Supercharged Toyota 3.4 cold start issue

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dsrtrcr01

Well-known member
Jan 31, 2005
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534
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So my buddy has a supercharged 3.4. Runs awesome. Recent supercharge rebuild, bigger injectors all the cool stuff. She rips.

The issue is when cold starting in the morning she misses. Sometimes a little... some times a lot (really bad) after a little it runs awesome. No engine light, no warnings. 2 mechanics said "ah it's fine"

Anyone have ideas or experience this?
 

84projectford

Senior Member
Sep 8, 2010
1,211
608
113
Phoenix Az
Tunes ecm or factory? How much bigger injector over stock? When were the plugs changed and factory heat range? If colder, how much and are they fouling from not getting hot enough?
 

84prerunner

2:AM Fabrication
Feb 7, 2008
21,669
225
63
Covina CA
bigger injectors huh? interested in hearing how that was accomplished, its a pain in the ass on the 3.4s. im guessing that is a major factor here.
 

SoupGFX

Member
Dec 6, 2013
184
116
43
San Diego
Did he put in the underdog racing 7th injector and the computer unit? When I did the 7th injector upgrade, it came with the obvious 7th injector and 6 bigger injectors. It also had a little computer unit with it. Also have him reset the truck computer. It might be using old data from before the injector upgrade. My auto mechanic showed me how to reset the computer. He said hold the positive and negative battery leads together for about 30 seconds and it resets the computer. The truck will run a little weird for a few days as it learns how you drive.
 

dsrtrcr01

Well-known member
Jan 31, 2005
4,128
534
113
Got some answers:
He is running the URD 6 injectors kit. Apparently they run larger Bosch injectors and only 6 instead of 7
Smaller pulley with something about self tensioning...
colder denso plugs. He said something about iridium IK22 or something like that
Computer has some URD spec tune as recommended by URD

Been block checked, Valves checked, no coolant loss at all.
 

84projectford

Senior Member
Sep 8, 2010
1,211
608
113
Phoenix Az
compression checked?

id pull a couple different plugs and snap some pics to post up.

afr gauge in the rig? curious how rich they made it at cold start.
 

04yfzkid

I are smarts
Mar 21, 2007
33,495
375
83
Flagstaff, AZ
My guess is either the cold enrichment is too rich, or the coolant temp sensor is bad and reading colder than it already is. I've seen cars not even start from a bad CTS making it stupid rich. I think the last one I did was on a completely stock crown vic. After we saw it was saying it's -60 on coolant temp, replaced the sensor, fired right up.
 

84prerunner

2:AM Fabrication
Feb 7, 2008
21,669
225
63
Covina CA
I’d bet it’s a tuning issue with the piggy back. That’s one of the major pluses to the 7th injector setup....they start and idle just like stock, changes only happen under boost. Even those are usually really rich from URD, I’d bet his truck is also very rich at cold idle.
 

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