Removing fuel at 6750rpm with spark active would feel soft and may cause a lean out issue. I am sure VAG or their suppliers (Telefunken) would know this. More than likely the TCI-h unit had the rev cut built in. All the K-jet 8v and carb'd cars had the hall input and 5v supply come from this unit. So I cannot see why there was not a hard coded coil output threshold built in once these inputs were used. I also sure there are ther would be measurement issues with old rev counters as well as aftermarket TCI-h units. It would be faster to reduce torque via timed spark retard than a fuel cut. Or aggressive spark retard with fuel on for flames!!!
I'm having exactly the same problem with my 1900cc 8v. For the last three years my cars revved and pulled freely to over 7000 rpm and I've never hit a limiter then the day before I did a sprint at Curborough the fuel pump relay (was stamped No2) packed in so I replaced it with a new relay (Stamped No62), now it won't rev past 6200 before hitting a limiter I didn't know I had. I've checked the rotor arm and its plain. I've only changed the fuel pump so it does point to this, the only other thing I can think of is that I have K star. Mike do you have K star and could this be the problem?
mike/alonzo a quick and dirty test to check if the limiter is the relay, bypass it temporarily with a chunky bit o wire with spade terminals on each end I'm still kinda sure its the pump relay, since like i say there are different relays available depending on if car had rev limiter in the hall sensor or not. Also if there was a rev limiter in the TCI-H then carb cars would have a rev limiter as well, and iirc they do not? Except the terrible exhaust manifold/downpipe design of course
I'm running raw Kjet - all stock 8v from an 89 scala, except for a 16v WUR. No ECU. If it is the relay, then a KR one would be your next best option after the 1600 Mk1 item.
It feels like an ignition cut to me. I was going to recheck this on VAGCAT, but it seems to be down at the minute. From memory, the spark amp seems to be the same unit for all (or almost all) engines, so I don't see how that can be the rev limiter - the different engines must have different limits (KR's are up near 7000, both my kjet 8v's cut just before 6500). However, if I get to the point where I've exhausted the other options, I'll start playing with them.
16v and digifant 8v dont use the hall sensing part of the tci-h, so theoretically rev limiter may be in that bit? But as I say if the TCI did have rev limiting that would mean carby models would also have one and I've found several posts on here that say they do not. Its been so long since I sold my driver I cant remember if I ever tested this theory out for myself edit: is it possible the relay could send a signal back down the rev counter wire to cut the ignition, since the coil trigger and rev counter wires are to the same side on the coil?
KR one isnt going to work on an 8v k-jet car, the k-jet 8v ones need a rev counter input to work whereas the KR one gets an earth from the ignition control unit. Yes you can make it work with some wire bodgery but it wont be safe as it wont cut out if you have a crash
Cheers Rubjonny, all fixed. My rev limiter is in the fuel pump relay, when I hot wire it its fine, revs all the way to above 7k and didn't kick in. Relay back in and its limited to 6400ish. Mike have you tried it without the relay?
Damn! Where's that humble pie?! Didn't try it yet - been working late, and trying to help someone with their car.
Just chatting about this with a mate - he's wondering if a normal 40 amp relay would do the job, and eliminate the limiter. If it's using the ignition impulse as the switching current, then that might do the job. Not sure on the impact of using a normal relay with a 100 times a second pulse... I'm guessing that the relay must be earthing the dizzy pulse, when it senses the rev limit being hit. Sneaky VW feckers
there are relays without a limiter in, as on some models they have the limiter in the rotor arm instead, so a bit of year matching and you should have your answer. id guess the non-limiter ones would be cheaper as less gubbins inside? edit: from zee MK1 section: 93590 FUEL INJECTION PUMP RELAY G1 1.6 F.Inj >7/82 19.80 93592 FUEL INJECTION PUMP RELAY G1 1.8 F.Inj 8/82 >12/83 23.20 92265 IGN.ROTOR ARM-6900rpm G1 1.8 F.Inj 8/82 >7/83 9.50 92270 IGN.ROTOR ARM-6700rpm G1 1.8 F.Inj 8/83 >12/83 8.50 MK2 section: 93592B FUEL INJECTION PUMP RELAY G2 1.8 8v F.Inj 8/85 >2/87 20.00 92270 IGN.ROTOR ARM-6700rpm G2 1.8 F.Inj 8/83 >7/85 8.50 92205 IGNITION ROTOR ARM G2 1.8 8v F.Inj 8/85 >2/87 3.20 From the above it would seem the early cars have the rev limiter in the rotor arm, and later cars its in the relay itself. Pretty sure I recal MK1 1.6 guys saying about removing the limiter simply by fitting a boggo rotor arm, as the 1.6 is a revvy little beasty, but dont quote me on that
On Mk1 Golf GTi's the relay has No2 on white paint, this didn't have a rev limiter in but the replacement I took out of a Scirocco Injection did, this had No62 painted on it so it looks like we need to find some old relays that still work.
No 2 Relay without rev limiter 321 906 059D Out of 1983 1.8 Mk1 GTi No 62 relay with rev limiter 321 906 059G Out of 1990 Scirocco 1.8 Injection Have another spare at home that has a different number on so will add that later.
For 321 906 059D these numbers also valid - 321 906 059E, 321 906 059F - 44.22+VAT Listed for: 82-83 Scirocco/Golf/Cabby 84-92 Cabby/Scirocco (JH code lump) 83-96 LT 82-88 Passat 321 906 059G is a current part number, but deleted. listed for: 83-92 caddy 84-92 scirocco 86-87 golf/jetta 84-93 cabby
Check if there's one in that early scirocco shell, before you scrap it! Are GSF relays genuine Bosch/other OEM supplier ones, or pattern tat?
The other relay I have also has a rev limiter and it has the No63 on it. Part number 321 906 059F this has a date of 2 9 92. Not sure what it came out of as it was just a spare my brother had. Will make sure I take the one out of the 82 Scirocco GTi before it gets scrapped.
thats not good news then, seems like the non limited relay is discontinued from VAG then edit now i think on it, I'm sure I read there were some cars with an electric power steering which had a rev-pulse input relay?
