Rattys latest EFI project

ratty 63 · 2005-12-29T01:08:06+00:00

Introduction Firstly, a little background for those of you who don’t know what my Brother and I are currently up to – we are both building (or re-building) Bajas. Both of the cars are based around circa 1965 body shells but have undergone a huge number of modifications to make them even more capable than the basic Baja. My brothers car has been rebuilt several times, each time to make the vehicle less likely to suffer from whatever had continually failed in the last ‘version’. This time it was a conversion to IRS as Dave had decided that he had better things to do than to spend every second weekend replacing Swing Axel gearboxes! Whilst he was at it he fitted 4-wheel disc brakes, converted the brakes to dual circuit, re-manufactured the lift kit, and repaired some rust patches and dents that had appeared since the last rebuild. The 2.1 litre Type IV engine was also refreshed as it was showing signs of uneven compression due in part to failing heads. In the last ‘version’ of this car, the engine was fed by a modified Kombi EFI system – modified only in physical appearance (to fit into a Baja and fit over the Porsche fan shroud). The ECU and EFI components were straight out of a Kombi. This system worked fine for the most part (far better than any of the Carby combinations that he had tried), however the cold start function would cause the engine to hunt at idle, and it appeared to be running too rich at certain loads and too lean at others, most likely due to a changed (from stock) vacuum pattern. Now, due to bigger valves and other ‘secret’ mods to the refreshed engine, Dave decided that the stock system was no longer going to do the job – it was time to go aftermarket. He had seen what I had done with my Delco/Kalmaker set-up and liked the look of it, so he suggested that he might be able to borrow the entire system that I had installed on my test engine so that he could get his Baja finished and over to Frazer Island for the Christmas/New Year period (as he does almost every year). At first I wasn’t too keen to just hand over this rather expensive system, but I then considered that it would give me an opportunity to finally get this EFI system out on the road and learn the ins and outs of tuning an EFI system from scratch…at no risk to my engine!

56astro Custom Title Time!

1,772 posts · joined Aug 2002 · 12 Oct 2007, 8:51 am

#616156

Slowly, unfortunately!
:jesus

VW car, VW engine ...... keepin it "real"
35MPG on 101.3kPa

nbturbo Veteran Volks Folk

2,171 posts · joined Dec 2002 · 12 Oct 2007, 12:47 pm

#616171

Ratty-mines running like a dream.Didn't have any joy with the Delco-tried to get a base file for an AJUN chip-but no go.So bought a Haltec and played with that for a while with little success-so took the car to a Haltec agent.He's got it running really sweet.Will get it out to run the motor in and get used to driving it.It's pulls really hard thru each gear with only light throttle opening and the gear changes are really quick and tight.

ratty 63 Custom Title Time!

1,083 posts · joined Oct 2003 · 16 Oct 2007, 5:07 pm

#616821

Hi folks,

Just a quick one today....

Last night my brother mentioned to me that his car was lacking even more (than usual) grunt at high revs, and he had noticed that on a long run on the weekend (around 800km) that the car felt like it would run out of fuel if WOT was used for any more than approx. 20 seconds. He wanted to hook up the laptop and see what the oxygen sensor was reporting, but I suggested that he double check everything to do with the fuel supply system before I hooked up the laptop and wasted another couple of hours sitting in the passenger seat of his Baja (only to diagnose a mechanical problem rather than a tuning problem...again).

He has just called me to tell me that during his lunch break he removed the fuel filters (2 X low pressure filters that feed the surge tank and 1 X EFI filter, mounted after the HP pump). He said that the low pressure filters were clearly 'flow restricted' (ie: blocked), and the HP filter weighed about 3kg once the fuel was drained from it.

At this stage he hasn't given the car a run (ran-out of lunch break 😀), so we are not certain that the new filters have fixed the problem... but it has to help!😂

I'd love to know what sort of mud laden fuel he uses, as most of my cars will go for years without a fuel filter change.

R 🙂

40hp, 6V and ...er... slowly making improvements 😂

It's nice to be important, but it's more important to be nice!

Founding member of the Gold Coast Dub Club Inc. 🙂

ratty 63 Custom Title Time!

1,083 posts · joined Oct 2003 · 25 Oct 2007, 11:20 pm

#618220

Hi all,

Dave tells me today that he is having trouble with the engine hunting at idle ..... but only when the headlights are on! 🤪

I feel that it is obviously going to be a voltage related issue (which, coming to think of it has shown it head very early on in this conversion... does anyone else remember?). I have just checked the requested idle (vs battery voltage) variable and I have noticed that there is about a 100 RPM step between the requested idle less than 9.9 volts and the requested idle at greater than 12.7 volts... so I don't believe that this is what is causing the problem.

I suppose that I should put my multimeter on his battery and find out what voltage is coming out of his Porsche alternator - he tells me that the volt gauge does drop quite dramatically when the car is at idle (as opposed to running at revs), but not as far down as 10 volts, so I wonder if his Alt is looking for attention (again - this will be the 4th or 5th time we have had to look at/repair this alt if its not right this time 😬 )

Anyone else have any suggestions? Has anyone else had any experience with Porsche Alternators? Are they reliable (or has Dave ended up with a lemon)?

R 🙂

40hp, 6V and ...er... slowly making improvements 😂

It's nice to be important, but it's more important to be nice!

Founding member of the Gold Coast Dub Club Inc. 🙂

11CAB If ya got it....Baja it

4,674 posts · joined Aug 2002 · 26 Oct 2007, 6:18 am

#618240

They dont like dust. My Boss used to have to have the Porsche Alt repaired every second race or so when he was running the Porsche motor.

65 Meyers Manx
68 Country Buggy (KO 367)
68 Country Buggy (KO 669)
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76 Baja Kombi Twincab

ratty 63 Custom Title Time!

1,083 posts · joined Oct 2003 · 29 Oct 2007, 1:05 pm

#618667

11CAB wrote:They dont like dust. My Boss used to have to have the Porsche Alt repaired every second race or so when he was running the Porsche motor.

Graham, what was the most common fault? Was it just bearings or was it something else (brushes, windings, diodes)?

R 🙂

40hp, 6V and ...er... slowly making improvements 😂

It's nice to be important, but it's more important to be nice!

Founding member of the Gold Coast Dub Club Inc. 🙂

11CAB If ya got it....Baja it

4,674 posts · joined Aug 2002 · 29 Oct 2007, 6:10 pm

#618705

I think it might have been the diodes.....just wouldnt charge

65 Meyers Manx
68 Country Buggy (KO 367)
68 Country Buggy (KO 669)
68 Country Buggy (KO 789)
68 Country Buggy (KO 815)
68 Baja Bug
76 Baja Kombi Twincab

ratty 63 Custom Title Time!

1,083 posts · joined Oct 2003 · 30 Oct 2007, 9:20 am

#618779

11CAB wrote:I think it might have been the diodes.....just wouldnt charge

Yep - been there and replaced (some of) those. This is what I suspect is causing the problems that Dave is having now. I'll just have to find the time to have another look at it.

R 🙂

40hp, 6V and ...er... slowly making improvements 😂

It's nice to be important, but it's more important to be nice!

Founding member of the Gold Coast Dub Club Inc. 🙂