Is it possible to determine fuel mixture rich/lean in a D jet CSi ?

[neon]

Have been obsessing on this one for a good bit after enriching my mixture by boosting my fuel pressure approx 3 psi seems to have helped to some extent a hot running condition .
Is there a way to determine mixture composition other than the old school spark plug inspection, which is an art I do not have a good handle on.
I have seen the reference to CO at the exhaust but don't know how to go about this.
Thanks

Dana in Hartford, CT

 

[sfdon]

Under a 100 bucks…

CT Emissions | Find a Test Center Near You

ctemissions.com

Or -

Install a Wideband air fuel meter.

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[adawil2002]

Contact Sports Car Restoration in Plainfield Connectict.

123 Whiting Street
Plainville CT 06062
United States

(860) 793-2002

They should be able to tune & adjust to 2.8%- 3.0% CO.

Yet generally if you are running D-Jet & your Throttle Position Switch & Manifold Atmospheric Sensor are working properly. Fuel pressure should be 27psi. On the injeted CSLs are set at 36psi.

Idle should be 1000- 1100rpm on cold start & settle near 900rpm when the cold start injector slows down.

As I understand the overall mixture is modified with the knob on the back of the ECU.

Mine is tuned for Sea Level & have driven as high as 12,500 feet.

 

[bill]

27 psi? That is a little less than 2.0+.1 Bar that jetronic.org specifies. Mine is set to 28 psi. I’ve having severe hesitation problems that might be caused by running too lean so I might try a 1-2 psi increase (Thank you SF Don…) Not to mention I’m not sure the MAP sensor is correctly set.

 

[neon]

Under a 100 bucks…

CT Emissions | Find a Test Center Near You

ctemissions.com

Or -

Install a Wideband air fuel meter.

AEM Electronics 30-0300: 30-0300 X-Series Wideband UEGO AFR Sensor Controller Gauge With X-Digital Technology - JEGS

Get the Best Performance with AEM Electronics 30-0300 X-Series Wideband UEGO AFR Sensor Controller Gauge With X-Digital Technology 30-0300 parts at JEGS. Shop Now at the Guaranteed Lowest Price!

www.jegs.com

Thanks as always Don !

 

[neon]

Contact Sports Car Restoration in Plainfield Connectict.

123 Whiting Street
Plainville CT 06062
United States

(860) 793-2002

They should be able to tune & adjust to 2.8%- 3.0% CO.

Yet generally if you are running D-Jet & your Throttle Position Switch & Manifold Atmospheric Sensor are working properly. Fuel pressure should be 27psi. On the injeted CSLs are set at 36psi.

Idle should be 1000- 1100rpm on cold start & settle near 900rpm when the cold start injector slows down.

As I understand the overall mixture is modified with the knob on the back of the ECU.

Mine is tuned for Sea Level & have driven as high as 12,500 feet.

Thanks Andrew - Time for a visit to Nate at CSR or possibly even Mario at VSR1. The working hypothesis is that the MAP sensor may be causing slight lean mixture, no way to know on these MAP sensors. I have not trie adjusting the knob on the back of the ECU.

 

[adawil2002]

If your MAP sensor isn’t working. Anything else you try to do with the TPS & Fuel Pressure is only going to do so much if the MAP sensor doesn’t work.

VSR has a vendor who is able to rebuild MAP sensors, they are controlled by the ECU, according to the Blue Book, they are color coded at the factory. Experience has demonstrated a good ECU & MAP will work no matter what the origonal color code was. The ECU controls the MAP

VSR had my MAP rebuilt in 2016 when my Coupe couldn’t be tuned of run when set to the Blue Book specs.

 

[bill]

If your MAP sensor isn’t working. Anything else you try to do with the TPS & Fuel Pressure is only going to do so much if the MAP sensor doesn’t work.

VSR has a vendor who is able to rebuild MAP sensors, they are controlled by the ECU, according to the Blue Book, they are color coded at the factory. Experience has demonstrated a good ECU & MAP will work no matter what the origonal color code was. The ECU controls the MAP

VSR had my MAP rebuilt in 2016 when my Coupe couldn’t be tuned of run when set to the Blue Book specs.

Adawill, do you have the Blue Book specs? I’d be real curious to see them. Is VSR’s vendor FI Corp in Tracy, California? Setting the MAP requires an LCR meter to measure coil reactance (Henries) in the MAP at various vacuum levels. Right now I am going with the procedures developed by PB Anders in the 914 Club: see members.rennlist.com/pbanders (for VWs anyway.) It would be helpful to see BMW specs…

 

[neon]

If your MAP sensor isn’t working. Anything else you try to do with the TPS & Fuel Pressure is only going to do so much if the MAP sensor doesn’t work.

VSR has a vendor who is able to rebuild MAP sensors, they are controlled by the ECU, according to the Blue Book, they are color coded at the factory. Experience has demonstrated a good ECU & MAP will work no matter what the origonal color code was. The ECU controls the MAP

VSR had my MAP rebuilt in 2016 when my Coupe couldn’t be tuned of run when set to the Blue Book specs.

