1.3 Motronic Up-Grade & 2.7i How To

[ATL_E30]

In the very early stages of collecting parts for this. I have a stock 88 325 super eta, so my question is do I need to collect parts for 88+ or can I get an i manifold, ecu, etc from a pre 88?

Thanks in advance!

[MrWolf]

I've got a 06/86 e (Motronic 1.0 system) that I'm doing a 1.3 upgrade on. I'm ready to swap out the harness and the 1.3 harness fits right on to my stock c101 connector. I know when people had the older square connector some wire splicing needed to be done, but I'm not sure about this.

Do I need to move some wires around or can I just plug the 1.3 harness into the 1.0 connector and go?

I took a photo and there are clearly some pins on the 1.3 side that won't be connected to anything on the 1.0 side.

I think the answer to my question is "Yes" but I'm not sure if I've read about systems getting fried from just plugging and playing. Wanted to be sure before I reconnect the battery.

Been doing some digging, and now after reading this post and its entire 30+ pages twice now, I still haven't found the definite answer. I'm concerned with the same issue that lateracer posted above back in 2010. I've got a near identical setup to his, '86 eta, swapped i head and all necessary parts, using an '89 i harness and 380 ECU, the harness c101 connector fits the body, but the pins don't match exactly. Many have mentioned it's "plug and play" but unlike a few success stories on here, I'm not "firing right up". Here is the engine harness with 12 pins, and the body side with 11 spots.



Does something need to be spliced in here to get it to run? I feel fairly confident everything is connected correctly, but don't know what I am missing. When I turn the key I don't hear the fuel transfer pump, when I jump the fuel relay it fires right up, so pump is good, checked the relays - good, starter engages and engine turns over but it doesn't fire up. I've tried swapping the crank ps and halifax ignition sensor connectors, same results. There are a few wires near the ECU connector that I have no idea what they go to. One brown (should be a ground?) and the other blue/red. Anyone have an idea what these are for?



If anyone who has done the e to i swap and encountered similar issues I'd really appreciate a point in the right direction. I'm so close!

[jeffnhiscars]

Swanny can you clarify. I have a '86 325es, building a 2.7i using a harness from a '87 325i convertible (i think - not positive though). Build is complete but wont start and I'm thinking it has to do with the C101 pins not matching. 12 pins on the harness, 11 pins on the fuse box side.

How can you identify if the injectors are opening? I'm using 19# yellow tops that I refurbished myself, they worked fine when checked with a 9v battery prior to install.

I think my big problem is fuel delivery. My fuel transfer pump runs when jumped, but not with the relay in and the key turned. Relays are good when checked with a 9v, and all the relay terminals checked good with a voltmeter against the Bentley manual. I'm thinking it has to do with the C101 pins. Those electrical diagrams you posted are completely Greek to me. Hoping you can shed some light.

I used a dash bulb (low wattage) between the harness and injector as a test light to see if the ecu was firing the injectors. To test the actual injectors pull the rail and point the injectors at a piece of cardboard. If it gets 6 wet spots they work

[MrWolf]

Which harness do you have and what ECU? Its possible with the late harness the injector connection has corrosion causing firing issues. Are you sure fuel is getting into and through the rail?

I had to jump a relay to get my fuel flowing properly in my 87is. Took time with the ETM chasing down wires to get it all sorted out since they're a weird in between model.

Swanny can you clarify. I have a '86 325es, building a 2.7i using a harness from a '87 325i convertible (i think - not positive though). Build is complete but wont start and I'm thinking it has to do with the C101 pins not matching. 12 pins on the harness, 11 pins on the fuse box side.

How can you identify if the injectors are opening? I'm using 19# yellow tops that I refurbished myself, they worked fine when checked with a 9v battery prior to install.

I think my big problem is fuel delivery. My fuel transfer pump runs when jumped, but not with the relay in and the key turned. Relays are good when checked with a 9v, and all the relay terminals checked good with a voltmeter against the Bentley manual. I'm thinking it has to do with the C101 pins. Those electrical diagrams you posted are completely Greek to me. Hoping you can shed some light.

