Big problem, please help
 

As you all know, I just got my turbocharged N/A running.. It idles fine.. My prob is that it wont rev past 5500rpms. It sounds like its hitting a rev limiter. I can get it to go to 6k if I take it up slowly. When I get to around 3000rpms my EGT's skyrocket and around 4k I'm hitting 900*C. I suspected my secondary injectors but I swapped in my old ones (which I know work fine) and it does the same. I've read that it could be caused by my high pressure 255lt/hr Walbro Fuel pump, or a bad fuel pressure regulator (or both), but wouldnt that richen the mixture causing EGT's to drop? I also noticed that it happens when the car is about to reach positive manifold pressure. It wont ever go past 0 psi. Any suggestion would be appriciated.

Can't help you any on the turbo problem, but one thing is universal regardless of what type of engine is being discussed. High EGT can only be caused by a very lean mixture of late ignition timing.

I know enough about the turbos on this site to know that a high volume fuel pump and larger secondaires are vital.

Your problem sounds as though your secondaries are not working at all.

This is relvinnian: If that were the case, the car would have this problem less, when fuel is added via AFC. This is orginally what we had suspected, hence the injector swap. Later the AFC was leaned out as much as possible, and the car was able to rev to 6500 rpms, more freely. The exhaust is puffing white PURE RICH smoke even on full lean setting. Obviously something is wrong.

Currently I am leaning towards a faulty FPR, which is somehow allowing extremely high rail pressure. Comments?

Also, we have swapped 02 sensors, checked the AFM, and adjusted the TPS (which is reading 1kohm/4.5kohm).

Thanks
-Brian

your timming is probably way to high. I doubt the N/A ecu retards it enough. try retarding it at the CAS and see if that helps.

what size injectors are you using?

edit. the timming would cause the high egts. but probably not if you are just reving at idle?? I doubt that would stop it from redlinign at idle either. so probably a fuel thing.

check your secondary injectors, make sure they are seated correctly

Ok, lets assume that my secondary injectors arent working properly. How do I go about fixing the problem? I know they're getting voltage, I've measured... However they arent grounded while the car isnt running, which I assume is controlled by the ECU to control when they fire. I've tried two sets of injectors and get the same results. Any suggestions would be appriciated.

Also, the injectors I had in the car when I first started it measure from 2.8-5 ohms when I measure them. My stock injectors measure a straight 2.3 ohms. Could the other injectors have screwed up my ECU? If so could I just reset the ECU somehow?

Another bit of info... I have removed my ACV and blocked it off... If it doesnt seal completely could that cause any of the problems I'm having?

Remove the negative battery cable and push the brake pedle. That'll reset the ECU, but I don't know if it'll help you :/

Thanks, but I've already tried that... Same thing... :(

:

Re-measured both sets last night, and they both measure 2.3-2.4 Ohms.

Well, it'd be nice if you had an air/fuel gauge to tell us where it was running. You say it smokes white like crazy? Also, fix your vacuum leaks, those don't help any. And also, your TPS should read up to 6K ohms, not 4.5. What does it sound like when you hit 6,000rpm?

Like I'm hitting a revlimiter..... Actually... It sounds a lot like detonation, minus the metallic rattling sound. And it does it 4krpm if I just floor it.. And 5500rpm if I bring it up slowly.

Ok, today I was messing with some stuff, ran a ground wire to the engine, fixed my EGT and boost gauge wiring, and unplugged the vac line from my pressure sensor. I also reset my AFR (fuel controller). Now the car will rev to 7k in neutral so I took it for a drive. Still stops revving at around 4k and it wont hit boost at all... I tried with and without the pressure sensor plugged in and get the same results. For some reason I get the feeling its boost related. Whenever I hit 0 manifold pressure, no matter where it is in the rpms, I hit what seems to be a fuel cut or somthing. Even with the pressure sensor unplugged. Could it be a faulty AFM?

Dumb question but how leak-free is your ducting?

I had a problem with running like crap on my (factory) turbo car and it turned out to be a loose hose clamp on one of the hoses between the turbo and the throttle body. When the turbo was pressurizing the intake tract, it'd leak out through the loose clamp, so the engine would run extremely rich to the point of misfiring, because the air had already been measured by the MAF. When off boost it wouldn't leak and it would get the correct amount of fuel.

The white smoke worries me... normally super-rich running is black and sooty, not white. White would be oil (possible turbo seals shot?) or coolant (not sure how it'd be boost related)

I just went through my intercooler piping to check for leaks and found none. One thing I did find though was my ACV blockoff wasnt sealing. I took off the plate and I can see where its blowing by. Could this whole problem be caused by the ACV not being blocked off??

