3.0 D-Jet to 3.5 conversion

chicane

chicane

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Has anyone made a fuel injection to carburetor conversion, and if so what was involved parts and mod wise?
 
In short: Don´t bother
I´ve been through all sorts of carbs: Old Weber DCOE, new Weber DOCE, freshly rebuilt Zeniths, none of those setups runs as well as the good old D-Jet I had on my previous 3.0SI (rustbucket) after I´d fixed the D-Jet.
the FI is superior
 
Re: FI to carb conversion

chicane said:
Has anyone made a fuel injection to carburetor conversion, and if so what was involved parts and mod wise?
Click to expand...

Its the reverse of doing a carb to FI conversion. :wink:
 
What I really wanted to ask is has anyone migrated to a later model Jetronic conversion.
 
x_atlas0 said:
chicane said:
What I really wanted to ask is has anyone migrated to a later model Jetronic conversion.
Click to expand...

Rather than a Moronic from carb or D-Jet?
Click to expand...

The motronic seemed reasonable until I found out that it looks like you have to replace the transmission for this conversion and I am not interested in doing this. Also, if I go Megasquirt do I need the OEM air pressure sensor?
 
chicane said:
The motronic seemed reasonable until I found out that it looks like you have to replace the transmission for this conversion and I am not interested in doing this. Also, if I go Megasquirt do I need the OEM air pressure sensor?
Click to expand...

Actually, with a Motronic 1.3 conversion, you can leave the drivetrain alone. With a Motronic 1.0, yes, you need an early Motronic bellhousing and flywheel, as the crank position hall effect sensor gets timed off the flywheel. With Motronic 1.3, the crank position sensor is tied to a modified harmonic balancer on the front of the engine, between the lower timing cover and the primary crank pulley. I did this with my coupe and it has worked out great so far. I was able to get the entire system (balancer, harness, DME, sensors, 3.5 intake manifold, the whole sheebang) for <300$. However, if you are going to use the later intake manifold, a 2002tii brake booster is required, not something easy to get.
 
x_atlas0 said:
chicane said:
The motronic seemed reasonable until I found out that it looks like you have to replace the transmission for this conversion and I am not interested in doing this. Also, if I go Megasquirt do I need the OEM air pressure sensor?
Click to expand...

Actually, with a Motronic 1.3 conversion, you can leave the drivetrain alone. With a Motronic 1.0, yes, you need an early Motronic bellhousing and flywheel, as the crank position hall effect sensor gets timed off the flywheel. With Motronic 1.3, the crank position sensor is tied to a modified harmonic balancer on the front of the engine, between the lower timing cover and the primary crank pulley. I did this with my coupe and it has worked out great so far. I was able to get the entire system (balancer, harness, DME, sensors, 3.5 intake manifold, the whole sheebang) for <300$. However, if you are going to use the later intake manifold, a 2002tii brake booster is required, not something easy to get.
Click to expand...

Could you lay out a complete parts list (if you have part numbers that would be great) of everything that you would need for the 1.3 conversion? What about the stock E9 air pressure sensor is that required or does the motronic setup use it's own?
 
chicane said:
Could you lay out a complete parts list (if you have part numbers that would be great) of everything that you would need for the 1.3 conversion? What about the stock E9 air pressure sensor is that required or does the motronic setup use it's own?
Click to expand...

There's an excellent Motronic conversion walkthrough on the firstfives website, it was an excellent prep for what I needed to do, including parts I would need. The full parts list largely depends on how far you want to take the conversion, as well as how stock-looking you want the install. It also depends on the version you want to install, in this case I imagine 1.3.

