hard starting..... boost leak?

[96-2g-talon]

I'm new to the 4g63t have some experience with the 420a but this has me stumped. Just bought this 96 talon tsi the kid i got it from didnt know what he had so i got a good deal. currently the car has the following mods hard piping for the ic, corld air intake, and tb also has aftermarket intake manifold, 3" down pipe and exhuast with a high flow cat, o2 dumped to the atmosphere. So when i got it it was running ruff but i knew it to be from all the vacuum leaks and open lines that the kid hooked up correctly all the above work was done by his mechanic and was given reciepts for it except the vacuum system which he tried to do on his own. So i get it home eliminate the evap and egr systems correctly with the ports on top of the tb capped, new lines for the bov fuel pressure regulator and turbo wastegate set up all per the chrysler dealer diagram. It had a few CEL that i took care of correctly by replacing coolent temp sensor, fuel pressure sensor, and manifold differential pressure sensor. Now im still having trouble getting it starting and once i get it started after about 20 trys i have to let it run for 5 minutes before i can even drive it. But once its running it runs like a raped ape. The only other problem is it idles around 2k constantly if its in gear with the clutch in or out of gear with the manual gear box in nuetral..........

Now my big question after that lengthy breakdown is could all this be caused by a simple boost leak or do I have a nasty little gremlin somewere else that i need to track down. I'm almost at my whits end with this car. Can anyone help I really dont know were to go from here except a boost leak test and compression test but what else???? Thank you so much in advance for your help.

 

[92AWDHX40]

http://www.dsmtuners.com/forums/articles-miscellaneous/217951-how-diagnose-no-start.html

basics are fuel, spark, and compression my cars would start with a boost leak.

 

[96-2g-talon]

Ya I kinda started tracking down the hard starting I replaced the spark plugs with NGK plugs gapped corretly with new wires and a new fuel filter going in tomorrow. My main concern is the high idle i know it shouldnt be up at 2k rpm. Could this high idle be caused by a boost leak? Im going to make a tester tomorrow and see if thats my problem. thanks for the help.

 

[josh408]

Have to checked or adjusted the BISS screw? Also if you car has a boost leak it would start but not run past a certain RPM (in this case, 2K rpm) track down every leak, fix it. Check spark plugs gap them at .028 try either NGK BPR6ES or BPR7ES spark plugs.

 

[96-2g-talon]

I just put in NGK BPR7ES gapped to .028 and car runs fine even at wot it just has a consant idle at 2k when the clutch is in or when in nuetral. I just didnt know if a boost leak will cause this ill try to look at the BISS screw tomorrow. And I'm hoping the hard starting is from the fuel filter keeping my fingers crossed. Thanks to everyone

 

[ShadyGST]

shfshgfhfhsgfhsfghgfshgfs

 

[Ozone302]

Sounds like a vacuum leak

 

[josh408]

Does it build boost?

 

[96-2g-talon]

All vac lines are brand new and zip tied on to prevent leaks. And i eliminated all uneccesary vac lines such as the ones from the evap and egr and i capped the vacuum ports on top of the tb. So i know its not a vacuum leak. i was thinking there might be air being sucked in at the tb would this cause my high idle?

Does it build boost?

yes it builds boost starting at 3250 rpm all the way to redline runs fine once its started just idles high this is my only problem with the car

 

[boost97gst]

My guess: Leak somewhere on the IM on TB. Very small leak, but a leak. You have checked that your butterfly closes completely right? That bit me once and it was so simple. You sound experienced, im sure youll find it. GL

 

[96-2g-talon]

I'm sure its the tb it has a stupid paper gasket on it right now I'm just going to take it apart later today and clean it out put new gaskets on it and see were it gets me

 

[GSLENK]

yes it builds boost starting at 3250 rpm all the way to redline runs fine once its started just idles high this is my only problem with the car

That sounds a little late to build boost even for a 14b (I guess you still have 25t.) Depending on what gear i was in I could start building boost (above 0psi) at nearly 2500 rpm IIRC. these are baby turbos and can build boost fast.

Heva you even done the Boost Leak Test? You may be surprised where leaks could be.

If its not a leak then theres only 4-6 possibilities left, and they are all in the TB FIAV, ISC, BISS, TB butterfly clearance.

IDK if a TPS or the Throttle closed switch could be affecting it also but I would check those also. If you really have no boost leaks, those are the onle possibilities I can think of.
(acronyms some ppl dont know below)
Fast Idle Air Valve
Idle Speed Controller (motor)
Base Idle Set Screw
Throttle Body
Throttle Position Sensor

I'm sure its the tb it has a stupid paper gasket on it right now I'm just going to take it apart later today and clean it out put new gaskets on it and see were it gets me

Mine has a paper gasket too. Its green/blue with a blue bead around the intake hole. Seals up just fine until you take it off.

I also didn't tighten my TB elbow bolts down all the way to spec once and I had a bad wandering idle till I tightened them down right.

 

[96-2g-talon]

So i mainly concentrated on the hard starting today i switched out the fuel pressure sensor for an adjustable one off of a gsx and checked on my spark plug wires since I trusted the old wire layout. After a checked my manual I found out the number 2 and 3 cylinder wires were backwards now starts on the second try and no idle surge after a cold start. As for my boost it now my turbo starts spooling around 2200 rpm and has a nice steady pull. I'm hoping no other nasty mistakes show up from the previous owner. Hopefully I'll get time to take a look at my tb tomorrow and do another boost leak test. Thanks for all the help

 

[boost97gst]

Wait, it ran with wires swapped? I mean it actually started??

 

[paynefuldsm]

Yes a dsm will start and run with wires crossed as long as they come off the same coil pack. The 4g63 uses what's known as a waste spark system. When the main coil fires the other one fires the remaining power from the other coil. Thus allowing it to run but not run great hence why the op had such late spool and the other issues.

 

[96-2g-talon]

So after clearing my CEL's and having it come back on i found my coolant temp sensor was throwing a code. I just replaced this with a new one so it must be the wire. From my research ive found that this is probably the source of the problem with cold starts and high idle. So now my new question is were does the wire connect to in the harness or does it go straight to the ECU?