08-28-2013, 04:29 PM | #1 |
Registered User
Join Date: Mar 2013
Location: Lufkin, Tx
Posts: 13
|
1990 454 tbi Help
Somewhat new to the website, I have 1990 Chevy v3500 454 Tbi. My problem begin a couple months ago. Been thru a bunch of old threads but cant figure this one out. Here's how it went down....
1. Truck started hesitating and missing under throttle. Idles fine. 2. replaced Egr valve 3. ran fine for a few weeks, then it started doing the same thing. 4. replaced Map sensor 5. ran good for about a month then....see #1 & #3 6. Today I did the old paperclip trick on the OBD connection. It read code 12. Drove it down to O'Reilly's today with it running like crap. They plugged into and it showed no codes either 7. Now I am starting to pull out what little hair I have left. It has dual tanks, it runs the same on either tank, so I would think that would rule out fuel pump issues. I just don't understand why I would replace something then run good for a few weeks then back to the same ole same ole. Your help is much appreciated! |
08-28-2013, 05:03 PM | #2 |
Registered User
Join Date: Jul 2012
Location: Des Moines IA
Posts: 1,250
|
Re: 1990 454 tbi Help
One thing I would check is the TPS voltage. Make sure it's nice and steady through the full gas pedal travel.
I would move to a wide band tester next to monitor a/f ratio to see if fuel is falling off or jumping up at the time of the stumble.
__________________
- 1981 Sierra 454, NV4500 swap - 2006 Z06, 25k miles - 1973 Nova - Project CarNova Virus on Youtube |
08-28-2013, 05:13 PM | #3 |
Registered User
Join Date: Mar 2013
Location: Lufkin, Tx
Posts: 13
|
Re: 1990 454 tbi Help
Thanks, I will check it out and get back with ya'll
|
08-28-2013, 05:25 PM | #4 |
Registered User
Join Date: Jan 2013
Location: east troy, WI
Posts: 341
|
Re: 1990 454 tbi Help
|
08-28-2013, 05:56 PM | #5 |
Registered User
Join Date: Nov 2011
Location: sarnia ontario canada
Posts: 211
|
Re: 1990 454 tbi Help
How old is the fuel filter. I had an old truck and the fuel filter plugged. I ran through the same things as you to find out the filter was crap. Changed it and everything worked fine after that.
|
08-28-2013, 06:33 PM | #6 | |
Registered User
Join Date: Oct 2003
Location: OC CA
Posts: 1,374
|
Re: 1990 454 tbi Help
Quote:
Fuel pumps usually are not a problem (but they do wear-out fast), but the fuel hose that connects outlet port to a fuel feed through turns soft and leaks after 23 years of service. Today's gas formulations contain ethanol (E10) which is unfriendly to older rubber compounds. If you end up replacing FPump and hoses make sure to replace the hose with SAE30R10 rated hose - Gates or Good Year make fuel submersible fuel hose. //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) |
|
08-28-2013, 07:23 PM | #7 |
Registered User
Join Date: Mar 2013
Location: Lufkin, Tx
Posts: 13
|
Re: 1990 454 tbi Help
Thanks so much for your help guys, all this is new to me. Been working on and racing dirt bikes most of my life (old age shut that down) and just plain don't know anything about these things. I have figure out how to check the TPS voltage and checking the fuel pressure. Just bought a Chiltons online repair manual to help me locate these things. Going to the auto parts store again here in a bit to get a filter and a fuel pressure guage.
|
08-29-2013, 01:15 AM | #8 |
Registered User
Join Date: Apr 2001
Location: DALLAS,TX
Posts: 22,066
|
Re: 1990 454 tbi Help
Fuel filter.
Fuel pump psi validation. O2 sensor functioning correctly? Temp sensors functioning correctly? Posted via Mobile Device
__________________
67SWB-B.B.RetroRod 64SWB-Recycle 89CCDually-Driver/Tow Truck 99CCSWB Driver All Fleetsides @rattlecankustoms in IG Building a small, high rpm engine with the perfect bore, stroke and rod ratio is very impressive. It's like a highly skilled Morrocan sword fighter with a Damascus Steel Scimitar..... Cubic inches is like Indiana Jones with a cheap pistol. |
08-29-2013, 06:28 AM | #9 |
Registered User
Join Date: Jun 2008
Location: Lubbock, TX
Posts: 2,047
|
Re: 1990 454 tbi Help
Not to dis this site at all, but the best site for your truck is the 454SS website - they've been working with your identical system for years, should have all the answers.
|
Bookmarks |
|
|