converting obd1 to obd2 (1 Viewer)

[semlin]

i did a search but can't see a discussion. this is strictly blue sky musing for now but has anyone converted an 93-94 obd1 truck to 96-97 full obd2 or considered what might be involved? there are more 80s in pick a parts all the time. i don't have a 96-97 fsm or any hands on experience for comparison.

my main query is whether a 96-97 ecu could run with an a442f tranny or whether you would need to get an overseas ecu and harness.

apart from that i'm thinking harness, ecu, new maf, new o2 sensors, fuse box. possibly new speedo cluster, maybe some engine sensors, throttle body, disconnect pair valve. what else? Are there any major components such as brakes that would need to be upgraded if you switched harnesses? any major foreseeable problems with the harness? Is the airbag controlled by the ecu and can it be fooled into passivity?

discuss...

 

[Scamper]

Aside from all the parts you've listed--which I agree are likely needed to be replaced--there are a number of sensors that would have to be added. But wouldn't it be cheaper and easier to just buy a '97?

 

[semlin]

well no actually. i'd lose a fortune if i sold my 93 and started over with a 97.
I have a 4x4 lab bumper that stays since it required a bobbed frame, 93-94 fit hanna sliders and i'd have to source a 93 front bumper if i took the arb off. plus i already have a 3 core radiator, a motor with a h/g replacement i did myself, clean fuel injectors and rail, birfs repacked, rotors replaced, a lift I like, etc...

...and a superior tranny

so it's really the best of both worlds

does the 96-97 have just a single o2 sensor btw the cat and manifold? the dual downpipes on my 93-94 might cause a problem.

 

[Scamper]

well no actually. i'd lose a fortune if i sold my 93 and started over with a 97.
I have a 4x4 lab bumper that stays since it required a bobbed frame, 93-94 fit hanna sliders and i'd have to source a 93 front bumper if i took the arb off. plus i already have a 3 core radiator, a motor with a h/g replacement i did myself, clean fuel injectors and rail, birfs repacked, rotors replaced, a lift I like, etc...

...and a superior tranny

meh Just a few more things to add to the "price" of getting OBDII. Oh...and the tranny thing...get over it

does the 96-97 have just a single o2 sensor btw the cat and manifold? the dual downpipes on my 93-94 might cause a problem.

The '97 has front and rear O2 sensors to feed the superior OBDII ECU that comes with the '97

 

[landtank]

a good place to start with this would be to list the sensors on the ECM for both configurations. I'll start from memory and add some later if I find them.

OBDII

MAF
TPS
IAC
Injectors
knock sensor 1
knock sensor 2
water temp sensor ECM
water temp sensor Guage
Oil pressure
Oil level sensor
bank 1 sensor 1 O2 sensor
bank 1 sensor 2 O2 sensor
crankshaft position sensor
egr temp sensor

and then the tranny stuff which would probably need to be addressed separately.

 

[semlin]

thanks landtank. you are thinking my way on this.

i have everything there but an egr temp sensor (federal 93) but i could probably grab that wherever i get a harness. it would make sense for me to source an EPC for this to figure out what parts switch over and what don't. i know the water temp sensor gauge is a match.

big questions so far are the tranny and the single o2 sensor. I'm certainly not looking to install a 97 exhaust and cats, and i doubt i can safely run the truck sampling only three cylinders with the forward o2 sensor.

 

[RavenTai]

airbags and ABS are separate ECU's and have their own diagnostic systems so all you have to worry about is the engine and transmission, all the engine stuff should bolt up, the transmission is the biggest stumbling block. do 80s from other markets have OBDII? I thought that was a US EPA regulation? I could see Canada rubber stamping it as we are almost one market in that sense, but elsewhere?


the transmission does not have much wiring to it on a 96, a speed sensor, 3 wires for the solenoids and a temp sensor

does the 442 also have 3 solenoids? if so how would the 442 do with the 343 shift points?

worst case you could dummy load the solenoid outputs of the ECU and make an electronic shifter, you will have a clutch less manual/auto trans. might throw a code if the ECU does not see it shifting when commanded though,


you are goign to have to run the 97exhaust or at least the 97 rear o2 sensor forward setup or a custom 2 into one, then o2 #1 , then cat then o2#2, exhaust.

 

[GXO]

If it runs so well why worry about codes?

Sounding more like unobtanium with the issues in the tranny...

 

[semlin]

raventai,

europe has obd2 and according to this site all 96+ toyotas are obd2 compliant
http://talktomycar.co.uk/Shop/Code_Readers/mj003.htm. having to buy a european wiring harness and ecu would not be a lot of fun.

can't confirm for australia but it looks like toyota was compliant from 96+.
of course i seem to recall oz 1fzfe engines don't have an EGR valve so I imagine they won't control a vsv for egr.

I believe the 44f has 3 solenoids. I'll see if i can track down shift patterns and gearing for the 343 / 442 in hi lo and power and compare. I am now thinking about the 7 pin cdl mod being the same for all 80s. hopefully, that means the transmission control relay, at least, is the same.

that leaves the exhaust. I can see welding a bung in for the back o2 sensor but not how to deal with the front. no way do I want to buy a whole manifold back exhaust system.

 

[landtank]

considering the OBDII trucks get better gas mileage and the rocketing prices lately, this might not at all be that expensive in the long haul. I'm not saying it would get paid for by fuel savings but it sure would get helped by them.

 

[Cattledog]

This thread may be a place to start. here

 

[semlin]

cattledog that is intriguing. 93-98 mkiv supras all use a karman vortex air flow system and seem to have the same o2 array so the virtual plug and play obd1 to obd2 ability makes sense. i'm not sure if i have the necessary wiring skills to catch all the adjustments to the harness that would be needed to convert the obd1 cruiser vaf to maf but it is surely worth researching to avoid having to pull the dash!

 

[landtank]

the first thing is to see if by chance the plugs are the same on the ECM. Since both the VAF and MAF are 5 wire systems it would be as simple as getting the 5 wires in the correct spot then putting the correct connector at the meter. This is possible since both systems use the same IAT sensor as far as readings go.

Here is a scan from the manual of the 4 connectors on the ECM

 

[cruiserdan]

Why are we fixing something that isn't broken?

 

[landtank]

Why are we fixing something that isn't broken?

I'll give you the same answer I give my wife.....because.

 

[cruiserdan]

It doesn't work here either...........

 

[landtank]

It doesn't work here either...........

you got it wrong Dan it's this one ...

 

[cruiserdan]

LOL!

OK, you got serve.

 

[semlin]

Why are we fixing something that isn't broken?

tell me about that extra wiper fluid bottle in your truck again

 

[semlin]

the first thing is to see if by chance the plugs are the same on the ECM. Since both the VAF and MAF are 5 wire systems it would be as simple as getting the 5 wires in the correct spot then putting the correct connector at the meter. This is possible since both systems use the same IAT sensor as far as readings go.

Here is a scan from the manual of the 4 connectors on the ECM

same layout but different labels.