87 ECU vs 88 ECU

[the_dingman]

I have a spare ECU from an '88 (Mine is an '87) and I've hooked it up a few times. My engine seems to run better, but the Check Engine light comes on. Does anyone know the differences between the '87 and '88 ECU and sensors?

 

[GonOvr]

'87 is a one wire O2 sensor, '88 is a four wire type.

'88 has an EGR time delay switch.

'87 has a vacuum advance distributor.

Im sure there are some other differences. Probably not a good idea to cross ecu between years. Unless you know for a fact that it will work. Could have done a lot more damage like burning up a harness.

 

[SV_Dude]

Do not, Do not, DO NOT do that again! You're lucky you did not fry your ECU. The 85-87 trucks/4runners use a different resistance fuel injectors than the later models. The lower resistance fuel injectors were used on 85-87, 88 and up are a higher resistance.

Yes, the 88 and up uses a 4 wire heated o2 sensor but from what I have found in the wiring diagrams the ECU's get the same reading either way. There's only one wire going into pin 15 on the 18 pin plug for the o2 sensor on all 22re ecu's. The other 3 wires are for grounds and the o2 sensor heater which run off the body wiring harness.

You can use any 85-89 22re ECU on your 4runner as long as you change the fuel injectors to match the ECU. You will also need to be sure you are using a manual transmission ecu with a manual transmission engine harness as the wiring is different between the auto and manual harnesses.

 

[the_dingman]

Thanks for the answers!

Trying to track down a misfire at idle when warm... Was thinking of the slight possibility of the ECU.

 

[SV_Dude]

I would check the small things first. Timing, spark plugs, spark plug wires. If you have the FSM there is a step in the EFI section and it tells you how to check your whole ECU with a multimeter to see if it's good or not.

 

[the_dingman]

Replaced plugs, wires, cap, rotor, PCV last week. Timing was set a year or so back when I did the chain/water pump/oil pump.

 

[SV_Dude]

Were you having any specific issues with your current ECU? I know you initially asked what the differences were in the ECU's but you never really stated why you were swapping them back and forth.

 

[the_dingman]

No, I just got curious a few years back and plugged in the 'spare' I have. Noticed it seemed to run smoother, but put on the CEL. With the misfire issue, I got curious if the ECU could be the problem, and this came to mind...

 

[SV_Dude]

If you're having misfire issues and you already did your plugs, wires, ect. then you may want to verify your timing. Maybe your distributor slipped a little and threw off your timing? Also, take the cap off your distributor and clean the contacts on the cap and rotor.

 

[Erockharder]

Bringing this topic back up, I just picked up a 88 v6 and it had 2 ECU inside, both stickers are pretty much unreadable, one had gray slots, other has yellow, yellow I can read some and it says (89661- "" ) (175"""- 10) and I can see (3VZ) just wanna make sure I'm using a correct ECU now that I've read this. The marks are just the numbers I can't make out