Mk1 rabbit pickup TDI swap. Instrument cluster and MFA wiring

I have a 1981 VW rabbit pickup with a TDI swap that I've been driving for 9 months, engine is a 1z, vnt15 turbo, top mount ic, "full" ce2 swap, a couple months ago I blew up the instrument cluster and just sourced another one and am trying to situate the wiring, tach worked with old cluster, speedo, temp, and fuel did not (ran a 2" temp gauge), ECM talks to vagcom and regularly analyze data, there is no speedometer value in vag, not sure if wiring or sensor, temp also ready around 35*c and does not move, not sure if wiring or sensor, the MFA also has an issue, LCD displays time and mileage but no communication with it, have MFA stalk, column and wheel from mk3 Passat, if anybody has a wiring diagram for MFA, speedometer, and temp? Or any tips on this delema? Will post pics of my rabbit if anyone's interested, new to the forums so thank you in advance, have gotten a plethora of information from this site and am extremely grateful! ?

Toyed with the truck a bit more today and found a break in my high oil pressure switch and got continuity between the switch and the g2 connector for both high and low (light and buzzer only come on above 2500, not throwing any codes for oil pressure but do have a ect code, can post a list of codes if needed, also have continuity to gauge cluster wiring. Also have continuity from vss to fusebox and through to instrument cluster wiring yet no speedometer reading (good known working cluster), have a good ground on vss wiring also, found a busted wire in loom for coolant temp sensor, repaired, no change, tested for continuity to fuse box and into cluster all good, good ground on coolant temp.sensor, what are the two blue wired for on the 4 pin plug in? Don't have a 1996 1z Passat wiring diagram, have used 1z Jetta diagrams but they don't match up wire for wire on some things, I'm leaning towards sensor issues since all gauges worked with my previous dash before it blew up (most likely culprit is the grounds by the monotonic plug), is anybody aware of test procedures for vss and coolant temp sensor? I read through the Vince Waldon oil pressure walkthrough and grounded the high pressure switch and the warming buzzer and light still came on, also tried disconnecting low pressure and grounding high pressure with no success, wiring is good to instrument cluster wiring, possible ground issue? Don't believe the oil pressure switch is bad because the chime and light still come on after they are "bypassed". Mechanical gauge used to test oil pressure, all within spec (engine had 56k at time of transplant, drove 3k before cluster blew, and an estimated 3-4k with no working speedometer or gauges, at which time I installed pod gauges and phone speedometer!) Any help is appreciated, slowly been working g every kink out of the system and am quite stumped on this, although it's only day 3... Btw I got to take it for the first few test drives with the vnt and upgraded ic and am very impressed other than the annoying beeping constantly, the power is night and day difference with a much lower spooling and picks up quite nicely, pushed my foot to far in 3rd and spun the tires free, only did it in second with the gt15, that's the joy about super light vehicles

Mk1tdiracetruck said:

Toyed with the truck a bit more today and found a break in my high oil pressure switch and got continuity between the switch and the g2 connector for both high and low (light and buzzer only come on above 2500, not throwing any codes for oil pressure but do have a ect code, can post a list of codes if needed, also have continuity to gauge cluster wiring.

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You wont get any codes for low oil pressure. The ECU has no idea what the oil pressure is.

You will get a code for the ECT if its not hooked up. And the ECT is not the same sensor as it is for the gauge and ECU, or atleast the same pins. I have the details of so many swaps in my head they are muddied together. IIRC, your engine should have a 4 pin sensor. Two are for the ECU, the other two are for the gauge. They both have totally different transfer functions(voltage vs temp) so if you started hacking stuff, no idea what you got now.

On the oil pressure stuff, you have 2 switches. One is on the filter housing, the other is on the head. The one on the filter housing is the one that triggers the buzzer. The one on the head just triggers the light. I think the one on the head is the one that is ignored under 2500.
These switches are not interchangable. The one on the filter housing is normally open, the one on the head is normally closed. This means with no oil pressure, the one on the filter housing has no current going through it. With no oil pressure the one on the head has current going through it, and goes to ground.

With that, if you never hook either one up, the bell will be going off because the one at the filter housing is not going to ground. The only way the one on the head will trigger is if the unhooked wire goes to ground. Same situation if you have a break in your wire that goes to the flange, or a dead short in the wire that goes to the head. Or if you swapped the senders around.

is anybody aware of test procedures for vss and coolant temp sensor?

