JRSTANGE
10+ Year Contributor
- 200
- 0
- Apr 11, 2010
-
Ballwin,
Missouri
Ok, I have have a 1990 gsx. I've have 550cc's on a 2g maf, afpr, 255walley and other mods.
Issue at hand is I drove the car last sumemr and everything was fine. I went to MOD last summer and when I got back I didnt drive the car for about a month.
The next time I went to start it up the engine started just fine as normal but, confirmed on my coolant gauge and datalogger once I hit 100-106*F the engine suddenly leans out and spits and sputters.
I've tried another ECM and replacing the caps in both ECM's and the same result. I'm not positive it's a ECM issue at this point. I also have a 180*F thermostat in the engine. If I remember right warm up mode finished about 160*F. So for it to lean it out like this at 100-106*F just isnt right. I've confirmed like I said the ECM is seeing the right coolant temp as it's the same on the gauge and datalogger.
I've also had the same result with the 1G maf and 450cc stock injectors. Some one else mentioned checking the grounds for the ECM and sensors were they connect next to the computer with the four black wires. They all appear to be ok as well does the pin out and traces on the board.
I'm totaly stumped on this. I can say once the engine is fully warm it seems barely noticeable at all unless it's just in my head. But, from a light rev it seems it can still be felt. As well it's not running as rich as it should under boost. By top end per the WB even on just 10psi I'm seeing 12.8 a/f's. Under driving everything else appears to be normal. I've checked the exhaust for any leaks prior to the O2 sensor and again all appears to be ok.
Is there something I'm missing or is there something else to check. I do have yet another ecm on the way, finally a eprom for future goals but, I dont for see it being the fix it needs.
Thanks for any help or ideas!
Additional info: I ran a dual core alumin radiator as well the coolant temp sensor was new as of last August.
Reading some other thread it appears to have a bad temp sensor with out popping a CEL and just give bad readings. A new one is like $18 bucks so I could try it. I just hate making a mess and or draining the coolant to do it. Might as well drain the coolant as the return line for the turbo needs to be replaced.
So another thread I was reading was saying it was the ignition. SIGH! This is sounding fun. http://www.dsmtuners.com/forums/bolt-tech/396322-runs-bad-low-rpms.html
Doesnt sound totaly the same but, very very close.
Found this interesting from here: http://www.dsmtuners.com/forums/newbie-forum/246709-car-runs-funny-when-cold-print.html
"There is a timer thats starts when you start the engine and ECT checks before the ECU will start dithering the idle mixture. One change made between 90 and later cars is that temp check with 90 cars waiting until about 106F and the later cars starting at 86F before trying to enter closed loop operation. The ECU doesn't start updating the fuel trims until the car as fully warmed up and the ECT is >= 186F."
I decided to check the wires to the o2 sensor. I cut back the plastic cover and found some of the wires have some cranks on the sheething but, the wires look ok. I decided to turn the car on and check and see if the heated nb o2 sensor becomes warm after a few seconds. Touching the sensor it never felt warm or hot to the touch. I went ahead and started up the engine and should have gotten a datalog to post but again at 100-106 it leans out from mid 11's to mid 14's and the nb looked like on the logger like it started cycling at that time as it should.
Is this all normal or not? Car seemed to idle ok and rev fine from what I could tell. need to go ahead and charge the a/c system and get some oil in it to keep from any future issues until I can have it done right.
once it cools down I'll get a data log to post from cold to warm up showing the issue. Who knows maybe it's normal I have no freaking idea. I'd need to drive it to see if there are driving issues as well with a/f's etc...
I'll just get a start up log for now since it's in the garage and blocked by two other cars.
