TheSamba.com :: View topic - ....just to be sure im on the right foot.

Wed Dec 14, 2005 8:54 pm

looking for the FI Ljet gurus, basically question concerns procedures for testing out the system to find failure to start issues, the basics; swapped 2.0 from rusty '81 into western '81 pure plug and play, has ran fine for the last four months, now winter has set on and am hell bent on getting it to fire, have spark, have good fuel pressure, double relay in good order, pulled cold start inector nice mist flow, tested series resistors good Ohms, on previous attempt to trouble shoot fuel pump let it sit over night and got it to fire ran enough to back down drive way and realign in garage to hook all the rest of A/box up and loose ends, thinking all is good and go out for a test drive and nothing, cranks but no start, IF fuel is reaching cold start injector shouldnt all FI have power, checked posts and found mention of grounds to FI's under plenum, have yet to check these/this ground. has me and other mech scratching heads, by the way this forum is just grate!!!!!!!!! very helpful info, any possible direction yall may point a brother in would be great. really need to fix this and represent my bonecrusher. also is this to be filed under vanagon syndrome or are airheads ambivilent to this dreaded syndrom. tanks.

Wed Dec 14, 2005 9:48 pm

Vanagon syndrome is only relevant to 86-91's. Have you checked/replaced temp sensor II over near 3rd cylinder injector? It's a cheap part, about $13 and is the cause of a LOT of driveability problems with F/I aircooleds. You can try cleaning and tightening the connection for it, but for it's cheap cost I would just replace it. It's also a good idea to keep a spare on hand just in case.

Thu Dec 15, 2005 3:06 am

You might also have a close look at the distributor's mag trigger wheel. If because of a worn bushing the points touch the trigger, or if magnetized particle contamination is present that allows conductive contact as they pass the trigger, you will have mysterious cold start trouble especially in cold weather.

Thu Dec 15, 2005 5:55 am

Has it been sitting for a long time?

Thu Dec 15, 2005 6:03 am

Keep it simple. It could be bad fuel.

Thu Dec 15, 2005 9:34 am

All the suggestions so far have been good ones. I'm not familiar with the LJet systems or air cooled engines but I am familiar with posting on this forum. My only suggestion regards posting. Having a title more along the lines of "Trouble with my LJet FI System" or "Can't get my 81 2.0 running" will attract the attention of those-in-the-know in much greater numbers.

Good luck with your van.

Thu Dec 15, 2005 10:28 am

thanks for all the tips 1) if i am correct the temp switch II VdubTech is reffering to was not even connected and i thought that may have been the issue but still no luck on firing. i am more inclined to believe this is an intermittent problem due to the fact that it just doesnt want to fire. again am i correct in (assuming) that fuel at the cold start injector ='s fuel spraying to the main 4 FI's i dont believe they are on the same elect. circuit or share the same ground, 2) Phil G ill check distributor out tonight since it is above freezing the spark at the plug wasn't as great as one may want to see but i still want to think it is something simple that i am overlooking 3) the van has been daily driver since the engine swap and the fuel i pulled off the filter was nice and clean not a sign of water. this engine also ran fine all last winter and was main source of transportation. the reason for the swap was finding a clean van in the area with a bad engine. ill miss the factory sunroof the old one had but not the rust that came with it.

Thu Dec 15, 2005 10:47 am

I agree with replacing the Temp Sensor II AND having a new spare on hand at all times (I keep a spare taped to my leg :shock: ). Use no "anti-sieze" on them. Here is the testing procedure http://www.ratwell.com/technical/TempSensorII.html

Also possible that the fuel pump is noit keeping adequate pressure in the fuel rail after it shuts off. It should hold about 14-16 psi for 20-30 minutes after you shut the engine down. Put your gauge on there and let it sit for a while. I assume you tested the pressure with and without the fuel pressure regulator in the loop as per your Bentley manual.

If this thing sat for a few months before you got it, the pump or the fuel pressure regulator are usual victims of dead gas. Might try the little trick of "submerging the fuel pump in a bucket of diesel fuel and reversing the electical wires a few times to try to get it to flush out crap inside the pump" before you spend $160 for a new one a Bus Depot. To quote Dirty Harry, "do you feel lucky?"

Fri Dec 16, 2005 1:29 am

the only place i made it to tonight was the villiage idoit ask for bobby if you are in maumee OH and tell them joe sent you, any way this van has not sat for any longer than since it has decided to act a fool I am half way through a tank of 89 octane ( i try not to put 87 in it 'cause who knows what youre really getttin) and i shall try to diagnose this weekend in futher detail i dont know what types of mechanics are addressing me but i hate to open a book to try and trouble shoot anything. period. i know this has to be a simple oversight on my part, once i figureit out ill be kicking myself all the way to sixty miles n hour.

Fri Dec 16, 2005 7:57 am

1) I would be surprised it would run if the Temp Sensor II was unplugged. Most of the time they won't start without it.

2) 89 Octane is not doing anything for you if you are correctly tuned (including timing).

Yours should say something like this:

Vanagon Federal 1980-1983 * 2000

Note: This Distributor also fits Type 4 (412) 1974
Distributor: VW 022-905-205S, Bosch 0231 170 093
Note: VW 021-905-205P, Bosch 022-905-205S, 0231 168 005
Timing Set At:: 7.5deg BTDC @ 850-950 rpm (Man Trans), 900-1000 rpm (Auto Trans) w/strobe, vacuum hose connected. (Bentley Table on Page 28.3 incorrectly states with hose disconnected).
Advance/Retard Range: Vacuum: 8-12deg Adv @ 7.9 In. Hg; Centrifugal: 9-14deg @ 1600 rpm, 21-25deg @ 3400 rpm

3) the injectors actually fire at the same time on one circuit and are all grounded under the air plenum by the brown wires going to the 3 way ground block where the engine "halves"bolt together.

You need the Bentley manual.

Fri Dec 16, 2005 8:39 am

Is it possible you plugged the ECU wire into the wrong side of the coil? I did that once. It's the white wire that plugs into the neg. side of the coil (I think)

Tue Dec 27, 2005 11:11 pm

thanks for the advice phil, got it fired up tonight. checked and had spark before but it was weak, after putting everything back to normal found loss of spark, inspecting points armature and comparing it to another distributor setup we realized they were shot swapped 'em and got spark at the points,plugs, etc..and jumped the van after a few cranks (fuel lines drained) fire!!! :P upon all this trouble shooting i have made a shopping list of parts to replace.

Sat Dec 31, 2005 2:22 am

Great! FI VW's are so dependent on a sound ignition system. Bad grounds and degraded or worn components are so often overlooked, but are easy to diagnose and cheap to fix. I like to confirm the proper operation of the ignition system before messing with fuel systems.

The diagnostic order:
1. Mechanical
2. Electrical
3. Fuel