1994 geo engine and tranny swap

[JBruen]

Ok...this is a long post but I thought it might come in handy for a few people out there. I've found a lot of help on this forum and I thought some payback might be in order.

The project:
Install engine and manual transmission from a 1991 Geo Metro 2 door (with crappy stereo) into a 1994 Geo Metro 4 door with a worn out automatic transmission and blown engine (but a great stereo and air conditioning and red instead of aqua-baby blue). I did this because I really wanted a 4 door commuting car with AC. This is not an endeavor for the faint of heart... That being said, I, with a little help from my friends, was able to accomplish this task on two weekends. Now understand this was strictly a white trash operation with logs for jack stands, a makeshift engine hoist made from logs, rope, and a 6"x6" beam, and plenty of empty beer cans lying about. What I’m trying to say is that a guy could do this in a day or two in a decent shop with good jacks and engine hoist.

This is the first time that I have attempted anything like this and Luckily I had the whole 1991 Geo with the manual transmission to use for extra parts, more parts from the 1991 would be needed than I expected.

We started by jacking up both cars and taking off the CV joints.(remove tires and disconnect hub assembly from struts. Be careful not to damage CV Joints that come out of the manual transmission as they will still be needed) We unhooked everything from the engine-blocks unbolted and lowered the engines and transmissions out from under the front of the car as single units. Note: The Automatic transmission has an additional mounting bracket on the rear.

Remove pedal assembly (brake, clutch and clutch cable) from old car and install it in new car. GRRR...This is a back-breaker. It also requires drilling 3 new holes in the firewall for the clutch cable and clutch cable retainer. These holes are blanked out on the inside of the firewall. I used a center punch to dent these holes from the inside out so that I could see where to drill them from the outside. To drill them from the inside I would have had to take off the dashboard and I wanted to avoid this if at all possible (thankfully it was).

Install manual gearshift assembly. This requires the removal of the entire automatic transmission shifting assembly as well as the rear automatic-transmission mounting bracket welded to the underside of the car. It isn't used with a manual transmission and it will get in the way of the anchor rod on the new manual shifting assembly. (cut off or pound flat)

Remove left front automatic-transmission shock-mount bracket. I did this with a chisel and a small sledge-hammer, crude but effective (be careful not to damage chassis and paint over any exposed metal). Drill new holes for the left-front manual transmission shock-mount bracket. **They do not match up with the old mounting bracket holes.** The position for these holes is blanked out on the inside of the chassis. Drill 3/4” holes through on the other side of the chassis to find the guide holes. This has to be done anyway in order to thread nuts on the bolts that hold on the new mounting bracket.

Fabricate a metal plate to cover the hole in firewall left behind by the removal of the automatic transmission shift linkage. This keeps engine compartment fumes from getting into the passenger compartment, always a good idea.

Hoist new engine and transmission into car. I will not even go into detail on how we accomplished this for fear that someone else might try our white-trash method and hurt themselves. Special note: I had to use the right front engine mounting bracket from the 1994 engine that I took out. For some reason the mounting brackets were different...maybe a 1991 to 1994 issue.

(Drink more beer.)

We had to install the manual transmission CV joint set from out of the 1991. The automatic transmission CV joint set is offset about 3” from the manual set and will not work with a manual transmission.(at least in my case it wouldn't. Maybe this is a 1991 to 1994 or automatic to manual issue...i don't know)

I cut off the multi-pin (shifter position) plug from the top of the automatic transmission. This gave me a very handy way to rewire the existing 1994 automatic wireing harness to work with the new manual transmission. It was an easy way to get the backup lights working and overide the safety relay that allows an automatic to start only when park. (The two center wires needed to be shorted together for the starter to work, the yellow and red wires needed to be wired to the reverse switch leads on top of the manual transmission for reverse lights to work, and the rest of the wires I cut off short and insulated with electrical tape for they serve no purpose with a manual transmission.)

Note: When switching engines from Metros made in different years you should probably change the block only and leave anything hooked to the wiring harness in place. This will eliminate any electronics incompatibilities notably distributor, carburetor sensors, intake manifold sensors, engine coolant sensors and other related vacuum hoses sensors and such. I learned this the hard way. When I got the engine changed over it would turn over but it wouldn’t start presumably because the distributor from the ‘91 wasn’t sending the right signal somewhere to operate the ignition system in the ’94. I re-installed the distributer from the 1994 and it started right up. Once I got this working the car would run but it started overheating because the radiator fan sensor wasn’t turning the cooling fan on. Sure enough the fan sensor from the ’94 was a different diameter (and probably a different spec) than the ’91 fan sensor. This required putting the temperature sensor housing I took out with the old engine back onto the engine I just installed. This wasted a lot of antifreeze..DOH. You will also want to make sure that you have some gasket paper handy in case you damage the gasket when you remove the engine coolant sensor housing.

I have probably forgotten some important points as I am writing this in retrospect but as I remember I will include them on the website I intend to post soon with some pictures documenting the project as well. Hopefully this is of some help to someone. My new Geo Metro is running great and getting about 50MPG. With todays fuel prices and my 120 mile per day commute I couldn't be happier.
Justin

http://www.roguecamp.com/georebuild/

[RossT]

WOW! And I thought i had my work cut out for me when my Japaneese Domestic Market "JDM" G10-L 1.0 metro engine showed up yesterday.

