1.3 Motronic Up-Grade & 2.7i How To

[deeze30]

The cam is not necessary, but man is it fun!

I bought a rebuilt 885 head with cam, adjustable timing gear, and chip, all at once from BimmerHeads. I don't recall the price, but it was a great deal all things considered.

I can't speak for the mark d tune, as one never experienced it, but I will say am happy with the sssquid tune.

Thanks for clearing up my concerns :up:

Now i just need to pick up this 325i parts car and get to workin :) maybe i'll consider rebuilding the head and anything else before i do the swap.

[Andy.B]

The cam is not necessary, but man is it fun!

I bought a rebuilt 885 head with cam, adjustable timing gear, and chip, all at once from BimmerHeads. I don't recall the price, but it was a great deal all things considered.

I can't speak for the mark d tune, as one never experienced it, but I will say am happy with the sssquid tune.

[deeze30]

I have a 'low compression' 2.7i (stock 2.7 bottom end with 885 head) with a BimmerHeads regrind cam and sssquid 2.7i 93 octane chip.

The car starts and idles fine in all but the coldest weather ( < 0° Fahrenheit).

I suspect the stories of it running rough or being hard to start are due to intake leaks, not the slightly lowered compression.

Is the regrind necessary? How much did that cost? How you like sssquid? Better than markd? Cheaper too

[Andy.B]

I have a 'low compression' 2.7i (stock 2.7 bottom end with 885 head) with a BimmerHeads regrind cam and sssquid 2.7i 93 octane chip.

The car starts and idles fine in all but the coldest weather ( < 0° Fahrenheit).

I suspect the stories of it running rough or being hard to start are due to intake leaks, not the slightly lowered compression.

[deeze30]

awesome thread

informative, been reading and makes me want to work on my eta right now haha

I'm in the process of getting a complete 89 325iC from someone for my 84 325eta. I know it was mentioned here that everything is pretty much swap i parts to e with NO machining or custom pistons (unless you want to) needed right? I also saw that bolting a stock i head to eta block will be a low CR, which is fine because i plan to turbo the car later down the road BUT it will cause the car to have rough idle and hard start.

Would buying a chip fix this issue? I'm trying to avoid any machining work because I don't have access to one and I know they can be pricey but IF i do, what part specifically and what machining needs to be done? and if so, how much you reckon it would cost? Thanks

[Regnar75]

Couple questions for you.

1st: About the starter. first you mention using the grn/blk wire on the top spade connector, but then later you said you removed it??? just left the grn/blk unplugged?

2nd: Where did you pull the wires that go to the c104? I understand that are coming off the harness from the ecu, are they seperated or do I have to fish for them?

3rd: Easier solution for oil level and oil pressure is to grab the correct sensors for the "I" correct?

4th: What did you do for the valve cover breather hose? Again, just grab one from the "I"?

Thanks, your quick quips are very helpful.

1st: keep it connected. it is your unloader relay. i took it off once because i was having an issue, which it resolved at the time, but i think i had a connection issue and it wasnt a permanent fix. id keep it in. il check today to see how i left it.

2nd:the connector should be coming from the tach area its a white connector. you have to open the wiring bundle going to the ecu to get to the wires that connect to the tach.

3rd: absolutely. just grab the new sensor and swap it out, same goes for the oil pressure sensor. its easier to grab the sensor that goes to the harness/ecu than to splice a harness.

4th: yep. just got a new I hose. my e hose was cracked but i dont think it would work anyway.

its been a while but i think i remember most of it. il see if i can take some pictures today.

[3vilE30]

Don't know where to put this sooo.

Bought an 86 325iS with an 154 super eta ecu
Replaced it with a 380 (late model 173) ecu.
Proves that all motronic 1.1/1.3 ecu's are interchangeable

I noticed the 380 ecu idles alot smoother than the 154.

[2mAn]

-Pay attention to how many prongs are on your starter. I have 2 studs and 2 spade connectors. Red goes on the right most with thick black battery connector. I put green in top and yellow on bottom. No issues yet.

-to get tach and econometer working use small connector in glove box (c104) and the harness into ecu, attach the black wire in harness to the Black wire on c104 and the black/white (not black/grey!) Of harness to Yellow/white of c104.

-oil level sensor and oil pressure sensors are both different from motronic 1.0 and require you to switch sensors or splice wires and make due. Grab the sensor from junkyard car if your on a budget.

