49 replies to this topic

[Wiggy]

One step at a time.

I take it that you're struggling to get the injector out?

Again, not sure about the SPi; but the MPi injectors took a lot of tugging, twisting and rocking to remove.

[xrocketengineer]

The radiator has a temp switch for the electric radiator fan. It is not controlled by the ECU. Probably your best bet is to clean the injector as suggested. That will also tell you if the injector coil is good when applying intermittent power to get the solvent to flow through. And definitely, connect the throttle switch if you have it.

Edited by xrocketengineer, 19 April 2019 - 11:06 PM.

[Wiggy]

Electrics just not my forte. But ill have a play and try and do that

Got the injector out - its spotless. Not alot to clean?

What is the little motor looking thing next to the injector ? Is it a mini pump ?

It's the inside that gets clogged with dried up fuel residue. You won't be able to see it. The professionals ultra-sonically clean them.

I have used a small syringe full of Unleaded, pushed into the injector with the plunger pushed hard to create pressure; then pulsed the injector with a 12V supply. Worked very well.

That sounds like good idea. Carburettor cleaner spray would probably do the job too.

I didn't think of carb cleaner, although I do have some. I soaked them in Redex (inside and out) for a couple of days, but it didn't do anything. God forbid I spend any money. So some invention was called for.

[Sprok]

One step at a time.

I take it that you're struggling to get the injector out?

Again, not sure about the SPi; but the MPi injectors took a lot of tugging, twisting and rocking to remove.

Yes got it out eventually !
Trying to rule out the fuel pressure regulator now. Its winning !!!
Will clean the injector first thing.

Edited by Sprok, 19 April 2019 - 11:34 PM.

[xrocketengineer]

I would be careful if you take apart the pressure regulator.  The diaphragm is delicate and there are no spares apparently. As far as the pressure goes, I have a story. I had a 1992 Chevy S-10 pick up with a 4.3 L V-6 with throttle body injection (TBI). It had similar operation to the SPI but with two barrels. It even used the same fuel filter of the early SPI and the fuel pump was very similar. All of a sudden, it started bucking in gear and doing all kinds of weird stuff but it would always start. I replaced the usual stuff, plugs, wires, then I put in a repair kit in the regulator/injector housing with no success. I replaced the distributor and still no joy. Finally, I got a fuel pressure test kit with a T-fitting that replaced the in line fuel filter. To my surprise, the engine was running and I was reading next to 0 pressure. I then took the truck bed off (easier than to remove the fuel tank from below) and replaced the pump. It turns out that the pump was fine too. The short hose connecting the outlet of the pump to the hard lines inside the tank had rotted and leaked the high pressure fuel back into the tank. But the problem was finally fixed.

So, based on my experience, if you can get any trickle of fuel to the injector, the engine should start or at least it should try to.  

[Pops_Guild]

I’ll mention this because no one else has. There will be a inertia fuel cut off switch on your SPI (black thing with rubber top,on the bulkhead to the right of your injection housing) That needs to work or be reset or no fuel will get to the injector. Your symptoms sound like that’s been tripped or it’s busted. Worth asking.

The Relay pack is also a common place for SPIs to fail. The ECU via that controls part of the fuelling functions.

SPIs are notorious for having problems because of bad connections and earths. I’ve experienced pretty much all of them over my 3year (and counting) rebuild. It’s worth checking all your earths are good etc.

[Sprok]

Thank guys. Ive pressed the inertia switch in ill try and test it late. All wiring etc brand new so cat imagine theres earthing issues. I took the inertia switch of the car so thats used.

As for the relay inside the black box. Ill have to look there too

[Sprok]

Wiggy

Ok ive got the injector out to clean but the inlet holes are guarded behind a turquoise circular clup with very fine gauze covering the holes. Unlike other injectors where you just get a hole.
I wonder wether the trick is to fire cleaning fluid in reverse ie up through the fuel outlet ??

[genpop]

As said before give an intermittend impulse of 12 V to the injector, you should hear a clicking noise then.  Einspritzdüse.JPG   44.95K   0 downloads

If you want to check the pressure regulator here is a pic too.  Druckregler.JPG   53.33K   0 downloads

I would check the injector, when working put everything together and try again. For checking the fuel pressure you only need an y-pipe some pieces of hose and a simple pressure meter of an bycicle air pumb or simular. ( should be good for at least 1,5 bar.) Mount the y-piece between ruber hose and metallic hose before the caburator, connect manometer to the y-piece too.When you switch on ignition, pressure must be more then 1 bar.thats enough.Take pressure regulator only apart if there is not enough pressure and you hear the fuel pump working.

And a picture of the injector from underneath. The needle in the center has to move when you give it 12 V.

Give the 12V only for very short time because this part is built for 5V only!  Oberteil _v_u.JPG   51.87K   0 downloads

Edited by genpop, 20 April 2019 - 07:49 AM.

[Sprok]

This superb thanks.

BUT how do i clean inside the injector ? Should i try pushing carb cleaner the reverse way ? Applying voltage in bursts?

Im using a 9v battery and i can hear clicking

Edited by Sprok, 20 April 2019 - 08:33 AM.

[genpop]

So you can only test it when build in.

Put all together. Without the plastic cup on top of the injector.Switch on ignition two or three times that fuel is provided. Now apply your 9 volt intermittend and have a look if fuel is spraying out of the injector.

[Sprok]

Fuel is not coming out
Heres one question - with the injector removed ad ignition on ie fuel pump running should fuel enter the throttle body.
I would think it should ? Without the injector blocking the fuel flow surely fuel should pump through the fuel inlet ?

Edited by Sprok, 20 April 2019 - 10:23 AM.

[Wiggy]

I don't know what the SPi injector looks like, but you might have to get creative to test it independently of everything else. Tubing or something like that. I had to push the plunger HARD to create enough pressure to unblock the injector.

I would be good to (if it's possible), because it will 100% eliminate or incriminate it.

PS. Mine clicked even whilst blocked.

[Sprok]

Right ive soaked the flaming thing in carb cleaner and operated the battery as it was submerged. Left for an hour.
Took it out and operated the battery again and im getting a splatter out of it. So i imagine with fuel under pressure that works.

Fitted to car - still no fuel.

STARTED OVER AGAIN

Decided to remove the “flow” fuel line of the throttle body and guess what ??!!
No fuel coming out now. Very odd. I had fuel before that said i hadnt removed the pipe last time just cracked the nut and fuel came out so i left it at that. Now i have detatched the rubber hose where it connects with the steel fiel pipe and theres nothing. Not even when fuel pump is running !!

Jeeeez what a saga

[genpop]

What about the back-line. Disconnect the rubber hose and test your fuel pump again.Maybe you have interchanged hoses on top of the fueltank.