"kangarooing" 2.1DJ

[mattk918]

New plugs, rotor arm, dissy cap, HT leads, air filter and adjusted AFM to run on unused bit of track and the only difference is it now runs worse than before I started (hotter the engine is the worse it gets). Now can feels it hiccup a bit on the run at 2500ish rpm as well as the nightmare at 1800rpm. Any advice about setting up the Throttle Position Sensor properly????

[syncrosimon]

Test the afm again, but like this. It will show up a weak spot on the afm. Use pins 2 and 4 on the afm. You are looking for a smooth voltage output. a worn track will cause the hiccup you describe.

http://www.youtube.com/watch?v=6Tn8dyzn ... annel_page" onclick="window.open(this.href);return false;

Full instructions here.

http://www.thesamba.com/vw/forum/viewtopic.php?t=369815" onclick="window.open(this.href);return false;

I would also check the timing, or try a tank of 98 to see if it is better.

Check tthe wiring for the temp sensor for the engine ecu, it's on the thermostat housing and has a plug with two wires on it. They cause frequent problems, but mostly at idle.

Test the throttle position switch with a meter, as per haynes manual or bentley.

good luck.

[mattk918]

Thanks for the advice. I will check the AFM again as well as the temp sensor tonight.

Anyone able to upload the relevant section of Bentley for setting up the TPS or know whether it is on the web somewhere?

Cheers

[wasserleaker]

if you can hear the switch click just as you open the throttle valve by hand (engine not running) and click again when you let it close, and the switch checks out with a multimeter,(its basically an on off switch, open circuit, or continuity) it should be set ok, the haynes book gives the gap at the throttle stop screw as 0.05mm to 0.10mm. if it is a bit gunky give it a good clean with carb cleaner spray. it switches the injectors off on over-run when above 1500rpm when the throttle is closed when working properly.

[syncrosimon]

Thanks for the advice. I will check the AFM again as well as the temp sensor tonight.

Anyone able to upload the relevant section of Bentley for setting up the TPS or know whether it is on the web somewhere?

Cheers

here you go, you need to be thorough with these injection systems, and work through the list one by one making sure all is good.

This is still from an American version of digijet which has a lambda probe, so you have to adapt a little.

http://www.vanagonauts.com/files/Digijet_FI.pdf" onclick="window.open(this.href);return false;

Simon

[mattk918]

I am beginning to lose the faith with this one. Reminds me why I stopped having old cars for a while..... too old to be reliable, too new to be simple! I must have checked and re-checked every connection in the engine bay now and it is still as bad (maybe worse!)

If there has been a dodgy connection, could the ECU now be in a limp home mode that needs resetting, or would it reset when the ignition was off? The only thing I have noticed is it drives exactly the same with the TPS connected as not, so it does still seem as if the problem lies there, though all tests indicate it's fine.... maybe only a problem when driving, not when static..........aaaarrrgghhhhhh

[syncrosimon]

Next thing to try would be to swap out your ecu for a known good one, and the afm. Some bad tracks on the afm only show when driving and fool the meter test.

I had poor running until I spent 80 quid and had mine rolling road tuned by a VW expert. The injection system is nearly the same as on an early golf, so the mechanics know what they are doing. That was a year ago now, I havent touched a thing, and my plugs are 3 years old.

I would change your temp 2 sensor as a matter of course.

A rolling road would show if your spark side was weak, or your injector side.

I have found that the DJ is very sensitive to ignition timing, and that is where the rolling road guy spent all of his time.

The DJ does not have a limp home mode, the MV does.

There could be a bad connection in the plug for the ecu, thats worth having a look at.

[mattk918]

checked connections on ecu, seem ok.

Only check that seems to be showing out compared to instructions posted seems to be the Hall Generator voltage checks on page 76 where it says the voltage should show 2V min for 1-2 secs then dropping to zero after turning ignition on. Advice from that test is to replace Hall Generator and Ignition Coil ! However most advice seems to be that the Hall Generator either works or doesn't, not as my problem i.e. working but not very well!?!?!?

Anyone anywhere near Northampton/Milton Keynes/Coventry sort of area who could let me test a known good Hall Control unit ??

[Pete Nice]

Have you checked for air leaks?

[mattk918]

Yes, can't find any...... though that doesn't necessarily mean there are none!

Any recommended or non-recommended brands/suppliers of Hall Control Unit (or Ignition Amplifier ?). They seem to vary wildly in price and I guess you gets what you pay for???

As i said in the ealier post, the idle stablilisation unit is bypassed, presumably because it is fubar'd, but I guess it has then probably had the idle speed and CO etc "tweaked" for previous MOTs. Maybe I should start by getting a new idle stablilisation unit and setting up from "first principles" ?

[Grun]

One or two things you may (or may not) care to try. They are taken from Haynes manual 3344 'Engine Management and Fuel Injection Systems'
The systems covered tend to be more modern than our digijet (Bosch Jetronic L derived I believe), but may be relevant.

1. Checking for spark from HT lead of coil to earth. Take the multiplug connector off the distributor, Identify the supply, signal and earth terminals and briefly flash a small jumper lead from the (O) to the (-) (Ignition on of course). Should get a spark jump the gap from the HT lead to earth.

2. Peel back the boot on the multiplug on the distributor and with it connected to the dizzy probe the signal terminal with the positive lead of a multimeter (Negative lead to earth) allow the engine to idle and you should get 7 to 8 volts average (or a duty cycle of approx 35 degrees on a dwell meter)

3. Engine stopped, remove distributor cap, multiplug connected, ignition on, meter positive to the signal terminal of the multiplug, (Meter neg to earth) turn the engine slowly by hand (ignition on) and you should see a voltage fluctuation between zero and 10 to 12 volts as the trigger vane cut out space moves in and out of the air gap. Not sure about the voltage as ours uses an external ignition amplifier so hall sender output may be much lower than 10 or 12 volts.

Mike

[terryvanman]

I had this on an mv motor...the answer was pull the wire/plug off the lambda probe when it coughs, then get home and re fix the wire/plug and its ok for the next 2/3 weeks and it does it again,,,,,it only seams to do it on a long run at a steady speed then when you take your foot off the gas and press it again to continue it starts to cough again.

this might help
http://aim.search.aol.com/search/redir? ... =1&s_cpr=1" onclick="window.open(this.href);return false;

[syncroand101]

Also had an intermittant running problem with some similar problems to yours on my old 2.1 DJ. Turned out to be the Idle Stabilser, small grey large matchbox size on the LHS of the engine bay - ruled it out through bypassing it by just plugging the two leads that go into it together...

[mattk918]

Also had an intermittant running problem with some similar problems to yours on my old 2.1 DJ. Turned out to be the Idle Stabilser, small grey large matchbox size on the LHS of the engine bay - ruled it out through bypassing it by just plugging the two leads that go into it together...

Mine does it when this is bypassed as well.....

thanks anyway

[mattk918]

I had this on an mv motor...the answer was pull the wire/plug off the lambda probe when it coughs, then get home and re fix the wire/plug and its ok for the next 2/3 weeks and it does it again,,,,,it only seams to do it on a long run at a steady speed then when you take your foot off the gas and press it again to continue it starts to cough again.

this might help
http://aim.search.aol.com/search/redir? ... =1&s_cpr=1" onclick="window.open(this.href);return false;

No lambda probe on this one I am afraid, thanks anyway....