BIB5566

[knapmann]

So today I was playing with another recent purchase. I got these air filters on ebay for £70. They seem to be filters for something else that have been modified to fit 911 Carbs. I bought them in the hope of getting them to fit my MFI, as they were only cheap I had not much to lose. I cleaned the filers out and re-oiled them then set about fitting them

The one on the RHS stack was simple, plonked it straight on. The LHS stack is much more problematic as people with MFI probably know there are clearance issues with the pump and the idle microswitch arrangement. My issue was largely with the MFI pump.




I gave it some thought and decided to cut out the base plate and weld it back in 10mm offset to move the filter to the left. Now it (just!) fits.








All done! Im very happy with this for £70!



After this I fitted my sill trims.

[IanM]

As you're not using the stock air filter housing with spray bars, you need to remove the solenoid from the top of the fuel filter.

[jwhillracer]

It ought to be OK just to disconnect the 12v feed to the solenoid, and/or cap off the outlet as belt & braces.
JW

[knapmann]

Good point guys, I already disconnected the wire but a plugging the end probably a good idea too.

[IanM]

So, does the engine start easily now?

[knapmann]

So, does the engine start easily now?

Hi Ian

Thanks for your tip with the injectors. I went out on the car today for the first time since and it started from cold much easier with the solenoid switched manually from inside. Obviously this solenoid hasn't been getting actuated in the past.

Im still having a lot of other running issues. Despite all my efforts the car will not idle consistently. I set everything at temp, go for a drive and its never consistent. Today I drove around for 30 mins, the first few junctions it idles OK, then the next few the engine just cut out totally, and I had to restart it on the hand throttle to keep it running. Next thing I know I'm reaching junctions and its doing the MFI surge cycle, as its idling so high. All without touching the engine at all and all with the engine at full temp... I can only think its the distributor still. I cannot see any other way that an engine can change so much from one idle to the next when the throttle is returning to it stop as it should every time. It can only be getting the same fuel and air, so it must be ignition?? I'm going to have to get it rebuilt to at least rule it out and at best fix the issue I hope. Is there a go-to place in the UK for distributor rebuilds?

Additionally to the idle issue the engine baulks a lot between 3k and 4k. Lets say I shift into 2nd at 2500rpm and floor it, it will rise to around 3k smoothly then baulk/hesitate through 3k-4k quite badly then rocket from 4k to 7k. Now I know it has S cams and they like the top end but I don't think I should be getting repeated whiplash regardless of cam choice. My solution was to stay above 4k which although it has its benefits Id rather not have to do at all times.

I can only think that this is either an MFI pump setting issue (rich or lean), or once again an advance issue.

I know that I really need to get this onto a rolling road with someone who knows MFI but its a waste of time/money if the key components are not working correctly and the distributor is one such component. So I need to get this rebuild before heading off for a session.

On the positive side my seats are way comfier!

[knapmann]

Other than going for another test drive today I started putting my doors together.

Double sided tape, Plastic backing, door cards, armrests and garnish rails. Pockets to follow!

Oh and yes thats a sexy RHD/LHD armrest combo!

[IanM]

Is there a go-to place in the UK for distributor rebuilds?

Try Neil Bainbridge. (not to be confused with Mike Bainbridge who's a gearbox man)

[satan]

Hi,

Before getting too embedded in rolling roads, distributor rebuilds and MFI (Check Measure Adjust is still the bible here I think?), can I suggest you check - and possibly replace - the points? If they're in poor shape or out of adjustment this is a quick and relatively cheap fix...

Cheers,

Chris

[knapmann]

So with my engine still causing me some headaches, and me not having any actual road insurance, ive stuck to garage tinkering this weekend. Not done a great deal.

I used some plastic colour rejuvinating stuff to get my door handles looking good again, before and after below



I then built up my drivers side door with pockets and speakers, I have to have driving tunes when driving my cars properly!



I'm waiting for some parts for the passenger side so thats still to be done. Interior is virtually complete now!

Chasing my engine issues I did a few checks. First I pulled my plugs to check the colour. Mainly im just checking that they all look the same, this tells me that the MFI pump is delivering the same fuel to all cylinders and that there are no air leaks causing any to run leaner than others. They indeed all looked the same. Ed Mayo et. al. says that the actual colour of the plugs is pretty much meaningless now due to our E10 petrol, you can no longer judge plugs by appearance. Im not sure how true this is but im happy they all look the same colour.



Next I tested the fuel flow. I was getting around 1500ml/min which is down on the recommended flow of 1800-2000ml/min. Im not sure if this is likely to be an issue. I then took out the fuel tank sender to see if the filter in the tank was clear which it was, so I dont think I have an issue with blockages. It is probably just a pump issue. I do think my pump is very loud when it runs, but I have no point of reference and it may be normal. I next plan to install a fuel pressure gauge to test this as well.

[Jonny Hart]

I doubt the distributor is causing the issues you describe. Check it springs back and the shaft has no lateral play.

A few weeks back, uneven idle, surging and hesitation was due to an MFI pump. Despite being rebuilt, it had to be returned for further adjustment. Now runs superbly.

[hot66]

for an mfi motor thats not stretched its legs and mainly being on tickover / moved about, those plugs look on the lean side. MFI tends to get set up on the rich side. Not saying this is the cause of any running issues, but just something to watch as you go forward.

Did you double check the pump timing ?

[stretch]

Have you done the 30 second fuel test from the return off of the MFI pump as specified in the workshop manual. ?
The pressure on the fuel filter housing may be a problem. Was on mine.

[knapmann]

I doubt the distributor is causing the issues you describe. Check it springs back and the shaft has no lateral play.

A few weeks back, uneven idle, surging and hesitation was due to an MFI pump. Despite being rebuilt, it had to be returned for further adjustment. Now runs superbly.

You may well be right, I have another distributor on its way to me. This will prove it definitively once I get it

[knapmann]

for an mfi motor thats not stretched its legs and mainly being on tickover / moved about, those plugs look on the lean side. MFI tends to get set up on the rich side. Not saying this is the cause of any running issues, but just something to watch as you go forward.

Did you double check the pump timing ?

I triple checked the pump timing. I agree it looks lean to me, I think it is running lean which is causing the stumbling in the mid range but I need it gas analysing to confirm this and to get the pump set up right.