Wierd(to me) and sudden problem

[RedRocket'90]

I had been driving my 90 to work a few days with no issues..The other day I got back to work from running my route..got in..car started right up.I drove to the area where I turn my paper work in and left the car running while I went inside to do so.When I came back out the car was not running:confused so I restarted it and it had a dead miss,like I had pulled a plug wire off.I checked all the wires,they were all secure..tried to wiggle the IAC to make sure it hadn't backed out a little,checked all the vacuum lines,all intact and hooked up.I drove the car about 7 miles home..about half way home I started getting a hazy smoke in the drivers compartment.I pulled to the shoulder and hopped out thinking the cats had somehow gotten red hot and were causing the carpet backing or something to smolder.There was no problem with the cats and the little bit of smoke dissipated and didn't return.During this whole time there was no check engine light,but after I parked it for a couple of hours and went to start it..I got the glow.I pulled the codes and got a 13, O2 sensor circuit which I knew about and need to replace..15, 22, and a 32.The EGR valve is new and all lines are connected...the TPS voltage is correct and cycles to a little over 4.0 at WOT.The coolant temp low is the only one I cant figure out...and it seems like an odd set of codes to show up all at the same time.So I was just looking for some fresh input...maybe a dead injector? maybe a bad ECM? The car wont stay running now when I try to start it unless I press the gas.I appreciate any input with this..or any ideas of what else to check.
Thank Ronnie

 

[gmjunkie]

I had been driving my 90 to work a few days with no issues..The other day I got back to work from running my route..got in..car started right up.I drove to the area where I turn my paper work in and left the car running while I went inside to do so.When I came back out the car was not running:confused so I restarted it and it had a dead miss,like I had pulled a plug wire off.I checked all the wires,they were all secure..tried to wiggle the IAC to make sure it hadn't backed out a little,checked all the vacuum lines,all intact and hooked up.I drove the car about 7 miles home..about half way home I started getting a hazy smoke in the drivers compartment.I pulled to the shoulder and hopped out thinking the cats had somehow gotten red hot and were causing the carpet backing or something to smolder.There was no problem with the cats and the little bit of smoke dissipated and didn't return.During this whole time there was no check engine light,but after I parked it for a couple of hours and went to start it..I got the glow.I pulled the codes and got a 13, O2 sensor circuit which I knew about and need to replace..15, 22, and a 32.The EGR valve is new and all lines are connected...the TPS voltage is correct and cycles to a little over 4.0 at WOT.The coolant temp low is the only one I cant figure out...and it seems like an odd set of codes to show up all at the same time.So I was just looking for some fresh input...maybe a dead injector? maybe a bad ECM? The car wont stay running now when I try to start it unless I press the gas.I appreciate any input with this..or any ideas of what else to check.
Thank Ronnie

What is the Coolant Level like??Has a Head Gasket blown!!If the system is low on coolant the Temp Sender won't read Steam Temp in the system!

 

[geekinavette]

What is the Coolant Level like??Has a Head Gasket blown!!If the system is low on coolant the Temp Sender won't read Steam Temp in the system!

I have to respectfully disagree 'O Master of the Junk... ;worship

The CTS (and/or temp gauge sender) is a simple NTC thermistor housed in a brass enclosure. Whatever temperature it is reporting is indeed an accurate representation of the medium in contact with it. I think maybe what you're getting at is that if air/steam is getting to the CTS it may not be as accurate in representing engine temperature as it would be if water were circulating (vs. air/steam)? For example if your average engine temperature is really 180 degrees...but because there isn't enough water in the system to transfer that heat to the CTS and it is only reporting 120 degrees, then the ECM will not go into closed-loop operation when it should and run pig rich and do all kinds of other unspeakable things.

