Ugh...what to do with my FI system?

adi #2 · Post by **adi #2** » 14th November 2009 - 3:42pm

Well, im completely at a loss now.

I got this piece of crap Vauxhall Chevette to drive around in for a while, but i miss VWs, once you drive a RR vehicle once, you can never go back to a FR and not hate it. It just dont wag its tail as happily as a VW can. Sure, it will slide on wet roundabouts all day, but the catastrophic sudden loss of rear grip, that we all know and love our VWs for, it just dont do.

Anyway, so i really need to get this 411 drivable again.

I am seriously totally confused. There seems to be NOTHING wrong with it. Iv checked and triple checked EVERYTHING, valve clearences, rockers, compression, static ignition timing, function of the distributer trigger contacts, all the injectors, iv had the inlet system to pieces and back together for the 3rd time now, its safe to say there are NO leaks.

It seems there is nothing wrong with anything. I dont get it, something must be wrong.

When i first got it, it used to run a little rich on startup, and would not really run properly until its had about 90 seconds to warm up.

Now its doing exactly thesame, only worst and it will not come out of that warm-up state.

I wander if the cylinder head temperature sensor is 'stuck' on a value? Because its cold resistance is OK (cant check its warm resistance because i cant even warm the motor up).

Maybe its worth pulling it out and trying its resistance at various temperatures.

Apart from that, i really dont know what to do. I dont want to put carbs on it, because those injection systems are supposed to be very good, and make the engine significantly more powerful then a carbed unit.

This must be something simple.

I know running rich during warmup is a common problem with Djet systems. Does anyone know what its caused by? Because i have a feeling this is just an extension of that problem.

shawn71 · Post by **shawn71** » 14th November 2009 - 4:46pm

Sorry can't help much on this one.

However it may be worth giving Volksfarmers a ring and asking Jane or Brian if they know of anything you might of missed. They are very knowledgable about the Type 4s and their little quirks.

Failing that, at the risk of advertising anotjer forum, try the shoptalkforum in the 411/412 section. A positive mine of information about these cars.

Good luck and if you can sort it stay with the FI!

kps70 · Post by **kps70** » 14th November 2009 - 7:35pm

I guess it also has to be worth trying to change the ECU to see if that's where the problem lies. I cannot wait until my FI system starts playing up.....

Post by **purplepeter** » 14th November 2009 - 7:53pm

might be worth going somewhere like maplins or rscomponents & buying a can of contact cleaner,which is safer & easier than faffing around with steel wool..then just go through all the connections methodically

plumcrazee · Post by **plumcrazee** » 15th November 2009 - 12:45am

mate the first thing i did was get rid of the injection system and put some carbs on

i went and got the kadron kit £450 ish i think but worth the money and gave a bit more go and never had to do any thing to them in 2 years

and my fi was fine lol just knobody knew anything about it

adi #2 · Post by **adi #2** » 15th November 2009 - 1:00am

Well, i kinda like this FI system. Iv never had anything to do with them before, but they are more accurate then any carb can ever be at fuel metering, and i kinda like big discreet analogue circuits anyway since i used to repair all sorts of old electronic crap.

I fixed alot of analogue synths (the music type that is) that was thesame situation, ''noone knows anything''. You just sit down and try to work out how it all works, eventually you get it, some of the rigs i fixed were horribly complex and home made so no literature. But that all takes time.

I guess gotto just sit down and figure it out. I got a piece of paper somewhere saying im an electronics engineer, so i should know all this crap hahahah.

Unfortunatly right now i just physically dont have the time to hook the ECU up to all my test gear and figure out how it works, i need a car, not a project. I actually drive vws, as daily cars, i dont have some modern wrong wheel drive piece of crap like most normal people, i actually DO drive old classics, as a daily form of transport, all around the UK and europe. So not having a car is a real problem for me.

Iv never been failed by VWs before, this is why i use them, they are normally 100% bulletproof as long as you look after them.

Actully, as a side note, where the hell IS the ecu anyway??? I havnt found it yet.

plumcrazee · Post by **plumcrazee** » 15th November 2009 - 9:21am

the ecu is behind the side panel by the back seat behinnd the driver. Well good luck with the injection system then dude hope you find the problem soon.. You will just have to find time

I know how you feel driving these dailly mine is as well and i am missing it now as its been off the road for 5 months while i welded it back together.

411ron · Post by **411ron** » 15th November 2009 - 3:45pm

--------------------------------------------------------------------------------

Hi taken me a few days to find this data hope it helps,
Injector resistance 2.4 ohms should deliver 7-8cc fuel when engine cranked for 15-20 seconds with accelerator floored difference between injectors no more than 10%
Trigger points test by voltmeter set to ohms middle pin to l/h then r/h cylinder 1+4 on 1 pin 2=3 on the other.
Pressure sensor terminals 7&15 90 ohms 8&10 350 ohms.
Cylinder head sensor 2,000-3,000 ohms cold operating temp less than 1,000 ohms
Air intake sensor 400-500 ohms @50 deg F
ECU terminals no 11 engine ground no 16 12v power from relay board
no 24 12v power
no 23 cyl head sensor
Mixture should be 2.0-2.5% @ 2,500 on a CO meter.
Some information states the Variant only has 2 earth wires from terminal 11 1 to the engine housing the other to the voltage relay.
The Relay board connections are riveted not soldered and covered with a rubber coating which cause a bad connection you can strip the rubber with solvent and solder.
Hope this is of help let us know what happens.
Ron

adi #2 · Post by **adi #2** » 15th November 2009 - 5:14pm

Hers what i got.

Vac sensor:
Primary - 90R
Secondary - 321R

Head temp sensor: 2.9K cold

Intake temp sensor: 446R cold

However, there has been a new development.

I tried an old trick of hooking up some propane to the inlet manifold. Petrol engines will start (and even run) like this if you get the amount of propane about right (redneck LPG conversion hahahaha). I saw this used once to get an expedition vehicle with a broken carb out of trouble. We hooked up a pipe to the propane stove inside, and ran a long lengh of pipe from the stove to the distributer advance line. This is not good for the engine, but it does work. Got the EV out of the swamp!

I tried sticking a blowtorch nozzle into the hole for the PCV line in the flexible ait duct, and guess what? It behaves exactly thesame. Still only firing occasionally. So it may not be the i injection system after all.

Will investigate further tomorrow.

shawn71 · Post by **shawn71** » 15th November 2009 - 6:10pm

Just noticed that you say that you have checked the static ignition. Have you tried to advance or retard it at all when you have tried to get it going?

adi #2 · Post by **adi #2** » 15th November 2009 - 6:13pm

No, i havnt actually touched the timing, just checked it, and it seems about right.

Should i move it?

shawn71 · Post by **shawn71** » 15th November 2009 - 6:37pm

If you can get it to run by moving it a fraction either way then its worth a try. I know the timing is meant to be set at 27 degrees BTDC at 3500rpm on an FI engine but first you have to get it to run...sounds like you have little to loose. You can always mark where you are currently at timing wise and put it back if it don't work.

Sounds like you have checked the majority of the FI anyway and if the propane trick made no difference it sounds like it could well be a timing/ignition issue somewhere.

I'd try it and see after ensuring the leads, plugs, points etc are servicable.

You can almost garuntee it will turn out to be something simple that we have all overlooked