New injectors.....cold start issue.

sleeperred90tgp · June 03, 2007, 06:38:22 AM

Quote from: 93luminaz34 on June 02, 2007, 02:05:50 PM
It doesn't seem to smoke so much once it starts, but it does run rough for a little bit. I definately plan on ohming the injectors when I get to pulling it apart next week.

Matt, you don't have to take it apart to ohm the injectors. You can ohm each bank (three injectors) by ohming the two little connectors for the injectors just below the computer. It should be 3 times the ohm's for one injector.

Jud

Prospeeder · June 03, 2007, 01:53:26 PM

you got 340 miles ona tank! LUCKY! I can barley get 210 miles on a tank.

TGP Nick · June 03, 2007, 02:39:47 PM

I just took my fuel lines off, cleaned them up, PTFE taped all threads and replaced all of the o-rings, put it all back together good and tight. No more fuel leaks and the gas smell is gone! Problem solved!

pontiac6ksteawd · June 03, 2007, 04:46:20 PM

Quote from: Prospeeder on June 03, 2007, 01:53:26 PM
you got 340 miles ona tank! LUCKY! I can barley get 210 miles on a tank.

Thats what I normally get.That tank I did all highway driving. saw as high as 28.2 mpg on the DIC when we first started the tank, lowest was 21.2

GOT2B GM · June 03, 2007, 09:15:49 PM

Quote from: TGP Nick on June 03, 2007, 02:39:47 PM
I just took my fuel lines off, cleaned them up, PTFE taped all threads and replaced all of the o-rings, put it all back together good and tight. No more fuel leaks and the gas smell is gone! Problem solved!

I'll have to check those lower connections as well.

Quote from: sleeperred90tgp on June 03, 2007, 06:38:22 AM
Quote from: 93luminaz34 on June 02, 2007, 02:05:50 PM
It doesn't seem to smoke so much once it starts, but it does run rough for a little bit. I definately plan on ohming the injectors when I get to pulling it apart next week.

Matt, you don't have to take it apart to ohm the injectors. You can ohm each bank (three injectors) by ohming the two little connectors for the injectors just below the computer. It should be 3 times the ohm's for one injector.

Jud

Yes, I've read that in one of your other threads, but it only takes like an hour or 2 to pull everything apart and get an accurate reading for every injector.

I want to take some measurements and do some comparisons of the injectors anyways, so I have to pull it apart.

Quote from: pontiac6ksteawd on June 03, 2007, 01:30:56 AM
If you get this hard start figured out, let me know. My TGP has been doing this all week long. Never dont it befor. I am NOT running the yellow tops, but the L36 Injectors. My car takes 2 to 3 trys to get it started. First crank, spit spit, stumble, die. Second crank, either it does the same thing, or starts up and runs perfect.

No raw fuel smell, no leaking fuel anywhere that I can find. Getting pretty good fuel milage actually, drove 340 miles on one tank this week. I still hate using this car as my daily driver...

Hopefully we can work together and get this figured out.

grinders_18 · June 03, 2007, 10:15:51 PM

Quote from: pontiac6ksteawd on June 03, 2007, 04:46:20 PM
Quote from: Prospeeder on June 03, 2007, 01:53:26 PM
you got 340 miles ona tank! LUCKY! I can barley get 210 miles on a tank.

Thats what I normally get.That tank I did all highway driving. saw as high as 28.2 mpg on the DIC when we first started the tank, lowest was 21.2

Why is your guys' mileage so horrible??? I get over 400 on a tank 9 times out of 10 - mostly highway mileage, but still. What makes yours so low?

pontiac6ksteawd · June 03, 2007, 10:19:55 PM

I think I need to go see a doctor and get a unleaded foot. This lead foot is going to be the death of the TGP..

Prospeeder · June 03, 2007, 11:18:12 PM

I drive my TGP pretty slow, its the cross over and injectors im sure

pontiac6ksteawd · June 03, 2007, 11:19:27 PM

I have a new cross over, and replaced the injectors with the L36 injectors.

mfewtrail · June 03, 2007, 11:50:05 PM

I have no problem going 450+ miles on a tank in my TGP. Purely highway driving, I could go further than that. The majority of my driving is highway. None of my cars are too bad on gas in the city though.

R Dubya · June 04, 2007, 09:37:28 AM

FWIW I can get a little over 400 miles on this cars full tank, the other one would get substantially less, I'd be lucky to get 320.

Matt I did use the top groove, I have no fuel issues or anything, that install went pretty smooth last year. The pink tops solved all my driveability issues, no hard starts or anything. I am pleased with my purchase, definetely.

TGP Nick · June 04, 2007, 11:38:35 AM

I can't wait to see what kind of mileage I'm getting now that my driveability and fuel issues are solved!! :icon_mrgreen:

GOT2B GM · June 05, 2007, 08:36:01 PM

Just an update,

Removed the plenum.

I pressurized the rail, and checked for fuel leaks at all connections, and there is none.

I pulled the rail/injectors out of the intake manifold and pressurized the rail again. The injectors did not appear to be dripping or leaking.

I ohm checked all of the injectors and they read between 14.6 and 14.7 ohms. The factory injectors were in the low 12 ohm range, would this difference (12 ohms VS 14.6 ohms) make a difference?

I replaced the injector o-rings with brand new GM o-rings, that seemed to fit more snug in the rail and the manifold.

Here's a pic of the o-rings (from new injectors VS from old injectors VS brand new from GM)

Here's a pic of the o-ring spacing, comparing new and old injectors, I use the slot seen just below the upper o-ring on the new injectors.

I pressurized the rail after I reassembled it, and got just over 40 psi of fuel pressure.

I let the car sit over night (6 hrs) and the fuel pressure had gradually dropped to 20-25 psi overnight. Would you consider this to be normal?

It started hard when I first started the car, but maybe this was due to having the fuel system all apart......but I doubt it.

I drove the car around a bit (50 kms) and it worked fine, I'm going to let it sit overnight now again, and see how it starts tomorrow.

Any ideas or suggestions?

TGed · June 06, 2007, 03:58:49 PM

Just a poke in the dark..

Maybe your fuel pump cannot give enough steady pressure and is causing the fuel to not atomize well enough. Therefore, causing the fuel to puddle and gives you the hard start. Once the pump gets use from the prior start, it probably stays operating like it should until it gets cold again (overnight) .

.02

GOT2B GM · June 06, 2007, 04:38:24 PM

Yup....car still starts hard when cold....

Quote from: TGed on June 06, 2007, 03:58:49 PM
Just a poke in the dark..

Maybe your fuel pump cannot give enough steady pressure and is causing the fuel to not atomize well enough. Therefore, causing the fuel to puddle and gives you the hard start. Once the pump gets use from the prior start, it probably stays operating like it should until it gets cold again (overnight) .

.02

hmmm thats a good point, how would I be able to check this without changing the fuel pump on a whim?

I didn't have this problem before installing the new injectors, but maybe these new ones require more pressure to atomize the fuel than the OEM injectors.

If I go ahead and change the fuel pump, I hear lots of people use Walbro's (sp)

What model / part number should I be looking at?

Thanks guys.