The Mortronic system doesn't use a MAP sensor to determine air going into the cylinders, it uses an archaic device called (appropriately) an Air Flow Meter, or AFM for short. This device is effectively a flap tied to a spring and a potentiometer. So it reports back the percentage of open to the DME. When this is coupled with a air temp sensor located in the AFM itself and the air density tables in the DME, you get the approximate (some would say very approximate) mass of air going through the device and into the intake plenum. In most modern cars, an alternate device, called a MAF (Mass Air Flow) is used to find the same information using forced convection heat transfer to approximate the velocity of air through a known cross-sectional area. The math isn't too bad as long as you stick to the first or second order models.
 
x_atlas0 said:
chicane said:
Could you lay out a complete parts list (if you have part numbers that would be great) of everything that you would need for the 1.3 conversion? What about the stock E9 air pressure sensor is that required or does the motronic setup use it's own?
Click to expand...

There's an excellent Motronic conversion walkthrough on the firstfives website, it was an excellent prep for what I needed to do, including parts I would need. The full parts list largely depends on how far you want to take the conversion, as well as how stock-looking you want the install. It also depends on the version you want to install, in this case I imagine 1.3.

The Mortronic system doesn't use a MAP sensor to determine air going into the cylinders, it uses an archaic device called (appropriately) an Air Flow Meter, or AFM for short. This device is effectively a flap tied to a spring and a potentiometer. So it reports back the percentage of open to the DME. When this is coupled with a air temp sensor located in the AFM itself and the air density tables in the DME, you get the approximate (some would say very approximate) mass of air going through the device and into the intake plenum. In most modern cars, an alternate device, called a MAF (Mass Air Flow) is used to find the same information using forced convection heat transfer to approximate the velocity of air through a known cross-sectional area. The math isn't too bad as long as you stick to the first or second order models.
Click to expand...


I found the walk thru, thanks. I found the parts list on FirstFives but it was for 1.1. I don't care about stock looking.

I don't have to swap harnesses do I?
If you could just give me the parts list that you used I will start from there, thanks I would really appreciate it.
 
chicane said:
I found the walk thru, thanks. I found the parts list on FirstFives but it was for 1.1. I don't care about stock looking.

I don't have to swap harnesses do I?
If you could just give me the parts list that you used I will start from there, thanks I would really appreciate it.
Click to expand...

That is a bit of a problem, mostly because I don't have such a list. You mentioned you are coming from a D-Jet system , so with that in mind, I can think of the major items you will need for a Motronic 1.3 swap:

1. Motronic 1.3 harness
2. Motronic 1.3 DME
3. All sensors attached to the engine harness.
4. Unless you feel like wiring it all, you will need the Motronic intake manifold, the B35 is preferred. (it will say 3.5 on the side, rather than 3.2/3.5)
5. Motronic fuel rail, injectors, regulator, possibly fuel pump. I don't know the pressure of the D-Jet system.
6. 2002tii brake booster
7. Upper timing cover from a B35
8. Motronic ignition system (cap, rotor, plug wires, possibly coil)
9. B35 valve cover
10. B35 throttle and throttle position sensor
11. O2 sensor bungs welded into downpipes (otherwise, the engine will run in closed-loop mode, killing gas mileage and performance, to a degree)
12. Motronic 1.3 harmonic balancer
13. Motronic 1.3 crank position sensor bracket (will be on the lower timing cover to get pick up from the balancer)
14. Motronic 1.3 coolant temp sensor (mounted on thermostat housing, plug in along with the coupe's original in one of the unused plugged holes. Original drives the gauge, new one drives the DME)

The last thing is kinda optional: a tune. Assuming this is going on the stock engine, a custom tune would be best, both to get the most performance and to prevent from running too rich or pulling bad timing. The cam profile of the B35 cars is different from the coupe's, along with the CR and displacement. Since the displacement is reduced, I don't think you'll be running lean, and there is a certain range of allowed variability due to the O2 sensors.

From a cost perspective, I got everything except for the 2002tii booster (and a tune) for ~300$ from a local wrecker.
 
x_atlas0 said:
chicane said:
I found the walk thru, thanks. I found the parts list on FirstFives but it was for 1.1. I don't care about stock looking.

I don't have to swap harnesses do I?
If you could just give me the parts list that you used I will start from there, thanks I would really appreciate it.
Click to expand...