Bill

 

[gmjunkie]

I have to respectfully disagree 'O Master of the Junk... ;worship

The CTS (and/or temp gauge sender) is a simple NTC thermistor housed in a brass enclosure. Whatever temperature it is reporting is indeed an accurate representation of the medium in contact with it. I think maybe what you're getting at is that if air/steam is getting to the CTS it may not be as accurate in representing engine temperature as it would be if water were circulating (vs. air/steam)? For example if your average engine temperature is really 180 degrees...but because there isn't enough water in the system to transfer that heat to the CTS and it is only reporting 120 degrees, then the ECM will not go into closed-loop operation when it should and run pig rich and do all kinds of other unspeakable things.

Bill

Yeah,Thats basically what I meant,if there is no liquid coolant around the CTS and Air/Steam the sender will Lie to the Gage and the ECM!! And will sometimes even make the Gage Jump from almost nothing to extremely hot and back and forth!! I should have said it won't read Steam/Air correctly in the system!!
Sorry for the confusion!!

 

[geekinavette]

Right on JunkMaster!

Could that cause the weirdness he's seeing though? You're thinking maybe he saw some steam from overheating? What about those codes? Pretty darn strange!

 

[gmjunkie]

Right on JunkMaster!

Could that cause the weirdness he's seeing though? You're thinking maybe he saw some steam from overheating? What about those codes? Pretty darn strange!

Yeah,Thats what I'm thinking,My wife Cooked one Bad for me once and the temp gage didn't even get above about 140 on the gage!!She said it was running cooler than usual,so she didn't bother to check the radiator!! It popped all sorts of Weirdo Codes!

 

[geekinavette]

My wife Cooked one Bad for me once

Are we talking Corvettes or Pot Roast? :L

 

[RedRocket'90]

my temp readings were fine..thats why I dont understand why it threw that code.The egr temp sensor and tps codes all appreared at the same time

 

[RedRocket'90]

well I replaced the IAC..the Coolant Temp Sensor..and pulled the TB off and soaked it in Chemtool all night then cleaned it with a toothbrush and carb cleaner...put it all back together and still have the miss.I did pull the pigtails off the injectors 1 at a time and found something unusual I think..When I pull 1-2-7-8 the engine has a noticeable difference in idle and sound.However...3-5-4-6 there is NO difference in the idle or engine sound at all,not sure if this is something someone can tell me about or not.I wasn't sure if mabey a circuit in the ECM went bad..or the just 4 of the injectors happened to go bad.
Thanx
Ronnie

 

[gmjunkie]

well I replaced the IAC..the Coolant Temp Sensor..and pulled the TB off and soaked it in Chemtool all night then cleaned it with a toothbrush and carb cleaner...put it all back together and still have the miss.I did pull the pigtails off the injectors 1 at a time and found something unusual I think..When I pull 1-2-7-8 the engine has a noticeable difference in idle and sound.However...3-5-4-6 there is NO difference in the idle or engine sound at all,not sure if this is something someone can tell me about or not.I wasn't sure if mabey a circuit in the ECM went bad..or the just 4 of the injectors happened to go bad.
Thanx
Ronnie

Are you sure it's not 1-3-5-7 "Left Bank" and 2-4-6-8 "Right Bank" :confused Anyway Check the fuses in the fuse box on the right hand side of the dash #'s 22 and 23!! I beleve (INJ 1) 22 go's to 1-3-5-7 "Left Bank"and (INJ 2) 23 go's to 2-4-6-8 "Right Bank"

 

[RedRocket'90]

yeah I checked the fuses and they are both fine..Im stumped..the only other thing I can think of is that it's EGR related somehow..or the 4 center injectors..lol

 

[gmjunkie]

yeah I checked the fuses and they are both fine..Im stumped..the only other thing I can think of is that it's EGR related somehow..or the 4 center injectors..lol

EGR may have a piece of carbon stuck in it!! I've seen that before,4.3's are really bad for it,and I've seen a few 350's do it!I take them off clean them and take 2 gaskets with a Stainless screen sandwiched between them on the exhaust side,Usually fixes them right up!!