(UPDATE) Not feathering the throttle anymore!

[Mazarin]

Ok, so here's what I've done:

 

Tested and reset the TPS

No vacuum leaks

Fuel is clean and pressure is fine

Spark is fine, even tested the plug wires

Injectors are clean, and the injector clips seem to be delivering decent signal

Checked the ECU and there doesn't look to be any water damage or shorts on it

Car was towed by a local shop looking to help. Was told the MAS was dead and the injectors were wired weird. Replaced the MAS w/ a GM MAS and MAFt. MAFt is wired and setup correctly. Car sounds much better when it runs, but I still have to feather the throttle.

Figured the O2 sensor was bad, replaced that and I still have the same issue.

Have a narrowband that was reading lean before the O2 replacement, now after the replacement it's reading barely into the optimal band.

I tried increasing and decreasing the fuel delivery w/ the MAFt, but I still have to feather, and if I increase it too much, I smell unburnt fuel, and the narrowband still reads lean.

 

When I open the throttle, the RPM's go down. When I let off the throttle, the RPMs go up or hold steady until the throttle closes. Car seems to get a little better the more I mess w/ this, but I'm still feathering the throttle.

 

I've lost my mind and have no idea what to do next.

Edited November 15, 2009 by Mazarin

[Scotty Dont]

Is the tps wired correctly? No dead spots?

[Komeuppance]

What's your fuel pressure at??

 

Did you check the spray pattern of the injectors??

 

Have you done a boost leak test??

 

-Robert

[Technology]

Ok, so here's what I've done:

 

Tested and reset the TPS

No vacuum leaks

Fuel is clean and pressure is fine

Spark is fine, even tested the plug wires

Injectors are clean, and the injector clips seem to be delivering decent signal

Checked the ECU and there doesn't look to be any water damage or shorts on it

Car was towed by a local shop looking to help. Was told the MAS was dead and the injectors were wired weird. Replaced the MAS w/ a GM MAS and MAFt. MAFt is wired and setup correctly. Car sounds much better when it runs, but I still have to feather the throttle.

Figured the O2 sensor was bad, replaced that and I still have the same issue.

Have a narrowband that was reading lean before the O2 replacement, now after the replacement it's reading barely into the optimal band.

I tried increasing and decreasing the fuel delivery w/ the MAFt, but I still have to feather, and if I increase it too much, I smell unburnt fuel, and the narrowband still reads lean.

 

When I open the throttle, the RPM's go down. When I let off the throttle, the RPMs go up or hold steady until the throttle closes. Car seems to get a little better the more I mess w/ this, but I'm still feathering the throttle.

 

I've lost my mind and have no idea what to do next.

 

I highlighted the problems with what you said.

 

First, get a wideband if you are going to be tuning your fuel with the maf-t. You are shooting blind without one.

 

Second, make sure the nose switch on the ISC is being activated when the throttle is closed. It's not in the TPS/ISC reset, and it should be because it's very important to have it working. It's a closed-throttle switch that tells the ecu to go into "idle" mode.

 

Try that.

[Mazarin]

Oh yeah, I guess I left that little detail out - I don't have an ISC. The ISC plug is gone and I haven't been able to find where it is.

 

Problem w/ the ICS, is that the car has ran fine w/o the ISC.

 

So whats the issue I gotta check w/ the injector clips?

[PDX87Starion]

Could be a bad injector. Have you swapped them out with known good ones? Are they the correct injectors?

[dstar88]

try grounding out the isc and mps. see if that works for you. both my isc and mps's wiring is bad and what ive done, is run a jumper wire to both plugs to the isc and mps to ground them out. if you can find the plug to the isc try that. then make sure your TPS is set. and unplug the battery to wipe out the codes.

 

with the isc just unplugged the computer thinks that the TPS is out of wack too becuase it cant see the ISC. which causes the car to run and accelerate like crap at times,. if you ground out the isc and mps. the computer will still throw the ISC code but not the TPS code and should let the car run normal. I found out that if they are not grounded out, the TPS code will be thrown no mater what.

