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Discussion Starter #1
Hello everyone

My car is 1991 Chevrolet Caprice Classic sedan.
Engine: 305 VIN e 5.0L

The car did hit full speed which is 80mph and after that it died immediantly and wont turn on back again.

The speedometer is stuck on full speed 80 mph.

It does not get fuel out of the injectors but the fuel pump works and im getting fuel out of the lines.

It runs great on starter fluid

The fuse number 20 which is for the ECM is not getting voltage on OFF position and on ON postion but gets voltage when I crank the engine. I removed the fuse 20 and cant get voltage either inside the fuse box.

Also the service engine soon light (SES) doesnt flash at start position and doesnt flash when i bypass the obd1 (ALDL) to read any codes. The SES light doesnt work and code 12 doesnt flash at all.

I connected another ECM 2 times. First time with the other ECM prom and second time with my own prom i swapped it to the other ECM and it still does not work

Need some help please what could be the problem??

Thanks


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Try disconnecting the speedo and see if it will start.
Maybe the "cut off switch" is still "cut off" and you say the speedo is stuck at 80mph which, to me, seems a bit low for a cut out speed, but perhaps that's your issue

remove and unplug speedo cluster and see if it will start.
 

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Discussion Starter #3
Try disconnecting the speedo and see if it will start.
Maybe the "cut off switch" is still "cut off" and you say the speedo is stuck at 80mph which, to me, seems a bit low for a cut out speed, but perhaps that's your issue

remove and unplug speedo cluster and see if it will start.


I will try what you said and let you now what happens. Thanks alot man


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Discussion Starter #4
Try disconnecting the speedo and see if it will start.
Maybe the "cut off switch" is still "cut off" and you say the speedo is stuck at 80mph which, to me, seems a bit low for a cut out speed, but perhaps that's your issue

remove and unplug speedo cluster and see if it will start.


I tried what you said and still the same problem. No fuel getting out of the injectors.

I first took out the speedo cluster. Didn't work

Second i used another speedo cluster which is working. Didn't work either

But what i saw is that the signal coming from the ecm or where ever its coming from to the speedo cluster is still reading 80 mph (stuck at this speed).

The way i knew this is that when i removed the speedo cluster I wiggled the cluster to make it go back to 0mph. Here is a picture showing it.
IMG_4125.JPG

And as soon i connect the speedo cluster and turn the switch to the ON position it gets back to 80 mph so i think maybe the signal telling the car its on full speed and cutting off fuel.

Is their anyway to reset the ECM or have this issue fixed??

Thanks a lot for your help!!




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Try unhooking the battery for 3 or 4 minutes and maybe it will erase whatever is telling it its still doing 80

Edit

You can try pulling the fuse for the ECM too and just leave it out for a couple minutes and then plug it back in.
 

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Discussion Starter #6
Try unhooking the battery for 3 or 4 minutes and maybe it will erase whatever is telling it its still doing 80

Edit

You can try pulling the fuse for the ECM too and just leave it out for a couple minutes and then plug it back in.


I tried it. Still same issue.


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Without a scan tool and some testing I'm outta ideas.
Maybe someone else has an ideas. Is there actually fuel pressure in the line ?
 

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Discussion Starter #8
I disconnected one of the 2 fuel lines that go to the tbi unit and bypassed the fuel pump from the red wire under the hood. The fuel pump worked and got fuel out of the line i disconnected.

So i think their is fuel pressure but the injectors aren't spraying the fuel out.


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The car did hit full speed which is 80mph and after that it died immediantly and wont turn on back again.

The speedometer is stuck on full speed 80 mph.

It does not get fuel out of the injectors but the fuel pump works and im getting fuel out of the lines.

It runs great on starter fluid
Would scan it, borrow a scanner if you have to. Strange it is cutting the fuel off. Might try letting the car sit with no power for a longer time than 30 minutes, like all day and see if it resets.

While I personally have never deliberately tried it, have heard of a "trick" to reset all electronics in a car by shorting the disconnected from the battery positive and negative terminals. I cannot positively say if it works or not.
 

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Discussion Starter #17
Would scan it, borrow a scanner if you have to. Strange it is cutting the fuel off. Might try letting the car sit with no power for a longer time than 30 minutes, like all day and see if it resets.



While I personally have never deliberately tried it, have heard of a "trick" to reset all electronics in a car by shorting the disconnected from the battery positive and negative terminals. I cannot positively say if it works or not.


Well I disconnected both positive and negative terminals from the battery for a whole day. Nothing happened still same issue.

But for the shorting the terminals I will try it today and see what happens.

Thanks alot for your help my friend.


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Discussion Starter #20
I tried all what you said guys and still no hope to get fixed. Same issue.

I don't know whats left to try.


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