4G64 Turbo idle surge on start up.

[SaronnoSpyder]

Hey guys, new to the forum (posting wise as i troll for answers or parts). I have 99 spyder gs, that i recently installed a 14b turbo (like 2 days ago). Running an 95 eprom ecu, walli 255, 450cc injectors, turbo throttle body, pretty much stock gst parts. First start and continuing, it will go up to about 2.5k for a few seconds and then go into idle surge between 800-1500rpm. Done a lot of research saying it could be the IAC/ISC or vacuum leaks, tps, egr etc. Im running ridiculously rich in WOT (9.1-9.8) on wideband. While driving, when the rpms get low enough the car will pull and then stop (imagine idle surge while drive but at a much slower pace). Under WOT, the car makes about 8-10 psi but feels like there is no power whatsoever. Swapped out an IAC i got from a buddy and no dice. CEL is on for a few codes: o2 sensor bank 1, o2 sensor overheating, IAC and knock sensor (havent hooked it up yet, going on tomorrow). Any input would be greatly appreciated. Anything to get better gas mileage and get it running right!

 

[BK85]

I can't speak to anything to do with the turbo, but my 4g64 had that same surging between 800 to 1500 after warm up. I took it to a mechanic that was sure it was a vacuum leak and sprayed carb cleaner everywhere for two days with no result.

Just to eliminate the IAC and TPS I pulled a complete throttle body off of a Galant 4G64 at the Pull and Pay. The problem went away immediately. I was so relieved that the problem went away that I never put the original TB back on.

So the problem must have been the IAC/ICM, the throttle position sensor or the throttle body itself.

I started to have idle issues on my other 2G that has a 420a motor, so this time I took apart the throttle body and cleaned everything with carb cleaner and the problem went away.

This may not be your problem, but you never know.

Good luck,

Bk85

 

[csadens]

If I am correct in assuming that this is the 2.4 L Spyder, you need to compensate for the higher engine displacement as that ECU is most likely tuned for a 2.0 L engine, not a 2.4. That would be my first stop, is getting something you can tune with. It sounds like the ECU is not properly configured, and this can make you run rich, lean, stuttering. Ive been there. And your injectors are a bit too small IMO, I run 680's on my 2.0 and 14b @ 15psi. Hope this helps.

It also sounds like you have an auto?

 

[SaronnoSpyder]

Sorry took a while to respond, had import alliance today (big car thing) and just got back. It is the 2.4L motor, and its manual. Ive tried unhooking the IAC and nothing happens. I unhooked the TPS, and the car started to go up in rpm. Im running 9.0 WOT, so i figured id downgrade from the walli 255 to the 190, didnt change a whole bunch, but felt a little better in response(still low power). Something interested that happened though, when i put the fuel line hose on, i kinked it slightly and it started up and ran fine for a minute before dying. Could FPR cause surging? Maybe i need to upgrade mine?

As far as the ECU tuned for 2.0, it is. Came out of a 95 gst(EPROM) but ive read on a write up that it should be fine to swap it over with no problem. Ill tear down the throttle body and soak everything in brake cleaner. Also, my brakes seem waaay less responsive. As always, i appreciate any input!

 

[jcart953]

Ive been there. And your injectors are a bit too small IMO, I run 680's

The 450ccs should be fine according to this site: Turbocharging the 4G64 - Page 2

SaronnoSpyder Sorry took a while to respond, had import alliance today (big car thing) and just got back. It is the 2.4L motor, and its manual. Ive tried unhooking the IAC and nothing happens. I unhooked the TPS, and the car started to go up in rpm. Im running 9.0 WOT, so i figured id downgrade from the walli 255 to the 190, didnt change a whole bunch, but felt a little better in response(still low power). Something interested that happened though, when i put the fuel line hose on, i kinked it slightly and it started up and ran fine for a minute before dying. Could FPR cause surging? Maybe i need to upgrade mine?

