The 5K stutter cutout misfire stumble breakup Thread [Merged 7-8]

[Newlogics]

My project 92 Talon just wouldn't be nice to me.

I figured that my smoking problem was due to my turbo leaking oil, since upper IC pipe had whole bunch of oil in it.

Now more porblems arize....

1st: It wouldn't idle normally, instead it revs up to 2K and drops back to 1K every like 2 sec. if idle is adjusted to be lower then 1100 rpm

2nd: When rmp reach 5K under WOT, it hesitates violently. As soon as rpms drop a bit, it's fine again.

(The good thing I fix the unlock buttons, 'cause it had shaved handles and you couldn't get inside by any means except a trunk....)

 

[L2RTSiAWD]

Above 5k cams will make a difference on a 16g. I don't think tuning is the problem. This turbo is just running out of power w/o cams to give that extra jolt.

 

[onegee]

hows ur clutch?? just throwing things out...pz

 

[1gTURD]

yeah i would go cams and springs. Sounds to me like valve float @5000 rpms

 

[DSMraver]

Datalogger? How's your knock/timing?

 

[44pirate]

I think you have to much fuel. Prolly pulling timing. What are you SAFC HITH settings at. Should be in the neighberhood of -40 to -50.

 

[TRBOTSI]

I have a great idea, give us your setup so we all aren't throwing ideas in the wind...

 

[OneFastGST]

what are some good cams for a big16g?
and about how much will it run me?

 

[25psi]

/\/\/\ If you plan on staying with the 16g get a pair of hks 264/264 cams

 

[Turboniam]

I am having trouble getting the car tuned right?

The car pulls hard BEFORE 5K and AFTER 5K, but between 5K-6K it stumbles and doesn't pull well.

I've increase/decreased fuel settings, but I can't seem to get anything to work right.

The strange part is that the car pulls hard EVERYWHERE in the rpm band BUT 5K-6K?

Anyone have any ideas besides the usual check your spark plug gap etc etc.

I have never come across a problem like this, nor have I heard of a problem of this nature??

What happens is that I'll start out in a gear and the entire rpm band will pull (5-6K is somewhat ok) decently, but then when I shift, in the next gear 5-6K totally blows??? It seems that especially at 5500 I encounter a stutter/low performance problem, BUT as soon as it hits 6K the car pulls like a banshee???

 

[Blktsi_awd_961]

I am having the same problem. Car pulls great untill i hit 5k, then it sputters, farts, and backfires. I tried richening it, leaning it out, changed plugs and wires and got nothing. If you figure out your problem let me know.

 

[Blktsi_awd_961]

does anybody have an idea, this has been causing me to lose sleep for weeks

 

[Turboniam]

Well, I may have found the "hole" in the fuel map?

Following a tip from a friend, I decided to slowly lower and lower the fuel settings even if I saw knock as long as it didn't get ridiculous... so far things look promising, but I need to continue working on the tune.

Here is my question: So far I have taken out around 8% of fuel over the entire cuve, but how come the car pulled what felt "good" before 5K and after it hit 6K, but not between 5-6K??? Can anyone exlpain this??

That is what really threw me off was the fact that only a small part of the powerband was acting up??

Blktsi_awd_961, here are some things to look for besides the usual info.

1. On my 90, the plug that is below the coil pack on my car has sometimes not been "snug" and at/around 5K the car would act weriod... it came loose on me today and I snugged it down again and tried to make the metal clip tighter to hold it. That fixed that problem.

2. Last summer, one of my injector pig tails was loose and the car would drive fine around town except for under boost at/around 5K... I wiggled the injectors one day and saw it was loose pressed it down and wiggled the wires there and took it for a spin, the car's 5K miss/problem went away... I ended up replacing all 4 of the injector plug pigtails.

3. Recently and AGAIN today, I have stumbled upon my fuel settings being WAY too rich... today I slowly took out more and more fuel and by the time I got tired of tuning, I had taken out about 8% of fuel... no knock whatsoever now... but I am going to fine tune it some more. So far though the results look very positive.

4. I was having a 5K problem recently (for several weeks) (I know, how many 5K problems can one guy have! ) and I couldn't figure it out... then one day I throw a CEL and it says coil pack... I replace it and the problem goes away! So the coil pack was the culprit, but it didn't throw a code until a few weeks AFTER I had been having the problem!

5. I was having another 5K problem and I was getting massive knock counts... turns out one of my bolts in the intake manifold had backed itself out and I believe it was causing the problem because I took it for a spin and it was fixed.

When I searched this board and dsmtalk.com I ran across other people that had found 5k problems to be wires that go to, or in and around the coil pack to not be "secured" well... some just made sure to have the wires connected firmly/securily and that fixed their problems.

HTIH... Hopefully, tomorrow I'll be able to verify that the fuel settings were way out of wack and all is well!

 

[Blktsi_awd_961]

Thankyou very much for all of the tips you gave me. Hopefully one of these will be the culprit. I have a feeling the coil pack is the problem, but like you the car pulls great untill 5k then once i get past 6k it goes away. I will try all these things later this afternoon and then post my results later. Hopefully one of these will fix the problem.


P.S. Is there any way to test the coil pack to see if it is bad without the ecu throwing the cel. Just curious...

