Hard Start when Cold

SteveZ82

Active Member
I've been chasing a couple of small issues the last year or so. I don't drive the car much this year because I moved and other life stuff got in the way. Anyway, I try to get the GN out at least 1-2 times a month to waken things up and put about 10-20 miles on each time. Mostly, as I've posted this before, I will get some knock when in about 17-18 psi boost so don't boost the car that much. The more pressing issue is hard starting when cold after been sitting. It hasn't done this when I bought the car, so this is fairly recent, and I chalk it up to it sitting for long periods of time. When it does start, it stumbles a bit then levels out and runs fine. Throttle is responsive, rides great, no issues. I'll list upgrades and mods now:

- TT 5.6 chip, 42lb, 16-18 psi
- adjustable FPR set to 42 psi line off engine warm
- New fuel pump (probably less than 100 miles on it) and filter
- RJC power plate
- Rebuilt cam sensor
- New plugs, wires, ICM and coil pack

Symptoms are hard cold start. I prime the fuel rails, key on off a few times, crank once, then twice, then three times and it springs to life. I notice that when the oil light goes off it tends to start right away, but that is new. When it starts, it stumbles up to about 1800 RPM, then settles down in about 30 seconds.

Symptom two, is after it's warm and parked for a bit, it starts right up but have a very rough idle in park that gets perfect when in gear. I checked the IAC and my scan master numbers and the IAC looks fine, but it's lean until it sees a gear, then it's all good.

I'm probably being nitpicky but I'm debating replacing my injectors. We suspected the FP leaking off was a bad check valve in the pump but it's still leaking off with a new pump. I talked to Eric at TT and they were bought as a kit from Cotton's according to his records. So, I don't know how old the injectors are but I'm guessing pretty old. I don't smell raw fuel, plugs look good, and I change the oil every year. Since I'm parking it soon for the winter, I'm thinking either replacing the injectors or taking them off and soaking/cleaning them. Thoughts there? I just hate the thought of an injector or two leaking into the cylinders.
 

Chuck Leeper

Toxic old bastard
Staff member
When the oil lite goes out the switch has closed to power the fuel pump.
Main fuel pump wiring could be an issue.
Key switch ok?
 

SteveZ82

Active Member
When the oil lite goes out the switch has closed to power the fuel pump.
Main fuel pump wiring could be an issue.
Key switch ok?
Key switch is ok. I just read about the oil sender on vortex Buick. Totally forgot about that. The wiring all checks out but I'll check again. And put my FP gauge on the rail and monitor start up.
 

salvageV6

Daily Driver
IACV, check the counts at cold and warm startup, and clean out the throttle body and IACV tip if it hasn't been done recently.
If you pull the injectors this winter just send them to Chuck for cleaning, flowing/testing.
 

SteveZ82

Active Member
Found out that I don’t have any power to the pump with key on. So the pump turns on when the oil light goes out. I can hear a click under the hood with key on and the fuses look fine. Probably the relay. I have a Hotwire kit installed.
 

Chuck Leeper

Toxic old bastard
Staff member
Found out that I don’t have any power to the pump with key on. So the pump turns on when the oil light goes out. I can hear a click under the hood with key on and the fuses look fine. Probably the relay. I have a Hotwire kit installed.
Probably looking in the right area.
The engineers were thinking ahead when they put the oil psi bypass in the system.
 

SteveZ82

Active Member
Probably looking in the right area.
The engineers were thinking ahead when they put the oil psi bypass in the system.
I didn't install the hotwire kit. It's a racetronix but don't know how old. Does anyone have installation instructions for that? I'm sure I can figure it out but thought I'd ask.
 

GNONYX

Well-Known Member
Look at this diagram and see if it looks like what is installed, and if it's not the same then it's time to replace the old with the new.

Also I agree with SalvageV6, remove the injectors and send them to Chuck for cleaning, flowing/testing. I too had Chuck cleaned, and flowing/testing my injectors.
 

SteveZ82

Active Member
Look at this diagram and see if it looks like what is installed, and if it's not the same then it's time to replace the old with the new.

Also I agree with SalvageV6, remove the injectors and send them to Chuck for cleaning, flowing/testing. I too had Chuck cleaned, and flowing/testing my injectors.
Thanks all. I ordered a new harness for the hotwire. It's definitely a racetronix as the inline fuse holder has that printed on it. My hotwire kit is a bit different with an inline fuse off the alternator. @Chuck Leeper, I'm probably going to pull my injectors this week as it's gonna start getting cold here soon.
 
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