3.2 swap looked all over couldnt find this answer

[EZ4U2ENVY]

Alright yes im in the process to convert atx to a mtx- i have searched the pages about this subject and found alot of info i could use.

But this one question i couldnt find actually possibly two.

1. are the axles from a atx and mtx the same or are they different??

2. is the computer in the 91 sho able to go into the 95 and work well or should it be upgraded to a 94 mtx or something

3. What things should be replaced while engine is out- im doing number of things like timing belt- rod bearings already have new water pump. cps- cid new t-stat anything i missing that would be good to do

Thanx guys
Your the best help

 

[Mr Anonymous]

1. Different
2. MTX and ATX use different harnesses. All MTX's use the same harness so '89 through '95 PCM's are interchangeable.
3. All the seals & gaskets you can afford.

 

[fredhurderjr]

Chris...

MTX "Harnesses" are slightly different, on the other end, for the accessories, etc. The plug connectors for the 90 Airbag sensor vs. the 91 are different shaped, for example, and the connectors for the alternators are different between the 91 & the 95 (MTX), for another example.

 

[Mr Anonymous]

fredhurderjr:
Chris...

MTX "Harnesses" are slightly different, on the other end, for the accessories, etc. The plug connectors for the 90 Airbag sensor vs. the 91 are different shaped, for example, and the connectors for the alternators are different between the 91 & the 95 (MTX), for another example.

Yeah, I knew that. wink I was more trying to point out that the pinouts at the PCM end are different between ATX and MTX, but that the MTX PCM's are interchangeable... BTW Fred, did you pick up your 'new' ATX yet?

 

[rangerj]

EZ4U,

OK EZ are you willing to do the research? If I understand this right you are going to put an 89 engine and MTX in a 95 SHO. Is that correct?

I do not think you have to gut the 95 wiring harness and PCM. If anything the 95 will have all of the wires you need, and many you do not need.

You need to study the two wiring diagrams for the two years and identify every wire that is already in the 95 that you need for the 89. Don't wory about the style of the connectors for now, we'll get to that.

This really is not as hard as it sounds. Both engines have pretty much the same sensors, eg TPS, CID, CPS, O-2s, AIB (or AIC) MAF, etc. Most of the connectors will be the same and the wire will be routed to the same place.

There may be a few odd wires or connectors that are different. This is why you trace every wire on the two wiring diagrams. As for the change in connector styles, it is relatively easy to swap the wires and connectors.

On the alternator, for example, you eather use the 95 alternator, or change the connector to fit the 89. I think the 95 Alternator will bolt up to the 89 engine mount for the A/C and Alternator. If you have to, you change the mount.

If you think you might be interested in doing it this way get back to me. I have not done this to a SHO yet, but I have done a few other cars.

Believe me, trying to swap the 89 harness into the 95 is a bad idea! And you should not need to. rangerj thumbs_u

 

[EZ4U2ENVY]

well rangerj,
Tomrrow im going to look at a car im possibly more than likely getting to swap the conversion. so tomorrow will confirm everything but im very serious about doing it your way instead of taking the harnes from my 91- because the 95 harness is of course better condition.

We are also thinking about new cams in it- but we dont really know how to do the valve lash and kinda intimidated by it but yet were gonna convert a atx to a mtx. go figure right.

We can do anything and everything- its just that first step is always the hardest to overcome. we never have done a valve lash so were not to confident yet.

But do let me know step by step process to help us out- thanx man

 

[rktmn]

I hope to have mine finished by the end of the month. Right now I am installing a quife in my mtx tranny, and I have replaced every seal and gasket on the engine and tranny. I also swapped in the 3.0 head onto my 3.2 block.

Here's a link to some

photos.http://groups.msn.com/JoseAFernandez/atxshoswaptomtx.msnw

 

[EZ4U2ENVY]

When do head gaskets usually give- and when should they be replaced..

 

[rangerj]

EZ4U,

Head gaskets are rarely an issue on the Yamaha 3.0L. There are a number of SHOs out there with 250,000+ miles on them with their original head gaskets in tact!

If you have a concern about the motor you intend to use, do a compression test, and cylinder leakdown test. If you pull the heads off of a well seasoned engine you may need to have the heads planed, and maybe have the block decked. Why take the chance if you do not have to.

Start making a list of the sensors for the 89 and 95. Then look up the part numbers. If the part is the same the connector has to be the same.

Next, the 95 parts that are a different number may be an improved sensor, and may fit the 89 engine. Why not use the improved sensor? For example, the Throttle Position Sensor has been improved, and is recommended as the replacement for the older SHOs. The connection is the same.

This is how it should go. One step at a time. Let me know when you are ready and I'll start throwing ideas at you. rangerj