Good point. MAP sensor was rebuilt last fall, courtesy of Sfdon, but some MAP sensors tend to give a lean mixture, others a rich mixture, is my understanding, probably needing to be calibrated to the particular ECU, or BMW spec, as Bill is alluding to, though that is supposition on my part.

 

[bengal taiga]

As I understand the overall mixture is modified with the knob on the back of the ECU.

My understanding is that the ECU potentiometer only affects fuel mixture at idle .

https://www.sw-em.com/bosch_d-jetronic_injection.htm#General_Information_and_Acknowledgements

https://www.djetronic.org/ecu-tester-v1

 

[tferrer]

Thanks Andrew - Time for a visit to Nate at CSR or possibly even Mario at VSR1. The working hypothesis is that the MAP sensor may be causing slight lean mixture, no way to know on these MAP sensors. I have not trie adjusting the knob on the back of the ECU.

That adjustment only affects the idle mixture. Has nothing to do with general running AFR. Get a portable tailpipe exhaust AFR meter and drive around. This is the issue with D-Jet. If something is wildly out of spec you have to rebuild (in the case of the MPS or trigger points) or go hunting for parts.

Note: the MAPs were calibrated to the ECU's hence the color coded dots but most nowadays are just rebuilt to the factory specs and they do fine. Have you swapped ECU's to see if there's any change? I swapped three out with no significant difference when I was hunting ghost...

@adawil2002 - Street Injected CSL's use the same fuel pressure as CSi's. There is no difference. 3L made 200hp and the 3.2L's made 206(ish). 36lbs of fuel pressure would be very high. Remember the injecttors on CSi's are HUGE (40lb). The only reason they run well in our cars is because the fuel pressure is so low.

 

[neon]

Tferrer - Thanks did not see your reply. I did swap out the ECU with a loaner when I was diagnosing a non running condition. Portable tailpipe AFR meter is an excellent suggestion, I did not know these existed.

Dana

 

[bluecoupe30!]

Gunsons Colourtune has been helping tune carburettors for decades. here is a video of its use helping dial in a BMW! I have no experience using in a FI car, but investment is minimal, and the fun rating is high

 

[Wes]

At the risk of opening Pandora's box the CSL seems to be especially fuel hungry and the moment and a little bit fumey. Has been stood up for a while.
The 'T' light on the dash also seems to like flickering too - suspect the sender unit either needs a clean or a loose connection - yes there's plenty of fuel in the tank.

Given I literally live at the end of the Earth (but thankfully at sea level) is there a simple way to check if I'm running rich and if the answer is 'yes' a way to re-adjust. My thinking is it involves some mandrake root, rabbit, top hat, wand and 'adjusting' the air/fuel mix on the fuel rail?

I've the mythical blue books, D-Jet manual (thanks @tferrer), red handled screw drivers and a 7yo that says the answer is using the work fuel card instead of paying myself) while driving faster to use the excess fuel. may not be the worst approach

 

[sfdon]

I would go for a nice drive and when I pull into the garage I would quickly turn off the engine.

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[Wes]

Hmm. Did 60km yesterday. Perhaps I pull a plug this arvo and take a look.

 

[Bert Poliakoff]

Adawill, do you have the Blue Book specs? I’d be real curious to see them. Is VSR’s vendor FI Corp in Tracy, California? Setting the MAP requires an LCR meter to measure coil reactance (Henries) in the MAP at various vacuum levels. Right now I am going with the procedures developed by PB Anders in the 914 Club: see members.rennlist.com/pbanders (for VWs anyway.) It would be helpful to see BMW specs…

I think FI Corp is shut down??

 

[tferrer]

I think FI Corp is shut down??

No its still up and running, it's just the gentleman that knew the inner workings of the ECU and knew how to re-flow the connections thought Covid was a hoax and ending up passing away. They can still rebuild the injectors and fuel pumps as I had them do it not too very long ago.

Testing the D-ject parts are all covered pretty well by Dr D-Jet. And yes, testing the MPS is covered but it's also been proven that units that test fine can sometimes be falty. That's when you need a sufficient supply of bat wing and eye of newt...

D-Jetronic from A to Z for all manufacturers

D-Jetronic article series by Dr-DJet

jetronic.org

 

[sfdon]

My early morning comment on FI Corp- Been in business for decades, Robert White Junior and his sister now run the show and are the nicest people you can imagine.

As far as the Vax denier - add his name to my long list of dead people I know or are I am related to who bet their life on political BS. Each of them died with the thought- Why didn’t I get the vaccine? Don’t drink the kool aid…. It will kill you.

 

[Arde]

My early morning comment on FI Corp- Been in business for decades, Robert White Junior and his sister now run the show and are the nicest people you can imagine.

As far as the Vax denier - add his name to my long list of dead people I know or are I am related to who bet their life on political BS. Each of them died with the thought- Why didn’t I get the vaccine? Don’t drink the kool aid…. It will kill you.

Sorry to hear that, and the others in your family Don you told me about.
Perhaps the only big name politician accused of being a Vax denier is RFK Jr. I have watched many interviews with RFK Jr. the last 5 days and he is not a denier, he is asking for long term testing of vaccines, especially infant vaccines. I was not familiar with RFK Jr before then. All in all I got a very positive feeling about him from his demeanor and answers on many topic, but I digress, again...