Not the best log since the car was not completely cool. But, you can see were it hits 106*f and leans out. However this time since the car was warm it went from a mid 12 to a lean out mid 14. I think was do just because the engine was still warm. Please, look it over and see if you see anything abnormal.
http://www.plastikhosting.net/uploads/JRSTANGE/06302011_datalog/2011-06-30_20_20_13.csv
http://www.plastikhosting.net/uploads/JRSTANGE/06302011_datalog/2011-06-30_20_20_13.pdb
ok, well i went ahead and connected the fuel pressure selinoid back up and decided to give it a go and see if it made a difference. I also started the log before i started the engine. Once the key was on I checked the heated o2 sensor and it never felt warm or hot in the same amount of time it took my wideband to heat up. I beleive that to be an issue.
Of course there was no change in connecting the selinoid but, when i get the log online you will have a better log to look at from a true cold start.
Also reading the service manual the narrowband should flip from 0 to .4 at idle and I was seeing close to zero to as high at .89. Then per the manual the voltage should be when speeding up the engine rpm between .5 to 1. But, I'm seeing regardless close to zero to .89 regardless of idle or speeding up the engine. I really wish I had another O2 sensor to try out before buying one.
The other thing is i dont have any CEL's. from reading it doesnt matter if the o2 is bad or if the heater circuit is ad it should pop a CEL.
http://www.plastikhosting.net/uploads/JRSTANGE/07012011Datalogs/2011-06-30_20_20_13.csv
http://www.plastikhosting.net/uploads/JRSTANGE/07012011Datalogs/2011-06-30_20_20_13.pdb
http://www.plastikhosting.net/uploads/JRSTANGE/07012011Datalogs/2011-07-01_18_14_06.csv
http://www.plastikhosting.net/uploads/JRSTANGE/07012011Datalogs/2011-07-01_18_14_06.pdb
ok, well everything seemed to be ok during the drive. The first log should be the warm up and the second one is the drive. However thats just a portion of the log. I'm not sure if the drive log capture my crazy knock! Like 43 counts of knock when getting on it. The knock is the same issue I had when at the dyno. This is still only 10psi. But, I'd expect to see a/f's in the 11's but, I see high 12 to low 13's. I dont know what to make of this. Normal driving though the a/f's look ok. But, when I excelerate I'd expect to see it rchen up a bit but, it stays at a steady 14.7 range.
Right now i'm not sure if I'm more concerned with the knock or the sputter during warm up.
Issue at hand is I drove the car last sumemr and everything was fine. I went to MOD last summer and when I got back I didnt drive the car for about a month.
The next time I went to start it up the engine started just fine as normal but, confirmed on my coolant gauge and datalogger once I hit 100-106*F the engine suddenly leans out and spits and sputters.
I've tried another ECM and replacing the caps in both ECM's and the same result. I'm not positive it's a ECM issue at this point. I also have a 180*F thermostat in the engine. If I remember right warm up mode finished about 160*F. So for it to lean it out like this at 100-106*F just isnt right. I've confirmed like I said the ECM is seeing the right coolant temp as it's the same on the gauge and datalogger.
I've also had the same result with the 1G maf and 450cc stock injectors. Some one else mentioned checking the grounds for the ECM and sensors were they connect next to the computer with the four black wires. They all appear to be ok as well does the pin out and traces on the board.
I'm totaly stumped on this. I can say once the engine is fully warm it seems barely noticeable at all unless it's just in my head. But, from a light rev it seems it can still be felt. As well it's not running as rich as it should under boost. By top end per the WB even on just 10psi I'm seeing 12.8 a/f's. Under driving everything else appears to be normal. I've checked the exhaust for any leaks prior to the O2 sensor and again all appears to be ok.
Is there something I'm missing or is there something else to check. I do have yet another ecm on the way, finally a eprom for future goals but, I dont for see it being the fix it needs.
Thanks for any help or ideas!
Additional info: I ran a dual core alumin radiator as well the coolant temp sensor was new as of last August.
Reading some other thread it appears to have a bad temp sensor with out popping a CEL and just give bad readings. A new one is like $18 bucks so I could try it. I just hate making a mess and or draining the coolant to do it. Might as well drain the coolant as the return line for the turbo needs to be replaced.
