Running Issues

4GTuner

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Sep 18, 2009
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Okay im losing the plot now , if it doesnt get fixed im going to sell her so i have less headaches.

Currently, all the time when you initially apply acceleration, the revs drop. If you smash on the accelerator it pretty much wants to stall so you have to very slowly apply revs to get it up and going.

car is running 93t, has 6 boost manifold , gt3071r, 550cc injectors, fuel pressure regulator and gauge, evo 3 piping and PWR cooler, Spark Plugs are fine, Haltech e8 (Map sensor was replaced recently) and also replaced TPS.

This has been an on going thing but i recon its starting to get much worse and its doing my head in.

If you know the problem FANASTIC, if not im happy to test things etc to enable progression but please no dumb anwsers etc like maybe you lost your cat.
 
is the fuel pump working correctly? in my old car (nissan) it did a similar thing, wasnt getting enough fuel even though you could still hear the pump, replaced pump and it was good
 
Did you calibrate the new tsp when it was installed? If you open the throttle and the ECU still sees 0% throttle position, it may cause what you describe.
 
make sure map sensor line has no cuts or cracks.....leaks. Whilst it is new, the sensor may not be seeing the correct vac if the line is stuffed.

try hooking up laptop and as george said...watch the tps values and also the map sensor
 
fuel pump is working good since fuel pressure is stable at the rail even under load. Will plug in laptop tonight and see if values.

The map sensor is threaded right into the joiner before the throttle plate. Wiring seems fine last i checked but ill check again.
 
well theres your problem MAP sensor goes after the throttle body it need to see both vacuum and boost. i think you mean the intake air temp is just before the throttle body. and even then that should be behind the throttle too.
 
shit yeah thats what i mean, MAP sensor is connected into the manifold sorry and yes the air temp is connected before the throttle plate. Would it make the biggest difference if its before? cause kinda dont wanna remove manifold and drill again for a maybe fix lol
 
Does it only happen at a certain rev point (i.e. only happens above 4000 rpm) or does it happen at any rev range?
Does it only happen on take off? or does it also happen when cruising then applying throttle?

My first guess would be an overfuelling issue, have you dyno'd it at all (to check the fuel air ratio)?

Alternatively it could be the clutch about to go. I had a similar problem a while ago, where it would accelerate for a bit (like go from 3k to 4k rpm) then drop (in that scenario back to 3.5k).
If it is a shagged clutch, then that would explain why it is worse when accelerating hard.

Personally, i would get a dyno run done first (and explain the situation the the dyno dude, so he can log transient throttle runs, rather than just a power run), to check the fuel ratios, just in case something funky has happened ruining your ratio's.
If that doesn't show any problems, then i'd get the clutch looked at.
 
okay tps is working fine as per haltech program (HALWIN)

i have videos also of when the car is idling with full throttle causing the car to stall

and another video of progression throttle
 
This video is showing tps signal with ignition on

https://www.youtube.com/watch?v=YVBPpFTwu7A&index=1&list=UULUrmV1yleUJEGiI1xnILMA

This video is the car running , once i go full open throttle car stalls

https://www.youtube.com/watch?v=DvEkz-jq-7o&index=3&list=UULUrmV1yleUJEGiI1xnILMA

And this is gradual throttle with car running

https://www.youtube.com/watch?v=2oYx4lxDKDQ&index=2&list=UULUrmV1yleUJEGiI1xnILMA
 
Hard to tell but it still looks like the TPS is fucky. In the middle video if you went full throttle, your TPS % was way down and because of that your injector duty was to low. In the gradual press you got TPS % and injector reaction. Need to try a few quick stabs of throttle with the car off and see if you get reaction on TPS %. Might be worth checking you a acel enrichment also, car just doesn't seem to be getting fuel. You running WB? What's it saying when the car stalls?
 
jack of all said:
You need a wideband...
Yep. ECU and software and stuff will tell you what's going into an engine. WB is the only thing that'll tell you what's coming out.
 
Okay. What is a decent brand wb. I want to fix this ASAP because I never really get to drive it
 
okay i ordered the wideband since atleast that will settle another problem hopefully.

where do i install the sensor in the exhaust ie location , dump or how far from turbo or close
 

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