MK1b engine into MK1a car - It Lives

[playmonkey]

Hi all

I have acquired a MK1b engine to fit into my MK1a.

At the moment I have the complete MK1b car to salvage any bits I might need to make the donor engine fit my MK1a

I'm sure this has been covered in a previous post so if anyone can point me in the right direction I'd appreciate it.

Cheers

[PW@Woodsport]

There is nothing to say really, it's all just a straight fit.

[playmonkey]

Brilliant, thanks "PW"

I thought I read somewhere the ECU was different or the loom or both....

Question though....

Should I fit the whole lot as it comes out of the other car, or am I ok to use the inlet and fuel rail from the 3 rib engine that's in the car already?

Cheers, PM

[Lauren]

The mapping on the early ECU is arguably better than the later one, but it doesn't hugely matter really.

The injectors are bigger on the later engines, but again it won't make any real difference. I would just fit the whole lot, much easier and nothing to gain from fitting an earlier intake.

I had a later engine in my MK1a, no problem. I've got a later engine from an MR2 in my AE86, again, no real issue.

It should all plug and pray.

[playmonkey]

Thanks for the answer.... will swap the whole lot, but might as well leave the earlier ecu in the car as it's already sat there.

Got the old engine out this morning, other engine coming out this afternoon.

Not a five minute job, is it

[PW@Woodsport]

but might as well leave the earlier ecu in the car as it's already sat there

Do not do that, bad things will happen, early cars run without an injector resistor pack, later ones have the resistor pack, you have to run the correct ECU with the loom/injectors/resistor pack.

As advised swap everything, including the new ECU, into the car.

[playmonkey]

Ok, thanks. I thought that might be the case from what I've been reading and I appreciate the confirmation.

If you can indulge me....

What part of the actual motor needs to use the resistor pack? If I was to swap the injection system complete from my original 3 rib, over to the 7 rib will it still cause problems with the motor, or is it just the induction systems?

I'd rather not have to change the loom, but don't mind swapping over the injection systems?

Thanks

[Lauren]

but might as well leave the earlier ecu in the car as it's already sat there

Do not do that, bad things will happen, early cars run without an injector resistor pack, later ones have the resistor pack, you have to run the correct ECU with the loom/injectors/resistor pack.

As advised swap everything, including the new ECU, into the car.

I had this on my AE86, Paul, it didn't actually matter, as I'm running an early ECU with the later injectors. Can't remember the exact conversation as it was a few years ago, but I remember going through this with you.

EDIT: so it seems it's not the same as the AW11. My mistake:

Ah, here it is:

Just spoken to Mark. The both are low impedance resistors. The AE86 ECU and setup it not the same as the early AW11.

It runs low impedance without a resistor pack.

You said:

That would make sense, but terribly confusing! Your AE86 ECU must be able to drive low imp injectors without a resistor pack, so pink Mk1b ones should then be fine.

What i don't like is Toyota making an early engined AE86 with the same colour and shape injectors as a Mk1a from the same era but changing the impedance, that's a bit naughty to say the least, i wonder how many people have bought some AE86 injectors and tried to use them in a Mk1a or vice versa?

I remember talking to Tom about this and now remember the two injector types resistance being somewhat the same.

That injector difference (but same colour/shape) would catch a lot of people out.

[PW@Woodsport]

Yeah we have seen people cross fitting early and late ECUs and running into problems, to be fair some of them had decided not to run the resistor pack, so to avoid any confusion now I advise keeping the whole lot matched, ie. if you have a Mk1a loom/injectors/ECU then use all of that, if you have a Mk1b loom/injectors/ECU/resistor pack , then use all of that.

I have also seen issues with using the wrong distributor type, from memory a Mk1a dizzy on a Mk1b setup resulted in backfires and a low RPM limit.

The mechanical engine is a straight swap, that is block and head, just use everything from the same revision that controls it, you even need to use the matching inlet manifold and Tvis, Mk1a had an IAT sensor in the manifold and different shaped TPS/Tvis VSV plugs.

