I have an 87 Turbo II...
The Car has a BNR stage 3 Turbo
Ported throttle body (with cold star butterflies removed)
Emissions removal
RTEK7 2.1
RC 750cc injectors (x4)
FuelLab Fuel Pressure regulator
R.P. Comp fuel Pump
FMIC
Innovate WB O2

New Plugs and Wires.

My problem is that under 3000rpm when I put the pedal to the floor the car cuts out and sounds like its misfiring... slowly it will began to climb until about 3000+rpm when it smooths out and has perfect throttle response.

It seemed fine before I put the car up for storage and now I have this problem

So first thing I thought It could be was bad gas, I drained the tank and put fresh 93 octane in with a little lucas fuel injection cleaner. This didn't fix the problem...

So I checked to see if it was running too rich, The WB 02 is reading around 14.2 under and over 3000rpm so I don't think its too rich...

We tested Ohm of the TPS and got around 1000 which is said to be right with no pressure on the throttle cable

Any help would be appreciated....

 

it could be your tune on the rtek, it could be bad grounds, it could be the wrong staging for your secondaries to come on, it could be a vac leak ... check these possibilities out first

 

Well I went with the provided tune, Like I said before AFR is perfect, but I'm not sure about Timing. Grounds are good I cleaned them all up before winter, and Vac lines are all new silicone lines.
What is an appropriate staging RPM for the secondaries?

 

Somewhere around 4k. However, other things are under affect, at this rpm, as well. Did you clean out your AFM, when you de-winterized it?

 

I did not clean the AFM... Please Explain

 

Tried that.. didn't do fix the problem, however I did re-orientate the MAF meter and that seemed so help a little...

But there still seems to be a issue under hard throttle under 3000k rpms

 

Check the Boost sensor.

 

What should I be looking for on the boost sensor?

 

Remove the sensor from the bracket to gain better access to the plug underneath the sensor. Remove the vacuum hose and plug it. The Brown/Red wire w/key to on should have 2.3 to 2.7 volts on it. The more accurate reading would be taken from the ECU at pin 2B but you could also take the reading from the sensor itself. The Brown/White wire should have 3.5 to 4.5 volts on it w/key to on. Black/White will have battery voltage on it w/key to on and this is pretty much a given but check it anyway while you're there just for kicks. Black wire is the ground. With the hose removed and plugged the TPS could be disconnected and this tricks the car in thinking it is under load so the car could be tested while in the driveway with engine running thus you could freely rev the car and see if the same problems exist. Lastly, checking the voltage on the various wires could also be done while the engine is running w/the hose removed and plugged.

 

Get some sensor-safe cleanser and spray it through the disconnected and removed AFM. Push the plunger (or flapper-door, depending) back and forth, throughout it's full range of motion.

Chances are some sedimentary crap will come out. Many times, general dust and light debris gunks up the contacts and or the spring, affecting the ease of motion and causing the afm to 'stutter.'

 

Sorry it took so long it was a busy weekend.

I cleaned the AFM with sensor safe cleaner...
I also mounted it level and with the right side up...
This didn't seem to help.

As for the Boost sensor, these are the results I'm getting:
Brown/red: 2.28v
Brown/white: 4.99v
Black/white: 12.2v
Could this be a problem?

Also I did the TPS unplug test and It seemed to be a little better after 1500rpm, but still existent lower then 1500rpm (also seemed to run really rich)

What should the TPS sensor read at say 1000rpm??? Maybe my TPS isn't reading correctly?

If you guys want I can post a link to a video of what the car is doing.

 

Boost sensor readings are clearly within spec.

EDIT: TPS reads 1 volt at idle spec and rises to about 4.5 volts when the throttle approaches 30%.

 

... Today I'm going to make sure that the TPS is "clocked" and reading correctly.

I'm sorta running out of things to try, I was hoping to get the car in paint this weekend. I would be a lot easier to drive it to the body shop then have to pay to trailer it.

Do you think that the timing could be off because of my Rtek???

Should I ask people with similar modifications for there RTEK maps???

Any help???

 

Okay, Here is a video of whats happening, (Ignore the stupid white face gauges, They are getting replaced)


About mid way through I turn the camera so you can see the delay from when my foot goes to the floor and when the rpms start to increase .

I hope this helps.

 

It shouldn't take too long to do so you might want to try to bypass the fuel pump relay and resistor to see if it is playing a role in your problem. To do this you would disconnect the plug at the relay and jumper the Blue/Red to the Blue.

 

okay I'll try that today too....

Thanks for your help!

 

why not try the RTEK section of this Forum?
Did you put a map in the Rtek 2.1??Or you you just have it set on 720x4 on the Injector tab?
I am running 750X4 on my 2.1 and I have No hesitation on the 720x4 setting with no Map in the Ecu Yet.

 

No, All I did was select 720X4 in the setup menu.
The car ran fine before I stored it.
I reset the Ecu and reset it up like I did the first time and it didn't fix the problem either.

 

kinda sounds like a AFM problem...not to sure though.

 

What is the condition of your spark plugs?
When was the last time you replaced your fuel filter?
Was the car running 100% before you stored it?

 

I remember having an annoying problem like that too turns out the Leading coils grounds needed cleaning..

 

The Rtek is capable of doing data logs so you could see what the sensors were reading exactly as the condition is happening.

 

The plugs are new.... as well as the wires. The fuel Filter was done 2 years ago, but my fuel lab FPR reads a steady 40psi.

By the time I got the car running last year I was only able to drive it around my neighborhood a couple of times, but the hesitation wasn't there...

I mean I have been back tracking my foot steps.

This weekend I will Clean up the grounds, Check the TPS voltage, Check / Clean plugs and check the fuel pump relay

 

Dumb question... where are the coil grounds located?
Do they ground through the bracket?

 

Brackets.