 

 

 

Daniel

Edited October 26, 2009 by dstar88

[Mazarin]

Where would I find the grounds for the ISC and MPS?

 

I took care of the massive exhaust leak last night w/ nothing to show for it still. If this grounding thing doesn't work, I'm gonna replace the injector clips next.

[dstar88]

bellow the line is what i sent to another member in pm's. he asked the same thing, sort of.. i basicly learned this from trying to do a isc/tps reset so many times, and realized that the wiring was all screwed up to the isc/mps. so i figured why not ground out the isc and mps like you do when you do a reset. that way it doesnt make the tps got out of spec again and make the car go haywire all the time will going down the road.

 

before you do this, make sure your iddle is where it should be, and your tps is in spec. then ground the isc/mps and the motor out so it has the fixed iddle. after you do that, unplug the battery so it clears the computer codes. then reconnect the battery, recheck the tps to make sure its in spec still. and the car should run fine.

 

just a reminder as well, the ecu will now ALWAYS throw the isc error code (code 6), it should not throw the tps code (code 5), unless the tps is out of spec or bad.

---------------------------------------------------------------

 

 

ok, so here is what i found. There are two plugs for the isc and mps of course. one is a 3 pin and the other is a 4 pin, one if these is for the little motor and the other is for the isc and mps.

 

 

so all you do is make 2 jumper wires with a male connector on one side and a female connector for the other side of the jumper wire. For the one with 3 pins to it, Unplug it and put one jumper wire to the single pin leaving the other two next to each other open. Do this on the male and female side of the plugs (pigtails).

 

for the 4 pin plug, one of the wires on each male side and female side is black (for mine at least), and that is the ground. do the same for that one as you did for the 3 pin one. just jump the black wire leaving the other three wires unplugged.

 

i wanted to just pull the male pins out of the pigtails but i didnt have anything thin enough to fit in there and pull them out. that way i can plug in the pigtail with only the 1 ground wire on each connector connected. the way i have it right now with the jumper wires kind of looks messy..but it works for now, till i can figure out how to pull the single pins out..

 

this one is the three pin., i believe:

http://i636.photobucket.com/albums/uu89/daniels_zx6/Photo0219.jpg

 

and this is the 4 pin one that my two fingers are pointing at:

http://i636.photobucket.com/albums/uu89/daniels_zx6/Photo0220.jpg

 

 

 

hopefully this makes sense..

 

 

Daniel

[Mazarin]

Ok, so I just need to ground the wire *from* the ISC?

[dstar88]

yup, and the one that controls the motor. if the motor is still being controlled by the computer (plugged in), i think it will still make the cars iddle hunt and cause problems. thats why they say to run a jumper there when you are doing the tps/isc reset.

 

 

 

Daniel

[Mazarin]

Ok, lets hope this is the issue. Ha, ha, ha.

 

I'll find out this afternoon.

[dstar88]

question.,

 

what version maf-t do you have? 1.3 or 2.2xx ?? pretty sure you have one of the newer version but thought id ask anyways.

 

 

 

Daniel

[Mazarin]

To be quite honest, I don't know. I used the 2.2 instructions and I'm not getting any error blinks on the MAFt, so.... Edited October 27, 2009 by Mazarin

[dstar88]

ok, yea. yours is most likely 2.xx then.

 

let me know if the situation gets better on your car.

 

 

 

 

Daniel

[matrapp]

I had the same problem with having to feather the throttle to get the car going. I did find a solution and now the car accelerates like it should. Try unplugging your coolant temp sensor and putting around 500-600 ohms in the connector after the car is warmed up. This keeps your ecu in open loop and richens the tip in air to fuel ratio. If that works you can wire around 300 ohms in series with one leg of the coolant temp sensor which will allow the coolant temperature sensor to work properly upon warmup and then keep it in open loop when fully warmed up. Believe me I feel your frustration. It's taken 3 years of troubleshooting that led to this. Also if you have a maf translator like I do, unplug the o2 sensor while tuning so it won't hunt. 13.3-1 air fuel ratio works good with a quest at idle. 14.7-1 will hunt all the way to 15 or 16 with the o2 sensor hooked up.

