kws

As mentioned previously, I'm having some running issues and I need to try and work out what it is. The issue has been getting worse the more I run and drive the car. It previously only happened under load at about 4000rpm, where the engine would fall on its face and cut out like you had turned the key off. If you kept the throttle steady it would recover with a surge as the revs dropped, but as soon as it got up to about 4k again, it would cut out. When stationary, and not under load, it will happily rev to its 6k redline. It's a very annoying issue. I had a couple of suspicions of what it could be, but I needed to do some testing to narrow it down. My first suspicion was that I must be losing spark, as the engine cuts so abruptly and I felt that if it were fuel it would kinda stutter out. The first thing I noticed was that the replacement coil the previous owner had fitted was a Bosch GT40. This is a 12v coil, and from what I have discovered, widely known to have issues with electronic ignitions. Now, the ignition system on my car is both a ballasted system and electronic. A ballasted system runs a resistor on the power feed to the coil, dropping the voltage, meaning the coil doesn't see 12v. So I was already running the coil under voltage. After testing and confirming the resistor was still in place, I removed this coil and refitted the original Ford coil that came with the car. Changing this resulted to a smoother idle (maybe, but probably a placebo), but the engine still cut out. The next thing was to check the lead positions, cap and rotor. I note that the cap and rotor have been replaced, and the old ones were with the car. The old cap is stuffed, but the old rotor looked OK, so I swapped that in after a quick clean. No change. Next was to confirm if I did lose spark or not. The only way I could think of was by thinking out of the box and using my timing light... So I connected it up, and strapped it to the wiper so I could see it when driving. Sure enough, when the engine cut, the light was still flashing away happily. That indicates I have spark (although, not if I have a good strong spark, but some spark is better than none). So this points me down a different path. I have air, and I have spark. Could it be fuel after all? I posted up on a few forums asking for help, and got some great tips on where to start looking. One of the easiest to do was to check the sensor plate in the AFM was clean. This plate is hinged, and lifts up with airflow as it gets sucked into the engine, which in turn pushes a plunger up and down to control fuel flow. Well, although the top looked reasonably clean, the underside was filthy (probably thanks to the incorrect air filter that was fitted) I gave this a thorough clean and made sure it was spotless. This made no change, but its good to know its clean now. I also, once again, checked the intake tube and boot for splits or cracks, but none found. All vacuum lines (all two or three of them) were checked, all OK. One thing that makes me suspect its possibly fuel, is the state of the new plugs I fitted. Even after a couple of runs around the block, a couple look almost unused. Maybe lean? From 1 to 6 in order. This is leaving a couple of possibilities, ones that I cannot test without further equipment. First is an intake manifold leak or the likes. Today my smoke machine arrived, so I could test this. It's just a cheapie, but makes a good amount of smoke, and has a pump to actually blow it out under pressure. After a quick test, I modified it to work how I needed it to. I salvaged a cap from a CRC rust convertor can, drilled a hole in it, glued some hose into it, and glued the cap onto the front of the smoke machine (as it just has a big nozzle on the front normally, for maximum smoke dispersion in da clubz) This hose then goes into a rubber glove with a finger cut off it. I find using one of these seals the intake pipe nicely with the wrist of the glove, but doesn't crush the rubber hose. I don't know if it's good or bad, but smoke testing the intake shows there are no intake or vacuum leaks. I tested with the throttle open and closed, to check the intake hose for leaks as well as the plenum/manifold, but nothing, not even a weep. So what left? Well, two things really. I need to test the fuel pressures of the system, but because the fuel fittings use banjo bolts and hard lines instead of rubber hoses, I can't use my existing pressure testing kit. I have a new kit on the way, which has all the fittings I need to connect into the KJetronic system. This will tell me if there is an issue with the Warm Up Regulator or the main pressure regulator. The whole system relies on having the correct pressures, so even a few PSI difference can make it all turn to custard. The other thing I need to do, once I have tested the pressures, is to remove the fuel distributor and injectors. I need to see if the plunger in the fuel distributor is clean and moving freely, or if it's sticky. I also need to check the flow and spray pattern from the injectors. It's possible either, or both, of these things are causing an issue. My main theory at the moment is a sticking fuel plunger, which is causing the engine to starve of fuel when it demands more. The worst thing you can do with a KJet system is to leave old fuel in it and not run the car regularly. This car has been off the road for years, and I don't know when it was last started and run, or how old the fuel in the system was. KJet runs at such fine tolerances that even a slight gum or varnish on a component can make it upset. I'm determined to work this issue out and get the KJet working properly as it's a cool system, and one I haven't worked with before. I have everything I need to convert to EFI and Speeduino, but I'm trying hard to resist that urge. Now we wait. Once the pressure test kit arrives, Its game on.

