Write-Up: Northstar Throttle Body Install

Abaddon wrote:

I'm willing to bet that the TPS sensor is messing with you somehow....I'd put the DHP into scan mode, and see if the sensor sweep is ok.  

You can start and even drive the car with the stock MAF tune on it and the N* installed. It will just run a little rich or lean at different RPMS.

Would I just be checking to see if it measured from 0% to 100%? It would make sense if it was the TPS because of the bodged wiring..... Thoughts on the coolant going into the engine?

matt270avian wrote:

Would I just be checking to see if it measured from 0% to 100%? It would make sense if it was the TPS because of the bodged wiring..... Thoughts on the coolant going into the engine?

Yes, you'd be checking for the 0-100 sweep, and make sure that it's fluid.
A better, more accurate way of testing it is to remove the TPS from the vehicle, and do the same sweep test with an Ohmmeter. I don't remember which terminals it is, but only one combination will show the sweep. Just probe 2 of them and turn the dial with a screwdriver. The sweep should be even and smooth. Any little movement will/should show a difference in resistance. Most bad TPS's end up with a big "flat" spot in the curve, thus causing the car to run like balls because the PCM is expecting something different.

If you're suspecting that coolant got into the engine, change your oil immediately. The car will still run fine with a little coolant in the oil, it will just waste the bearings over time.

Got the oil changed. There was a bit of coolant, but not even enough to make a difference in a quart sized bottle. I ran an extra quart through the system just to clean it out before I filled it. It's sitting on the charger again before I go back out and try to start it.

The TPS sensor seems to be working. DHP registered a full sweep from 0% to 99.609% (TP %) and 0.431 to 4.098 (TP V). Should I test the MAF/IAC, and if so how would I go about it?

matt270avian wrote:

Got the oil changed. There was a bit of coolant, but not even enough to make a difference in a quart sized bottle. I ran an extra quart through the system just to clean it out before I filled it. It's sitting on the charger again before I go back out and try to start it.

The TPS sensor seems to be working. DHP registered a full sweep from 0% to 99.609% (TP %) and 0.431 to 4.098 (TP V). Should I test the MAF/IAC, and if so how would I go about it?

Even if the IAC were bad, you should still be able to get it running with a little throttle. Only when you back off and let it idle on it's own would it quit running....it'd run out of air and choke.

It's possible that the MAF is garbage. Check to see what the frequency and g/sec are reading with KOEO. A horribly skewed MAF can give a running condition reading even if the car isn't running. You should see near 0 for both without it running. If you get a number other than 0, unplug the MAF and then see what it reads.

Out of curiosity, how did you wire the IAT?

if the MAF is unplugged , shouldnt the VE table still be able to keep the car running?

Matt, you said you tried this and it still choked, right?

charlieRobinson wrote:

if the MAF is unplugged , shouldnt the VE table still be able to keep the car running?

NOT if there's a wiring problem fooling the PCM. Screw the VE table and lets find the problem.

Abaddon wrote:

charlieRobinson wrote:

if the MAF is unplugged , shouldnt the VE table still be able to keep the car running?

NOT if there's a wiring problem fooling the PCM. Screw the VE table and lets find the problem.

That's what im saying. If it doesnt run (even like crap ) on the VE table with no MAF, then there's probably something else other than the MAF going on.

What happens if there's resistance in the signal wire on the MAF? Doesn't matter what the VE table does, the PCM is going to read that resistance as a MAF value, and run the car "accordingly". If he unplugs the MAF, and the PCM is reporting a Hz or frequency other than "0", there's a problem. That's why I wanna know what it says both ways

Or, the IAT is causing it to be pig rich (deekster reference).

I'm back on stock EVERYTHING right now, as I said earlier. I'm about to go back out and try again. The MAF/IAC/TPS were all good before I did this, so it would be my luck if they chose this time to die.

You didn't unplug the Injector harness or something else? Out of gas?

Well, it started and ran (rough) but it puked coolant everywhere and smoked a good bit. Looks like a generous dose of RTV wasn't enough so I'll be ordering new gaskets soon. Hopefully no coolant got into my fresh oil.... Pulling the TB now to see if any coolant made it's way into the intake.

