DIY PROM Do It Yourself PROM chip burning help. No PROM begging. No PROMs for sale. No commercial exchange. Not a referral service.

ZZ4-Cammed 355 Cold Start Issues...

Thread Tools
 
Search this Thread
 
Old 07-22-2006, 11:18 PM
  #1  
Member
Thread Starter
 
TPI Monte SS's Avatar
 
Join Date: Jun 2001
Location: Bergen County, NJ
Posts: 287
Likes: 0
Received 0 Likes on 0 Posts
Car: 1988 Monte SS
Engine: ZZ4-cammed TPI 355
Transmission: World-Class T5
ZZ4-Cammed 355 Cold Start Issues...

Hey all,
I'm just getting into the tuning/PROM burning for my project. The victim is running a '165 MAF with $6E code and unplugged 9th injector. I started with a stock 305.bin, and have been working with that. So far, I've changed the injector constant to 22 (running 22 lb. LT1 injectors) and messed with the idle speed vs. coolant temp in an attempt to get this car to idle while in open loop.

The first time I start the car when it's cold, it fires and dies right away. The second or third time may get it to run long enough for me to step on the throttle a bit and keep it alive. After I get it out of the driveway and into 1st gear, it will generally run like crap for a minute until the temp comes up a bit; backfiring through the intake, stumbling, surging idle, etc. Once the car is warm, it does settle into a nice lopey idle and is pretty smooth. Cruise BLMs are in the 140s and WOT BLMs have been in the 120s.

The motor is basically a budget-built version of a ZZ4 (355 ci, ZZ4 cam, World Products 58cc heads, 9.8:1 compression) but from what I've read here, most guys have had hardly any trouble getting the ZZ3/4 cam to idle. Am I looking at something in the code, or something mechanical (major vacuum leak that I'm not seeing/hearing?).

Also, are there any opinions on leaving the EGR in, vs. deleting it? It's currently installed, but does it have any impact with this cam?
Old 07-22-2006, 11:59 PM
  #2  
Moderator

 
3.8TransAM's Avatar
 
Join Date: Feb 2000
Location: Schererville , IN
Posts: 7,015
Likes: 0
Received 1 Like on 1 Post
Car: 91 GTA, 91 Formula, 89 TTA
Engine: all 225+ RWHP
Transmission: all OD
Axle/Gears: Always the good ones
Run the 89 350 code with the VATS deleted. It has no ninth injector or conversely run the 88 350 code and redo the appropriate cold start tables and work from there (ie: use the 89 cold start to compensate for the ninth injector u no longer have)

later
Jeremy
Old 07-23-2006, 04:31 PM
  #3  
Member
Thread Starter
 
TPI Monte SS's Avatar
 
Join Date: Jun 2001
Location: Bergen County, NJ
Posts: 287
Likes: 0
Received 0 Likes on 0 Posts
Car: 1988 Monte SS
Engine: ZZ4-cammed TPI 355
Transmission: World-Class T5
I was using a 305/5-speed bin because I have a 5-speed in the car. Will using a 350/auto .bin make a difference? Will the DFCO tables and such work allright if I flag the manual trans bit in 350 code?
Old 07-26-2006, 10:07 PM
  #4  
Member

iTrader: (2)
 
zipfast's Avatar
 
Join Date: Jun 2004
Location: PA
Posts: 184
Likes: 0
Received 1 Like on 1 Post
Car: 94 9c1 Caprice
Engine: LT1 (3-fity)
Transmission: 4L60E reBUILT
Axle/Gears: 3:08 POSI (out)
The stalling can be fixed by raising the CHOKE settings ie:
If it starts you have enough CRANK fuel then if it stalls you need more choke fuel, if it blows black smoke then you have to much CHOKE.
Old 07-26-2006, 10:32 PM
  #5  
Supreme Member
TGO - 10 Year Member
iTrader: (1)
 
RednGold86Z's Avatar
 
Join Date: Mar 2000
Location: Corona
Posts: 1,692
Likes: 0
Received 1 Like on 1 Post
Car: 92 Form, 91 Z28, 89 GTA, 86 Z28
Engine: BP383 vortech, BP383, 5.7 TPI, LG4
Transmission: 4L60e, 700R4, 700R4..
Axle/Gears: 3.27, 2.73
In order to pinpoint if it's a "choke" setting (i.e. afterstart setting), or just the MAF tables/injector constants that need to be fixed, reduce your injector constant to get the Idle and part load BLM to 118-128. Then let'r cool down and try another cold start.
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
jklein337
Tech / General Engine
2
09-19-2018 06:23 PM
Wade787b
TPI
2
09-29-2015 01:15 PM
nhra-trans-am
Southern California Area
14
09-17-2015 10:16 PM
mustangman65_79
Tech / General Engine
4
08-08-2015 12:07 PM
drathaar907
TPI
0
08-06-2015 04:20 PM



Quick Reply: ZZ4-Cammed 355 Cold Start Issues...



All times are GMT -5. The time now is 05:39 AM.