The Machine
Not broke? Try harder!
- Joined
- Sep 7, 2005
- Messages
- 124
I had a problem a while back where my 87 GN would backfire when starting it up. It would blow off the cap I had on the throttle body vacuum block for a future vacum brakes upgrade. I found a piece of easter egg basket grass hanging on my crank position sensor, and that was that.
The other nite after installing a ported exhaust elbow so I could do the whole two piece 3" downpipe & temp catalytic conv for emissions, I lengthened the wastegate actuator arm 1.5 turns since I need to replace my fuel pump & add the hotwire kit, & I took'er out for a spin to see if there were any positive results. I kicked it once, it knocked some & felt lacking in power. Then when I let off I heard some weird noises, only to find it had blown the cap of the vacuum block again. Never seen it do that unless it was backfiring upon startup. Got another cap & replaced it, but then while driving I could hear a kind of cross firing or missing coming from the tailpipes under normal acceleration, & I can feel it surging a little. Also, it's idling like crap. Passed emissions tho?
So far I've changed the plugs & tried another coil. The coil seemed to help, but it's still lacking power & idling badly. I checked the ground at the back top of the block, looked great & tight. Reset the ECM, checked for a cracked FPR hose. Today I checked the compression while a storm rolled thru. It was me against the almighty smiter
Pass side psi front to back:
140, 130, 125
Driver's side psi front to back:
145, 130, 150
Doesn't seem to be a head gasket, but it's my first compression test ever. Also, maybe it's my imagination, but I'd swear the factory boost gauge looks different under boost. Instead of stepping up light by light, each one very pronounced, they seem to flicker as the go up, almost like the boost is not as definite as it was before.
Hear's what my scanmaster is say'n:
AF @ idle = 3 & @ 3Krpm = 13 (seems low to me?)
L8 @ idle = 28
Bat @ idle = 13.8
Int @ idle = 128 & @ 3Krpm = same
BL @ idle = 128 steady with no change @ 3Krpm
MPH @ idle = 0 (duh)
CLT @ idle = 162 (the rain cooled everything down, except me)
ATS @ idle = 88 steady with no change @ 3Krpm
RPM @ idle = 850
TPS @ idle = 42 (steady with no dead spots up to 440)
IAC @ idle = 20 & @ 3Krpm = 30
cc @ idle = 01, 25, 45, 71, 91 etc
MAL = none
Does AF reading indicate a problem with the 85mm MAF sensor or the Tranaslator Plus? Maybe I should watch it under boost, cause I thought that went up to like 300 or something. Any ideas? I've read every related post I could find, & tried all the tricks I've found. This thing is starting to kill me here, & I'm low on funds to boot.
Thanx guys!
PS: I can provide a list of mods if needed.
The other nite after installing a ported exhaust elbow so I could do the whole two piece 3" downpipe & temp catalytic conv for emissions, I lengthened the wastegate actuator arm 1.5 turns since I need to replace my fuel pump & add the hotwire kit, & I took'er out for a spin to see if there were any positive results. I kicked it once, it knocked some & felt lacking in power. Then when I let off I heard some weird noises, only to find it had blown the cap of the vacuum block again. Never seen it do that unless it was backfiring upon startup. Got another cap & replaced it, but then while driving I could hear a kind of cross firing or missing coming from the tailpipes under normal acceleration, & I can feel it surging a little. Also, it's idling like crap. Passed emissions tho?
So far I've changed the plugs & tried another coil. The coil seemed to help, but it's still lacking power & idling badly. I checked the ground at the back top of the block, looked great & tight. Reset the ECM, checked for a cracked FPR hose. Today I checked the compression while a storm rolled thru. It was me against the almighty smiter
Pass side psi front to back:
140, 130, 125
Driver's side psi front to back:
145, 130, 150
Doesn't seem to be a head gasket, but it's my first compression test ever. Also, maybe it's my imagination, but I'd swear the factory boost gauge looks different under boost. Instead of stepping up light by light, each one very pronounced, they seem to flicker as the go up, almost like the boost is not as definite as it was before.
Hear's what my scanmaster is say'n:
AF @ idle = 3 & @ 3Krpm = 13 (seems low to me?)
L8 @ idle = 28
Bat @ idle = 13.8
Int @ idle = 128 & @ 3Krpm = same
BL @ idle = 128 steady with no change @ 3Krpm
MPH @ idle = 0 (duh)
CLT @ idle = 162 (the rain cooled everything down, except me)
ATS @ idle = 88 steady with no change @ 3Krpm
RPM @ idle = 850
TPS @ idle = 42 (steady with no dead spots up to 440)
IAC @ idle = 20 & @ 3Krpm = 30
cc @ idle = 01, 25, 45, 71, 91 etc
MAL = none
Does AF reading indicate a problem with the 85mm MAF sensor or the Tranaslator Plus? Maybe I should watch it under boost, cause I thought that went up to like 300 or something. Any ideas? I've read every related post I could find, & tried all the tricks I've found. This thing is starting to kill me here, & I'm low on funds to boot.
Thanx guys!
PS: I can provide a list of mods if needed.
