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13b Motor Swap Has Ignition Problem

Old 08-17-2005, 03:11 PM
Junior Member
Thread Starter
Join Date: Aug 2005
Posts: 4

Sorry for the intrusion, but I was hoping someone might be able to help me.

I swapped an 87 13b FI motor into an MG. I got it

running (amazing because the wiring is a nightmare

and i thought it was just gonna self destruct when i connected the battery). it

ran several times, but now it just won't. the tach

won't even move and it no longer has any spark (i pulled a plug and checked). i

swapped out both coil assemblies, the resistor

block, the computer and the distributor part. I'm ready to scrap this project

It has good ground to both the motor and the coils, everything seemed to work fine until i saw a leaking coolant line - which i fixed. the only difference is that I left the battery connected for about 1/2 hour (I had been disconnecting it). is there something that could've been burned out? there is 12V going to the coils (black / yellow wires). Also before I would see the tach needle bounce when the starter spun, now nothing (but the needle does still bounce when i first turn the key on) and one other thing is that it ran very rough above 4500 rpms, almost like it wasn't getting enough fuel (i'm running the stock 87 intank pump)

Anyway, do you have any idea what may have gone bad

or where my problem might be? I'm at a complete

loss any any suggestions would be greatly



desertmoron is offline  
Old 08-18-2005, 10:47 AM
Senior Member
Join Date: Oct 2003
Location: Fort Lewis Washington
Posts: 705

I would have to say check signal from the crank angle sensor. Then check signal going to the coils from the computer.

Do you have the battery hooked up to a charger?
ArmyOfOne is offline  
Old 08-18-2005, 09:40 PM
Join Date: Nov 2003
Location: Hampton, Virginia
Posts: 93

Check starter relay and check computer. Check your battery cables and check that you have clean grounds. Check resistor pack. I had a friend that we put a turbo engine in and was having issues with the computer. It will start, stay idle for a few minutes, give it gas, it will die and never start up again. This time we swapped the computer and has never had any issues thus far.
jerry is offline  
Old 08-22-2005, 10:45 AM
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Join Date: Aug 2005
Posts: 4

I checked the CAS and the 2 sets of coils I have - they're all fine. the grounds are good - the only thing really left is the computer. I did swap it out with an 'untested' one and the problem persists. Is there any way to test the computer?? If I have something wired wrong that's blowing the computer I'd really like to find that before I waste any other computers... The car did start several times and ran ok before this problem started. ARRRGGHHHHHHHH!!
desertmoron is offline  
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