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04-13-2015, 08:59 PM
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#1 |
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Registered User
Join Date: Aug 2011
Location: Leavenworth, KS
Posts: 51
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TBI issues
Need a little guidance. Not sure where to start trouble shooting. Even though it's an 87 I figured the TBI crowd is larger here. 1987 chevy half ton 305 TBI. Running smooth as butter than all of a sudden developed a horrible stutter under load. Sometimes it's half throttle, other times it's immediately off idle. Went ahead and tuned her up with plugs, wires, cap, rotor, fuel filter and just now a ignition control module. Old one failed after 3 or 4 passes with a low rpm fail? No noticable changes in condition. It's also failing to start often. Might be able to figure it out over the weekend. Also parts store didn't see any codes. Thanks ahead of time.
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04-14-2015, 07:33 AM
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#2 |
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Registered User
Join Date: Apr 2010
Location: Guntersville Alabama
Posts: 1,073
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Re: TBI issues
Need to check your fuel pressure . Pump may be going out and varying the pressure at times.
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04-14-2015, 09:02 AM
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#3 |
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Registered User
Join Date: Mar 2012
Location: Huntsville, AL
Posts: 1,000
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Re: TBI issues
Sounds like the in tank fuel pump is running out of steam. They arent the best pump in the world. I would check fuel pressure at the throttle body and make sure it stays steady under load. If not, the fuel pump needs to be replaced.
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04-14-2015, 10:29 AM
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#4 |
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Registered User
Join Date: Oct 2014
Location: Spearfish South Dakota
Posts: 407
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Re: TBI issues
I had an 88 GMC made in mid 87 the first thing that went wrong had rough idle and start was the Air idle control.
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83 c10 long Box Daily Driver 90 Jimmy parked 98 Road King/ 06 Road Glide In memorium 63 impala SS/ 65 Chevy Panel 65 GMC Short Box/ 68 Camero |
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04-14-2015, 01:08 PM
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#5 |
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Registered User
Join Date: Aug 2011
Location: Leavenworth, KS
Posts: 51
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Re: TBI issues
I have read that that could be an issue. If I unplug it, the choke light comes on and the idle increases. I guess I need to tap into the fuel line to check pressure. The pump was supposedly replaced right before I got the truck. New pumps go bad too. Would a scanner be able to test all the sensors through the port on the dash or need to be tested individually?
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04-14-2015, 10:24 PM
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#6 |
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Registered User
Join Date: Aug 2011
Location: Leavenworth, KS
Posts: 51
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Re: TBI issues
You said Air Idle Control. I thought you said coolant temperature sensor. If I unplug the cat or map the condition exists. Guess the only way to check pressure is with a kit? Also, is there even a check engine light? I have a 4 wheel drive and choke indicator below the speedometer and a e brake and seat belt below the fuel gauge.
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04-15-2015, 03:18 PM
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#7 |
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Registered User
Join Date: Nov 2013
Location: sumter sc
Posts: 79
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Re: TBI issues
Change the Coolant temp sensor, I just researched the very problem and everywhere I look it sez to change the... yes believe it or not the coolant temp sensor which is located right beside your t-stat housing
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04-15-2015, 07:06 PM
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#8 |
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Registered User
Join Date: Aug 2011
Location: Leavenworth, KS
Posts: 51
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Re: TBI issues
I always heard that if you unplug a sensor and the condition is the same, then that sensor is good. Hell it's only 13 bucks, why not. I'm waiting on my adapter to come in to check fuel pressure. Hurry up and wait!
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04-25-2015, 08:46 PM
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#9 |
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Registered User
Join Date: Aug 2011
Location: Leavenworth, KS
Posts: 51
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Re: TBI issues
Ended up being a weak coil. $26 later, runs like a top. Thanks guys.
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