[Swanny]

Some issues with the tach and fuel eco gauge. The body harness is going to be missing all the OBC stuff and a few other connectors on the body side are going to be different. Its been a minute since I’ve had to comb through the eta stuff so i’ll keep an eye out and see what else I can find. Please tell me you have your own copy of the ETM though as its much easier to flip and compare.

[RichiesE30]

What year is the shell?

87 eta shell


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[Swanny]

So I have a 87 I harness, is it completely plug and play? From what I've been reading it sounds like I'll still have to change the c101 connector wiring. Should I just cut the old plug off my eta harness and wire it to my new "I" harness? Thanks in advance.

What year is the shell?

[RichiesE30]

So I have a 87 I harness, is it completely plug and play? From what I've been reading it sounds like I'll still have to change the c101 connector wiring. Should I just cut the old plug off my eta harness and wire it to my new "I" harness? Thanks in advance.

[shootnjunky]

tagged

[LovelessAndroid]

In this thread digger touches on some good points
http://www.r3vlimited.com/board/showthread.php?t=304600

I've officially gone down the rabbit hole for the stroker build...

I am liking the 2.8L M52 more and more since I have all of the expensive parts and just need the crankshaft and spacer.

However, I have a follow up question too... instead of getting an IE 272 regrind or a Bimmerheads 274 regrind, if I run the stock cam will that yield the most low-end torque? Or should I at least aim for a 270 to make the most of it?

I stumbled upon the 2.8 article on E30wiki and it is pretty great.

http://www.e30zone.net/e30zonewiki/index.php/Building_a_2.8

[Swanny]

It's 88 harness and I'v checked every connection cleaned and used tons of eletric grease.....running a 173 dme

Get the ETM for 87 and 88 and go side by side. Probe test with a multimeter to be sure you have power where you need it.

[Swanny]

In this thread digger touches on some good points

http://www.r3vlimited.com/board/showthread.php?t=304600

[LovelessAndroid]

http://www.r3vlimited.com/board/showthread.php?t=193894 is another good thread for piston rod crank combos

So they immediately list the 2.7 stroker as ETA block, rods, and SETA pistons... however on Strictly ETA's website it shows the compression ratio of a stock SETA as 8.5:1. According to E30zone wiki, swapping an 885 head directly onto an ETA block will yield 9.4:1.

Why does the "default" stroker build use SETA pistons?

There appears to be a lot of conflicting advice between Strictly ETA and E30Zone, especially with the results of using 325e pistons with the 325i head...

I also like the idea of using the M52 crank with my 325i pistons which yields a 2.8L stroker, and the M52 crank can be found readily for under $100 and the price of a crank spacer. (Oh lawdy, just saw the price for the MM crank spacer... $200. Anyone selling one?!) Someone lists that combination as 9.3:1 without decking the block, 9.7:1 with the decking... so again I'm still in the same CR range of just swapping the 885 head onto the stock ETA block BUT I get to 2.8L.

Would decking the block 0.5mm require an adjustable cam gear? Or can I get away with it since I want to go to MSPNP and can adjust my ignition tables that way? It appears that I would need one.

[Bulldog]

It's 88 harness and I'v checked every connection cleaned and used tons of eletric grease.....running a 173 dme

[Swanny]

Ok....I made it to page 12....so I'm just going to ask....what I got is a 87 325e chassis just dropped in a 88 m20b25 with harness....getting spark and fuel pressure....but injectors won't open....everything checks out ....but what about cp101 plug is there any pins that need swapped around ?

Which harness do you have and what ECU? Its possible with the late harness the injector connection has corrosion causing firing issues. Are you sure fuel is getting into and through the rail?

I had to jump a relay to get my fuel flowing properly in my 87is. Took time with the ETM chasing down wires to get it all sorted out since they're a weird in between model.