[matrapp]

http://starquest.i-x.net/viewtopic.php?t=3024

 

http://starquest.i-x.net/viewtopic.php?t=3023

 

Here are two of my trials. It may help you.

[mitsuguy26]

check for pluged Exhaust pull the o2 sensor out and see how it runs

[mikec]

Have you verified the TPS output moves with the throttle? The TPS exists specifically to tell the ECU "driver just mashed the gas" and "driver just lifted" so the ECU can adjust the fuel injection appropriately. With a dead TPS, the engine acts like a carb'ed engine that has a stuck accelerator pump: mash the gas (or just ask for "normal" acceleration) and instead the engine bucks/stalls.

 

The TPS is the black cylinder on the front of the injection mixer assembly, 3 wires:

* One wire is a +5volt supply from the ECU to the TPS (green+red wire on the harness side of the connector, the wire from the connector to the TPS can be anything)

 

* One wire is a ground from the ECU (green+black wire)

 

* Green+white wire is the TPS output.

 

With the ignition key OFF, pry the rubber plug out of the wiring harness side of the TPS connector. Turn the ignition key ON. Use a voltmeter with long probes (insulated up to the tips... some meters have an inch or more of exposed metal and that's risky/dangerous here) to verify the +5volt and ground signals. Then connect to the green+white TPS output wire and to the battery "-" post. With the ignition key ON still, you should be reading around 0.5 to 1.0 volts. SLOWLY open the throttle (have a helper press the gas or just reach to the backside of the injection mixer assembly and rotate the sector by hand) while watching the TPS output voltage. It should smoothly, evenly, and in sync with the throttle position, increase to around 4.5 volts. Repeat a few times. If you see jerkiness/hesitation (even at one spot) the TPS is worn out. That "dead spot" will confuse the ECU. If the voltage doesn't vary at all, the TPS is either not installed correctly or the little plastic arm that connects it to the throttle shaft is busted. Remove the TPS from the injection mixer and inspect those parts.

 

mike c.

[Mazarin]

Yeah Mike. That was one of the first things I did, actually. TPS is good and increases steadily as I open the throttle. I'm @ exactly .50 @ idle.

 

The grounding didn't have any effect. So onto messing w/ the CTS.

 

Also, here's a couple pics I took last night. Pardon my ignorance, but anything look funny here(other than the wires not being neatly kempt?) there are 2 plugs you ca see that aren't connected to anything, might these be the problem?

 

http://img28.imageshack.us/gal.php?g=1020259.jpg

Edited October 28, 2009 by Mazarin

[dstar88]

man...i got so confused looking at those pics lol. thats allot of room you got there! wish i can make that much room..

 

 

what error codes is the ecu throwing? there should be new ones if you unplugged the battery, if there is any.

 

 

 

Daniel

[Mazarin]

Haven't checked the error codes recently. Perhaps I'll do that after work today.

 

As for the reasons I took pics of the area, Cokedoctor said he has a similar issue w/ a pinched wire near the resistor. The other reason was for those 2 disconnected plugs. I know the pics kinda suck, but the one near the MAFt is a black and white wired plug, and the other one is a blue-yellow-red plug. The plug is in the pattern of a triangle:

 

x#####x

###O###

##O#O##

x#####x

 

I got 2 days before I let the shop take it again!

[Mazarin]

Defeat admitted. Shop's picking the car up today. Let's hope they can find something this time.

[dstar88]

yea, dono what to tell ya man.. im sure the error codes could have lead you sort of in the right direction.

 

 

 

Daniel

[Mazarin]

Well, part of this has to do with the fact I'm moving tomorrow and the car needs to move with me. The shop offers free towing so I'm using that in tandem w/ the fact I've got no more time to work on it. That, & I'm frustrated as hell w/ it and I need it out of my sight lol.