JMS Racing where i dropped my car off to called me today. He did a boost leak test and found there were several boost leaks, one on the J-pipe and a few on the intake side. He was able to repair both of those. Also he said the car is a japanese 6-bolt with a japanese intake manifold, and that the
2ndary throttle body was causing the wrong amount of air/gas and was causing the missfire. So the throttle body is also getting replaced and should be ready to go by Sunday!! XD

 

[bmx77802]

if that doesnt help you with your misfiring, do the poteniometer mod that was posted up previously i think it was magnus motorsports that wrote up the article. its the last thing on the bottom before the pinout diagram for the ecu. just did it tonight and took care of all missfires i was having. i also did a BLT and i have a boost leak up by the injectors so i will be getting new injectors o-rings tommorrow.

 

[Texastornado]

Whoa thats nice. I'm pricing GM MAFT's at the moment and I think the shop I have my vehicle at stocks them. Not too sure how hard it is to install it, but I read up on it and how it increases air flow in the 1g engines.

 

[Texastornado]

UPDATE!!

Ok so today I'm going to pick up my fixed car. The guys at JMS racing in San Antonio did a great job and also explained a lot about what was going on.

1st off there were several boost leaks. Frank (mechanic) JB welded the leaks on the J-pipe and re coated the pipe black.

2nd, the engine had the cyclone intake and they replaced it with the stock one.

3rd, the throttle body needed replacing

4th, it was missing the MAP!

The main reason for the missfire was that intake not opening up right and not allowing the correct amount of fuel in. Also it was getting some boost creep. Jumping from 10psi to 20.

Ill post later this afternoon to see how the car is running. If all is well then I hope the solutions in this thread can help other fellow DSMers out that may be having similar problems. I took it to shop that works mainly on DSMs and EVOs and are damn good at it