Morgans Exocet build thread

[snowbird1]

Unlikely to be timing belt, more likely to be a fuel pressure problem. I think the '90 MX5 has a pressure regulator in the fuel tank, a single line to the fuel rail and a return line teed into the fuel line near the tank. I don't remember a electronic fuel pressure regulator so the P1250 code is a bit odd.

[themorgster]

It’s a 1999 NB with feed & return fuel lines.

I’m getting the p1250 because I have removed the PRC solenoid. I don’t think it’s required unless you live somewhere hot enough to boil fuel! It was running fine without it for a few weeks.

FPR could well be it. They are normally fairly hardy but I may have (did) rigged the fuel feed and return lines the wrong way round when I first tried to fire it up so probably weakened it (somehow), now it’s gone... maybe.

I have a slight oil leak from the cam cover, so I have to have it off anyway, so I’ll check the timing then.

[snowbird1]

The fuel return line should connect to the pressure regulator on the rear of the fuel rail, the vacuum line should connect to manifold vacuum. If the pressure regulator diaphragm is bad the vacuum line can suck fuel into the manifold.

[themorgster]

I checked the timing and I’m positive that it’s correct. See below.

The car runs so rough (popping, hesitation, stalling, won’t rev, barely idles, very rich, black plugs etc) that I’m convinced it’s an over-fuelling issue, it’s so extreme, I doubt it is a sensor, most likely the FPR. Various sources suggest that it’s located inside the fuel tank on my 1999 1.8 NB (with return feed) but I think the image below is the regulator, which is on the fuel rail. Can someone confirm this before I go mad please! Assuming it is the FPR, I disconnected the vacuum hose (from the top) and it was dry, as it should be, does that mean it’s ok?

I’ve got a fuel pressure gauge on order, so all should be revealed soon...

[1055]

A bad cam or crank sensor will cause that issue.. as will a faulty MAF. check voltage off the MAF. disconnect your cam and crank sensors while running. if disconnecting and nothing changes.. then its probably a bad sensor

[Stiggy]

its back to the common point on all kit car builds, if it worked as a donor then why has it developed faults in the transplant? It only takes an injector wire to find ground and it will stay open causing over fueling. Perhaps the bulkhead grommet is an issue or the injector wires are squashed touching the corner of the hot head?

[themorgster]

I initially discounted those sensors because they aren’t throwing a p code. Further research reveals that bad sensors don’t always throw codes on the MX5. I tested the voltage on the MAF, it seemed to be ~2v @ 1000rpm and rose steadily with rpm increase. Unplugging either of the cam or crank sensors kills the engine immediately. The crank sensor mounting is cracked, so I’ll replace it in any case. The crank plate doesn’t wobble, and the 4 teeth seem to be in good order. I’ll be rechecking the grounds and injector wiring as suggested next.

It was running ok after the transplant (high idle due to a bad temp sensor, probably caused by flushing the coolant). Then I had to re-gasket the water pump (timing belt off etc), and that’s when it started to go wrong!

[themorgster]

I checked the fuel pressure and it was running 20psi after the filter, so I replaced the filter and it’s now running 30psi (60 if I crimp the return hose). So fixed right?.... wrong! It was much better but not “fixed”. I hooked the multimeter up to the throttle position sensor and the voltage fluctuated slightly, so I replaced it. Better, but still a bit lumpy. I also replaced the crank position sensor as someone had “modified” the old one and the bracket had cracked. Probably trying to advance the timing by changing its position. That had no effect at all. Then I noticed the plate was slightly bent with a wobble when the car was running, just the plate, not the pully. I have a new plate in order, I’m hoping that fixes it so I can get on with the build!

[themorgster]

Success! It was still a bit lumpy after the timing plate change so I swapped the fouled plugs out and now it runs sweet! I’ve also finished reducing the loom, and everything works apart from one strange thing... the indicators (left or right) flash at “normal” speed, but the hazards flash double time! The other day the indicators stopped working altogether, I picked up the hazard switch and they started working again. I gave the switch & plug a good spray with contact cleaner and now the indicators work again, but the hazards are still fast. I took a look at the wiring diagram and checked all the grounds, which are good, but from the diagram it looks like there is a lot going on inside the switch unit (Mk2 NB), is it likely to be this or the relay?

[themorgster]

Performance fuel filter fitted and secured with x2 p-clips to the tank.

[themorgster]

Started work on my adjustable cycle wing mounts. I drilled some stainless tube (which fits over the wing stay) and then welded on an ‘weld nut’ with a brass bolt in (used to line it up, but won’t weld in). I then replaced the brass nut with a grub screw. Below is the “test” piece...

[themorgster]

I used the original MX-5 filler coupled to a flexible pipe. It’s not the best looking, but it is cheap and the hole is small enough to enlarge to a more aesthetic filler at a later date. It will need a tether as the key comes out.

[themorgster]

Been busy fitting the wings. I bonded the stainless slider pipes with the grub screws to the grp with liberal amounts of Pu adhesive and gave the wires a good coating too in order to protect them. The sliders (to adjust and remove the wings) work really well, just a few things for people to note if they are planning on doing the same thing:

1. You may need to scrape off the powder coat from the top of the wing stays. This is to allow the pipe (bonded to the wing) to slide easily over the stay. I’ll give them a greasing which will inhibit rust.
2. It’s really important to get the two stays 100% parallel before bonding the pipes in otherwise they won’t slide off!
3. Waterproof plugs for the lights required so the the wings can be removed easily. I’ll probably mount these lower down on the stays or on the wishbones.
4. Point the grub screws toward the front of the car (following rotational direction of the wheel) so there is less chance of damage / getting crudded up.

[themorgster]

I wanted some recessed led number plate lights, but couldn’t find exactly what I was looking for so I bought some relatively ugly (and cheap) universal bolt on jobbies, cut some holes in the underside of the rear cover lip and used Pu adhesive to bond them in from the inside. The visible profile from the rear is minimal and there is no white light projecting backwards, which should keep the IVA inspector happy.

[bewgy]

I tried the noise test today, ran the engine upto 5,000 rpm with my phone 500mm behind the exhaust in the direction the exhaust is pointing. The maximum noise level was 90 dba, IVA states 99 so I think I do not need to add a silencer. I am running the same mid box and silencer as you, maybe the flexible hose helps?

I do have some small leaks at two of the joins but don't think that would make a difference? Did you say that you was getting 115, that's really loud, maybe the try with a different app.

Don't think my neighbors were best pleased today...