- the valve cover vacuum hose is different if your using all I parts (your e hose will not transfer)

Edit.

- had some starter issues and removed top spade connector and now it works no issue.

Couple questions for you.

1st: About the starter. first you mention using the grn/blk wire on the top spade connector, but then later you said you removed it??? just left the grn/blk unplugged?

2nd: Where did you pull the wires that go to the c104? I understand that are coming off the harness from the ecu, are they seperated or do I have to fish for them?

3rd: Easier solution for oil level and oil pressure is to grab the correct sensors for the "I" correct?

4th: What did you do for the valve cover breather hose? Again, just grab one from the "I"?

Thanks, your quick quips are very helpful.

[Maad325]

So I have an I bottom end would it be best to use the i pistons and e rods? Or would i rods and i pistons work well?

[Regnar75]

^i think you have a solid setup with just that. if your daily driving it the 3.25 will give you better mpg, i have the 3.73 and it was a HUGE upgrade in acceleration over the 2.93 (although i do miss shifting from 2nd gear at like 70mph). but even now the MPG isnt bad and its a blast. it shocks everyone who sits in it with acceleration. i think a 4.10 would be pretty awesome, as long as your good at shifting :)

ive read that the 525 is a better ecu than other motronic 1.3's but idk enough about the hardware or software to be certain.

not to mention, the best LSD diff, is the one you already have, let it ride bro.

[jayuuey]

thanks for the replies. I'm pretty torn on getting the cam upgrade. My motor has 275k and I don't see myself refreshing the bottom end just yet. I think i'll just stick with the standard cam right now.

My plan is,
refurbed 885, stock cam, motronic 1.3
stock eta bottom
17# injectors from mepeh
stage 1 sssquid 327i
Probably stick with my 3.25 lsd unless I can get a good trade deal for a 3.73

[Regnar75]

-How many miles on your bottom end (assuming untouched)?
225k before the swap as well

-Did you upgrade the cam, i.e..274, etc. ?
nope went with 885 head and stock cam

-Does an upgraded cam require hd rockers?
stock cam, stock rockers for me

-What rpm does power drop off after the swap?
mine starts pulling at what appears to be just before 3k all the way to about 6k, i usually shift at 6200ish anyway. still pulls above 6k but not as strong, feels better to just shift and get back in the sweet spot.

-Does the motor feel right in upper RPMs?
I love mine, ive driven a 325i with a cam and it didnt feel nearly as strong as my motor now. idk what you mean about feel right but yes...im sure it does :)


just match your o2 sensor to the harness/ecu you have, motronic 1.3 (525 ecu) is a 4wire o2 sensor. IDK about fuel rail differences in ETA SETA and 325i

just cut with a dremel, or a chisel, or a hammer, or just hope. any of the typical hole-making-in-e30 tools

[squidmaster]

So I've got a built 2.7i seta with the transmission out of the 88 e28. Also I have the 525 ecu and a wiring harness off of a 1991 325i. I've heard rumors that I'll need a oxygen sensor off of a 1991 325i? If so is it plug and play? Not in the bung but on the other side, I'm getting a custom exhaust done so I just need help with the other side and don't know which sensor to get.

Also I'm hearing rumors that I'll need a new fuel rail?

Any help please..

you might need a new fuel rail-- it depends what chassis year the engine is going into. stock 325e fuel lines are setup for opposite-side return rails, and later model 325i (after 89+ I think?) have same-side returns. I believe I have a spare opposite-side return rail if you need one.

just get a new o2 sensor for the 325i (4-wire). It's a good part to have in working order.

Another basic q. How did you enlarge the hole for the wiring harness? dremel? hole saw?

good luck using a hole saw on something that's already a hole haha. Dremel or small angle grinder would work fine. Be careful, wear eye protection, and go slowly.

[jayuuey]

Another basic q. How did you enlarge the hole for the wiring harness? dremel? hole saw?

[ColbsE30]

So I've got a built 2.7i seta with the transmission out of the 88 e28. Also I have the 525 ecu and a wiring harness off of a 1991 325i. I've heard rumors that I'll need a oxygen sensor off of a 1991 325i? If so is it plug and play? Not in the bung but on the other side, I'm getting a custom exhaust done so I just need help with the other side and don't know which sensor to get.

Also I'm hearing rumors that I'll need a new fuel rail?

Any help please..