Fuel pump probs
Our blue Evo2 developed an alternator fault, the charge light stayed on. This is an easy component repair, the diode at the top of the alternator goes faulty.
But getting the alternator off the car is a nasty job, while the unit was at the menders and that area of the car disassembled, I decided to renew the engine belts, water pump and tensioner bearing.
All this was done, oil & filter changed and the alternator returned to it's position, the engine turned over by hand, then it started up ok, so I bolted the covers on and fired it up again. It wouldn't start. So where to start looking? I couldn't hear the fuel pump when the ignition was on, I did suspect the alarm at first, the car has been a bit reluctant, seeming to start on the 3rd press of the key fob.
But I tried the easiest thing first, I whipped the fuel pipe off, and it was dry as a bone.
So the first check is at the fuel pump relay. To make room for the relocated radiator header tank, the Evo2 fuel pump relay set is behind the air filter box on the inside of the front wing.
So the air box was removed and I changed the relay. No difference. So I ran a live wire over and only got the rad fans working, still no juice to the fuel pump. I tested the car's live input and got nothing either.
The fans and pump relays, and some other items, are fed live from the battery all the time, there's a 2nd lead off the battery that goes to a bank of 3 fuses near the wiper motor.
I tested these fuses at their tops, and they all seemed ok, the test light lit on them all. So I double checked and removed the pump fuse, it had a corroded contact in the fuse holder, so it had got hot and melted the fuse plastic down the feed side. So it was live on the top, but not contacting the output pump side.
Result! The fuse was well knackered, a clean of the holder and a fresh fuse, bingo!
A short time ago, I bought a fuel pressure testing kit on Ebay, it was from Hong Kong and only £14, so my expectations were low! However, it does seem a good kit and it was useful on this repair, the kit has lots of fittings, I can use it for oil pressure testing too.
The Delta's pressure regulator releases fuel from the system and returns it to the tank at over 2.5bar, so I could measure the fuel pressure up to the regulator, at idle this was 2.5bar.
The fuel pressure regulator is controlled by a pipe to the inlet manifold, the vacuum adjusts a sprung diaphram in the regulator.
So under power when the injectors need more fuel, the low inlet vacuum allows the diaphram to close increasing the fuel pressure
allowed to the injectors.
So pressure regulators can be adjusted, but it's the pressure released
from the fuel rail after the injectors, that sets the pressure at the injectors. All injector fuel pressure sensors work this way, adjusted by manifold vacuum. Newer cars have an in-tank pump and regulator combo, so we're lucky with the Delta that it's easy to locate.
Corroded fuse holder
Here's the fuel pressure tester fitted in line just before the pressure regulator. The regulator should give 2.5 bar to the injectors, the pump was giving just that pressure, so it's just enough
There's an earthing point under the air box, so I sanded it and the fittings, cleaned them, and bolted it up tight. I gave the earth bolt and the body corner a dab of waxoyl. Well a bit more than a dab!
I put the air box back and fitted a new filter to this. I put the top back, and gave it all a wipe.
Finally, a test drive. Any excuse for a drive! The Delta started 1st try, and ran well on the road, boosting to 1bar. The car ran smooth and fast, just as it should be, this Delta is a lovely car and now runs as well as it looks.
Best of all, no dash lights! All systems looked good, oil pressure, temp, only needle moving was the fuel gauge.....much joy!!
A man wiping up his mess
A dash with no warning lights
Finally, this is a selection of the components changed in this operation.
The relay blades have been sanded before, so this problem must have been on-going, and not properly resolved.
These little Italian fittings probably reached the end of their designed life many years ago!
So it's worthwhile checking the easy little things first.
You'll notice the mounting hole on one of the relays.This and the other end relay support the 3 relay set and it's holders to the inner wing. As I only had plain relays with no mounting brackets, I had to quickly fabricate a little support bracket to hold this end up against the pull of gravity. A compromise, but it works, so far so good!