97 1.9 Z3 Cranks, but no start

[Cardriver333]

I just got a Z3 that cranks and all the lights work, but won't start. There's gas in the tank and all the fluids are there, but the coolant looks bad. I sprayed starter fluid in the air intake and nothing. Replaced the spark plugs and ignition coil and no spark. The ECU has a printed sticker saying "THIS UNIT IS UNREPAIRABLE AND IS BEING RETURNED "AS IS"". The trunk had 5 extra DMEs, 2 extra EWS II, WI-WA LOW II, 3 extra ignition coils, and one extra VDO 274 box. The ignition where you turn the key looks like it was replaced and the key works in it, but the key does not lock the doors so i think the previous owner tried switching out all of the security system. He told me the wiring harness was fried, but I don't wanna take his word for anything. The battery and starter were tested at autozone and they said it was good. The battery currently reads 12.25. Any advice is appreciated. Also, I'm pretty sure the fuel pump is out.

 

[t-tony]

If the fuel pump was inop. spraying starting fluid would make it fire, if not start. I would think you are missing a spark. The ECU sticker is shouting out to me that there is more issues to be looked at. How much did you pay for the car? Where are you located ?

Tony

 

[Cardriver333]

If the fuel pump was inop. spraying starting fluid would make it fire, if not start. I would think you are missing a spark. The ECU sticker is shouting out to me that there is more issues to be looked at. How much did you pay for the car? Where are you located ?

Tony

Yeah, I think it has something to do with the ECU and have tried plugging in all 6 of them with starter fluid and still got nothing. I'm in Sacramento and paid $200. I just hooked a multimeter up between the negative cable and negative terminal of the battery and pulled fuses until i saw a reading drop which I think indicates a short. The only one that had any change was #31 which says it controls antitheft, clock, electronic immobiliser, instruments cluster, and on board computer.

 

[NZ00Z3]

You're going to have a world of fun. Sounds like someone has been there before and tried lots of things and couldn't get the car to start.

Has the car been stolen and resold? Anyway to check?

Under the bonnet/hood there is a black box where the DME lives. In that box is a black cube of 4 or 5 fuses. With the key in position 2, there should be 12V DC to earth on both sides of all fuses.

• Have Voltage = Security system has released and the car should start and run
• No Voltage = Drive away protection is still enabled. Car will not start.

Do the test and report back.

 

[Cardriver333]

You're going to have a world of fun. Sounds like someone has been there before and tried lots of things and couldn't get the car to start.

Has the car been stolen and resold? Anyway to check?

Under the bonnet/hood there is a black box where the DME lives. In that box is a black cube of 4 or 5 fuses. With the key in position 2, there should be 12V DC to earth on both sides of all fuses.

• Have Voltage = Security system has released and the car should start and run
• No Voltage = Drive away protection is still enabled. Car will not start.

Do the test and report back.

I don't think it was stolen there are pictures of it in the guys driveway on google maps and he's an older guy. If I attached these pictures right you should be able to see I think that box of 5 fuses you're talking about has been bypassed.

 

[NZ00Z3]

Do you have a set of wiring diagrams for your car? There are 6 that cover the production run of the Z3. Get your build date (MM/YY) and check the date range in the right bottom corner on the front page of each set of diagrams. The diagrams are in the "Resources" section of this forum. See the blue ribbon at the top of your screen.

You need to find the main DME relay, physically and in the wiring diagrams. It is powered by two fuses, one for the control (coil) and one for the switched contacts. Check that with the key in position 2, that the relay has power from both fuses and that it is closing and providing power to its controlled circuits.

 

[Cardriver333]

Ok. I found the diagram and I found the engine control module relay physically and on the diagram. Here's the link.97 z3 wiring diagram

I've been staring at this thing for a couple hours and I don't exactly know how to check that the relay has power from both fuses and that it is closing and providing power to its controlled circuits. I am working on it though.

 

[NZ00Z3]

Remove the relay and check that the base has the 2 power supplied with the key in position 2. Use the diagrams for the pin out.

Slowly out it back in with the key in position 2 and listen for the "click" as it operates.

 

[Cardriver333]

Ok, i was in the process of that when i noticed some wires had been cut and added. Here's a photo from under the air intake. At this point I'm wondering should i just find a new wiring harness?

 

[NZ00Z3]

You're going to have a world of fun. Sounds like someone has been there before and tried lots of things and couldn't get the car to start.

Yes you can get another wiring harness. Is it just the engine harness or has someone sliced and dices the main car harness too?

Have a look at the EWS wiring under the dash. Has it been sliced and diced as well?

At this point, you need to consider if it's worth all the effort and the continual ongoing costs until you either finally get the car up and running or decide to sell it or part the car out to partly recover incurred costs.

 

[Cardriver333]

Yes you can get another wiring harness. Is it just the engine harness or has someone sliced and dices the main car harness too?

Have a look at the EWS wiring under the dash. Has it been sliced and diced as well?

At this point, you need to consider if it's worth all the effort and the continual ongoing costs until you either finally get the car up and running or decide to sell it or part the car out to partly recover incurred costs.