Sounds like you may have filled the cylinders with coolant??? The only way for that to happen is if the coolant ports on the S/C weren't sealed off and were spewing into the S/C itself. Pull the dipstick and have a look-see. It'll look milky if there's a ton of coolant in it. Weird.....

Will it start if you unplug the MAF sensor? Is the IAC opening?
Also, you may need to adjust the idle set screw. The IAC should technically take care of it but on mine I had to increase the stop a bit to get the idle smoothed out.

Abaddon wrote:

Sounds like you may have filled the cylinders with coolant??? The only way for that to happen is if the coolant ports on the S/C weren't sealed off and were spewing into the S/C itself. Pull the dipstick and have a look-see. It'll look milky if there's a ton of coolant in it. Weird.....

Not sure... I'm waiting for a bit for the fresh RTV to seal and then I'm going to give it one last hoorah. I also forgot to put the non-N* MAF table back on it, so I just did that as well. It also threw a TPS code (0122) so that might explain some of it. I'm going to check the oil, but will probably flush it again anyways. Better safe than sorry, no?

matt270avian wrote:

It also threw a TPS code (0122) so that might explain some of it. I'm going to check the oil, but will probably flush it again anyways. Better safe than sorry, no?

Ah. Ye 'olde TPS Low Voltage code!
Absolutely better safe than sorry!!!

Abaddon wrote:

Ah. Ye 'olde TPS Low Voltage code!
Absolutely better safe than sorry!!!

Is the low voltage referring to the battery or the wiring/sensor?

Have you reset the codes since you unplugged the TPS? It will throw the Low Voltage code if you had it unplugged?

And its referring to sensor voltage.

th3fr4nchi5e wrote:

Have you reset the codes since you unplugged the TPS? It will throw the Low Voltage code if you had it unplugged?

And its referring to sensor voltage.

Yes, codes have been reset. I'll mess with the wiring tomorrow then, right now I'm off to work.

Grabbed oil and plugs on my way to work. Luckily I have a decent but of coolant and distilled water left. Once I get home at 10 its wrenching through the night until the damn thing starts.

matt270avian wrote:

Grabbed oil and plugs on my way to work. Luckily I have a decent but of coolant and distilled water left. Once I get home at 10 its wrenching through the night until the damn thing starts.

Hell yeah, man. Can't wait to read your results in the morning!

It's ALIIIVVVEEEE and not pissing itself. Progress videos coming soon. Right now it's shower, food, bed (possibly all at once). Got home at ~9:30 and just got back from the test drive.

Well, I started it this morning and at first it didn't want to idle. Then it went to a really high (3500-4000RPM) idle and stayed there for the whole trip to school, and when I was stopped I was doing about 1600RPM in drive. The car wouldn't shift into 4th, but I think that's vacuum line related. When I turned into school the idle dropped down to normal but was all lopey like I had a massive cam and wouldn't shift out of first. This is when I think the fitting on the lower barb of the throttle body popped out (the one that goes to the transmission and something else). Alongside the 0122 code I threw a 1122 code, also for the TPS. Is there a fuse somewhere that I can check? I'm 99% positive my wiring is good.

No fuses. The PCM supplies a 5V reference, the ground, and the return signal wire.

FYI, the 5V reference is shared with the IAT, EGR, ECT, MAP, and A/C pressure switch.
If you have a bad vacuum line, the MAP would throw everything off and possibly report TPS codes.

Abaddon wrote:

No fuses. The PCM supplies a 5V reference, the ground, and the return signal wire.

FYI, the 5V reference is shared with the IAT, EGR, ECT, MAP, and A/C pressure switch.
If you have a bad vacuum line, the MAP would throw everything off and possibly report TPS codes.

Thanks, I'm having some of my friends grab me some line and fittings while I'm in class so I can rig something together in the parking garage. It would make sense if it was the vacuum line throwing the TPS code because it drove/idled fine last night.

So everything seems good, and it's SNOWING