'73 FI type3 refusing to start

[nitro_warrior]

Hoping you can give me some ideas, i'm at a bit of a loss with my Injection type 3 not starting.

Its a project car which I got in an non-running state. Earlier in the year I got it running and it was ok, would idle unattended, needed a bit of a tweak but was ok, but after I fitted the air filter its not wanted to start. Now when I remove the air filter and revert it to how it was it still doesn't start.

If I pump the throttle 20 or times it splutters, no more than each cylinder firing once. If I don't pump it doesn't do anything.

I get a spark, and there's fuel in the lines.

On the rare occasion it does bite and run (without the airfilter on), it will only keep running with constant pumping of the throttle, you can't hold it at low or high revs to keep it going. And it backfires loads, but I think the backfires come through the inlet.

The final thing is the coil gets really hot, too hot to touch hot.

Any ideas? I'm a bit stuck. Cheers.

[Editor]

Check the points are operating - opening and closing - and that they are clean and properly gapped. Corrosion may have developed. Put a spot of grease on the cam and fibre follower in case it is wearing.
If the distributor has risen up and isn't getting drive, the ignition points may be closed all the time which will heat up the coil, and the trigger points below won't be opening and closing either so the FI won't be squirting.

It's probably a simple fault if it was working. but it may not be simple to find exactly what has changed!

[type3]

Do a full service (points, plugs, timing etc.)
Check all FI earths (e.g. ECU, injectors and anything else)
Check VR (and power to ECU)
Check all vacuum hoses
Clean FI points in dizzy by carefully drawing a sheet of paper through them

[nitro_warrior]

Thanks for the suggestions. I decided to buy a fuel pressure tester to check all was well.

On turning the ignition, when the pump primed nothing happens. I eventually bypassed the relay to run the pump continuously. After a good few seconds, the pump started pumping and the pressure climbed to 28psi. But when I turned the pump off the pressure dropped of straight away to 0psi. (though on one occasion the pressure climbed only to 22psi and then dropped to 0psi with the pump running)

No fuel pressure would explain the reluctance to start and why frantic throttle pumping helps.

I suspect the pressure regulators ok is it reaches 28psi. I presume the pump has a non return valve to stop the pressure leaking out? Any way to check it?

[purplepeter]

http://www.vwtype3and4club.org.uk/_docs ... haul-2.doc

[nitro_warrior]

http://www.vwtype3and4club.org.uk/_docs ... haul-2.doc

Ah excellent that looks good. I have had the pump off and run it in a bath of diesel and it seems to pump ok. But I didn't dismantle it at all.

If that fails to sort my problem are there any after market pumps, or pumps from other cars that can be used? Or am I best sticking with VW ones?

Cheers.

[Editor]

A Ford Ranger (USA pick-up) pump works. Somewhere on this forum the part number or model was given quite recently, ISTR.

It's here.
viewtopic.php?f=26&t=6166

[nitro_warrior]

Well some progress.

Tonight I took the pump off, then following the guide I dismantled it.

The first thing I noticed was that I couldn't see the Pressure Release Valve PRV in that it was stuck in. That would explain why it wasn't holding pressure. But I couldn't do anything to get the PRV to move so I took the back plate off.

Now it didn't exactly explode apart, but I had a moment of head scratching as I only had one big spring that didn't seem to push the valve all the way in. On inspection of the diagram I noticed there must be a 2nd smaller spring. But I couldn't for the life of me find one on the floor that might have sprung loose. So i'm 70% sure it's been dismantled in the past and the little spring omitted.

I happen to have a box of random springs, so I picked one that fitted, crossed my fingers that the stiffness was ok and reassembled.

Unfortunately only partial success. The system now holds pressure, but only at 10psi.

I guess my spring isn't strong enough and the PRV is releasing to early, letting the fuel get back to the tank as in figure 3. I suspect it's new pump time.

[nitro_warrior]

Well reading some of the other threads I found a picture to clarify what small spring I was talking about

From here

The spring I put in probably wasn't as big as that, so I think I will swap it for a bigger one, seeing as I have some.

Failing that i'll track down a new pump. But why a Ford Ranger Pump? They look like normal electric fuel pumps, is there anything special about them?
If that is the case I might just go for a generic one as they are a bit easier and cheaper to get my hands on like this one on ebay

[Editor]

Looks like the wrong fuel hose sizes - probably solvable though. I think the other pump has the same size for the 7mm hose on a Type 3 or 4. It's just that the US guys have already found a compatible pump, though it's not got the third (return) fitting. I guess either would need the original electrical plug removing.