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I cant remember if the VSS is connected to 12V or 5V supplied by the ECM. But the VSS is a hall effect sender. If it has power, its output pin will alternate between 0V and its input voltage as you slowly turn the shaft.

Don't believe the oil pressure switch is bad because the chime and light still come on after they are "bypassed".

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Bypassed how? To bypass it, you need to ground the sender at the filter housing, and unhook the sender at the head.

My engine does have the 4 pin ECT, haven't "hacked" anything, was just testing continuity between ECT and the pin it connects to fusebox then the pin it transfers to the instrument cluster, never tested anything but continuity, also I don't have a oil pressure switch on the head, just 2 on the filter housing, a brown and a grey (grey high pressure, brown low pressure), by bypassing I grounded the grey and left the brown unhooked, have no light below 2500 with brown connected or disconnected, but still get light and buzzer whether grey is grounded or not. And since oil pressure is just monitored by the cluster I tested continuity to the cluster and have flow to both high and low pressure but the buzzer still goes off. As for vss I haven't tested for any power supplied to it, just for ground and continuity to cluster which is good (so I'm assuming there must be a break for the input voltage or it is receiving no input voltage), and I have tried both combinations to temperarly bypass. Also followed Vince Waldon a diagnostic procedure with no success. As for the ECT. It has a ground on the brown wire and flow to cluster through the yellow and black. Haven't messed with the blue wires but I'm assuming they are connected to ecu. Does this sensor need an input to operate correctly? And the vss. With key on I should receive either 5 or 12v on one of the three wires?

My last AHU/1Z swap was in Spring 2015, so pardon my rustiness, haha. I also never convert over to CE2, so what I do and what you do will have some differences. However, I am starting another build now, so I have to dust off my Bentleys again. I really need to take better notes.

Sorry about the hacked comment, hope you didn't take it the wrong way. The post you had there kind of bounced from this to that so I was trying to follow everything. And for some reason pictures popped in my head of the average persons swap with 50 cut wires and Ace Hardware butt connectors holding everything together, LOL...

I might get a chance to sit down with the wiring diagrams tonight and re-acclimate myself to the specifics. One problem i have ATM is all that stuff is at home, and I almost never am on the computer at home. But a few minutes ago I added the forum to my tapatalk, so I can post from my phone in the shop from now on too..

Haha no offense taken but solder and shrink tube is the only way and in a pinch, high quality shrink tube butt connector. Mechanic for a living and I know what poor electrical connections can do. Didn't have any issues with gauges or buzzer, then cluster blew, got a new one (difficult to locate) then installed it and all these issue arose, had car running and driving to verify all gauges worked before I pulled cluster. Sorry about being all over the place with my posts I'll keep it more organized from now on, kind of been scattered for the past couple of days with work and the demon rabbit. Been driving her like a grandma under 2500 so the buzzing doesn't occur. Is it just me or did VW find the most annoying tone to use for their buzzer? Lol. So about the wiring. I need to invest in a Bentley, during my swap I used wiring diagrams off of the internet and thoroughly evaluated then before even touching anything. Have had very few electrical issues other than a ground and chaffed wires from rubbing (obviously my dumb fault) since then I have re covered wiring in conduit to protect it and fixed all wires that were damaged (total of 4 or 5), for specifics on engine if it will help at all, ecu is a bk unfortunately but planning on a jb swap with GQ chips in the future, engine it out of a 1997 VW Passat, trans is a 5sp manual, as in "full" swap i used wiring pigtails off fusebox and connected to factory mk1 light harness, radio and heater are fused with power coming from the power distribution on fusebox, engine wiring is all Passat, retained every needed component, currently have 2 sensors with broken connectors (reverse switch and the sensor on intake horn for ccv, have new connectors ordered), as for the oil pressure issue I'm relatively stumped being as the circuit is "simple", but there has to be something I'm missing, did replace the high pressure switch due to it leaking while my cluster was blown (grey in color) and was contemplating whether than would cause the issue but by grounding the wire going to the high pressure it should bypass that sensor. And as my low pressure seems to be operating correctly (no light below 2500) that part of the circuit is working, the odd part of this dilemma is the buzzer and light do not come on above 2500 at idle or in 1st gear, only 2nd and above and triggers at a little over 2k in 5th, plan on testing whether the switch develops a ground when revving in neutral once I get off work but I'm thinking it will develop a ground in neutral since the light and buzzer don't trigger. We will see..

