1G CE light flashes on and off. (check engine)

[wolf alchemy]

1990 Plymouth laser rs turbo. 94% stock. Struts, wheels, exhaust manifold.

So...it happened after I floored it when the light turned green. Not sure when exactly but I noticed it when I hit 65....1-3 miles after hitting 65 and it stayed on/off (stayed on for while, turned off. 1/2 sec then on. Then off after awhile 1 sec. Drove longer then off for 7 secs. Then on for awhile again then off for maybe 20 secs then on till I slowed down below 50 and never came back on)
So I checked it and its only code 21(coolant sensor)

 

[wolf alchemy]

Its not flashing. It stayed on for while, turned off. 1/2 sec then on. Then off after awhile 1 sec. Drove longer then off for 7 secs. Then on for awhile again then off for maybe 20 secs then on till I slowed down below 50 and never came back on. That's not flashing. Unless you meant on and off.

 

[DSM1G90]

Mine did the same, but I never did any sort of WOT, but the CEL would go a bit crazy (and with the same 21 code) during low speed town traffic.

Here's the oddity of it all: my starter was getting a bit tired during this time and knew that the starter was thinking on going. Thus, I did the starter changeout. Interestingly enough, I had more power and no more CEL code 21 stuff.

I think that bad starter was taxing my electrical system in a way that the current needed to run the ECU was also being taxed that the temp sensor was the "weakest link" in the system to get affected - thus the CEL and the 21 code were the results of this crazy issue.

I know, odd, but that's as far as I can gather.

-DSM

 

[wolf alchemy]

This hasn't happened in a long time and I just had a new starter plate and starter installed. Old owner threw away starter plate

 

[NismoDSM]

misfires maybe?

 

[wolf alchemy]

Rsepower seemed fine. It was making a slight ticking I have a video but no idea how to post it.

 

[DSM1G90]

Before the starter, I had to replace the power transistor and coilstack, for I was getting areas of misfire on occasion...and that definitely gave me a CEL with the same 21 code also.

I kinda fought ignition issues this last winter, but got that all cured and solved with parts replacements.

Now, thing starts right up, runs smooth, and gets up and scoots great down the road.

I haven't seen that pesky CEL for months now.

 

[Mischif]

Loose pins on the harness for ECT, broken prongs on the ECT, or time for a new ECT. All pretty simple fixes.

 

[wolf alchemy]

Is it normal for our cars to take 4-8 seconds to fire up?