He is not able to see any positive manifold pressure, therefore the intake is not pressurized. The idle is not affected, yet the car still performs poorly in vaccum as revs increase. Also, I can ASSURE you the car is running heavily rich. When sitting with the car idling for 2 minutes or more the richness is so strong it burns your eyes, makes you light-headed. Very distinguisable.

I'm seriously at a loss here. I've never seen a problem like this that has not been easily fixed.

Josh, please check your plugs and adjust the CAS.

Another thing I just thought of... When I removed the ACV, Air pump and took off the cats.. I never capped the split air pipe. I dont know jack about emissions crap... So could this be a problem? I'm going to go through the entire intake system and cap off everything that doesnt have somthing attached (and looks like it should), re-check the intercooler ducting, check the capped nipples on the intercooler, , check the spark plugs and check the timing. I hope this is simply an intake leak. That'd be much better than an electrical problem. Please keep the ideas comming.... Anything I havent thought of will be helpful. That way I can check all the systems one at a time to find the problem.

And one other thing... The idle is effected a little. I've always had problems with the car stalling because of my 9.5lb flywheel. But its even worse now. It idles at 1100 rpms when its warming up and at around 300-400 when its warm..... just BARELY running.. Sounds cool as hell, but isnt normal... Not normal = not good.

If you removed the split air pipe, there will be a large nipple at the back of the lower intake that is now exposed. Cap it.

Other than that...I have no idea...The only thing that keeps running through my mind is "huge vacuum leak....running rich"...

When I first started mine, I could not get the engine above 5000 RPM. It would just completely bog. The problem was that after the secondaries opened up, it just ran WAY rich. A little tuning on the S-AFC and the problem was solved.

Maybe thats my problem then... I'm running the high pressure 255lt/hr Walbro with 680cc/min secondaries. And I had probs running extremely rich when the fuel system was stock... I should probably look into getting a new FPR (which I suspected to be the prob when the fuel system was stock). Anyone have one they wanna sell cheap?

I'm still not entirely sure its the FPR, and wanna eliminate all other options before spending $90 on a new one.. So..... bump to the top.

Try another TPS, or unplug your current one and see if it helps any. My t2 did the EXACT same thing when I first got it, hence th reason I now run with no TPS. IT would not let me boost or go past 4krpm most of the time, and never past 6000rpm. I have also seen variations of the same effect be a TPS.

You run with no throttle position sensor?? Or are you talking about somthing else?

I run with NO TPS, you read right. My engine runs on an afm, intake air sensor, 4 injectors, and boost sensor. There is nothing else on the engine.


YOu dont have to have a TPS to run. Some cars will not want to idle at first without it, and have to be readjusted. IM not suggesting this as a permanent solution for you unless you want it to be so, but rather a way to troubleshoot. IF you have spare TPS', try another.

I tried it with the TPS unplugged.. Starts up and idles... But it wont rev over 2500rpms.. It revs, drops, revs, drops, revs, drops.... Like I were pushing the gas and letting off very quickly...

..... Oh yeah.. and the car still hasnt seen boost.

No other TPS' to try? Yours m,ust be one that doesnt like to run w/o it...

wow thats crazy no tps, I drove with mine unplugged for about 5 miles, seemed fine but bogged out at 4k and barely idled, you might wanna try to pull the main engine fuse to cause a temp lean condition, but prolly won't help, prolly should pull all the emisions off and get rid of that stupid vaccum rail, block off the egr, bac, split air, dunno

Get a fuel pressure gauge and put it in line to find out what the pressure is. Why waste time guessing?

Fuel pressure regulator bad. I doubt it. Chunk the WALDO for now.

Buy some wire taps and tap into your secondary injectors with a meter. Go driving. If the 12v does not drop significantly when you hit 3500 rpm under full throttle, then you have a ECU problem.

I doubt if its a TPS problem.

Its hard to fuck up a block off plate. Flat piece of metal with some rtv b/t it and the manifold. Leave the half dollar size check valve in place. Put some vaseline on it (check valve) so you can use it again.

If you have a blockoff plate, the split air pipe does nada. Could care less if its blocked off or not.

Chunk the WALDO and put you original pump back in til later. You need to get the pig to run first.

Did you put a orifice in the boost line?

What ECU are you using?

What boost sensor are you using. The n/a's won't cut the mustard.

Have not seen boost. Maybe the turbos bad. Maybe there is too much restriction in the exaust.

What size injectors??? Missed that answer..

