8D-intermittant low blms-causes???
05-04-2005, 11:08 AM
#1
8D-intermittant low blms-causes???
Well, I was about ready to tune WOT with my wide band when suddenly the blms dropped;at idle areas to 108, and everywhere else to 110 to 118 range-and I had it at 128+/-2.....
If anyone remembers I had asked about mat count tables; I'd had to increase it a lot at mat temp of 80 and up; but I then later only increased it slightly to nail it down.
Now I'm realizing that the blms have been changing on me; and it's not just weather temps throwing me off-I'm afraid this tune has been pretty spead out time wise due to more snow (I'm ready for summer!) and work schedule-so I've been slow catching on to this problem.
Last night the blms dropped-tried reflashing a prom, with/without the romulator/ new ecm etc. Then without any further changes the idle surged up a bit-dropped back to 800 and instantly the blms were perfect again at all ves.....????
The kpa/vac has been consistant; so now I racking my brain as to causes before I can con't to tune.
A sticking egr could cause some of these symptoms-but then the kpa/vac should drop, yes??? My only other thought is the afpr-but then if it's leaking/sticking??? it shouldn't just recover???
The next time it does it I'll try to quickly check the fp......
I believe I've R/O software possibilities with all the swaps I did last night....
If anyone has ever seen this problem-or has some ideas on it-PLEASE throw me a bone....this is drivin me nuts!!! Thanks!!!
If anyone remembers I had asked about mat count tables; I'd had to increase it a lot at mat temp of 80 and up; but I then later only increased it slightly to nail it down.
Now I'm realizing that the blms have been changing on me; and it's not just weather temps throwing me off-I'm afraid this tune has been pretty spead out time wise due to more snow (I'm ready for summer!) and work schedule-so I've been slow catching on to this problem.
Last night the blms dropped-tried reflashing a prom, with/without the romulator/ new ecm etc. Then without any further changes the idle surged up a bit-dropped back to 800 and instantly the blms were perfect again at all ves.....????
The kpa/vac has been consistant; so now I racking my brain as to causes before I can con't to tune.
A sticking egr could cause some of these symptoms-but then the kpa/vac should drop, yes??? My only other thought is the afpr-but then if it's leaking/sticking??? it shouldn't just recover???
The next time it does it I'll try to quickly check the fp......
I believe I've R/O software possibilities with all the swaps I did last night....
If anyone has ever seen this problem-or has some ideas on it-PLEASE throw me a bone....this is drivin me nuts!!! Thanks!!!
05-04-2005, 12:47 PM
#2
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Car: 91 GTA, 91 Formula, 89 TTA
Engine: all 225+ RWHP
Transmission: all OD
Axle/Gears: Always the good ones
Possible canister close issue?
Is it active when your experiencing this at any times?
Also, grd grd grd grd grd.
ECM and 02 grds should be on the back of the cylinder head., they like to come loose and wreak havoc when they do.
Also if using any type of ZIF socket or adapter make sure all pins are tight and engaged, this will also cause weurd issues.
Try burning a fresh bin and seeing if it helps any, sometimes they get messed up. Its happened to almost everyone here at least once.
Check the basics twice for you jump in too deep.
later
Jeremy
Is it active when your experiencing this at any times?
Also, grd grd grd grd grd.
ECM and 02 grds should be on the back of the cylinder head., they like to come loose and wreak havoc when they do.
Also if using any type of ZIF socket or adapter make sure all pins are tight and engaged, this will also cause weurd issues.
Try burning a fresh bin and seeing if it helps any, sometimes they get messed up. Its happened to almost everyone here at least once.
Check the basics twice for you jump in too deep.
later
Jeremy
05-04-2005, 04:46 PM
#3
Originally posted by 3.8TransAM
Possible canister close issue?
Is it active when your experiencing this at any times?
Also, grd grd grd grd grd.
ECM and 02 grds should be on the back of the cylinder head., they like to come loose and wreak havoc when they do.
Also if using any type of ZIF socket or adapter make sure all pins are tight and engaged, this will also cause weurd issues.
Try burning a fresh bin and seeing if it helps any, sometimes they get messed up. Its happened to almost everyone here at least once.
Check the basics twice for you jump in too deep.
later
Jeremy
Possible canister close issue?
Is it active when your experiencing this at any times?
Also, grd grd grd grd grd.
ECM and 02 grds should be on the back of the cylinder head., they like to come loose and wreak havoc when they do.
Also if using any type of ZIF socket or adapter make sure all pins are tight and engaged, this will also cause weurd issues.
Try burning a fresh bin and seeing if it helps any, sometimes they get messed up. Its happened to almost everyone here at least once.
Check the basics twice for you jump in too deep.
later
Jeremy
I had reburned....I've added xtra grounds previously......
I'll be damned-the ccp!!!
Thanks for canister hint!!!!
Turns out I had an intermittant vac hose leak to the vac valves that would open and close them; and the elec. valve is stuck open; plus the charcoal can is saturated; after filling the gas tank it actually has fuel dripping out the line from fuel tank to charcoal can....even at idle the blms would hit bottom at times.....no command on ccp....
I had no idea that damned thing could effect F/A that dramatically!!!
Thanks again-I was really starting to go crazy chasin this!
05-04-2005, 08:29 PM
#4
Further F/U and Qs.....
turns out that the ground on to close the ccp valve shows 12v on a volt meter, but it's not enuff ground to turn on a test light or the solenoid.
Checked the continuity of the wire, plenty of ground to the ecm.
Tried 2 different ecms. Everything else works no problems. egr passes test. tcc functions etc etc.
I'm about to plug the line to the charcoal can inside a vac line so it passes visual smog...but it really bugs me that the ecm can't send a good enuff ground to energize the solenoid-jumping a direct ground does energize it.
Just to double check-the ccp output for 730 is F7????
Also another thought; I'm using a bin from 91 vette in a 730 ecm-that wouldn't cause any problems should it???
Thanks for any more info!
turns out that the ground on to close the ccp valve shows 12v on a volt meter, but it's not enuff ground to turn on a test light or the solenoid.
Checked the continuity of the wire, plenty of ground to the ecm.
Tried 2 different ecms. Everything else works no problems. egr passes test. tcc functions etc etc.
I'm about to plug the line to the charcoal can inside a vac line so it passes visual smog...but it really bugs me that the ecm can't send a good enuff ground to energize the solenoid-jumping a direct ground does energize it.
Just to double check-the ccp output for 730 is F7????
Also another thought; I'm using a bin from 91 vette in a 730 ecm-that wouldn't cause any problems should it???
Thanks for any more info!
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