I don't know what non-return valves there might be on these pumps either.

[nitro_warrior]

Before getting a new pump I replaced the spring for a more comparable one to the picture. But now the pump wont pump. It spins but no pressure and gets to the it from the tank. Not sure if its just not priming or something else, either way it builds no pressure.

I tried moving the pump around, pinching lines, and even fitted a bulb type hand pump briefly to try and get it going all to no avail. Its certainly testing my patience if nothing else!

[kembiff]

That picture was from an old thread i started ages ago. One of the first annoying things my square suffered from.
I can possibly shed more light on it if the old thread does not show you what you want?
I also bought a second hand pump to keep in my attic with all the other spares!!!

[nitro_warrior]

Well at last an update.

I got hold of a new pump, a generic thing from ebay, like this



It has a 12mm inlet and 10mm outlet, the outlet went on fine to the hoses and I bought a 12mm to 8mm adapter for the inlet.
So after wiring it up, it worked pressure up to 28psi and more importantly the engine started. It doesn't hold pressure but i'm not overly worried about that, as it gets up to pressure pretty fast.

So fingers crossed it seems ok. Need to tidy up the fuel plumbing (think i'll need to drain the tank for that) and sort the timing, but at least the projects moving in the right direction.

Thanks all for the advice on this!

[Editor]

Is it the same diameter as the original pump to fit the mounting clamp?

If it does the trick, it's better than the sort of money they charge for new Bosch pumps.

[kembiff]

nice one - put it on a thread showing alternative parts which is on here somewhere mate.

[nitro_warrior]

That pump was £28 including delivery. Plus I got a 12mm to 8mm adapter and some 12mm fuel hose.

I haven't checked it fits the existing mount yet as I need to tidy up all the pipes. But it looks like it should be really close. If it doesn't fit it will only need a little packing out or bending to accommodate it I reckon.

Once I tidy it up and check the fitting I'll make a note of it.

[shawn71]

Looks like the type of pump I'm going to have to find for my 412 at some point as mine is starting to get slightly damp. Do you have a part number for the pump at all?

[nitro_warrior]

OK, may have some teething issues... Now that it's running I went out to set the timing tonight.

But it still isn't running right, checking my pressure gauge, whilst running the pressure is right down below 20psi. Stop the engine and run the pump it goes up to 28. I struggle to believe the pump can't keep up with the engine and I know it's running.

One thing I want to check is what's the common practice for fuel filters. I fitted a random inline one from halfrauds that I have fitted between the tank and the pump, but I wonder if that is throttling the supply too much? I'm going to remove it and see what happens.

But in the meantime any suggestions? I guess most FI systems with fuel tank pumps won't have a filter before the pump.

[Editor]

I would expect the proper fuel filters to be better than the 'random' one you fitted, unless it has a similar overall size. The ring main feature of the Type 3 means a constant flow is going through the fuel lines and returning to the tank. I don't know how normal that is for other systems.

Don't leave the filter out once you've established if it helps, as you might block an injector if there's debris in the fuel. That's why the FI filters are finer than the normal.

[type3]

If it's a clear plastic one it'll be fine. But be aware there's two sizes. The small one is for low pressure (carbs) and the larger ones are for FI.

[nitro_warrior]

I was planning on fitting the fuel filter after the pump. Not sure if the filter is for carb or FI come to think of it. It's a metal cased filter as my logic when i got it was it would be better up to pressured systems. It's pretty big too, slightly smaller diameter than the pump.

I'm also aware the pump is meant to have a 12mm inlet and i'm running it through a 8mm hose. I'll investigate some more over the weekend.

[type3]

The metal ones are usually found in K-Jet systems which can handle up to 80psi.

[Editor]

I would have thought it better not to have mucky stuff reaching the pump at all. I would suggest you place it where VW did!

[nitro_warrior]

The metal ones are usually found in K-Jet systems which can handle up to 80psi.

Maybe that's it the pump is rated to 3 bar (45psi). If the filter is much runs a much higher pressure then maybe there's too much resistance. Certainly as that's at the Low pressure part of the system.

[type3]

Yep, seems possible. As Dave says, try it breifly without and go from there.