1987 Silverado 350 TBI Auto., hard start, won't idle

87Silverado · 03-08-2006, 10:51 AM

Hello, I am new to this forum and I am looking for some assistance. I have a 1987 Chevy Silverado with 70k miles. It has a 5.7 (350) with TBI and an automatic transmission. It will start however, it won't idle. I was driving home from work on the highway and it began to miss and sputter, losing power. I exited the highway and the truck would die and not idle. I had the vehicle towed to my home. I have replaced the following to attempt to resolve problem.

New distributor and rotor cap
New plugs (AC) and plug wires
New fuel filter
Checked PCV valve (functioning properly)
Checked EGR valve (functioning properly)

The truck had been sitting for several months before I started to replace the parts listed above. I had put fuel stabilizer in the tank at that time. I have checked the new plugs after starting and forcing the vehicle to idle by stepping on gas pedal and they appear to be carbon fouled indicating a rich fuel mixture. The check engine light does not come on during rough running.

I have tried to advance/retard timing by turning distributor which has not helped. The only thing that I can remember that was odd was that for several months before problem listed above was that when vehicle started and idled the engine would "lope" at idle ( there would be a small pulse or lope in engine rpm at idle).

The only other things that I can think of is a possible vacuum leak or bad gas.

Any ideas?

thanks,

87Silverado

scottie · 03-08-2006, 01:34 PM

i would guess either a vacuum leak or a bad fuel pump. my friend had a similar prob with a 5.3 liter vortec (different engine, but similar symptoms) and it turned out to be the fuel pump.

gmtech · 03-08-2006, 04:07 PM

If it is running that rich all of a sudden it is probably the coolant sensor located in front of the throttlebody 2 wires try disconnecting it and see if the idle changes at all it is probably bad and is reading -40 degrees f and giving engine alot of fuel

chevyguy · 03-08-2006, 07:20 PM

I had the temp sensor go out and had the same symptoms you are talking about.

87Silverado · 03-08-2006, 10:39 PM

Thanks for all the ideas and I will certainly follow your input!!

Regards,

87Silverado

87 flatbed · 07-08-2007, 05:56 PM

Help!! Have 87 1-ton 4x4 7.4l TBI and cannot get a whine noise from either tank. Could the fuel selector valve be stuck between left and right? Open to any ideas... Thanks fellas, 87 flatbed

87 flatbed · 07-08-2007, 06:17 PM

Can anyone help? I have 87 1-ton 4x4 dually 7.4l TBI, and I can't get fuel from either tank. No fuel pump whine noise from either side. What to do?

thomas · 07-08-2007, 06:45 PM

i have an 87, but with a 5.0 and i had the same problem not too long ago. i had loose wires and a nasty distributor cap. i would try taking the plugs out and looking at them. they might be worse than you expect...

75K30 · 07-08-2007, 07:20 PM

87 flatbed:
you need to start your own thread. You will not get much action from the guys / girls here. This is an old thread and ofte overlooked because it is dated from March 8th 2006.
Start a fresh thread with a new topic desribing your topic, and more eyes will be able to view it, and you will get much better results.

03-08-2006, 10:51 AM	#1
87Silverado Junior Member Join Date: Mar 2006 Posts: 4	1987 Silverado 350 TBI Auto., hard start, won't idle Hello, I am new to this forum and I am looking for some assistance. I have a 1987 Chevy Silverado with 70k miles. It has a 5.7 (350) with TBI and an automatic transmission. It will start however, it won't idle. I was driving home from work on the highway and it began to miss and sputter, losing power. I exited the highway and the truck would die and not idle. I had the vehicle towed to my home. I have replaced the following to attempt to resolve problem. New distributor and rotor cap New plugs (AC) and plug wires New fuel filter Checked PCV valve (functioning properly) Checked EGR valve (functioning properly) The truck had been sitting for several months before I started to replace the parts listed above. I had put fuel stabilizer in the tank at that time. I have checked the new plugs after starting and forcing the vehicle to idle by stepping on gas pedal and they appear to be carbon fouled indicating a rich fuel mixture. The check engine light does not come on during rough running. I have tried to advance/retard timing by turning distributor which has not helped. The only thing that I can remember that was odd was that for several months before problem listed above was that when vehicle started and idled the engine would "lope" at idle ( there would be a small pulse or lope in engine rpm at idle). The only other things that I can think of is a possible vacuum leak or bad gas. Any ideas? thanks, 87Silverado

03-08-2006, 01:34 PM	#2
scottie Senior Member Join Date: Jan 2006 Location: South Florida (Palm Beach), originally from south of BOSTON Posts: 644	i would guess either a vacuum leak or a bad fuel pump. my friend had a similar prob with a 5.3 liter vortec (different engine, but similar symptoms) and it turned out to be the fuel pump. __________________ im a straight shooter with upper management written all over me

03-08-2006, 07:20 PM	#4
chevyguy Senior Member Join Date: Sep 2005 Location: ALABAMA Posts: 3,160	I had the temp sensor go out and had the same symptoms you are talking about. __________________ When i die, i dont want to walk gracefully thu the pearly gates and turn in a unused body. i want to go sliding thru sideways and turn in a body that has been completely used up.

07-08-2007, 06:17 PM	#7
87 flatbed Junior Member Join Date: Jul 2007 Posts: 3	fuel problems with my flatbed Can anyone help? I have 87 1-ton 4x4 dually 7.4l TBI, and I can't get fuel from either tank. No fuel pump whine noise from either side. What to do?

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03-08-2006, 04:07 PM	#3
gmtech Senior Member Join Date: Dec 2005 Location: farmville Va Posts: 343	If it is running that rich all of a sudden it is probably the coolant sensor located in front of the throttlebody 2 wires try disconnecting it and see if the idle changes at all it is probably bad and is reading -40 degrees f and giving engine alot of fuel

03-08-2006, 10:39 PM	#5
87Silverado Junior Member Join Date: Mar 2006 Posts: 4	Thanks for all the ideas and I will certainly follow your input!! Regards, 87Silverado

07-08-2007, 05:56 PM	#6
87 flatbed Junior Member Join Date: Jul 2007 Posts: 3	Help!! Have 87 1-ton 4x4 7.4l TBI and cannot get a whine noise from either tank. Could the fuel selector valve be stuck between left and right? Open to any ideas... Thanks fellas, 87 flatbed

07-08-2007, 06:45 PM	#8
thomas Junior Member Join Date: Jul 2007 Posts: 6	i have an 87, but with a 5.0 and i had the same problem not too long ago. i had loose wires and a nasty distributor cap. i would try taking the plugs out and looking at them. they might be worse than you expect...

07-08-2007, 07:20 PM	#9
75K30 Senior Member Join Date: Jul 2006 Posts: 2,543	87 flatbed: you need to start your own thread. You will not get much action from the guys / girls here. This is an old thread and ofte overlooked because it is dated from March 8th 2006. Start a fresh thread with a new topic desribing your topic, and more eyes will be able to view it, and you will get much better results.

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