That is a bit of a problem, mostly because I don't have such a list. You mentioned you are coming from a D-Jet system , so with that in mind, I can think of the major items you will need for a Motronic 1.3 swap:

1. Motronic 1.3 harness
2. Motronic 1.3 DME
3. All sensors attached to the engine harness.
4. Unless you feel like wiring it all, you will need the Motronic intake manifold, the B35 is preferred. (it will say 3.5 on the side, rather than 3.2/3.5)
5. Motronic fuel rail, injectors, regulator, possibly fuel pump. I don't know the pressure of the D-Jet system.
6. 2002tii brake booster
7. Upper timing cover from a B35
8. Motronic ignition system (cap, rotor, plug wires, possibly coil)
9. B35 valve cover
10. B35 throttle and throttle position sensor
11. O2 sensor bungs welded into downpipes (otherwise, the engine will run in closed-loop mode, killing gas mileage and performance, to a degree)
12. Motronic 1.3 harmonic balancer
13. Motronic 1.3 crank position sensor bracket (will be on the lower timing cover to get pick up from the balancer)
14. Motronic 1.3 coolant temp sensor (mounted on thermostat housing, plug in along with the coupe's original in one of the unused plugged holes. Original drives the gauge, new one drives the DME)

The last thing is kinda optional: a tune. Assuming this is going on the stock engine, a custom tune would be best, both to get the most performance and to prevent from running too rich or pulling bad timing. The cam profile of the B35 cars is different from the coupe's, along with the CR and displacement. Since the displacement is reduced, I don't think you'll be running lean, and there is a certain range of allowed variability due to the O2 sensors.

From a cost perspective, I got everything except for the 2002tii booster (and a tune) for ~300$ from a local wrecker.
Click to expand...

OK, thanks I will lookup the part numbers but what range of cars (models and years) should I be looking at to pull these parts off of? If it is Motronic 1.3 I am assuming 1988 or later, correct? Only 5 and 6 series or can I look at some of the 3 series?

Also, what's the deal with the 2002tii booster?
 
chicane said:
OK, thanks I will lookup the part numbers but what range of cars (models and years) should I be looking at to pull these parts off of? If it is Motronic 1.3 I am assuming 1988 or later, correct? Only 5 and 6 series or can I look at some of the 3 series?

Also, what's the deal with the 2002tii booster?
Click to expand...

Indeed, the Motronic 1.3 was used in post-88 cars, like the E34 and E32. I do not know if the E24 ever used the 1.3 system. The E28 did not, nor did the E30, as it never had the M30.

The 2002tii booster is required because the stock booster physically doesn't fit with the B35 intake manifold. The 2002tii booster gives about 1/4" of clearance. The B35 harness doesn't fit on the log-style intake manifold, nor the fuel rail, so some custom work is required to make the log manifold work with Motronic 1.3, if you are going to try to keep the original booster.
 
x_atlas0 said:
chicane said:
OK, thanks I will lookup the part numbers but what range of cars (models and years) should I be looking at to pull these parts off of? If it is Motronic 1.3 I am assuming 1988 or later, correct? Only 5 and 6 series or can I look at some of the 3 series?

Also, what's the deal with the 2002tii booster?
Click to expand...

Indeed, the Motronic 1.3 was used in post-88 cars, like the E34 and E32. I do not know if the E24 ever used the 1.3 system. The E28 did not, nor did the E30, as it never had the M30.

The 2002tii booster is required because the stock booster physically doesn't fit with the B35 intake manifold. The 2002tii booster gives about 1/4" of clearance. The B35 harness doesn't fit on the log-style intake manifold, nor the fuel rail, so some custom work is required to make the log manifold work with Motronic 1.3, if you are going to try to keep the original booster.
Click to expand...

Thanks! Do you have any pics? Now by harness you are just referring to the engine harness correct? I don't need the complete harness (including fuse/relay box) from say a 89 E34? Also, which of these parts need to come out of a 535i say and which parts are more generic and can come out of any 6?
 
