ecu unit 1800E

[arcturus]

An acquaintance here has been chasing his tail over a back firing engine. he has been "advised that it could be the ECU unit 0280000017. Wants to know if and where available Help

[godfather 1]

You can get those units serviced still via Bosch Classic service I think but it is often some other smaller issue like air leaks (e.g. the induction hose) or the TPS or the distributor trigger points.

I am absolutely not a mechanic (so could be talking rubbish) but I have had a few 1800e cars and have one now. The Throttle Position Sensor/Switch is a particular suspect (the black blob on the side of the plenum) often secured by an upper and lower screw.

Rightly or wrongly, I have found very small clockwise or anticlockwise adjustments to this can solve poor running after loosening the top and lower securing screws. I am not sure how you rotate the TPS if there are 4 screws as I think there are on pre 72 cars.

I have had a couple of TPSs re-built but, although the pcbs were replaced, the restorers often seem to bugger up the wipers in them.

With ignition turned on (but engine not fired), check that you can hear 20 'tick/click' noises from the injectors as you manually turn the throttle cable. If you don't have 20 clicks, your car wont fire/run properly.

Could also be the trigger points in the distributor.

[arcturus]

Could you please clarify what and where the "plenum" is. Not aware of this term. Will be talking to the original poster later today.

[mocambique-amazone]

He mentioned the throttle part.

The plenum is the part of the inlet manifold. The bootle part. On the front the butterfly, to the side the runners to the head.

Read carefully this
https://oldtimer.tips/en/d-jetronic/66-introduction

Every thing you need is writen down there from Volker aka Dr-Djet!

Step by step you will find the fault
I'm too fare away for bad luck
D-jetronic isn't really difficult. You won't even need special tools. Only a multimeter and a gauge and a vacuum pump

Good luck, Kay

[kishor]

Originally Posted by arcturus

An acquaintance here has been chasing his tail over a back firing engine. he has been "advised that it could be the ECU unit 0280000017. Wants to know if and where available Help

Hi

I am of the opinion, it's nothing to do with the ECU. They hardly ever go wrong. Check basics first. New plug, point gap, timing, valve setting. My guess is that the timing isn't right.

Ta
Kassie

[c1800]

May have been mentioned, but the plug leads could be mis connected.

Have an 1800E myself , while my ECU continues to work, in all my reading I have the impression that if an ECU fails, it’s dead.

Ditto on the old timer link, good info there.

More links to info

http://pcbunn.cacr.caltech.edu/jjb/P...D-Jetronic.pdf

http://w107.pbworks.com/f/DJetronic.pdf

http://volvo1800pictures.com/documen...lt_tracing.pdf

Check also fuel pressure, maybe the cause of backfiring

[arcturus]

Spoke to the guy yesterday' He said that his "mechanic" had removed the unit and it was covered in green mold inside! Hmm. It seems as though the car had been out of use for some time before he bought it. Just wish I had gotten my hands on it before his "mechanic" He has been in contact with Bosch for more info.
For my own personal education I must study K jets. never know when the knowledge might come in useful. personally I'm old fashioned and prefer carb's

[Ron Kwas]

arcturus;

I highly recommend the following book: Bosch Fuel Injection & Engine Management by Charles Probst, Published by Robert Bentley Publishers SB ISBN 0-8376-0300-5 Theory of operation, development, and practical troubleshooting information. An excellent reference for D-Jetronic, K-Jetronic and later vehicles.



In the most basic terms, the D-Jet is an "open-loop control system" in that the analog control circuit (ECU) supports and takes inputs from the various sensors, decides on the proper fuel for operating conditions, then dispenses that based on the amount of time Injectors get their power pulse. Later, the Lambda sensor was developed so that the actual result of this complex calculation could be checked, by "sniffing" the exhaust. That made it a "closed-loop control system"...making the electronics digital, air-mass, multiple and preheated Lambda sensors, cats, are all further developments of this brilliant system...the book covers it all, including the Constant Injections System CIS, which is a mechanical variation...equally brilliant.

See also: http://www.sw-em.com/bosch_d-jetronic_injection.htm

I also recommend studying the Kerfoot circuit shown there and Anders theory of operation and waveforms (Linked), and the troubleshooting guide is also very good: http://volvo1800pictures.com/documen...lt_tracing.pdf

Cheers

[c1800]

May be a long shot but some judicious cleaning of the mold by gently brushing it out, then something like contact cleaner might be an option. I have no idea if contact cleaner would be appropriate for this purpose, so if someone knows they could chime in.

[SwissXC90]

Originally Posted by c1800

May be a long shot but some judicious cleaning of the mold by gently brushing it out, then something like contact cleaner might be an option. I have no idea if contact cleaner would be appropriate for this purpose, so if someone knows they could chime in.

Contact cleaner and a toothbrush.
Always worth a try.