New Guy and 1990 GT build up
#62
Now it has a manual computer and I know there is a wiring issue on pin 30 between the two with the neutral safety switch but I'm not sure how that would cause an idle issue.
Still stumped as the idle problem is almost the same as it was before I rebuilt the engine so it must be a wiring harness issue or a TB issue or maybe my vac tree is cracked but something has carried over, even though most of the sensors are new with the fresh engine build.
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#63
From the time and money your sticking into this, I feel your pain lol. I'm just going to offer moral support as this ones way out of my league of knowledge.
But which AFR reading do you trust? A calibrated wideband is hard to argue with, and a mixture that lean on a cold start up says the ECM isn't getting a accurate temp from ECT sending unit. I'm just guessing here.
Also, just noticed your in Florida, there's a big difference in cold start temps that I'm used to lol. My wideband holds 13.0-13.5 at cold start up for the first couple minutes, then switches to open loop when operating temps reach normal. Then sweeps between 15.0-16.0 at idle.
But which AFR reading do you trust? A calibrated wideband is hard to argue with, and a mixture that lean on a cold start up says the ECM isn't getting a accurate temp from ECT sending unit. I'm just guessing here.
Also, just noticed your in Florida, there's a big difference in cold start temps that I'm used to lol. My wideband holds 13.0-13.5 at cold start up for the first couple minutes, then switches to open loop when operating temps reach normal. Then sweeps between 15.0-16.0 at idle.
Last edited by 88 orangepeel notch; 10-17-2014 at 08:56 AM.
#64
Forms the time and money your sticking into this, I feel your pain lol. I'm just going to offer moral support as this ones way out of my league of knowledge.
But which AFR reading do you trust? A calibrated wideband is hard to argue with, and a mixture that lean on a cold start up says the ECM isn't getting a accurate temp from ECT sending unit. I'm just guessing here.
Also, just noticed your in Florida, there's a big difference in cold start temps that I'm used to lol. My wideband holds 13.0-13.5 at cold start up for the first couple minutes, then switches to open loop when operating temps reach normal. Then sweeps between 15.0-16.0 at idle.
But which AFR reading do you trust? A calibrated wideband is hard to argue with, and a mixture that lean on a cold start up says the ECM isn't getting a accurate temp from ECT sending unit. I'm just guessing here.
Also, just noticed your in Florida, there's a big difference in cold start temps that I'm used to lol. My wideband holds 13.0-13.5 at cold start up for the first couple minutes, then switches to open loop when operating temps reach normal. Then sweeps between 15.0-16.0 at idle.
Also my Bin Editor dash board and datalog won't register the ECT data and just says 20.. the whoe time. Also the ACT stays at 100, like both of those aren't registering. So I need to trace them and check to make sure they aren't faulty.
Thanks for the data example of your car. I will do the recalibration of my wideband to make sure its reading correctly then proceed to the ECT/ACT issue.
Edit: Sorry, Thought I posted this already. When I did the leakdown and changed plugs Champion RC12YC the old plugs were soaked in gas and very sooty/black. Makes sense with rich smoky exhaust.
Last edited by JBeachstang11; 10-16-2014 at 12:06 PM.
#65
OK, I just reread this entire thread and have to say your much more patient than I am lol.
But just a couple ideas that cured some similar problems on my car. Redo all grounds if you haven't already. The 3 that I did were neg. cable to block. This was the bad one on my car. PO painted the block and never took the paint off when reattaching the ground cable. Then the one from motor to firewall, and the computer to body ground. Since this is a fresh motor, I'd assume the block connections are good, but you never know.
Also, what is your wideband showing for AFR during normal driving, then what's it at idle on a warm motor when its surging.
And one more thing, it may be time to think about smoke checking vacuum leaks. There's a sticky over at Corral on building your own, and they say it works great.
Now I'm no more knowledgeable than you at this, I'm just trying to think logically as to what is causing the surge. Seems once it goes open loop, it starts with the problems. Cold start ups are fine?
But just a couple ideas that cured some similar problems on my car. Redo all grounds if you haven't already. The 3 that I did were neg. cable to block. This was the bad one on my car. PO painted the block and never took the paint off when reattaching the ground cable. Then the one from motor to firewall, and the computer to body ground. Since this is a fresh motor, I'd assume the block connections are good, but you never know.
Also, what is your wideband showing for AFR during normal driving, then what's it at idle on a warm motor when its surging.
And one more thing, it may be time to think about smoke checking vacuum leaks. There's a sticky over at Corral on building your own, and they say it works great.
Now I'm no more knowledgeable than you at this, I'm just trying to think logically as to what is causing the surge. Seems once it goes open loop, it starts with the problems. Cold start ups are fine?
#66
OK, I just reread this entire thread and have to say your much more patient than I am lol.
But just a couple ideas that cured some similar problems on my car. Redo all grounds if you haven't already. The 3 that I did were neg. cable to block. This was the bad one on my car. PO painted the block and never took the paint off when reattaching the ground cable. Then the one from motor to firewall, and the computer to body ground. Since this is a fresh motor, I'd assume the block connections are good, but you never know.
Also, what is your wideband showing for AFR during normal driving, then what's it at idle on a warm motor when its surging.
And one more thing, it may be time to think about smoke checking vacuum leaks. There's a sticky over at Corral on building your own, and they say it works great.
Now I'm no more knowledgeable than you at this, I'm just trying to think logically as to what is causing the surge. Seems once it goes open loop, it starts with the problems. Cold start ups are fine?
