Nathan Faunce

perfect that answers question on the head at least thank you, mines a 2000, the CTS is on the thermostat housing top front of engine so I'll just plug that one off

Turbo X_J

2 different things (NMP)



Do you have one of these? If not you should get one.
http://www.pacificcoastmanuals.com/2...ce_manual.html

Nathan Faunce

I do not only the factory one, makes a lot of sense though, I'll probably and up doing that however for just getting it running sake I'll just plug that port for now at least

Caish

buddy had the IAT sensor go bad,
it loaded up and ran like crap nearly didn't get home.

Nathan Faunce

alright I changed the ground strap around and I no longer have codes coming active, however it still will not run, and is running extremely rich when I start it holding my foot on the throttle, so back to basics injectors stuck open? Or anyone have any other ideas?

Nathan Faunce

iat is reading correctly through my ethos scanner, tried unplugging and starting no change

CoffeeCommando

Your throttle position sensor should be rechecked now that you have that ground re-attached. See if it's operating evenly by turning it very slowly.

Did you ever pull out the idle air control valve on the throttle body to make sure the plunger isn't stuck closed or almost closed?

CoffeeCommando

It seems like if a sensor fails in a short it messes with the ECU. I think that's why Redneck garage guy said if you suspect a sensor to unplug them all one by one to see if the problem is cleared. If it is you found a bad sensor and it needs replaced.

Nathan Faunce

I put a new tps on it last night as it was jumping on me and was obviously a problem, I'll yank the IAC today just didn't have any carb cleaner and it was getting late, it was also flooding out which I guarantee was attributing to my problems, I could physically see gas sitting in the intake manifold. I'm letting the pcm cap drop while I'm out running errands and will do the remaining checks when I get home, and see what happens

CoffeeCommando

... sounds like you may have actually had a stuck open injector. Unless your cylinders are just so full of fuel from over-cranking and not starting it's backing up into the manifold. Either way you probably need to pull the spark plugs and dry them out with some compressed air and a blow drier or heat gun. Running too rich for too long can cause an injector to stick open. If you want to know for sure pull the fuel rail off with the injectors still on and have someone turn the vehicle over. Since you have a bunch of fuel in the manifold/maybe cylinders, make sure your spark isn't connected so you don't get any unexpected surprises.

Letting the PCM cap drop? I don't follow.

Nathan Faunce

yeah that's kinda the conclusion i came to also. I pulled plugs and let the engine sit in the heated garage over night and the next day installed plugs after looking in cylinders with my borescope to ensure there was no fuel, and with in about 10 seconds of cranking i had another pool of gas in the low point of my intake manifold, the wiring is firing them exactly as they should be per my noid lights, I have a new set of injectors on order just waiting for them to get here, also p1694 and p1697 came back, went through the factory trouble shooting found my wiring to be fine but pcm is shot, also waiting on that to show up, pcm cap drop is resetting the memory of the pcm, draining the capacitors so that it resets it's memory to start fresh and have no stored fuel trims or anything that could be effecting it while trying to start

Nathan Faunce

On the pcm diagnosis also triple checked the crank position sensor, ohmed found original to be failed and new one to be in spec, pcm codes would not come active with original sensor installed but would come active when scan tool tried to connect to the pcm, with new sensor that is good installed codes would come active immediately, was a new one for me but something to look for in future, somehow the failed sensor was tricking the pcm into thinking everything was fine, when in reality the pcm itself was failed

CoffeeCommando

Might be the PCM just has internal oxidation. You can always take it apart and see. I saw a video where one guy had to resolder a terminal up at the harness connector. Another time someone legitimately had built up oxidation on it that just needed cleaned because the PCM wasn't fully sealed.

Nathan Faunce

yeah I opened it up to check and see if there was something blatantly obvious before I went through all the wiring, unfortunely there was no oxidation that I could see and i didn't see any broken solders l (I also didn't look very hard) I was half tempted to try the freezer trick (old master tech from jeep i know would throw bad jeep ecms in the freezer for a couple hours, somehow it would make everything contract and would start working for a month or so again, I called bull**** on it when I heard it but it legitimately works somehow) but just decided to check out my wiring and found it's all good

djgrayxj

Note from DJ
There is a possible that you may have a vacuum leak between your 2000 intake manifold and whatever year head you have.
The 87<>95 heads have the port for the coolant temp gauge sending unit.

Head casting number by years
It is easy to determine what head you have. On the driver’s side, about halfway down the cylinder head between #3 & #4 fuel injector but below the valve cover clean the lip of the head with a rag or solvent if really greasy. With a good light, you can read the casting number of the head.

Head casting number by years
Casting numbers are as follows:
Year............Casting No
1987-90......2686
1991-95......7120
1996-99......0630
2000-01......0331

The early '87-'90 non-HO heads have low intake ports that flow rather poorly. The later HO heads have higher intake ports that flow more air by allowing a straighter shot into the cylinders. The '91-'95 HO heads with casting no.7120 have the highest intake and exhaust port airflows, especially at lower valve lifts where it is most important, and are the best for performance. The '96-'99 0630 heads are almost identical except that they don't have a port for the coolant temp gauge sending unit.