As far as i can tell every other wiring looks good for the most part. And I picked it up for a few hundred as something to learn on so i know you're probably right, but I wanna learn this stuff so I'm gonna keep trying. I stayed up all night pulling the air intake and engine wiring off.

 

[NZ00Z3]

OK, so you're looking for an engine harness for the same engine type as your car, a M44, from a Z3.

www.RealOEM.com is the place to go to for part numbers and to see what other cars used the same part.

• Put the last 7 digits of your VIN number into the search tool. This will give you the parts for your car's build.
• Bookmark the page, you'll be back often.
• Search for the part number of the item you are looking for.
• Click on the part number and it will show you what cars used that part.

I had a look at a generic USA 97 1.9 Z3.

• All harness are just for the Z3.
• For the manual transmission, there is only one option
• For the auto transmission there are 2 options. Either the car has option S205A or not
• What is option S205A, I don't now. This is where you head off into the internet and find a BMW build Decoder. Put your whole VIN number in and it gives you the full option list for your Z3. Many are now paid services. Here's one that used to work, haven't tried it lately. https://bimmer.work/

 

[Cardriver333]

OK, so you're looking for an engine harness for the same engine type as your car, a M44, from a Z3.

www.RealOEM.com is the place to go to for part numbers and to see what other cars used the same part.

• Put the last 7 digits of your VIN number into the search tool. This will give you the parts for your car's build.
• Bookmark the page, you'll be back often.
• Search for the part number of the item you are looking for.
• Click on the part number and it will show you what cars used that part.

I had a look at a generic USA 97 1.9 Z3.

• All harness are just for the Z3.
• For the manual transmission, there is only one option
• For the auto transmission there are 2 options. Either the car has option S205A or not
• What is option S205A, I don't now. This is where you head off into the internet and find a BMW build Decoder. Put your whole VIN number in and it gives you the full option list for your Z3. Many are now paid services. Here's one that used to work, haven't tried it lately. https://bimmer.work/

That's great! I really appreciate your help. I have a manual so that makes the choice easier. I'll buy a harness right now.

 

[Cardriver333]

So I pulled the engine wire harness out because there were cut wires. I bought a replacement engine wiring harness, key, ignition, EWSII, DME, and lock set.

I don't see any damage to any of the remaining wires so if i replace these pieces should that solve the security lock problem? There's also this box above the pedals. Do I have to replace it too? I don't think the pieces I ordered come with one

 

[t-tony]

Does that help?

Tony.

 

[Cardriver333]

Does that help?

View attachment 212745

Tony.

Haha yeah, as you can see I don't know how the formatting works on here.

 

[t-tony]

I just copied the picture, rotated it 180 deg. and uploaded it. Thought it may help with reading numbers etc.

Tony.

 

[NZ00Z3]

The photo of the black box is your EWS. I'm guessing that the white box with the yellow connector in the photo of the items you purchased is the EWS in that set. They are different.

A couple of options:

• Find a kit of items that match your car.
• Work through the EWS wiring for the different models/year builds and patch the later version EWS into your car.
• Have a look through all the parts that came with the car and see if you happen to have the original DME that matches your EWS. This assumes that the EWS installed is the original. You can check by scanning it to see if the VIN number matches your car.

You are going to need a scanner with BMW software and to be able to code new modules to your car. This is an interesting case as your Z3 is a 97, so the DME is OBD2 but the rest of the car is OBD1/ADS. Read this thread. https://zroadster.org/threads/how-to-scan-early-model-z3s-pre-build-date-03-98.39937/

Attached is a file on the EWS family.

 

[Cardriver333]

Here are all of the electronic boxes in the car minus the BMW AG EWS which is the picture of the black box under the steering wheel. The document you just shared says it is the transmitter/receiver module. I think i sorted through and put the original set back together. These all came from under the glove box except the DME. You can see on the DME it says "This unit is unrepairable and is being returned as is".

And here is a photo of all the other electronic boxes that came with the car.

 

[colb]

Seems to me with all those modules you need to check what part numbers were fitted to your car when it was built so you know the part numbers it should be fitted with. No good just fitting any module to the car they have to be the right one for the car. Recent job I sorted on a Z3 for a member with an airbag issue turned out that the wrong part number module had been fitted before he got the car and following a self inflicted fault when he turned the ignition on with a seat disconnected gave him an airbag light that couldn't be cleared. He had tried fitting a used module from ebay with the same part number but that proved to be locked up with crash data that couldn't be cleared. Research using Realoem parts site revealed that it was indeed the wrong part number for his car. Managed to source a correct module from one of our resident breakers and that was installed on the car followed by coding it to the car with NCS Expert which turned off the air bag light and restored the module to full working condition. Worth noting Realoem will list modules that are suitable to be fitted retrospectively or not if the part number list displays more than one module in the listing for your car.
Go to Realoem enter the last 7 letters and digits of your Vin number and take a look at each of your modules part numbers and compare the pile of modules you have.

RealOEM.com - Select Your BMW Model

RealOEM.com BMW Parts website. This site can be used to look up BMW part numbers and approximate part prices. The Parts are grouped into diagrams and diagrams are grouped into categories and subcategories

www.realoem.com

The one you have with the label saying unrepairable would appear to have been sent off for repair and found to be totally duff and unrepairable so thats going to be a paperweight.