$1300 in Repairs - Still having problems?!?

[b4christ15]

Well, I just got my car back after being in the shop for 3 weeks. Ended up needing new valves as well as a head gasket (which I replaced with a 3 layer metal one) and some head work done. The car seemed to drive alright after an hour or so, but when I got on the highway the problems started. Between 2k-3k RPM the car will start to sputter and RPM needle will speradicly(sp?) bounce about 300 RPMs up and down when I'm barely touching the throttle. If i try to give it gas, the car goes nowhere and makes a very loud sputtering noise. So I tried letting off the gas and have the car coast for a few seconds to see if it'll go away. It does but only for a little then it'll start to act up again. It doens't do it in stop and go driving so I'm really confused about it. I told my mechanic (who by the way is a very reputable DSM guy and has owned plenty of his own including a 450+hp talon) about it but since its kind of hard to explain but he thinks its just the random misfire of the 6 bolt swap. Im not sure what the hell it is and I can't be spending more money to fix it if its needed. Sorry for the long rant, but I'm really upset about the whole thing and any advice would be GREATLY appreciated. Thanx in advance - Blaine

 

[super97gst]

ok, this could be lots of things. im gonna give you a few ideas to work with. first off check all the ecu grounds, if there is an ecu ground problem it will make the needle jump. if everything looks good in that area you might want to try putting new plugs and wires on. a secondary plug going bad or a plug wire not making great connection will make the tach needle jump, just not very much. the reason i say plugs and wires is because you said it is fine in town and crap on the highway. in town driving you are not putting much of a pull on the motor. when you get out on the highway and hit 55 or 60 the engine has much more of a pull on it, resulting in the ignition working harded to put spark to the plugs and wires.

i would try the ecu grounds first, as that wont cost anything. but i am leaning toward you having an ignition problem. plugs and wires should fix this, if you havent done a complete tune up lately now might be the time.

 

[Old Mitsu Tech]

Scan computer and pull the codes. If it's obd II it should give you an idea of what's going on. Even if the CEL is not on you can have a code.


Good Luck

 

[b4christ15]

I dont think its the plugs or wires cause the were also replaced when the car was in the shop but ill still check them. As for the ECU grounds, how would I got about checking them? I'll try checking them first, then move on to pulling up codes.

 

[stars]

"but he thinks its just the random misfire of the 6 bolt swap"


When I was redoing the interior on my 90 Tsi, I found that the factory had painted the interior which the grounds should have been exposed to bare metal but yet they had a thin layer of paint I had to remove and scrape down to the bare metal just to make sure there was a ground. Engine compartment was the sameway. I redone all the grounds plus made one for the engine compartment with 5 leads to ground to various parts, ie alt, head, etc and ground that back to the neg batt terminal. Since you been pulling wires, chances are something has been pulled from its connector or socket. Check ECM harness connectors for broken/bent terminals and check the pins on the ECU. The ignition systems are the easiest to troubleshoot in the world. There are not many parts on a 1G to begin with. Chances are replace spark plugs and spark plug wires and it should solve your misfire problem. If the mechanic cannot fix a simple misfire then you need to take it too someone for another opinion.

 

[b4christ15]

"Chances are replace spark plugs and spark plug wires and it should solve your misfire problem."

This was done while my car was being fixed over the past couple of weeks. I'm pretty sure this isn't it. As for the grounding for the ECU I'll check for them in the morning. Thanx for the advice

 

[Ultimatedsm]

Well, I just got my car back after being in the shop for 3 weeks. Ended up needing new valves as well as a head gasket (which I replaced with a 3 layer metal one) and some head work done. The car seemed to drive alright after an hour or so, but when I got on the highway the problems started. Between 2k-3k RPM the car will start to sputter and RPM needle will speradicly(sp?) bounce about 300 RPMs up and down when I'm barely touching the throttle. If i try to give it gas, the car goes nowhere and makes a very loud sputtering noise. So I tried letting off the gas and have the car coast for a few seconds to see if it'll go away. It does but only for a little then it'll start to act up again. It doens't do it in stop and go driving so I'm really confused about it. I told my mechanic (who by the way is a very reputable DSM guy and has owned plenty of his own including a 450+hp talon) about it but since its kind of hard to explain but he thinks its just the random misfire of the 6 bolt swap. Im not sure what the hell it is and I can't be spending more money to fix it if its needed. Sorry for the long rant, but I'm really upset about the whole thing and any advice would be GREATLY appreciated. Thanx in advance - Blaine