Yes, I used the oriface for the boost guage line. Using the stock N/A ECU. Using a Greddy boost sensor for the guage, the car still uses the stock n/a pressure sensor. I dont think the turbo is bad... Its trying to boost.. It seems that right when I'm about to get into some boost the car stops it and runs like shit... Otherwise its fine. I can drive around fine as long as I keep a very low load on the engine and the rpms down. As far as exhaust restriction.. I dont think so.. I run a 2.5" DP, MP, to a N1 single catback.. Though I do have some exhaust leaks. And I currently have my stock 460cc injectors in until I get this figured out.. Then the 680cc's go back in.

Until I get this fixed, I'm gonna keep this thread on top.. I'm gonna go buy a fuel pressure tester today.

did you try the timing suggestion? that sounded like a pretty good place to start.

Just checked the timing.... Timing is right on the mark and advances the same regardless of whether the pressure sensor is hooked up or not.

Ok... just went to go get a fuel pressure tester... $40.... forget that... I'd rather just buy a fuel pressure gauge to mount in the car to monitor at all times.

Ok.. So lets recap...

Car wont boost over 0 psi manifold pressure
Car seems to hit a fuel cut or rev limiter at either 4k or 6k rpms (depending on engine load)
When driving in first gear I tried to slowly take up the revs and it started bucking voilently at around 5k rpms
Car was running rich (suspected FPR at fault) when the fuel system was stock
Car is now running a Walbro high pressure 255lph fuel pump
Timing in spec
TPS in spec
Battery charged
Intercooler ducting checked/bypassed/then checked again
I can see the turbo blades spinning freely, and the boost gauge shows its trying to make boost

I'm leaning toward it being a fuel problem. The secondaries seem to be fine. So I think its the fuel pressure. I cant reinstall the stock pump tho as I had cut the wires for the walbro harness. I'm not quite ready to spend a lot of money on somthing thats not a sure thing, so I dont wanna try an expensive FPR and have it not work. Does anyone else have a differing opintion or does it seem to be a problem with the fuel pressure?

P.S. Thanks for all the help so far. I really appriciate it.

There is absolutely no doubt that it is a fuel problem. It is going WAY rich at that point.

I'm thinking that it's the fuel pressure regulator. Perhaps your stock one is not working correctly? Have you tried electronically turning down the fuel (noticed you have an HKS controller)?

I think your use of the n/a boost sensor is the culprit if not one of the culprits. I'm real tempted to put my na sensor in my turbo to prove it. Probably won't.

I may be way off base here, but a n/a is looking at vacuum and atmospheric pressure. The turbo is looking for vacuum and boost pressure.

Thats not clear is it. How about the n/a car never sees boost pressure does it? Now its seeing what???? Boost pressure. Does not seem right to me. The ECU has to be confused. In my pea brain thats the way I see it.
Just a thought anyway. That coupled with a Waldo that is over whelming the fuel pressure regulator.

Just guesses. Nothing else.

I think I'm gonna have to agree with HAILERS here... I just took the turbo outta the intake system and vented it to atmosphere and ran the car NA (with a turbo in the exhaust but not in the intake system) and it revs freely to 8k+ easy like it use to and the turbo blows a fuckload of air and blew the venting duct around. :) So its a problem once I start hitting boost. I just dont get what it could be. The pressure sensor only controls timing right? Well I've tried it with and without the pressure sensor hooked up and get the same results. Must not be the fuel system as it runs fine without the turbo hooked up. In light of new info, anyone have any new thoughts?

Another thought... Are the TII and N/A MAF sensors the same? Could mine be topping out? Also... When I was running it N/A, bypassing the turbo... When I revved it up, it hits 0 manifold pressure just like it does when I have the turbo hooked up... Cept when its run N/A it runs fine.

Ok... Maybe I was wrong.. I just drove it as an N/A (with the turbo bypassed) and it wont rev higher than 6k when under load.. Like its misfireing. And it makes no power at all over 4k rpms. I think I'll bite the bullet and buy a new FPR.... Now its only a matter of whether I should get a stock replacment, or upgrade my fuel system with an SX adjustable and run my fuel rails in parellel. If its not the FPR...... Well.... I'm gonna cry...

Get your ass over to my place and pick up my pressure sensor. Try it. Then buy a fuel pressure guage or ask on Cols racing. Remember with FPRs, the regulator that wants THE MOST pressure wins. If your stock one is creating too much fuel pressure, an aftermarket one won't work.

Today I installed a new stock FPR(well, used, but working), a TII TPS, and a TII pressure sensor. With all that, it runs much nicer and revs freely to 7k in neutral. So I took it for a drive.... Same fucking thing... As soon as I'm about to pass 0 manifold pressure the car wont rev any higher. I'm starting to run out of ideas here...