But just a couple ideas that cured some similar problems on my car. Redo all grounds if you haven't already. The 3 that I did were neg. cable to block. This was the bad one on my car. PO painted the block and never took the paint off when reattaching the ground cable. Then the one from motor to firewall, and the computer to body ground. Since this is a fresh motor, I'd assume the block connections are good, but you never know.
Also, what is your wideband showing for AFR during normal driving, then what's it at idle on a warm motor when its surging.
And one more thing, it may be time to think about smoke checking vacuum leaks. There's a sticky over at Corral on building your own, and they say it works great.
Now I'm no more knowledgeable than you at this, I'm just trying to think logically as to what is causing the surge. Seems once it goes open loop, it starts with the problems. Cold start ups are fine?
I did check those grounds before but I will definitely do that again as I could have missed it or messed one up since.
Haven't driven with the WB yet but I will try to get a quick trip in soon and report back, thanks for that idea.
Smoke check is a great idea and I'll do that. Never now even though they look good and didn't change with carb spray. Check anyhow.
That is absolutely it. The smoking begins once closed loop takes over.
Thanks so much Orange. I'll check all these and get back.
#67
Preliminary findings after checking those things. Car starts and runs 100% better. Still had a hint of smoke but it is cut down massively. Took a short drive around today, couldn't even do that before.
Did replace all vac lines though, changed oil again, still had a tinge of gas smell, new plugs also, the old ones were covered in gas/soot. Numbered them and saved them.
Did test fuel press and found it was low, 35ish regular, then barely 38/39 with vac off.
Also seemed to bleed off a little bit immediately after priming. Punp is still 190lph left from other owner, may be on way out.
AFR was all around 13-15 when I was in the throttle. No real WOT since motor till has less than 500mi on it.
I still want to check the hegos wiring and make sure the voltages are correct. Hegos were reading well on the datalog, but comp died and didn't save. I'll run another.
did pull codes
KOEO
15 rom fail
31 Can or EGR
81 Therm
82 Therm
85 Can purge or Trans shift circuit or Excessive fuel press/flow
84 EGR
96 Fuel pump circuit
KOER
94 Secondary air circuit
44 Air management inop
31 Canister/EGR
13 Normal idle not in range (it was high so I dropped it and checked tps, pulled batt)
39 AUTO overdrive circuit
43 Engine too warm (was barely in the middle)
1
14 Ignition profile pickup erratic
Did replace all vac lines though, changed oil again, still had a tinge of gas smell, new plugs also, the old ones were covered in gas/soot. Numbered them and saved them.
Did test fuel press and found it was low, 35ish regular, then barely 38/39 with vac off.
Also seemed to bleed off a little bit immediately after priming. Punp is still 190lph left from other owner, may be on way out.
AFR was all around 13-15 when I was in the throttle. No real WOT since motor till has less than 500mi on it.
I still want to check the hegos wiring and make sure the voltages are correct. Hegos were reading well on the datalog, but comp died and didn't save. I'll run another.
did pull codes
KOEO
15 rom fail
31 Can or EGR
81 Therm
82 Therm
85 Can purge or Trans shift circuit or Excessive fuel press/flow
84 EGR
96 Fuel pump circuit
KOER
94 Secondary air circuit
44 Air management inop
31 Canister/EGR
13 Normal idle not in range (it was high so I dropped it and checked tps, pulled batt)
39 AUTO overdrive circuit
43 Engine too warm (was barely in the middle)
1
14 Ignition profile pickup erratic
Last edited by JBeachstang11; 11-02-2014 at 10:12 PM.
#68
I have this same issue going on minus the smoke once my idle settles down to under 1000 after a min or so of warm up time, my fast wideband pegs the lean at 21-22, I have smoke tested for a vac leak and trust me none exist, replaced lower intake gaskets due to gasket shift into the port, no change in afr and have checked fuel pressure......only time it pegs 21 is idle...would make sense that it's a vac leak but it's not, I might swap my mass air with another to see if that cures the issue and I still need to back probe HEGO at ecm to check if it really is lean based off hego sensors......oNE THING YOU HAVE UP ON ME IS MINE RUNS A CHIP whereas your's runs a portable tuner so you can see more going on than I can, I've even pulled the chip and no change and I have no boost leaks.
#69
I have this same issue going on minus the smoke once my idle settles down to under 1000 after a min or so of warm up time, my fast wideband pegs the lean at 21-22, I have smoke tested for a vac leak and trust me none exist, replaced lower intake gaskets due to gasket shift into the port, no change in afr and have checked fuel pressure......only time it pegs 21 is idle...would make sense that it's a vac leak but it's not, I might swap my mass air with another to see if that cures the issue and I still need to back probe HEGO at ecm to check if it really is lean based off hego sensors......oNE THING YOU HAVE UP ON ME IS MINE RUNS A CHIP whereas your's runs a portable tuner so you can see more going on than I can, I've even pulled the chip and no change and I have no boost leaks.
Seems exactly what mine is doing, 20-22 lean at idle then 13-15 on the throttle. My XE274HR has some duration so I'll attribute it to that.
#70
Interesting man. As I understand it big cams will cause Widebands to read lean at idle from all the fresh air during overlaps. I know you mentioned your compression previously but not cam setup.
Seems exactly what mine is doing, 20-22 lean at idle then 13-15 on the throttle. My XE274HR has some duration so I'll attribute it to that.
Seems exactly what mine is doing, 20-22 lean at idle then 13-15 on the throttle. My XE274HR has some duration so I'll attribute it to that.