Jump to content
adragonr

LE2-Jetronic - Help Needed

Recommended Posts

Hi All,

 

After a fairly exhaustive check, clean, rebuild schedule I'm seeking some advice on my running issues with a 1985 520i with LE2-Jetronic.

 

My major issue is that it starts, and idles at 800-900 rpm,  and after 30 seconds, cuts out and smells like it running very rich.  Car hasn't been on the road for 3 years.

 

Mine has no Cold Start Valve.  No Thermoswitch. But does have an Air Slide Valve and far too many vacuum lines for my taste.

 

For reference, I have fitted new distributor cap, rotor arm, spark plugs, blue temp sensor, air filter, timing belt, water pump.

 

I have cleaned the air slide valve and some other coolant passages that were blocked.  I have also trialed known good fuel pressure regulators and injectors.

 

The previous owner did play around with the AFM but unfortunately did not mark the start point so I have no idea what the correct position is.

 

Prior to replacing the timing belt etc the car ran, and at the very least got up to temperature, however, had no power, struggled to get above 35mph, spluttered under load and was generally dangerous. 

 

I am now just trying to get it to run long enough to bleed the coolant system.

 

For reference, it will stay running so long as I keep the idle at ~1000rpm on the throttle.

 

Any advice that people can provide would be much appreciated.

 

Cheers

Share this post


Link to post
Share on other sites

Hows your ignition timing? I ask because I see that you changed the cam belt and unless you marked the oil pump/distributor drive pulley you may have disturbed the timing removing and fitting the belt.

 

What part of the country are you in?

Share this post


Link to post
Share on other sites

Sorry, I should have also stated that I have tried a known good AFM and it ran like a pig, wouldn't even idle without throttle.   However this AFM was from a 1988 E30 320i (M20B20 with motronic).  Injectors were also from the same engine.

Share this post


Link to post
Share on other sites

really?   that's odd, not much experience of the BMW's using the Bosch systems but the psa stuff work very differently, the screw on the Jetronic unit physically alters a bypass passage so the flap moves more or less, on a Motronic unit the screw is on a mixture potentiometer.

Share this post


Link to post
Share on other sites

The afm is just a flap with rheostat and temp sensor so it doesn't surprise me its common to other models it's what the ecu does with the info that changes and if p/n is the same it is the same. Sold my old afm,s to a ford owner as sane Bosch part for some old ford. 

 

If running vey rich something is telling it so. Not sure what inputs the le set up has. 

Share this post


Link to post
Share on other sites

Sounds like it may be a fuel pump relay although generally, they either work or they don't. Could be a faulty coil winding in the coil or the distributor, or that weird ignition thing down on the inner wing that looks like two AA batteries side by side. Failing ignition, but the injectors still going - shit running and stinking of fuel.

 

It may be the throttle position switch being out of adjustment, or full of oil. You should hear a faint click as the throttle is opened. That click is a tiny microswitch inside telling the ECU to switch from idle to part load maps. If it's trying to idle on part load fuelling it will absolutely stink of fuel and barely run. So I'd take the throttle body off, remove the idle switch (2 crossheads), open it up with a small flat blade screwdriver and clean it out. They are normally full of old oil so a good wash out with petrol or brake cleaner is needed. Refit it and set the switch up so that the unit clicks as you just open the throttle. Not sure if a 1985 car will have the vacuum operated throttle damper (manuals only iirc). This switch is set incorrectly by amateur mechanics trying to set the idle speed on the throttle body and not on the AFM.

 

This is the first thing I'd check.

 

Jesus, LE Jetronic. Glad I've left all that behind!

Edited by Sir Anthony Regents-Park

Share this post


Link to post
Share on other sites

Thank you very much for the feedback.

 

I actually haven't thought to check the TPS so I'll give that one a try. 

 

I know, I've said for some time if I need to spend money on this engine I'll rip it out and put something else in as that was always the plan. Just may happen sooner than I planned! 

Share this post


Link to post
Share on other sites
19 hours ago, adragonr said:

Thank you very much for the feedback.

 

I actually haven't thought to check the TPS so I'll give that one a try. 

 

I know, I've said for some time if I need to spend money on this engine I'll rip it out and put something else in as that was always the plan. Just may happen sooner than I planned! 

 

Just unplug the TPS to see if it is playing up.

Share this post


Link to post
Share on other sites

Just a quick update for all.

 

Unplugged TPS.  Made no difference

 

Pretty sure its an electrical/AFM issue.  Looking for a replacement to evaluate at least.

 

All the wiring checks out however I did have to replace the earthing strap in the alternator to get sufficient charge and had some issues with power at starter so need to take a look at all wiring probably.

Share this post


Link to post
Share on other sites

Just for everyone's reference it was a fuel pump relay causing an intermittent fault along with a minor misadjustment of the AFM.  Now sorted and running so looking for a set of wheels now so that I can start the long journey to fully roadworthy and onto my daily driver.

Share this post


Link to post
Share on other sites

I have a full set of e28 alloy wheels removed from mine complete with tyres before I replaced them with 16".

Edited by Taffy 1

Share this post


Link to post
Share on other sites

OK mate, incidentally, if you had problems with the earth strap on the alternator - that would cause charging problems which in turn would cause problems turning over the engine.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×