EC engine starting problems

[type4org]

Hi guys,

Does anyone here have experience with the EC engine (1.8l, 76hp, L-Jetronic)? For a long time I've been having a starting problem where it takes way too long until the engine fires up. It's worst when cold, but also happens when the engine is warm or hot.

I've tested almost all components that are reasonably easy to test using an official VW troubleshooting guide. So I know components like the air flow meter, the cold start valve, the thermo-time switch, the dual relay, the cylinder head temp sensor, the aux air valve are OK. I did replace the thermo-time switch, but I think it's not really broken.

Has anyone come up against starting problems like this? I have a feeling there is some easy solution here that I'm not seeing.

jens

[raygreenwood]

You have either a weak ignition, poor compression, no advance on start up...or your fuel mixture is slightly off...too rich or lean. Have you tested the fuel pump and regulator? Also..check very carefully for vacuum leaks. Also....if you still have points..get rid of them and get a pertronix. What sparg plugs and wires are you using? Ray

[type4org]

Once the engine is running and warm it runs very well. It has plenty of power, there is no hesitation and it sounds good, too. That leads me to the assumption that the ignition system is OK, and it is well-adjusted (I did all the dwell/ignition adjusting already and put in new plugs).

I have not gone into the fuel system yet (except for removing the cold start valve to see if it's leaking and/or activating at all, which showed no problems), especially testing the available fuel pressure and the regulator's behavior. That will be my next step.

I'm also thinking there might be some bad ground connection. I have to try and locate the main ground strap between body and engine block.

jens

[type4org]

Answering your other question, I'm using the standard ignition system and the plugs recommended by the original literature.

I don't doubt that moving to a Pertronix setup has its advantages, but I know for a fact that the standard setup can work extremely well. For several years there never were any problems and the engine would start up *immediately* under almost all conditions. It was actually amazing and uncanny how quick it started every single time.

jens

[raygreenwood]

Yep...I also doubt it is ignition related. Try this....take the key to the first position....3 times...so you hear the fuel pump buzz...three times....before starting the engine. Do not use the accelerator pedal at all. If it starts better, you are experiencing either weak fuel volume giving too slow of a build to pressure, or...you have a weak fuel pressure regulator. This can also include any small vacuum leaks....though they should not bother the regulator too much, they can cause a rich start if the regulator is getting "0" vacuum at allwhen turning over.
Your fuel pressure should be minimum 18 psi at 1 bump of the key before starting...and should not drop. It can be average of up to 25 also. The higher the pressure on the turn of the key...ther better.
The gorunds could be a problem. The ground to the block...is at the tail of the trannmission on the left side, attached to the body. There are several bundles of ground wires important to injection, on the case centerline under the plenum. Ray

[type4org]

Hi Ray,

Thanks for all your help. It's actually not possible to test fuel pressure by just turning on the ignition. The fuel pump is activated by the air flow meter as soon as the flap starts to open (like when you're cranking the engine). I had suspected that a slow pressure buildup could be the problem, but then I did a simple test where I turned on the ignition and pushed the flap open a bit to let the fuel pump run for a while. I could hear the fuel sloshing in the pressure regulator. The engine did *not* start any easier after "pre-pressurizing" the fuel system that way.

Right now my "favorite" suspicion is overly high fuel pressure, or ground connections. The engine is running quite rich overall (CO value 3% as opposed to the 0.2-1.2% factory spec when warm). I hope to test the fuel pressure in a couple weeks when I get back from some trips I'm taking.

jens

[raygreenwood]

Yep..you are right about the flap. But...that is also why I suspected weak compression at one point. As the engines get old...and vacuum pressure drops way down until they are wramed up...they can actually have trouble getting the flap off the stop.
High fuel pressure could be a problem. That could be caused by a regulator that is not holding vacuum or suffering from avacuum leak. If thats the trouble and you are running very rich all the time, then there will be a lot of fuel left over from turning it off...causing a flooded state when starting again. Sometimes you can check to see if this is happenng by driving hard...then pulling into the driveway and running the engine at about 3000 for about 15 seconds to use most of the fuel and then shtting down immediately while at rpm. Cutting the ignition shuts the injectors off. Then let it cool and see if it starts easier. Ray

[albert]

allo 412 fans , all my car have injection systheme from 1970 and i see some curious problem afther appx 100k,m the électric pomp come overheat and stop or geve me power wen she is cold only , no problem cold start ,pressure ok ,afther 15-20or 1hrs she stop copletly,no buz , noting , if i whait 30min. the car star back ,run 20 min. stop again , do the test if your ear the buz from the pomp wend is warm , no buz,no pomp , look for électric connection at the pomp it is very important , clean the contact,w. green pad instal new therminal connector ,if you d,nt see noting do the test witch spare pomp for 2-3 days good lock

[raygreenwood]

Thanks Albert! What Albert is getting at, is that...especially in cold weather...corroded contacts both at the pump and in the relay can cause fuel pumping problems until the thing gets started and warm. It can also cause such a high load at the connecting terminal that the pump overheats from getting too low of current.

Yes, you can check the fuel pump output on your L-jet. Take the boot loose and open the flap with your fingers...or simply plug two wires to the pump in the front end and hook them to the battery (best way to check basic operating pressure). You also check pressurewhen the vehicle is running. Thats most important. You need to know idle and wide open throttle pressures. Ray

[albert]

hallo ray , the overheats at the pomp is not cause only by bad contact , some time wen the pomp is old ,the seal beatwind the gaz and the électric winding cause a short circuit (witch the wather in the gaz ) wather and électricity d,ont make good mix and the pomp is not copplettly short for to blow fuse but just for over heat (the best test is, test the résistance wich ohm meter on the 2 contact if it is normal résistance on the winding ) (if you have good meter the tolérance is 10%from original résistance if not you have short circuit )on the car witch gaz inside , plus afther 100kmm the roller inside the pomp came square and hard to turn and the motor overheat but witch that the noise from the pomp is very strong , the best you do the test witch good one for 2-3 days

[raygreenwood]

Yep you are correct. Though some pumps have fuel purposely cooling the windings. D-jet and early L-jet are like that. Fuel cirulates around the armature. Overheating pumps are also a sgn of several other things. Either worn roller cells...which cause overspeed of the motor and cavitation...because the otor runs relatively unloaded...or a restriction at the sock filter. Volvos with D-jet burned up loads of pumps this way. Ray

[albert]

yes ,ray i see some time , (inside the motor he have 2 électric brush) for to geve the power at the rotor , some time the motor turn witch only one good brush on one side ,the auther side is on the pusher spring , the pump run,but the noys is very strong ,plus she take more and more amperes , the fuse d,ont blow but the motor over heat , and the résistance witch ohm-meter is double of original résistance , plus if the sleeve bearing (on the pump side ) is old the rotor stick on the stator and the motor stop by intermitence ( over heat) a ok for non technician people that is chinise linguage , but for to came at the good test , do the test witch second pump ,