It's when mixing and matching starts that problems can occur, just keep everything revision relevant and it will plug and play.

[PW@Woodsport]

I'd rather not have to change the loom, but don't mind swapping over the injection systems?

Surely your new engine has the loom already on it though?

It would be a simple case of passing the loom through the boot wall and plugging it straight into the ECU/COR/N1 connector.... in the engine bay it just plugs into the M2 connector.... done.

That's way way simpler than changing over the entire loom/injectors/rail/tvis and inlet manifold from your old engine?

You would also need to swap distributors over which means getting it back in on its helical cog on the correct tooth and redoing your ignition timing.

I would just use everything with the new engine.

[playmonkey]

Hi yes, I can take the loom from the donor car along with the engine and ecu.

I suppose it was just the fact that all the parts and loom in my car are clean and tidy whereas the donor car parts and loom are messy and I haven't got time to clean everything before installing.

Now you have mentioned the distributor though, I feel it is prudent to swap the whole lot over.

Your comment about being simpler than changing everything over... I had already removed the plenum and rail etc to make it easier to remove the engine - maybe I didn't need to do that?

Questions:
1 - I keep seeing pink injectors mentioned but mine are green?
2 - Where would I find the resistor pack. I can't remember seeing anything extra in the donor car engine bay. Tried to search for images but came up blank.

All interesting stuff. Thanks for your participation.

Just read back through the comments and I'm coming to the conclusions that most people would remove the engine complete with all ancillaries AND loom still attached? I read that you had to undress the engine and move the loom out of the way before removing.... Oh dear....

[PW@Woodsport]

No the whole engine/box/loom drops out without removing anything from it, takes me approx 45-50mins to remove a Mk1 engine, I don't even need to remove the wheels.

Green injectors you say... they aren't Mk1 then I don't think.

Mk1a - grey injectors/ square plug- no resistor pack
Late Mk1a substituted red injectors/ square plug- no resistor pack
Mk1b - Pink injectors/ rounded plug with resistor pack

I've never seen or heard of green Mk1 injectors before, they sound like AE86 ones.... I would probably fit everything from your old engine now.

[PW@Woodsport]

Resistor pack (if equipped) is beside the coil.

[playmonkey]

Thanks for the info....

Seems like I've been wasting a heck of a lot of time taking all the bits off the engine to remove then...Grrrrr. Oh well, live and learn I suppose and always ask a second and third opinion

Coil packs looked the same on both engines. I'll have another look tomorrow. (and both are running green injectors) but they are both race engines.

I'll dress the donor engine with everything and pop it in complete then. Great!

One thing I did notice. On my original damaged engine, the butterflies were nice and clean but on the donor engine they're quite gummed up. Would a good slosh of injector cleaner in the fuel help clean those off? Don't want to be stripping anything down prior to the refit.

Cheers
PM

[PW@Woodsport]

The fuel injectors are after the tvis rail so additives won't work, just clean it up in some wd40 or diesel.

[playmonkey]

Yup, thought as much but worth a shout. WD40 it is then.
Much appreciated.

[playmonkey]

Just an update....

Ok, the injectors on my 3 rib are grey, the injectors on my 7 rib are red. Both the injector plugs are square and both coils have a coil igniter fixed to it. Would show a picture but not sure how to add one....

Because the previous owners of each car have had different positions for their ignition cut off switches, the donor loom has been chopped around and it makes it a bit more difficult to fit into my car.

Question.... Even though the injectors are different and coil packs are the same, would it be ok to use the existing loom as it makes fitting easier?

Thanks, in anticipation....

[playmonkey]

Well, changed the whole lot and she fired up pretty much straight away. In fact she started better than when the engine was in the donor car

Few plugs left over but nowhere to put them so I guess they're redundant.

As there are no water leaks i'll replace with coolant in the next few days then bleed it properly.

Considering this is the first time I've removed and replaced an engine in an MR2 i'm quite pleased that it fired up on demand.

If I can help anyone with my experiences, please ask.

Thanks for all the help in the previous posts.

Cheers

[Lauren]

Great stuff, glad you got it sorted.