Tj tdi

Anyone know what psi the alh tdi coolant operates at?

Been trying to diagnose coolant coming out of the jeep rad cap (18psi it will hold) as it reaches operating temps 86-88*C and up. Flushed the heater core and rad, no blockages. Alh out of a beetle and mated to the tj driveline runs well but struggles to supply hot cabin heat in the winter.

Alh operates just as it does in my jetta wagon with warm up but the coolant keeps leaking out of the rad. Im guessing the tdi coolant system runs at a much higher pressure. Can anyone chime in? The expansion tank holds pressure just fine. Im also thinking the leaking doesnt allow for pressure to hold and temps to maintain a hot op temp.

92*C thermo stat is brand new
Coolant lines are clear of debris
50/50 g12 and deionized water has less than 700km on it

For future reference with a rad cap on a tdi, you can use pliers to tighten the rad cap clamps. I tightened mine and the leak has stopped.

So was the 18lb cap sufficient after you tightened the cap?

My Ahu in a 99 TJ has never leaked. Basically the same motor. This is also with a custom pulley on the water pump that slightly over drives the pump + more flow and pressure.

Maybe your cap is bad or even your radiator is in question.

Some feedback. Rad cap was holding but the plastic to aluminum connection gave up and began to leak. Replaced rad and everything was running smooth again. Rad cap was replaced as well.

***new issue***

Now I have another issue. Came off the highway and was idling, waiting for the traffic lights to change and the engine died (turned off). Attempts to restart showed no glow plug light (was at operating temps) but just turned over.
I did notice 2x the rpm at idle dropped perhaps 100 rpm while I was idling and the 3rd time the idle dropped, the engine died.

Swapped relays 109 and 180. No success. Glow plug light will not come on and the engine just turns over but will not start - doesn't sound like it is trying to start and its turning over at the typical speed it used to, when starting.

This has the rocketchip 2 tune - other sources I've read with similar symptoms stated the ecu could be toast. Considering the RC2 tune can be swapped into a new 99beetle ecu, is this the next course of action from a trouble shooting perspective?

VAGCOM will not connect to the ecu but it can read another alh tdi jetta 2003 no problem. Any assistance is a plus as this frankstein tdi jeep is my daily.


EDIT: starting in sub zero temps I am still not getting the glow plug light. Also, if I get a stock 99 beetle ecu, is it safe to run the factory tune on 1019 injectors, 11mm pump, and vnt 17?

What error do you get when trying to connect via VCDS? "No response", or "too many communications errors"?

Have you checked with a multi-meter that power is going to and from relay 109 correctly?

To me it sounds like the 12v the ecu should get during start/run isn't happening. Or the ECU has a more significant internal problem.

May be time to make yourself a 80 -> 121 harness adapter?

It sounds like no power to the ECU or no power to the pump fuel solenoid... which is controlled by the ecu.

Thanks guys.

I was getting NO RESPONSE when trying to connect.

I'm going to go and check power to 109 and 180 with a multimeter as well as test all the ecu pins. Is this (link below) the correct pinout to follow?
http://forums.tdiclub.com/showthread.php?p=3947232

I jumped the solenoid from the battery and blew something just now. Now I'm not getting the glow plug light or the pre-start power light, but was before.

80 to 121 pin ECU swap: What are some benefits to doing this?
And is this (link below) the correct procedure for converting that you're referencing?
http://forums.tdiclub.com/showthread.php?t=363743

No response would lead me to think the ECU isn't getting juice - which would explain it not running. I would be careful jumping things directly from the battery with no fuse to protect the component. Just testing for continuity or voltage ought to tell you want you need to know. If you absolutely have to apply 12V to something ECU/sensor related which is delicate I like to use a 12V power supply from some old router or modem etc. which puts out low amperage.

Do you know where the TDI harness is tied into the Jeep wiring? In my 121 pin ECU there are only two or three wires that need 12V to wake up the ECU - so I would be looking at those connections. I don't know the specific differences for the early ECUs so I can't comment on which pins/wires should be getting 12V.