Ok, I hope this helps...

VSS:
Pin 1: 12v
Pin 2: output signal. Goes to G1/11, to U1/11 to pin 27 on the cluster.
Pin 3: ground
Note!
Pin 7 from the cluster goes to U2/2, to W/1, to pin 43 of the ECU. This is where the ECU gets the speed signal from.

Coolant Temp Sensor
ECU portion
Pin 1: Reference Voltage(5v)
Pin 3: Signal to ECU.
Gauge portion
Pin 2: Ground
Pin 4: To Gauge. Goes to G2/3, to U2/9, to pin 23 on the cluster.


Oil Sender.
On one the flange.
Goes to G2/10, to U1/13, to cluster pin 28. Unhooked triggers. Grounded not in alarm.

One on the head:
Goes to G2/11, to U1/5, to cluster pin 9. Alarms when grounded.

You should have one on the flange and one on the head as shown.



Sent from my SAMSUNG-SGH-I337 using Tapatalk

That helps tremendously, will go through tests with those values, but there is one issue I see, I have 2 switched on the oil filter housing, there isn't one on the head, where the switch is on the head in the pic is where my turbo feed line is.. all material I have referenced with this issue state there is one on the oil filter housing and one on the head, yet I don't have one on the head, oddball?

Maybe its because yours is a 1Z, not an AHU? Its been almost 3 years since i seen a 1Z.

Allright so I've been extremely busy the past couple days and would like to update you, I am getting no power to vss or ect, this would mean my ecu isn't giving it power or there is a break in the circuitry? Also I have had no luck with my oil pressure switch issue, just been driving her below 2500 lol, but the one on the filter housing (low) is functioning properly, the one on the head (second one on housing in my application) is ungrounded even when revved past 2500, (buzzer or light never come on in nuetral or 1st), I have not tested for ground inside cab at fusebox yet but this is my next step to monitor it while driving to see if it is grounding once pressure is reached, also tried grounding the high switch and alarm still triggers.. I'm beginning to think cluster fault.. only drove the car 15 feet and let it idle up to temp to make sure everything was good never got it above 2500..

Update on the truck, do you have access to the MFA wiring for the cluster? Have the stalk but it will not communicate with the display, would looking for a different ecu be a good bet?

As for the MFA question I asked in the previous reply, does the lcd display stay on all the time? For the connector on the fusebox MFA Switch Wiring Harness Green
V/01-MFA Switch (Memory ½)-Gauge Cluster (MFA) Red/White
V/02-MFA Switch (Ground)-Ground (for gauges/warning lights) Brown/White
V/03-MFA Switch (Mode)-Gauge Cluster (MFA) Blue/Yellow
V/04-MFA Switch (Reset)-Gauge Cluster (MFA) Yellow/Red

MFA wiring is definitely grounded and have a display on LCD of milage, time, and trip, no communication with stalk, yet all wiring is presumably hooked up. Where are the 4 wires on the v connector supposed to be hooked to? MFA stalk? Do not currently have a intake temp sensor and would like to install one which I believe the MFA has the function to read. But as of right now just trying to get everything back in working order. One other thing. I would also like to get my cruise control working which I never played with during to initial swap. I know I have to get the power feed issue to sensors fixed (which I have been researching with no luck besides possible relay 109 issue which was replaced 4 months ago with gray) before even thinking of cruise control but a little insight on what's involved would be appreciated.

Reviving this dead thread for not following up! Turned out that the high side switch was incorrect being opposite. Vss had a chaffed wire from ecu. Mfa had a bad stalk.

We want picks of the car and engine bay

Pics at time of post do not have hoodscoop or top mount ic, currently wrapping up an ALH swap into it as we speak http://s32.photobucket.com/user/pre..._20180807-091005_zpszkqgzslh.png.html?filters[user]=145799023&filters[recent]=1&sort=1&o=5

link was misformatted. found this on your list, with hoodscoop?

http://photobucket.com/gallery/user...E4MDgwNy0wOTA5NDJfenBzaGlmcHZmdGEucG5n/?ref=1

ToxicDoc said:

link was misformatted. found this on your list, with hoodscoop?

http://photobucket.com/gallery/user...E4MDgwNy0wOTA5NDJfenBzaGlmcHZmdGEucG5n/?ref=1

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Link was dead. I have plenty of pics on my Instagram Dub_nasty