1990 Lumina 2.5L ICM remove and replace guide

[bigtimmy45]

I hope this will help someone now that I know how it should be done sans chiltons and other repair guides

first, disconnect negative battery cable - then (if you can reach it) disconnect lead wires from ICM - I also removed spark pug wires at same time knowing I was gonna replace them as well with firing sequence already saved for future reference

there are 4 tiny bolts with 8mm nuts that hold the coil packs, ICM and ICM bracket in place kinda like a sandwich - if the bolts wont turn and you can remove nuts with no problems, carefully remove coil packs first then the ICM - if they start turning in their holes like mine did, there are 3 bolts that holde the bracket onto the engine - 2 are 10mm and 1 is 13mm

if you arent gonna replace crank position sensor, this would be a good time to think about going ahead and doing that anyway as it is bolted to the bottom of the bracket and may get broken during this repair

it will all be very tight in behind engine and firewall but it can be done without removing any other parts of the car - once bracket is removed, I washed it carefully and then soldered the 4 bolts to the holes so they dont turn in their hole when I install the nuts

after replacing crank position sensor onto bracket, carefully reinstall it so as not to break new sensor - then put ICM onto bracket but dont put nuts on just yet - put coil pack on that will be on the bottom (so to speak) then the one on top - noting the firing sequence, then replace spark plug wires and you should be good to go

I have posted this because the most important pieces I was hunting for wasnt in the chiltons nor anywhere online - it is in reference to the ICM bracket - there isnt even any picture with it in common to the ICM so I am trying to save someone else heartache when they have to do this to their 2.5L - it doesnt necessarily have to be exclusively 1990 nor just Lumina sedan

[jeffcoslacker]

[john51md]

Originally Posted by jeffcoslacker

There must have been a design change... My 91 with a 2.5 had the same setup, BUT... it did not have bolts thru the back of the coils and nuts on front, the backplate was threaded and nutless bolts went thru the coils from the front, threading into back plate. And the head of the little bolts was if i remember right, 5.5 or someting MM.

[bigtimmy45]

Originally Posted by john51md

There must have been a design change... My 91 with a 2.5 had the same setup, BUT... it did not have bolts thru the back of the coils and nuts on front, the backplate was threaded and nutless bolts went thru the coils from the front, threading into back plate. And the head of the little bolts was if i remember right, 5.5 or someting MM.

except for the tiny size you are mentioning, that would have been a wonderful setup for me - I am already on my way to reinstalling everything now

jeffcoslacker moderator, where were you when I needed you LOL - I coulda used that picture but it was all a very good learning experience for me anyway without it - I wouldnt have been broke down for about 2 weeks this way though - I am sure someone will find this posting helpful - this is a great forum, at least for luminas

[bigtimmy45]

Originally Posted by bigtimmy45

I hope this will help someone now that I know how it should be done sans chiltons and other repair guides

first, disconnect negative battery cable - then (if you can reach it) disconnect lead wires from ICM - I also removed spark pug wires at same time knowing I was gonna replace them as well with firing sequence already saved for future reference

there are 4 tiny bolts with 8mm nuts that hold the coil packs, ICM and ICM bracket in place kinda like a sandwich - if the bolts wont turn and you can remove nuts with no problems, carefully remove coil packs first then the ICM - if they start turning in their holes like mine did, there are 3 bolts that holde the bracket onto the engine - 2 are 10mm and 1 is 13mm

if you arent gonna replace crank position sensor, this would be a good time to think about going ahead and doing that anyway as it is bolted to the bottom of the bracket and may get broken during this repair

it will all be very tight in behind engine and firewall but it can be done without removing any other parts of the car - once bracket is removed, I washed it carefully and then soldered the 4 bolts to the holes so they dont turn in their hole when I install the nuts

after replacing crank position sensor onto bracket, carefully reinstall it so as not to break new sensor - then put ICM onto bracket but dont put nuts on just yet - put coil pack on that will be on the bottom (so to speak) then the one on top - noting the firing sequence, then replace spark plug wires and you should be good to go

I have posted this because the most important pieces I was hunting for wasnt in the chiltons nor anywhere online - it is in reference to the ICM bracket - there isnt even any picture with it in common to the ICM so I am trying to save someone else heartache when they have to do this to their 2.5L - it doesnt necessarily have to be exclusively 1990 nor just Lumina sedan

ammendment: when getting bracket ready for reinstallation, dont try to solder the 4 little bolts with 8mm nuts onto it - I just tried and it wont work - HOWEVER, using "krazy glue" and a bit of baking soda works wonders - you put the glue onto the bolts (at the bolt holes) while they are in the bracket holes and then sprinkle some baking soda onto the area where there is glue - let sit for about a minute and then remove excess baking soda - it will hold tons better than straight glue alone and your bolts wont spin in their holes after you get the bracket onto engine

[jeffcoslacker]

Originally Posted by bigtimmy45

except for the tiny size you are mentioning, that would have been a wonderful setup for me - I am already on my way to reinstalling everything now

jeffcoslacker moderator, where were you when I needed you LOL - I coulda used that picture but it was all a very good learning experience for me anyway without it - I wouldnt have been broke down for about 2 weeks this way though - I am sure someone will find this posting helpful - this is a great forum, at least for luminas

The first time I looked I didn't find that pic...was looking at the section about the DIS on your car...but there was a section on the ICM itself that I missed first time around...sorry...

[john51md]

this is what my V6, and the 2.5 looked like, except 2.5 had only 2 coils. Bolts instead of nuts. Its strange because even my 89 Z24 had bolts. Every new dis modual i have bought had threaded hols too

http://64.233.169.104/search?q=cache...lnk&cd=2&gl=us