 

[JTS Swindler]

Ok, it's a 91' laser RST

Car won't rev past 4.5k rpm, does just fine for about the first 15 minutes the car has been turned on and can go all the way to redline... but after that it just basically sticks at 4.5k - 5k rpm which makes me think its overheating... but the heat gauge is fine... The car stutters real bad and feels like its misfiring... sooo, any ideas would be helpful... Ive searched the forums a bit but no one seems to have had this problem.

Thanks again.

 

[turbofanatic]

well when my 91 tsi did this it was because it had thrown a roller rocker. take the valve cover off and see whats going on under there.

 

[tylerwal]

i just purchased my 92 dsm 2 days ago and i have basically the same problem; around 4k rpm, it fills like i hit a wall

 

[JTS Swindler]

Come on, any ideas would be helpful...

 

[HiFi TSi]

I just got a 91 TSi AWD knowing that it had this misfire problem thinking I could fix it. _Well, I've tried numerous things and have had no luck, so I was wondering if anyone might be able to help out. _Basically what happens is that I can go WOT up until 4.5k and it'll sputter, and if I keep on the gas it will misfire throughout the rest of the rpm range. _It does it consistantly no matter if I go from a stop or downshift on the highway. _
Here's what I've noticed on my logger when this happens::
- 0 knock
- timing stays at 18deg
- o2 voltage stays at 0.92 and then leans out to 0.8-0.86
- fuel trims are 139%, 115%, 116% from low to high
- plugs show even burn except #4 was literally half white
- does not misfire with car in nuetral under no load
Here's what I've tried replacing::
- Plugs and wires are new, NGK plugs gapped at .030
- new 02 sensor
- new MAS
- coil pack and power transistor
- injector #4 thinking there might be something in it
- fuel filter
I am still going to try swapping ecu's with a friend tomorrow to see if that does it, otherwise I am stuck and in need of some advice. _Thanks

 

[me612]

did u look at the wires going into the ECU, maybe they were tapped into if an SAFC was installed before, and when ripping it out some of the wires broke or were not reconnected right. maybe the whole damn ecu is shot too. Maybe there is something wrong internally on that #4 cylinder. maybe try a compression test to make sure everything is good and there isn't like a hole in the piston. other than that i dunno man, good luck!

 

[HiFi TSi]

Well, I did some more investigating and found out that the ecu is fine after switching in a good one and the wire harness also appears to be ok.

I still believe that this is either fuel or ignition related. So I checked my fuel pressure today and here's what I found out. At idle, it was 42 psi, and with the vaccuum removed from the FPR, it didn't change. So I swapped in another FP solenoid and this time I got 34psi at idle and about 42psi without the vaccuum line connected at the FPR. I still was having the problem, so I resistance checked the solenoid and it is an open circuit, infinite resistance. So, my guess is that I have two bad solenoids each with opposite problems (the original one ohmed out at 40 but the vaccuum ports not functioning), so I'm going to try and replace it with a new one and see what I get. I also have a feeling that my base pressure is also too high. According to a vfaq, it should be more like 36psi and 27psi. I don't know why it would be so high without any fuel modifications. Any ideas about any of this?

 

[Mike 99GSX]

I'm helping a friend work on a 98 GST and I'm starting to get a little stumped. The relevent mods are 255 pump, S16g, FMIC, AFC, 650s, Greddy Type S. Magnacore Plug Wires, NGK Plugs. Basically what happens is that the turbo spools up fine and pulls but at 4K, the car starts to sputter and buck and then at about 5500 it levels out and pulls fine to redline. I've datalogged a few runs last night and everything seems normal. He gets a slow timing climb from 3500 to 7000 which tops out at 21 degrees in the top of 3rd so no timing is getting pulled in the problem area. So far he has: changed plugs, changed plug wires, swapped coil packs, swapped to a 1g BOV, swapped injectors, changed fuel filter. We have thoroughly tested for boost leeks and found none. It holds 18 PSI and it bleeds off real slow so there's nothing significant. Also, radical adjustments to the AFC do not seem to affect it at all either. Whether we go -10 to -40 the problem does not change. If anyone has any other suggestions they would be appreciated.

 

[my_gst95]

How far are the plugs gapped? My NGK BPR7ES's did that when they were gapped to wide. Just a suggestion.

my_gst95

 

[Mike 99GSX]

Originally posted by my_gst95
How far are the plugs gapped? My NGK BPR7ES's did that when they were gapped to wide. Just a suggestion.

my_gst95

.028. He's used both 6ES and 7ES with no difference. What's got me stumped is how its fine after 5500

 

[sophat34]

just out in a new motor and still have this problem, when ever I get on the car, wot, it misses from 4k to 5.5k rpms. I have timing set and have a dsm link and just keep getting missfire codes, normal for 1g cas swap. I will try and get a log tomrow. I have changed plugs from b6es to b7es and now have b8es in the car. I am wondering if its the coils or the ignitor as they are the only things left from the original motor. any help you guys can give me is appreicated. thanks

 

[SpeedFreak03]

How old are the plug wires? Also the plugs are NEW, right? Maybe its the coil pack, if its original that could be the problem (they do wear out over time because the "jelly" they use for cooling eventually hardens up and the coil pack overheats and dies). Try replacing wires first if they're old. Good luck!