I am going to replace the engine in my 91 metro with one of these low mileage untis direct from japan. The mileage etched into the side of the
engine says "37,450"

It's my first time too! I was happy that i myself can lift the litte beast.

Thanks for your effort on your post. My job now looks ten times easier.

[geozukigti]

Nice work Next time, get a DOHC setup for a toy You seem to know what you're doin, so you shouldn't have any troubles. Still gets about 28-32mpg, and it's a quick little bugger.

[JBruen]

For now I have too many "toys" in my driveway but thanks Geo-z...I will keep that in mind. Something with a bit more power for passing would be nice. It sounds like an elegant engine...no?
After doing the engine/transmission swap, the check engine light,which has never been off in this car was off for about 20 miles and is now back on again. Irritating. Any ideas? I must have reset the ECU when I disconnected the battery or harness. I suspect something in the EGR system but I do not have a code reader and have not yet been willing to plunk down the $50 that all the mechanics want to read the code for me. (although I will probably have to do this soon) Tonight I will try taking off the EGR valve and see if it needs cleaning. It sounds like I should not put off doing this for too long anyway as it might adversely effect my exhaust valves. Does anyone know how to reset the ECU?...tail light fuse?...which fuse is this?...believe it or not I'm flying without a manual here

BTW...are there any sources for new 1.0L 3cyl. engines for these cars? I am also intrigued by your new engine RossT. Good luck with your project.

you gotta love a car with an engine that you can almost lift in by hand!!

cheers,
Justin

[JBruen]

I have the rebuild website posted for your viewing pleasure. If you are on dial-up the pictures will take some time to load...sorry.

http://www.roguecamp.com/georebuild/

Cheers,
Justin

[geozukigti]

Nice site You can get the check engine light to flash you codes. If you look at the fusebox, there's an empty spot, raised more than all the other fuse slots. Stick a fuse in there, and it'll flash the codes on the dashboard. And yea, the GT motor is quite the elegant motor! Forged crank, forged rods, 10:1 compression, 100hp, and an almost limitless redline. My old swift with a chip, I shifted at 9800RPM's when racing. It'll also hold 70-80mph without breaking a sweat, and going uphill on freeways, you don't need to downshift.

[crazyinkc]

Nice site. You might try using the ECM out of the 91 since the ECM's are different for manual to auto. You may have to put the 91 dizzy back in though. The check engine light is probibly from the ECM not seeing the trans controller.

[JBruen]

Hey thanks Geo-z...sure enough engine code 51. What is engine code 51 anyway. So I removed the EGR valve and sure enough the whole system was totally clogged including the valve all the way back up the manifold passage. What a mess. Wish I had known this before I had the whole car put back together.

So I disconnected and reconnected the battery to reset the check engine light (this seems to work) and I'll be off on a test drive here in a little while.

Thanks for the suggestions crazyinkc, I will keep that in mind, but switching the ECU might mean changing out the distributor, carburator, wiring harness and who knows what else. Plus it would mean crawling under the dash to change the entire ECU. I would be more likely to clip the wire to the check engine light. ;-)
Justin

[mik13usa]

Keep us updated on the progress!!

[JBruen]

Well hells bells...after cleaning all of the carbon out of the EGR system and making sure that all associated hoses were clear, I'm still getting trouble code 51. It was good for about 16 miles and then the dreaded check engine light went on.

I guess what I need to do now is figure out if the vacuum switch is working and letting vacuum get to the EGR valve. Doen anyone know a good way to do this? There are two wires going into the vacuum switch which I presume go to the ECU. Does anyone know what event triggers this switch? O2 level maybe? Is the sensor on the exhaust manifold the O2 sensor? If it were bad could it be causing "EGR circuit failure? There are still a couple of extra plugs on the harness left over from taking out the automatic transmission and putting in the manual. One I think might be for the automatic transmission fluid thermometer. And one was a magnetic coil transducer positioned over some gear in the automatic transmission. Some sort tachometer but I'm not sure which gear it was gauging or for what purpose. Could it be part of the EGR circuit maybe?

Any ideas?

Justin

[JBruen]

Well I tore apart the EGR system again to see if I could find any more problems that might be causing the "check engine" light with engine trouble code 51. As it turns out the exhaust passage going from the EGR valve to the intake chamber was clogged again. I must not have done the job well enough the first time.

So I took the intake manifold off and cleaned it again. This time I used a whole can of carb cleaner and lots of compressed air and even managed to get a piece of nylon cord fed through to "floss" out the passage. Ugh! Yuck! Gunk everywhere! The previous owner must have been running the engine on tar or something. It took me an hour to get the black mess off my hands.

The upshot is that 70 miles later no "check engine" light. Yay! I'm not ready to call it good just yet but that is the longest the check engine light has ever been off in this car. So it looks like it is possible to switch from an automatic transmission to a manual transmission in a Geo Metro and not have the check engine light on all the time.
Cheers,
Justin