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Kodachrome

New e28 525i - won't accelerate!

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Still better than bloody k-jet though

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Updates:

Changed more things, big ones are the FPR, ignition coil and all the injectors. Coil made a minor difference but the injectors had a dramatic affect, both positive and negative. The injectors are the (known good) Ford Mustang type with the updated pintle. Resistance and flow should be the same as stock and they are a drop in replacement.

 

Following observations directly after injector swap:

- Idle went down to a struggling 600rpm. Perhaps some vacuum leak around the old injectors is now sealed? The old injector ends were caked in dirt. 
- Actual idle quality however is now pretty poor, very warbly (and not in a good way) with moderate shaking, not sure if misfiring or what.
- Drive quality is the opposite (of idle), vastly improved, good pickup, smooth and quiet etc. I mean, best I've had with it, by far. 
- Wife was driving behind me and she pulled out and got in front (in a 550i, wasnt hard). She later told me the e28 stinks of burning and fuel.


I tweaked the idle speed up again with the adjustment screw and left it at 900rpm. Drove around, felt great. When came to a stop again idle had crept up to 1300rpm now!?
Adjusted it back to around 750rpm, minor shaking and un-eveness, a compromise. 

Any ideas? Maybe I should get the CO mix adjusted by someone with the CO meter?

Edited by Kodachrome
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9 hours ago, Kodachrome said:

Updates:

Changed more things, big ones are the FPR, ignition coil and all the injectors. Coil made a minor difference but the injectors had a dramatic affect, both positive and negative. The injectors are the (known good) Ford Mustang type with the updated pintle. Resistance and flow should be the same as stock and they are a drop in replacement.

 

Following observations directly after injector swap:

- Idle went down to a struggling 600rpm. Perhaps some vacuum leak around the old injectors is now sealed? The old injector ends were caked in dirt. 
- Actual idle quality however is now pretty poor, very warbly (and not in a good way) with moderate shaking, not sure if misfiring or what.
- Drive quality is the opposite (of idle), vastly improved, good pickup, smooth and quiet etc. I mean, best I've had with it, by far. 
- Wife was driving behind me and she pulled out and got in front (in a 550i, wasnt hard). She later told me the e28 stinks of burning and fuel.


I tweaked the idle speed up again with the adjustment screw and left it at 900rpm. Drove around, felt great. When came to a stop again idle had crept up to 1300rpm now!?
Adjusted it back to around 750rpm, minor shaking and un-eveness, a compromise. 

Any ideas? Maybe I should get the CO mix adjusted by someone with the CO meter?

i think those injectors will be over fueling the 2.5L by heaps 

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59 minutes ago, BM WORLD said:

i think those injectors will be over fueling the 2.5L by heaps 

They shouldn't be as they flow the same as OEM. The 525i, 528i and 535i all use the same injector anyhow, there is no lower rated 525i version. Presume the ECU handles this.

http://bmwfans.info/parts-catalog/13641276149/

Edited by Kodachrome

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1 minute ago, Kodachrome said:

They shouldn't be as they flow the same as OEM. The 525i, 528i and 535i all use the same injector.

 

http://bmwfans.info/parts-catalog/13641276149/

ok have you changed the afm yet for a known good working one ?? i have one 

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1 minute ago, BM WORLD said:

ok have you changed the afm yet for a known good working one ?? i have one 

Yeah, Auto38 in Wellington sourced one, sold as known good!

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Checked your ICV? If you adjusted the idle with the throttle body stop that’s not really recommend and will explain the higher idle once it’s warmed up.

The idle is supposed to be constant and controlled by the ICV, assuming it’s working properly it acts as a secondary throttle allowing more air in. However it can’t decrease the amount of air lower than what the throttle body lets in. Which is why the idle speed will increase once warmed up if the throttle stop is open too far. 

(That or something silly like what happened to me where my alternator belt snapped and the idle raised to 1500 RPM, but you’d notice that)

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I dont have an ICV in the M30 version, its an (even more primative) "Air Slide Valve", which I understand is the correct adjustment spot. 

http://bmwfans.info/parts-catalog/E28/Europe/525i-M30/R-A/apr1983/browse/engine/cooling_system_water_hoses#1272103_8

 

 

Im going to double check the fuel rail is tightened properly.. I suspect one of the bolts threaded out when reinstalling.

Edited by Kodachrome
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Oops, I forgot you had L jet rather than early motronic

Edited by eliongater

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7 hours ago, eliongater said:

Oops, I forgot you had L jet rather than early motronic

All good, you would think it would have an ICV because.. like it should!  However I figured the problem out! The is a vacuum line on the bottom of one of the Crank Ventilation hoses (the one towards the front of engine on the flexi intake tube after AFM) that I didnt see. It pulled out not up at the top, but around the back bottom of the intake manifold itself. Only found it by tracing each vacuum line individually and found it dangling!

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