It is the random misfire problem when you install a 6 bolt into a 2g. If it doesn't happen on stop and go because the computer is in open loop. Once you are coasting, the computer goes to closed loop and then it detects the misfire. Anyway, you need a DSMLINK to cure that or this:

Problems!
IF CHECK ENGINE LIGHTS OCCUR! TRY THIS:

(Blake Heisler's Fix for misfire Check Engine Lights (CELs) when putting a 1G Cam Angle Sensor (CAS) on a 2G)

Many people using the 1G CAS on a 2G head have been running into problems with misfire engine codes while at cruise. Many different things have been blamed for this and many different fixes have been attempted.

This fix will keep the ECU from looking for misfires at all. This is the criterion that must be met before the ECU will start to look for misfires:

1. 300+ seconds of steady state RPM less than 80% throttle position

2. Engine coolant temperature -10C or higher

3. Intake air temperature -10C or higher

4. Barometric pressure greater than 76 kPa

Now if we can get one of these values outside of the criteria the ECU won’t check for misfires. The value that would be the easiest to change would be the barometric pressure sensor. We’re going to add resistance to this value so that the ECU will see less barometric pressure than what there really is. This will also lean the car out so you should see a performance increase as well. Depending on the car and altitude you might need to add more fuel with an AFC.

So let’s get started, Parts needed:

A 10K potentiometer (although a 5K would probably do just fine). These are available at any electronics store, if you go to Radio Shack ask for a volume control knob because they don’t know what a potentiometer is

Wire strippers

Soldering iron

Step 1: Remove the access panel on the driver’s side of the center console. You should now see four plugs with a ton of wires going to them.

Step 2: Pull out the top plug, it’ll be the one that’s the hardest to reach. Locate wire #85. It’s orange with a white stripe.

Step 3: Cut the orange wire in half. Solder one end of the wire to the center peg of your potentiometer. Solder the other end to either the left or right leg, it doesn’t matter which. Turn your potentiometer all the way counter-clockwise.

Step 4: Plug the harness back in and start up the car. It should sound like it did before you did any modifications. If the idle is choppy or the car won’t run you turned your potentiometer the wrong way.

Step 5: Add resistance to the barometric pressure sensor by slowly turning the knob on the potentiometer. Drive the car around; if you get a CEL then add some more resistance. Keep doing this until you no longer get the CELs.

That’s it, special thanks to Marco for pioneering this mod and to all the guys on the DSM1Gina2G Yahoo group for all the discussion, ideas, etc.

-Blake Heisler



Anyway good luck with this, I have a 95 with a 6 bolt and had the same problem, I just got a DSMLINK and boom, everything ran like stock again.

 

[Spyderman7]

I've done a few 6 bolts swaps.Some would multi miss fire, some did'nt.I've fixed them with DSM link and the 5000 ohms potentiometer.DSM link is safer,but if you don't have the money $2.93 for a potentiometer will work.The orange wire is on the fourth plug up on your ECU,fourth wire up. The potentiometer has 3 terminals.If you solder one wire to the center and one to the left,turn the knob counter clockwise.If you solder to the right one turn the knob clockwise.Which ever way you turned,just turn it back a little,you don't need much.If you go to far you'll lean out and boom.Don't adjust while the motor is running.Check Engine light should go away.Sometimes it'll comeback after a few weeks, just turn if off give a small adjustment.You may notice the car does'nt feel quite as strong .But if you solder a wire to each side(not center)of the potentiometer and install an on/off switch you can over ride while racing.I've done both and DSM link is definitly better.Good luck be careful

 

[b4christ15]

Are you sure its the random misfire? I had the 6 bolt installed back in june and it never did this until now. I've had misfire before and it would happen at a steady cruise at about 4k in 5th and it only happened once in a while. This is something totally different. The CEL isn't even on. Im kinda stumped so far

 

[Ultimatedsm]

My misfire happend only a day after I installed my 6 bolt. The 95's seem to detect them faster, I don't know why. Anyway, those are your two options, DSMLINK, or the less expensive way. I really recommend the DSMLINK though, all your drivability issues with the 6 bolt will be gone with the link.

 

[Spyderman7]

Check to see if your shop disconnected your CEL.It's been done many times.