As far as the ECU tuned for 2.0, it is. Came out of a 95 gst(EPROM) but ive read on a write up that it should be fine to swap it over with no problem. Ill tear down the throttle body and soak everything in brake cleaner. Also, my brakes seem waaay less responsive. As always, i appreciate any input!

I have a similar problem with Idle surge but only when the car first starts up but then it dies down. Took it to the stealerships and they told me its the ISC but so long as the idle goes back down everything should be fine for now. You also might want to invest in a data-logger to see whats going on. I use evoscan and the total price came to about 40 bucks (25 software, 15 cable). I'll be turbo charging my car pretty soon so ill definitely be looking at any potential problems you may be having but good luck and keep us posted.

 

[csadens]

Displacement is important, as far as I am aware. Putting different fuel pumps in might change things a little bit, but before you go tearing your engine bay apart ti find a blown fuse, try giving it a proper tune. If your fuel trims are setup for 680cc injectors and a T25 (not that anyone in their right mind would use 680s on a t25), that 14b is just being flooded with fuel. This will bog you down at WOT. Is your ECU ready (chipped) for a tuning program? It is very important to have at least a proper base tune for your setup. Even a slight change (such as engine displacement or injector pulse) can have an effect on tune.

Also, if you do not have an adjustable FPR, you need one to run both 255 or 190, since the stocker gets overrun. Good luck

@jcart Bigger Injectors (Stock 4G63T 450cc Injectors OK with turbo car resistor pack wired in) Its always a good idea to at least go with 550s

 

[black91awdturbo]

Displacement is important, as far as I am aware. Putting different fuel pumps in might change things a little bit, but before you go tearing your engine bay apart ti find a blown fuse, try giving it a proper tune. If your fuel trims are setup for 680cc injectors and a T25, that 14b is just being flooded with fuel. This will bog you down at WOT. Is your ECU ready (chipped) for a tuning program? It is very important to have at least a proper base tune for your setup. Even a slight change (such as engine displacement or injector pulse) can have an effect on tune.

Also, if you do not have an adjustable FPR, you need one to run both 255 or 190, since the stocker gets overrun. Good luck

You need to do some reasearch! You do not need an adustable fpr for a walbro 190. Also the 2.4 wont through off the stock ecu with the 450's at all, and your way over blowing the effects of 2.4 on a stock set up. The 450's will be fine for a low boost 14b setup.

OP it sounds like you have a boost leak have you done a test for that yet?

 

[SaronnoSpyder]

hmm, i might have to pick up that evoscan then, atleast till i can get the change together for dsmlink.

csadens, it is a stock ecu. Investing in an AFPR seems like a great idea, especially if mine is getting overrun. I know one thing ill have to figure out is which vacuum lines need to be blocked off/not blocked off. None are super apparent as of yet.

Yeah im keeping low boost, WOT it stays pretty consistent around 8-9 psi, but she spits a bit and cant really get into higher rpms cause its running super rich.

 

[black91awdturbo]

It sounds like you have Vac leaks, and boost leaks. Your Fpr is fine for a 190lph pump! With the 255lph that is a whole other story. You need to get a vac diagram trace down what you need delete what you don't. Then do a boost leak test.

 

[SaronnoSpyder]

Yeah definitely. Ill have to troll around on the web and find something. If I had to guess, I'd say IAC and vac leaks, but ill know in a couple days when i get some free time to diagnose it. Ill keep you guys posted! If you guys come up with any other ideas, please dont hesitate to chime in!

 

[csadens]

Do a boost leak test. When it comes back negative, tune it.

