86 c4 l98 inconsistent revving
Thread Starter
4th Gear
Joined: Feb 2023
Posts: 4
Likes: 0
86 c4 l98 inconsistent revving
I've got an 86 with the l98. It has been off the road since at least 08 and I've been trying to get it running. It cranks up fine and idles decent but doesn't rev well at all. If I slowly give it gas it will rev as much as i want to but if I do it at any more speed it won't rev.
I Checked compression and they are all around 120 psi.
I've tried removing air filter and didn't do anything.
I've took the plenum and pipes off plenty of times.
I'm stumped at this point
I've checked timing, fuel pressure, changed injectors, changed coil, changed the module under the distributor cap, changed maf sensor, tps, iac valve, intake air sensor, vacuum lines, changed fuel pump, fuel filter, blew lines out to tank, changed maf burn off and power relays, o2 sensor, and I can't get it running right at all.
Edit: I just remembered that I had to use silicone to seal the distributor cap as well because the original parts were dry rotted but it was running about the same before and after that
I Checked compression and they are all around 120 psi.
I've tried removing air filter and didn't do anything.
I've took the plenum and pipes off plenty of times.
I'm stumped at this point
I've checked timing, fuel pressure, changed injectors, changed coil, changed the module under the distributor cap, changed maf sensor, tps, iac valve, intake air sensor, vacuum lines, changed fuel pump, fuel filter, blew lines out to tank, changed maf burn off and power relays, o2 sensor, and I can't get it running right at all.
Edit: I just remembered that I had to use silicone to seal the distributor cap as well because the original parts were dry rotted but it was running about the same before and after that
Last edited by C486@16; Feb 17, 2023 at 08:22 AM.
Melting Slicks
Joined: May 2014
Posts: 2,895
Likes: 592
From: New Port Richey FL
Find a scan tool and check o2 sensor if its not reading right it will make the car surge a bit and it falls under the world of they should be changed every few years or at least looked at
Last edited by s carter; Feb 16, 2023 at 06:33 PM.
Pro
Joined: Mar 2006
Posts: 521
Likes: 143
From: Caribbean/Florida
I guess your car must be in limp mode, or a clogged catalytic converter, but if its not electrical it must be a fuel issue. Maybe fuel pump filter sock could be collapsing or lastly the fuel regulator may be malfunctioning. Good luck, let us know what it turns out to be, thanks, Cheers, Jarrod
Pro
Joined: Feb 2009
Posts: 655
Likes: 164
From: Vancouver Washington
I have had that issue in the past.
I advanced the timing from 6 to 12 BTDC and that fixed my issue. I suspect my timing mark has slipped on the balancer.
Give it a go
When you set your timing was the ESC wire disconnected?
I advanced the timing from 6 to 12 BTDC and that fixed my issue. I suspect my timing mark has slipped on the balancer.
Give it a go
When you set your timing was the ESC wire disconnected?
Thread Starter
4th Gear
Joined: Feb 2023
Posts: 4
Likes: 0
My esc wire was disconnected and I'll give it a go. Thank you
