Author Topic: Need help 1987 V10  (Read 622 times)

Offline farmboy2188

  • Newbie
  • Posts: 3
  • Newbie
Need help 1987 V10
« on: December 06, 2022, 07:03:37 PM »
Hey this is my first post, I have a 1987 Gmc v10 with the 350 tbi (2.02 heads mild hydraulic  comp cam, dual plane intake) i was driving and when i stopped at a red light and applied throttle it started to knock bad almost like itís detonating so i went home and did the usual when that happens change fuel filters flush the tank new fuel in with conditioner, make sure all the spark plugs have good spark change the coil and reset the timing to 0* the factory spec, i did all this and itís still doing it so i made sure all the valves and rockers were in spec and it doesnít have lifter tick so thatís fine but it starts great, and drives fine until itís above 1800 rpm under load or you stomp on it so iím lost what it could be any one have any ideas much appreciated?


Sent from my iPhone using Tapatalk

Offline JohnnyPopper

  • Senior Member
  • ****
  • Posts: 2363
  • Old Goof
Re: Need help 1987 V10
« Reply #1 on: December 06, 2022, 07:50:40 PM »
How old are the cap, rotor, and, wires?
1957 Apache 3100 235 Inline 6, 3 on the tree
1973 C-20, 3+3 454 4BBL TH400  Water Injection
1978 K-10, 350 4BBL TH350 NP203 M.M. Part time Kit/Hubs
1980 C-10 under construction

Offline farmboy2188

  • Newbie
  • Posts: 3
  • Newbie
Re: Need help 1987 V10
« Reply #2 on: December 09, 2022, 02:53:32 PM »
The cap rotor and wires have 10,000 km on them tops i replace all that when the motor was done


Sent from my iPhone using Tapatalk

Offline JohnnyPopper

  • Senior Member
  • ****
  • Posts: 2363
  • Old Goof
Re: Need help 1987 V10
« Reply #3 on: December 09, 2022, 07:40:14 PM »
Thanks,

You said you checked the plugs- replace them? or examine them?

Did you look under the inside of the cap at the rotor?

The problem sounds electrical to me. Things are calm up to 1800 rpm, or trouncing it. So it loses stability under those conditions.
1957 Apache 3100 235 Inline 6, 3 on the tree
1973 C-20, 3+3 454 4BBL TH400  Water Injection
1978 K-10, 350 4BBL TH350 NP203 M.M. Part time Kit/Hubs
1980 C-10 under construction

Offline farmboy2188

  • Newbie
  • Posts: 3
  • Newbie
Re: Need help 1987 V10
« Reply #4 on: December 14, 2022, 10:46:43 PM »
Yeah the rotor and cap are fine no moisture and anything i think then and the points are clean the plugs are all great no build up or hot spots


Sent from my iPhone using Tapatalk

Online bd

  • Global Moderator
  • Senior Member
  • *****
  • Posts: 6368
Re: Need help 1987 V10
« Reply #5 on: December 15, 2022, 11:10:56 AM »
OEM TBI?  Any trouble codes stored?  Have you verified the fuel pressure?  What color is the spark?
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline Mike81K10

  • Site Supporters
  • Junior Member
  • ******
  • Posts: 777
Re: Need help 1987 V10
« Reply #6 on: December 15, 2022, 12:58:28 PM »
Keep in mind that you could have got some bad fuel or a problem with your fuel system could exist.
"Tell me and I forget. Teach me and I remember. Involve me and I learn." -Benjamin Franklin

Offline JohnnyPopper

  • Senior Member
  • ****
  • Posts: 2363
  • Old Goof
Re: Need help 1987 V10
« Reply #7 on: December 15, 2022, 08:29:18 PM »
"Yeah the points are clean"


Sent from my iPhone using Tapatalk

That's the problem right there!  ;D ;D ;D

Did you see any tracers on the cap or on top of the rotor?

I think 10 K miles is a good time to do a tune up myself, but hey... ::)
1957 Apache 3100 235 Inline 6, 3 on the tree
1973 C-20, 3+3 454 4BBL TH400  Water Injection
1978 K-10, 350 4BBL TH350 NP203 M.M. Part time Kit/Hubs
1980 C-10 under construction