Register or Log In To remove these advertisements. |
|
|
|
Thread Tools | Display Modes |
01-26-2011, 05:03 AM | #1 |
Registered User
Join Date: Jan 2011
Location: Destin Florida
Posts: 32
|
87 Runs poorly when cold
My 87 has a rebuilt older "orange motor" 305 in it w/ the complete 87 tbi setup on it installed from the po.It also has the 700r4 & 2:73 gears. The motor has less than 1,000 mi. on it. It has a new complete tune up, egr valve, coolant sensor, rebuilt tbi, new vac. lines, new fuel pumps & filter. I also verified the timing.When cold it fires right up, but then starts idling down roughly & stalls if I dont keep feathering the throttle @ 1,800 RPM'S or so. It also runs rough while driving /stopping untill it warms up. When it does die it always fires right back up. Once warm it smoothes out somewhat & has good power/pick up w/ no stalling, but its not what I'd call perfect.The outside temp. seems to have no factor on this issue. The fuel injectors werent replaced on the tbi rebuild & they have 255,000 mi. on them. Could that be whats causing this or could it be one of the emission sensors? I am @ a loss here & dont want to start expensive parts swapping on a whim. Thanks in advance.
__________________
"Full throttle Silverado" |
01-26-2011, 09:52 AM | #2 |
Slots go on anything!
Join Date: May 2003
Location: Richardson, TX
Posts: 5,957
|
Re: 87 Runs poorly when cold
You might try the 88-98 board. There are some sharp TBI guys over there, that generally don't come over here much.
__________________
1974 Jimmy- 5.3/4L80e/NP241 |
01-26-2011, 11:03 AM | #3 |
Registered User
Join Date: Jan 2008
Location: Old Saybrook, CT
Posts: 61
|
Re: 87 Runs poorly when cold
probably a bad temperature sensor. Its telling the computer that it is warm all the time and therefore it is too lean when it is cold. If the sensor was working properly the computer would know that the engine is cold and would richen up the mixture. Instead, its your right foot keeping it running until it warms up and then the "lean" mixture is the right mixture to keep it happy.
__________________
1989 V3500 nv4500/np205 255-85-16 BFG Mud Terrains, 4inch skyjacker kit, 2 inch body lift. "Yea, it was a fuel supply problem. A rod came through the block and cut the fuel line." |
01-26-2011, 01:25 PM | #4 | |
Registered User
Join Date: Oct 2003
Location: OC CA
Posts: 1,374
|
Re: 87 Runs poorly when cold
Quote:
Check Fuel pressure (and fuel filter) - It is common for fuel pumps to get tired after 24 years in service (255k miles). //RF
__________________
"The Beast" 1975 Chevrolet C20 longbed 350/700R4! with 3inch body lift Dual Flowmasters Super 40's! TBI retrofit completed (2007-07-29) New 383CID (+030) 08-304-8 9.5:1CR x36,005 (2012-12-17) |
|
01-26-2011, 01:35 PM | #5 |
Registered User
Join Date: May 2007
Location: East Haven, CT
Posts: 882
|
Re: 87 Runs poorly when cold
I've had the same issue with my 87 305 tbi and still do to this day. Worse when it's really cold out. I replaced the CTS with no luck. I believe it actually started doing this after I installed the TBI spacer. Not positive but I don't remember the issue before that install.
Once it gets up to temp, idles and runs great. Sounds like I have a lumpy cam on the first initial few minutes. Fuel pressure is also at 13.5 psi
__________________
87 Chevy 2wd SWB: 305/700r4 Dual Exhaust, K&N Filter, Injector Pod Spacer, TBI Spacer, Belltech Front Sway Bar, Corvette Servo, Western Chassis 4/6 and c-notch Last edited by chevymotocross; 01-26-2011 at 01:35 PM. |
Bookmarks |
|
|