Last weekend was a productive one on the TVR, starting with wrapping up the fuel hose replacement job I started earlier. I was held up with the wrong filter, so I did some more research and ordered what I hoped was the correct filter (using the number off the existing filter) Thankfully it was the right one. The early cars with the filter under the car use a Ryco Z399 filter. A set of nice new copper crush washers and on went the fitting I had to replace the hose from the pump to the filter, as I was doing away with the accumulator, and the existing hose was both incorrectly rated, and starting to perish 1/4" hose is pretty small, and not that common here, but I found Repco stocks Gates Barricade hose, which is bloody expensive per meter, but some of the best hose available. You'll note in the photo above that the old hose is J30 R6 rated, which is safe to about 50PSI in an injection system (despite saying a higher rating on the hose). The Bosch MFI system runs at about 80PSI, so although that hose had been working OK, I wasn't going to trust sticking with an R6 hose. The Gates Barricade hose is safe for 225PSI as it is a J30R14T2 rated hose. Since I had been doing all this work on the bench first, it was time to move to under the car, where I got a timely reminder to always check your lifting points. The TVR had been in the air on the Quickjacks for a week now, and unknown to me it had settled on the front blocks, and they had started to tilt and slip. It's possible it would've been OK, but it's not worth the risk. I dropped the car back down and reseated all the blocks. ALWAYS check the car is secure before getting under it, even if that means giving it a good shake or shove. Better it falls off the stands onto the ground, than onto your head. With the car safely in the air again, I refit the new filter to the mount and secured the bolts and ground straps. I wanted a nice straight hose from the pump to filter, but due to the proximity and angle, the only way I could do it was a loop back from the filter. At least this time I don't need to wrap the hose in tape to stop it from being rubbed through where it was touching the body, as it had been... And here is the new hose Once everything was happily in place, I torqued both banjo fittings up with my torque wrench. They don't take much, just 18-20NM, but it's essential they are torqued correctly. I have heard much talk about not using the moulded hex on the ends of the filter or disaster can strike. I don't know how true that is, but I didn't need to secure the filter as the mounting clamp held it tight anyway. After mixing some more injector cleaner into 10L of fresh petrol, I slowly poured it into both tanks, keeping a close eye on the new hose joins. When everything appeared to be dry and sealed, I reconnected the battery, and turned the key and listened as the system primed. I let it prime for a short time and checked all the high pressure lines, and once satisfied they were dry, I fired the beast up. Everything still looked good. Winning. With the car still in the air, I planned some more maintenance. I wasn't sure when the last time the driveline oils were done, so like usual, I spent hours pouring over fluid specs, and eventually settled on a Nulon fully synthetic 75W-85 GL4 for both the gearbox and diff. Nulon sells it in these nifty little baggies, which at first I thought were a gimmick, but I'll tell you now, its way better than a bottle. The gearbox is a bit of a pain to get at due to the exhaust, which chills out directly under the drain plug, and allows only a small space to access the fill plug. Always undo the fill plug first, just in case. One thing that always bothers me is getting oil on the exhaust, as even if you hose it with degreaser or brake clean, it'll still stink as it burns off. There was no way to avoid oil pouring on the exhaust with the TVR, so I settled for being smart and using some plastic sheet wrapped around the exhaust. Worked a treat. The old fluid actually looked really good, so I suspect it hasn't done a lot of miles in the car, but its probably still been in there a few years. The diff was easier to access, with the drain plug smack bang on the bottom, and the fill plug on the back. Both were bloody tight but came off when I asked nicely. Yeah, the diff will probably need some seals at some point, but that's down the list a bit for now. I used three and a half bags (1L each) between the gearbox and diff. Here we see the squeezy bois chilling at the watering hole One thing I noticed with the bags is that it can be hard to get the last little bit out. What you can do is join the two bags together, and drain one into the other. I also reused hoses between bags, leaving me with one unused, clean, hose to stick back onto the half full bag to use later. With the fluids changed (except engine oil, I still need to do that) I lowered the car back down and took it for a quick spin. Unfortunately the running issue seems to be getting worse. It used to just be under load at about 4000rpm the engine would fall flat and cut out. Now it happens randomly and is almost undrivable. Watch the video with subtitles on as I note where it has issues. You can see it revs happily with no load at the end. I had my suspicions of what it could be, but I needed to do more testing.