I also have 5 E-30's and I assure you they are all Motronic 1.3. One good feature that would be nice to have is the self diagnostics that is activated by tripping the throttle position switch full open 5 times. http://www.verrill.com/car/e30_faultcodes.shtml I think all you would need is a light bulb to flash. I have taken parts off 1989 5 series that had the same system.
Jef Rolison
1971 3.0csi 2210088
1974 3.0 Bavaria
1988 325iX
1989 325iX
1989 325iX
1989 325iX
1989 325iX
Click to expand...
 
I also have 5 E-30's and I assure you they are all Motronic 1.3. One good feature that would be nice to have is the self diagnostics that is activated by tripping the throttle position switch full open 5 times. http://www.verrill.com/car/e30_faultcodes.shtml I think all you would need is a light bulb to flash. I have taken parts off 1989 5 series that had the same system.
Jef Rolison
1971 3.0csi 2210088
1974 3.0 Bavaria
1988 325iX
1989 325iX
1989 325iX
1989 325iX
1989 325iX
Click to expand...
 
jefrolison said:
I also have 5 E-30's and I assure you they are all Motronic 1.3. One good feature that would be nice to have is the self diagnostics that is activated by tripping the throttle position switch full open 5 times. http://www.verrill.com/car/e30_faultcodes.shtml I think all you would need is a light bulb to flash. I have taken parts off 1989 5 series that had the same system.
Jef Rolison
1971 3.0csi 2210088
1974 3.0 Bavaria
1988 325iX
1989 325iX
1989 325iX
1989 325iX
1989 325iX
Click to expand...

Even if they are Motronic 1.3, they do not use a M30, which is the main issue. So, the harness is wrong, the AFM is wrong, the tune is wrong, the injectors are wrong, and so on.
 
jefrolison said:
I also have 5 E-30's and I assure you they are all Motronic 1.3. One good feature that would be nice to have is the self diagnostics that is activated by tripping the throttle position switch full open 5 times. http://www.verrill.com/car/e30_faultcodes.shtml I think all you would need is a light bulb to flash. I have taken parts off 1989 5 series that had the same system.
Jef Rolison
1971 3.0csi 2210088
1974 3.0 Bavaria
1988 325iX
1989 325iX
1989 325iX
1989 325iX
1989 325iX
Click to expand...

Even if they are Motronic 1.3, they do not use a M30, which is the main issue. So, the harness is wrong, the AFM is wrong, the tune is wrong, the injectors are wrong, and so on.
 
x_atlas0 said:
That is a bit of a problem, mostly because I don't have such a list. You mentioned you are coming from a D-Jet system , so with that in mind, I can think of the major items you will need for a Motronic 1.3 swap:

1. Motronic 1.3 harness
2. Motronic 1.3 DME
3. All sensors attached to the engine harness.
4. Unless you feel like wiring it all, you will need the Motronic intake manifold, the B35 is preferred. (it will say 3.5 on the side, rather than 3.2/3.5)
5. Motronic fuel rail, injectors, regulator, possibly fuel pump. I don't know the pressure of the D-Jet system.
6. 2002tii brake booster
7. Upper timing cover from a B35
8. Motronic ignition system (cap, rotor, plug wires, possibly coil)
9. B35 valve cover
10. B35 throttle and throttle position sensor
11. O2 sensor bungs welded into downpipes (otherwise, the engine will run in closed-loop mode, killing gas mileage and performance, to a degree)
12. Motronic 1.3 harmonic balancer
13. Motronic 1.3 crank position sensor bracket (will be on the lower timing cover to get pick up from the balancer)
14. Motronic 1.3 coolant temp sensor (mounted on thermostat housing, plug in along with the coupe's original in one of the unused plugged holes. Original drives the gauge, new one drives the DME)
Click to expand...


I'm looking at this again and I had a few questions:
1. What sensors am I looking for with this harness?
2. I am assuming that the ECU must be from a manual car? (do you have the Bosch part number?)
5. The fuel pump for these cars will not work it is an in-tank pump
8. What do I do with the old distributor? Remove it and try to find some cover plate?
9. What do I need this valve cover?
 
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