@black91 All Ive done since I got my car was research, and trial and error with tuning. I'm just going through my experiences hoping that it will help or benefit this guy in some way. Displacement is indeed important, changing mine made it surge, as did incorrect injector size and airflow... why couldn't it happen for Saronno? If you have access to a tuning program, I would try to get that at least dialed in for a 2.4 with 450's, set the ignition timing, airflow. But +1 on the boost leak test, but not exactly sure how that would cause idle to surge. Might stall out, but less likely to surge. I wouldn't know, I haven't really had any boost leaks that I can recall (Im only a year old to DSM's)

EDIT: Besides, Ill never get my 30 posts if I don't at least try to help

EDIT2: Also, a dead or dying alternator can cause an idle surge. I surged all the way to 1700 RPM on a dead alternator in my 420a. On the DSM it will only surge to about 1100-1200 for me (dying alternator)

 

[jcart953]

@jcart Bigger Injectors (Stock 4G63T 450cc Injectors OK with turbo car resistor pack wired in) Its always a good idea to at least go with 550s

Yea but your missing the point the 450ccs should be fine for his setup. You stated that his injectors are "to small" giving the op the impression that he should probably go buy bigger ones. My point was to simply state your suggestion was wrong for his setup and would not contribute to fixing his problem. Thats it! Now if he stated that he was trying to make 500whp or something then your suggestion would have been validated.

hmm, i might have to pick up that evoscan then, atleast till i can get the change together for dsmlink.

Yes it works wonders. I recently just bought mines and I must say its a great tool. Great for clearing/diagnosing codes, data logging and even has the ability to simulate a dyno (can also use logs with virtual dyno simulator) to see what hp you getting. However, dont take those numbers to be absolute just ball park. All around though great investment.

EDIT: Besides, Ill never get my 30 posts if I don't at least try to help

Haha yea I know what you mean

EDIT2: Also, a dead or dying alternator can cause an idle surge. I surged all the way to 1700 RPM on a dead alternator in my 420a. On the DSM it will only surge to about 1100-1200 for me (dying alternator)

Really?? for me it was always the 3 flashing dashboard lights. Brake, coolant, and battery light and then bam! dead alternator

 

[GST2012GSX]

Well, for what i have read you need a way to manage your fuel. The easy way will be with a s-afc, the 450 injector are just fine. Also you realy need to put a knock sensor, well thats if you dont want to mess up you engine. Thats one of the first things you have to consider,now for the idle surge and you not feeling the boost. Make sure to do a boost test rember this engine has never seen boost so you will have to replace some gaskets and injector orings. Since you have a idle surge most likely you have a vacum leak and for that you have a boost leak. Just get your self a safc, please put a knock sensor and do a boost test. "Dont run your engine with out the knock sensor"

 

[SaronnoSpyder]

Yeah the knock sensor will be getting wired up this week hopefully. Im thinking when i get the vacuum leak fixed the fuel problem will fix itself. Its a bear to trace down all the vacuum lines and figure out where they go. Maybe ill take the TB off and spray it down with some cleaner and then go from there.

 

[jcart953]

Yeah the knock sensor will be getting wired up this week hopefully. Im thinking when i get the vacuum leak fixed the fuel problem will fix itself. Its a bear to trace down all the vacuum lines and figure out where they go. Maybe ill take the TB off and spray it down with some cleaner and then go from there.

I just found this while browsing the site, apparently someone on here is having a similar issue anyway this link might help out more:
http://www.dsm.org/how-tos/tttt/tttt3.htmll

 

[SaronnoSpyder]

Yeah I've read through that numerous times trying to pull ideas. I'm going to get an ohm meter and test the iac now.

Edit 1: New update. switched out a iac with a buddy and still didn't change anything. As I was revved it up to back it out, let off the gas and it died. Can't get it to start now. Changed plugs thinking it fouled them out but no dice.

Edit 2: Getting no spark whatsoever. not sure whats going on

 

[GST2012GSX]

Well soronnospyder after trying find out the problem my diagnostic is that my iac is trash, by the way I was having the same problem. The way that I find out was by disconnect the iac while the car was iddle, the rpms supposed to go up, and in my case this the car did nothing so now I'm trying to get me an extra iac or a used throttle body which I think is a lot cheaper. Ill let you know how goes.

 

[jimbob_843]

My stock 2.4 turbo setup i had ran fine with stock injectors until i turned tue boost up. Keep it low you should be ok.