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FFS

Car

Doorstop

Wedge.

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Please Sir, may I have another?

Please.

New one please

Big page is big.

I feel like with the way it dies, a spark is a spark. It cuts so hard I would expect at least a period of no spark, but the flashing doesn't miss a beat. I'm resisting the urge to Speeduino it. I have everything here for a full efi conversion, but I would rather learn and master the KJet system. I'm weird like that (aren't we all, on here?). I tried to read the plugs but haven't go far. The old plugs were jet black, and the new plugs still look almost new after a couple of blats around the block. I do know it's not fouling the plugs, so that's a start. I'm suspecting the fuel distributor may be sticking, but want to measure pressures before ripping it to bits.

The plan now, is that I have a pressure testing kit on the way, along with new plenum gasket and injector O-rings. Im going to smoke test the intake, and fuel pressure test for main and control pressures. After that, the plenum will come off, and injectors out for flow testing and to check the pattern.

I dont believe these use inserts, but I have a set of Viton O-rings on the way. I also have a smoke machine on the way to smoke test in the intake before i pull it all apart.

Ive heard this about the fuel distributor, due to tight tolerances, but there are some good guides and kits to rebuild the WUR. I would need to get a fuel pressure tester if i went down that route as my one doesnt work with KJet.

Yeah, i think its at a point of pulling the injectors out and seeing what is happening with them. @Alfashark did you disassemble the warmup regulator or fuel distributor on yours?

I removed the accumulator because it was stuffed, but that wouldnt cause running issues (maybe hot starting issues, but it starts fine). The lines seemed pretty clean and not much came out of the old filter when i drained it. I have bypassed the emergency cutoff, so the fuel pump runs when the key is on. I have noticed lately when the engine cuts out, if im not rolling it will take a few cranks to get it to fire up again.

Right, so some super dodgy testing including a timing light and reversing up my busy street, I can confirm that when the engine cuts out it still has spark. The timing light still flashes as the revs drop. Also tried another coil. Have just cleaned the KJET air flap disk thing, and throttle body. Neither made a difference, but the issue is getting much worse the more i run the car. I can't get to the end of the street now, and if I push on when it cuts out it pops and crackles from the exhaust. I suspect it may be lean? Guess the next job is to remove the plenum and take the injectors out and see what their flow is like?

Ok, so reverting back to original Ford coil results in smoother running & idling, but more cut outs at random times. This is a quick video I made showing the issue. Make sure subtitles are on.

So the previous owner fitted a Bosch GT40 coil.... a 12v coil. When I checked the voltage across the terminals with the ignition on, i get about 7v. Guessing the ballast resistor is still fitted. What would the negatives of running the coil at 7v? Obviously I wont continue to run it like that, but I cant seem to find anything saying that the effects of under volting a coil is. E: so it also turns out it is widely known that you should not run a GT40 coil on an electronic ignition, as it can cause spark breakdown at higher rpm. Guess what im doing tomorrow.

There aint much of an exhaust on this, so wouldnt think there is an issue there. I have been told to check the oil filler to see if there is suction, indicating a leaky intake manifold gasket or not. The dizzy looked okay but seemed quite easy to move the mechanical advance when you twist the rotor by hand, but not sure if it should move that easily or if its normal. No obvious play in the shaft (heh).

Tank is vented to atmo normally (its not exactly cutting edge stuff this car) but will test with a cap open, and the cologne has cam gears. Ignition timing appeared to be spot on when i checked it with the light earlier. I have a scope, but dont really know how to use it. Care to point me in the direction of how to check spark with it? The cologne has about 2 vacuum hoses. I replaced the one to the vacuum advance, and the other one is for the brake booster.

Coil was replaced by previous owner (i need to confirm its ballast or not), and I believe the tacho still reads normally when it cuts