I do know from playing with mine, one wire "wakes up" the ECU, and then the ECU sets off relay 109 which sends power to several other systems- so your problem may not be relay related.

The thread you link for the conversion is a good one and the spreadsheet inside is very helpful. The benefit is that you can flash tunes via ODBII. I just threw it out there since you thought your ECU may be dead - but throwing in a new 99.5 ecu will get you back on the road sooner if that is indeed the case.

Thanks for the input Smelly.

I tested all my pins. The smaller of the two connections had no voltage across any pin. The larger connection had 5 pins that gave a signal without the ecu connected.

Those 5 pins are as follows, as per the ECU pinout with the bottom left being #1 and top right being 52.

Pins 9, 33, 46 and 47 all had 12v (11.7 something). And pin 51 had 5v (5.03).

The sticky thread for pinouts is for the 121 pin ecu... so perhaps a benefit would be being able to reference all the pins? I found the 80 pin ecu pinout which suggests my 5 powered pins are as follows:
9: brake light switch #3
33: Power supply relay #9
46: clutch vacuum vent #2
47:Hot in run or start
51: instrument cluster


Both relays below were tested with the ECU plugged into the harness and the key in the glow plug on position.

Relay 180 test:
top middle @ 12v
top right @ .01v
btm right @ .01v
top left @ .01v
btm left @ 0.0v


relay 109 test:
top middle @ 12v
top right @ .1v
btm right @ .01v
left @ 0.0v

Solenoid on pump is not showing any voltage when the key is in the glow plug or start position.

TDI wiring harness is connected to the jeep computer. The jeep underhood and glovebox fuse boxes are still intact and functioning.

Going off of the excel file linked in this thread:
http://forums.tdiclub.com/showthread.php?t=395019
I interpret that as basically saying if Pin 47 is getting 12V, The ECU should wake up, and send 12V via Pin 33 to relay 109, which should engage the relay. At which point the 30, 85, and 87 legs of the relay should all have 12V.

So, on the one hand it sounds like your relay 109 is either faulty, or there is a break in the connection between the ecu and the relay.
On the other hand - I would think you should be able to log-in via VCDS either way if Pin 47 is getting power and your ODBII port is getting 12V. So maybe there is a problem with the ECU?

For the IP solenoid, I could be remembering it wrong, but don't think it's always hot with the key turned to "on". In my Golf I used it to trigger the lift pump relay. I hear it run for just a moment when I turn the key to "on" and then it shuts back off if you wait a few seconds. It then kicks back on when running- and perhaps cranking when the ECU tells the injection pump a quantity of fuel greater than 0mg/stroke to inject.

I would in this order:
-Rule out a problem with the solenoid by supplying 12V from another source or remove the solenoid and physically remove the plunger temporarily (since that is free)
-Try a new relay 109
-Try a different ECU

Got it. Thanks

So pin 47 is key for the ecu to turn on? I'm also swapping a 99.5 alh into jeep. An xj. Tackling the wiring this weekend. Any tips where to start?

It sounded like the one based on the OPs testing and the guide linked in this thread:
http://forums.tdiclub.com/showthread.php?t=395019

That being said - I have no personal experience with the 80 pin ecu so I can't say for certain. You will want to acquaint yourself with the excel file in the linked thread. Lot's of other good threads in the conversions sub-forum that document the general approach if starting from a full harness out of the donor. Start with a roll of painters tape, sharpie, and some good tunes. I've heard that brake cleaner works well to de-stick the harness tape.

try a stock ecm, but don't drive unless you install a stock map sensor... my buddy had a chipped 80 pin in his vanagon and the ecm failed (would get really hot before shutting down) we swapped in a stock ecm and no heat no shutdown ... he is now running a 121 pin

I put a stock ecm in the jeep today as well as a new 109 relay. Getting the power and glow plug lights as well as it turning over. Seems the battery needs a charge as it has not yet fired up and is showing 9v on the dash. Charging now and will report back, but it seems that both my ecu and relay 109 went out at the same time.

