Help!!! DSM falling on its face!

[mrbill86]

Ok everyone, my car is falling on its face between 3500 and 4500 rpm. Almost seems like it's out of time or misfiring. I will take a video and upload it when I get the chance. Sometimes it wont do it, but most of the time, it does. I had a 90 laser fwd turbo and took the engine out of it and put it in a 91 tsi awd. I swapped all the sensors necessary, ex. cas, ptu, coil, throttle body, etc. Car is completely stock. Here is what I have done to fix the problem but have had no luck what so ever:

replaced plug wires
boost leak test
new plugs ngk6s gapped 32
changed clutch, pressure plate and clutch bearing
tested ptu-passed
tested coil pack-passed
replaced fuel pressure regulator
replaced fuel filter
replaced fuel pump
tested fuel injectors-passed
completely redid all the timing-ignition and engine. timing is perfect
replaced lifters with 3g lifters
alternator is good
battery is good
compression test-don't remembe exact numbers but all were between 130-150psi

I really don't know what else it could be. I do know that the transmission is rattling when first started and cold. Once it warms up, it doesn't rattle anymore. Could it possibly be the transmission? Should I upgrade the fpr? Please help!

P.S. I forgot to mention that it never once did this when it was in the laser and I was running 17psi.

 

[gofer]

new plugs ngk6s gapped 32

I'm not sure why I keep seeing this around this site but the Mitsu specs for spark plug gap is .028-.031. Gap them to the tightest spec, .028" and see what it does between 3.5 and 4.5.

You also said you did all your timing components but did you adjust the CAS to 5* using a timing light?

 

[DSM1G90]

I forgot to mention that it never once did this when it was in the laser and I was running 17psi.

the Laser and the TSI are actually two completely different animals even though they contain the same between the two makes - like a Chevy 350 and a Pontiac 350 setup.

Thus, you can't expect the same when doing a total switch like that. You have to do some adjustments.

You have to think about the ECU since they are not the same between the two axle styles.

Thus, you might have to start over..and agree: do the plugs at .028 - del facto standard with BPR6ES plugs for the 4G63 turbo motor.

 

[davidreckless]

Bill listen to Gofer, dudes a champion!
Kennys told me what all he's done. BTW Brian Teal is on here you might ask him.

 

[mrbill86]

Yes I did use a timing light and set it to 5* and grounded that wire when I did it. Also, all the sensors are for the 91 and the ecu that was in it was a 91. Replaced it with a ecu out of a 92 laser awd 6bolt with 4bolt diff. Doin the same thing with both ecu's. And I will regap to 28 and see if it helps.

 

[mrbill86]

Well gofer, I did what you said, I regapped to .28 and it still did not work. I think I'm going to have to redo the BLT and make sure it's good. Here is my video. Sorry if it is crappy quality.

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[Talipse96]

Will it do the same thing while in neutral?

 

[gofer]

Sorry to hear regapping the plugs didn't help any, I promise that once you do resolve the problem though it won't miss now in the higher RPM.
By looking at your mods list it shows your still on the stock 1g MAF, if you don't find any boost leaks you should put in a 2g MAF and see if the issue resolves itself. You boys in OK seem like you know each other pretty well, someones gotta have a 2g MAF laying around you can use.

 

[mrbill86]

It doesn't do it at all in neutral. And I will try that gofer. I do have a 3" gm maf sensor, just need the translator is all. Well thanks for all the help everyone and as soon as I figure out what it is, I'll let everyone know.

 

[LTUDSM]

try to lower the boost to 14 psi...... i see youre running stock setup,so 17 psi is to much for it.... its high possibility ,that youre not getting enough fuel to run that much boost..... BTW check your TPS,make sure its plugged in and look at your o2 sensor,it might be on its way out.......

 

[rtincher22085]

sound like its pulling timing as you try to accelerate my .02 hope you find the culprit, maybe a weak coil?

 

[mrbill86]

Well like I said,I was able to run 17psi all day in my laser with no problems. Also, I did have a walbro 255 and still did it. I tested the coil and its good. As far as the tps, that could be a possibility. My check engine lights is on and its throwing a tps signal. When I give it gas, the light goes off so I know the tps needs adjustment. Ill try that as well and let you guys know.

 

[LTUDSM]

Well like I said,I was able to run 17psi all day in my laser with no problems. Also, I did have a walbro 255 and still did it. I tested the coil and its good. As far as the tps, that could be a possibility. My check engine lights is on and its throwing a tps signal. When I give it gas, the light goes off so I know the tps needs adjustment. Ill try that as well and let you guys know.

and like i said check your 02 sensor ,Thats what i noticed in your video post,that when you gave gas, the check engine light disappears,and thats,why i came up with the TPS idea... if TPS won't solve the problem.. let me know the results after you fix the TPS problem

 

[enash99]

Well like I said,I was able to run 17psi all day in my laser with no problems. Also, I did have a walbro 255 and still did it. I tested the coil and its good. As far as the tps, that could be a possibility. My check engine lights is on and its throwing a tps signal. When I give it gas, the light goes off so I know the tps needs adjustment. Ill try that as well and let you guys know.

Can you data log the issue? Also you can check the TPS with your volt meter. I had a TPS issue and I checked it using the chiton book. Test the resistance across pin 1 and 3 I believe it was. I have to look back in my book to be sure. PM me if you want me to send you the details on testing it.

 

[GST98 PR]

If you have a walbro 255 then you should check if your fuel regulator is working properly. . .



(i hope this help you)

 

[mrbill86]

Well I replaced the O2 a little while back so I don't think that's it at all. And ill try to mess with the tps today. I have a stock setup and don't have the equipment so I can't data log it. Also, I was thinking fpr when I had the walbro in it so I changed it out and nothing. Then downgraded to stock fuel pump and still nothing. I even swapped the fpr again. So not too sure. But I will mess with the tps today and let you guys know.

 

[prdsmracer03]

Could it be the Cam angle sensor?

 

[cam081409]

Just a thought, mine was doing the same thing, check the vacume lines especially the one on the egr valve and the top of the TB, That was my problem and it was doing the same thing as yours on stock boost.

 

[mrbill86]

Think I may have found the source of my problem. I think it's the transmission guys. Here just very recently, my transmission has been making more noise and when I'm driving it regularly, it's starting to jump a little. So this weekend, I'm going to do a fwd swap since I do not and cannot afford another awd tranny right now. I'll let you know if that was it or not.

 

[mrbill86]

Well I replaced the transmission and it got a lot better. It doesn't do it nowhere near as bad but it still does it. I'm wondering if my entire drive system is screwed. I'm going to do one more blt and check everything again before I go replacing the tcase and rear diff.

 

[mrbill86]

Problem solved guys. I tried adjusting the tps and wasn't having any luck so I just decided to replace the stupid thing and hasn't done it since. Guess I should have just done that a long time ago. Oh well, at least I know all the other things I checked and replaced are good. Thanks for all the help guys.