So another thread I was reading was saying it was the ignition. SIGH! This is sounding fun. http://www.dsmtuners.com/forums/bolt-tech/396322-runs-bad-low-rpms.html
Doesnt sound totaly the same but, very very close.
Found this interesting from here: http://www.dsmtuners.com/forums/newbie-forum/246709-car-runs-funny-when-cold-print.html
"There is a timer thats starts when you start the engine and ECT checks before the ECU will start dithering the idle mixture. One change made between 90 and later cars is that temp check with 90 cars waiting until about 106F and the later cars starting at 86F before trying to enter closed loop operation. The ECU doesn't start updating the fuel trims until the car as fully warmed up and the ECT is >= 186F."
I decided to check the wires to the o2 sensor. I cut back the plastic cover and found some of the wires have some cranks on the sheething but, the wires look ok. I decided to turn the car on and check and see if the heated nb o2 sensor becomes warm after a few seconds. Touching the sensor it never felt warm or hot to the touch. I went ahead and started up the engine and should have gotten a datalog to post but again at 100-106 it leans out from mid 11's to mid 14's and the nb looked like on the logger like it started cycling at that time as it should.
Is this all normal or not? Car seemed to idle ok and rev fine from what I could tell. need to go ahead and charge the a/c system and get some oil in it to keep from any future issues until I can have it done right.
once it cools down I'll get a data log to post from cold to warm up showing the issue. Who knows maybe it's normal I have no freaking idea. I'd need to drive it to see if there are driving issues as well with a/f's etc...
I'll just get a start up log for now since it's in the garage and blocked by two other cars.
Not the best log since the car was not completely cool. But, you can see were it hits 106*f and leans out. However this time since the car was warm it went from a mid 12 to a lean out mid 14. I think was do just because the engine was still warm. Please, look it over and see if you see anything abnormal.
http://www.plastikhosting.net/uploads/JRSTANGE/06302011_datalog/2011-06-30_20_20_13.csv
http://www.plastikhosting.net/uploads/JRSTANGE/06302011_datalog/2011-06-30_20_20_13.pdb
ok, well i went ahead and connected the fuel pressure selinoid back up and decided to give it a go and see if it made a difference. I also started the log before i started the engine. Once the key was on I checked the heated o2 sensor and it never felt warm or hot in the same amount of time it took my wideband to heat up. I beleive that to be an issue.
Of course there was no change in connecting the selinoid but, when i get the log online you will have a better log to look at from a true cold start.
Also reading the service manual the narrowband should flip from 0 to .4 at idle and I was seeing close to zero to as high at .89. Then per the manual the voltage should be when speeding up the engine rpm between .5 to 1. But, I'm seeing regardless close to zero to .89 regardless of idle or speeding up the engine. I really wish I had another O2 sensor to try out before buying one.
The other thing is i dont have any CEL's. from reading it doesnt matter if the o2 is bad or if the heater circuit is ad it should pop a CEL.
http://www.plastikhosting.net/uploads/JRSTANGE/07012011Datalogs/2011-06-30_20_20_13.csv
http://www.plastikhosting.net/uploads/JRSTANGE/07012011Datalogs/2011-06-30_20_20_13.pdb
http://www.plastikhosting.net/uploads/JRSTANGE/07012011Datalogs/2011-07-01_18_14_06.csv
http://www.plastikhosting.net/uploads/JRSTANGE/07012011Datalogs/2011-07-01_18_14_06.pdb
ok, well everything seemed to be ok during the drive. The first log should be the warm up and the second one is the drive. However thats just a portion of the log. I'm not sure if the drive log capture my crazy knock! Like 43 counts of knock when getting on it. The knock is the same issue I had when at the dyno. This is still only 10psi. But, I'd expect to see a/f's in the 11's but, I see high 12 to low 13's. I dont know what to make of this. Normal driving though the a/f's look ok. But, when I excelerate I'd expect to see it rchen up a bit but, it stays at a steady 14.7 range.
Right now i'm not sure if I'm more concerned with the knock or the sputter during warm up.
Last edited:
