boostedlt1

iTrader: (2)

alright no one replied to my other thread so i'll start a new one with my new problems.

replaced the head gaskets on my motor. before i blew the head gasket the motor was fine, pulling crazy hard under boost and had just a very slight rough idle (iac counts were ~110, needed to drill my tb hole larger)

now after swapping head gaskets and and putting everything back together (head gaskets are the only thing that was changed, along with compression from ~9:1 to ~9.4:1)

now i'm getting codes for:

-hi res failure
-low res failure
-ignition control circuit open
-ignition control circuit grounded
-pcm prom error (this code shows up twice)


the opti is a gm unit with less than 5k miles and is about 6 months old.

icm is orginial.

pcm is original, re-tuned for the motor/turbo set-up.


sometimes the car will run fine. then the fuel pump will cut off, i'll lose fuel pressure and the motor will die. the second the motor dies the fuel pressure is instantly restored. while idling it will stumble and the fuel pressure will stumble with it, with my hand on the relay i can feel it clicking on and off repeatedly while the fuel pressure bounces around as the pump turns on/off.


so what do you guys think?

opti?
pcm?
icm?
something else?


i pulled the harnness off the pcm and checked all the ground wires with a test lite, they were all grounded. i'm thinking maybe the pcm ground wire that attaches to the block could have been damaged during the head gasket replacement, since the pacesetter headers sandwich it between the primary
and body


thanks for the help

96LT1355Z28

iTrader: (2)

Have you replaced the PCM ground (the one above the starter)? I didn't see your other thread but how do the pins look in your opti harness and are the grounds present on the passenger head near the coil?

The fuel pump "cutting off" is deffinatly a problem but I don't know enough about the fuel system wiring to be much help. If you have a hotwire kit maybe check the relay?

RamAir95TA

iTrader: (2)

Check the wire connection to the optispark.

SS#502

I had the same problem last year with my car, changed this, changed that. After much chasing wires and components it was really bad corrosion in the battery cables themselves... Does sound like some kind of ground issue though. Is your ground at the ICM solid? I would check all your factory connectors for corrosion and wear. Sometimes the pins in the connectors get pushed back and give you an intermittent contact.

boostedlt1

iTrader: (2)

i'll go check the opti harness, i dont remember it looking bad when i unplugged it, the harness is about 1.5 years old

all three ground wires are present and tightly bolted on the icm.


does anyone know which wire coming out of the pcm is the ground that attaches to the block? i looked up the wiring pin out but there were like 5 pcm grounds. i tested them all with a test like and they were all grounded, however it is kind of intermittent so i'd like to just cut that wire at the pcm and re-wire it

Sc0tt30

iTrader: (6)

On a 97 it is Red 2 that is the ground that goes to the Right Side of Engine Block.

boostedlt1

iTrader: (2)

re-did all the battery cables today since my voltage was always low. now i've gone from 12.2 volts with the factory cables to 11.5volts with the new 0/1 cables... fml...


fuel pump still keeps randomly shutting off for a second or two randomly. need help!

merim123

iTrader: (11)

too many variables in play, need to break it down and make sure the components individually are ok.

For the fuel pump relay, you hear it clicking, try another one from the car to rule that out. option two, go key on, and move it around and see if you can get it to click on/off, that will tell you if you have a loose ground in the area or some other issue in the area. if you can set it off by moving your hand around, something isn't right in that area. Take the fuel pump relay off and test the ground in the harness to make sure it's a good ground. I like doing a continuity test to test the ground.

boostedlt1

iTrader: (2)

I replaced the relay and it did the same thing, wiggled all the wires around with my hand and the relay and wouldn't do anything.

Should I do an ohm test on the ground wire? Any idea which one is the ground wire?

boostedlt1

iTrader: (2)

cleared the codes and hooked a wire up to the fuel pump prime connector to keep it running.
now i have a code for:
-loss of hi res signal
-est circuit open
-est circuit grounded
-pcm prom error (twice)
-Maf
-blown a/c relay
_________________

boostedlt1

iTrader: (2)

anyone wanna buy it? i hate this thing

merim123

iTrader: (11)

sorry man, never saw any of those codes personally, so can't comment. Is your battery in the front or back? is that maf stock or not? what troubleshooting have you done, tried and what were the results. The more you share, the more you'll get responses from people. Hard to go off of what you just have.

96TransAmboosted

iTrader: (8)

You need to back prob the options harness to make sure your getting correct voltage to each while its plugged in.

Now have you driven the car at all with the new tune?

If so did you ever have a ses light?

Did you re install the ground harnesses on the drivers side head and are they all good tight and connected?

Do you have just a scan tool or an actual scanner like the tech 2 or modis?

boostedlt1

iTrader: (2)

battery is in the front of the car.

maf is stock. screened and all.



yeah i put ~1,000 miles on the new set-up and it was running perfectly fine. then i blew a head gasket and tore it down, put new head gaskets on, put it back together and i was driving it, it was running better with the 0.4 bump up in compression. only problem i was having was it would stall when i'd slow down for lights or turn while going slow (common iac problems) so i drilled the hole a little bigger in my throttle body cause my iac counts were ~110-120, now they're down to ~30ish. drove it for a couple days then realized my fuel pump was just shutting off randomly killing the car.

i just have a regular 'ol scan tool and also datamasters and free scan. when i have my scan tool hooked up it will lose the connection pretty frequently and i'll have to reconnect. so thats why i'm thinking its a bad pcm. there's one locally on craigslist for $50, might try to pick that up after work tomorrow, doesn't say if it's off an auto or manual car though :/

also i noticed today on the scanner (never did this before when i was getting the opti codes) that my timing was stuck at 5 degrees and 25 degrees and would just randomly jump back and forth between only those two numbers..

i started getting an awful noise as well..can't tell if it's bearings in the alternator (that was rebuilt when i built the motor so only 1k miles on it) or the bearing in the opti

thinking maybe the dowel pin on my comp cam might be too long?

SS#502

I had an Opti from Autozone that ate itself, the rotor shaft pushed foward and the rotor went into the cap, maybe pull your opti out and double check it?

LSWHO

iTrader: (1)

I started having this problem recently too. Weird. I ended up frying my PCM hoping to get one last tune loaded.

boostedlt1

iTrader: (2)

can i borrow your new pcm? haha

Snkebait95

iTrader: (16)

Im pretty sure ive had both the hi and low res failure codes once, and the ignition control circuit open/grounded codes another time. With The hi and low res failure codes my problem was my opti. For the ignition control circuit codes my problem was my icm or coil i forget.

idformula

I had a very similar problem, mine, the car would be fine running great, then just die all of a sudden and wouldnt start, the coil connector had a short in it.

SS RRR

iTrader: (2)

Reads like an electrical issue of some sort.