Since it's been cold out lately my car has been starting up colder in the morning and just about each morning whenever I go to start my car (88 350 iroc) the service engine soon blinks rapidly and the car idles really low and sometimes shuts off. This goes on about 5 minutes until the car seems like it warms up then it runs fine and then the light stops blinking all in all. It to me seems like it's taking way to long to warm up and the light shouldn't be going off in the first place. Any ideas to what it is? My dad told me it's probably a electrical problem

 

Normally SES blinking rapidly indicates lean or rich condition. You need to check your DTC's to see what it is.

 

Lean or rich? And DTC?

 

Blinking SES light Indicates: Severe Engine misfire detected; damage to catalytic converter possible. it means your engine is running so terribly that the raw fuel being dumped out of your exhaust my kill the cat

 

The exhaust doesn't smell bad at all normal and it misfires a little bit but not really bad. I doubt it's the caralic converter.. as I said it only blinks and acts up during the first 5 minutes it's started on a real cold morning but when it seems like it's warmed up it runs great. Any other suggestions??

 

no no no, i did not say it IS the cat, i said that a blinking check engine light means that the ECM detects a misfire that is strong enough to melt down your cat.

 

Oh! Okay but I want to fix the problem what could it be? We just put fresh spark plugs in and the distributor looks fine and the wired the same. What else could it be? Why does it only happen when it's cold out?

 

probably related to the coolant temp sensor mounted in the manifold

 

Hello Chevy8588!!

Is this true for ODB I??? I thought that when the SES light blinks rapidly on OBD I, it means the ECM is in the Field Service Mode, and blinking two and one half times per second tells you it's in Open Loop, and if it's blinking once per second, it's in Closed loop!!

 

this is true when the ECM is placed in field service mode, but the ecm MUST be manually placed in field service mode, his car will not start in field service mode, then resume normal operation later. during normal operation, a blinking check engine light is as stated above.

 

Hello Chevy8588!!

Well, they say you learn something new every day!!



I knew this to be true for OBD II, but never knew this to be the case with OBD I!!

Is this referenced in the FSM??

 

Our car's are obd1 and they do not have a crank sensor to pickup misfire so your problem is something else.only late 95 and newer obd 2 cars can pickup misfire and store it in the pcm

 

So does this mean it is the coolant temp. sensor or what? Id rather know
so I can get this problem fixed instead if leaving my car someone and having them look at it only for 100$

 

not necisarily correct, our motors fire injectors and such based off of a reluctor ring in the dizzy. so the ecm can sense a severe misfire condition, though there are no parameters to set a light

 

Hello antoine!!

That's what I figured, that's why I asked Chevy8588 if there was a reference in the FSM to what he said!!

He has a point though about the dizzy, however you'd think that the FSM would reference to this!!!

 

I don't know any iroc z28 that the ecm can pickup misfire,the misfire is picked up from the front by the crank sensor that reads crankshaft vibration.

 

Hello 88blackiroc!!

I would look for a short to ground on your ECM's diagnostic terminal, terminal B of your ALDL connector, or the SES light circuit on the ALDL connector, terminal D!!

Terminal B grounded while running puts your ECM into the Field Service Mode, terminal D is the circuit for the SES Light!!

Either one grounded will give you a SES light, terminal B grounded while running will give you a light that flashes rapidly, terminal D grounded to something that is giving you a ground/not ground pulse will flash at that rate!!

Since it flashes until it warms up, check a short to ground to the CTS????



Best guess wins!!!!