99 Beetle TDI ECM is from a 5spd, manufactured sept 5, 1998, replacing the previous 99 tdi beetle ecm from dec 29, 1998.

Here's a question, do the automatic ecms have removable chips for the tune while the manuals have them soldered to the board? The replacement stock ecm has them soldered to the board... so I'm guessing there was a difference.

Still unable to connect via vagcom.

Same issue. Turns over with glow plugs and power light active as they typically would be. Getting oil pressure but its not firing so I'm thinking fuel.

Is there a way to remove the solenoid from controlling the fuel flow to test that? I know there is a plunger with a spring and plastic bit inside. Not sure if its wise to remove them to try running it. Any advice is appreciated as the dash is responding as if there are no issues.

If it is better to run a line from the positive terminal to the solenoid to keep it active, do I remove the wiring harness connection completely? Last time I tried to start it with the harness connected and the solenoid jumped I seemed to have caused more issues.

Have you loosened any injector lines to see if fuel bubbles out?

No but that is next. I replaced the fuel filter and same issue just now.

I noticed the glow plug light stays on 12-14 seconds and its just above freezing currently - this is very long compared to startups in the past at these temps.
For reference, compared to my 03 alh jetta who's glow plug light stays on for ~4 seconds, it's crazy long.

Am I chasing the right problem going after the fuel issue? I feel there might be something else I've overlooked but I will try fuel next.

I would crack the #3 injector line (while cranking) just to make
sure it is getting fuel first.

While it is handy to confirm that fuel is reaching the injectors - I would be concerned about still not being able to communicate with the ECU. Does your cable and computer combination work fine with your 03 TDI?

You're sure the ECU you got doesn't have any type of immobilizer?

Few points to add now:
- Too many response from controller msg when connecting to engine via VCDS
- Start procedure: turn key, glow plug light stays on a while, then battery voltage drops to 9(min) on the dash, glow plug light turns off and CEL comes on. If I leave the key in this position, the glow plug light starts flashing.
- No immobilizer on this year beetle ecm
- fuel supply:#3 injector open during an ~8 second crank. Wrapped the fuel linewhile it was open in a shop towel and check it. It was not wet. It only smelled of diesel very lightly. I am assuming it should at least show some signs of fuel spillage.

So fuel is not reaching the engine from the pump.

Solenoid ideas? Pretty sure the 11mm pumps die slowly and give a noise as they begin to die - obviously there can be odd cases, but i'm trying to follow the most probable path.

VCDS note: vcds connects to my b5 s4 almost immediately... the 03 jetta it gives the same too many communications error as the jeep

Edited: Testing the speed sensor yielded a response on the pins when grounded. My mistake, but it's nice to cross that off the no-start potentials.

I tested the lift sensor (via http://forums.tdiclub.com/showthread.php?t=322537 )and I'm getting 116 ohms.

The coolant glow plug 50A fuse shows no signs of damage.

So I'm back to not getting fuel pressure at the injectors. Can anyone recommend a next course of action? The glow plugs staying on for a very long time has me concerned that i'm missing something simple...

Dang - I keep checking this thread hoping to find you've sorted this out. Must be frustrating.

Being able to check for codes and watch what's going on during cranking in VCDS sure would be helpful. Might be worth getting that sorted out if it's not an issue with just the Jeep. Anybody nearby with another version that you can confirm works on your 03?

A few ideas/comments:

-You can remove the plunger and spring from the fuel cut solenoid. If it runs be prepared to stall the engine in case your QA can't.

-You might probe your pump wiring to see if there are any obvious problems there - I remember seeing diagnostic procedures on the forums in the past, at least for the QA.

-Have you confirmed that your new relay 109 and glowplug relay (180) are now behaving correctly? Based on your earlier test I don't think they were being triggered and thought you might have a wiring issue between the relays and the ECU.

-Maybe a dumb question- but have you checked the four or so fuses that are fed by relay 109 to make sure none are blown?

Minor progress; I followed directions a thread stated for bleeding injector lines after installing injectors (my injectors were not touched) but loosening injectors 1 and 3 allowed me to prime both injectors and I can confirm I have fuel now.

This also means my solenoid is working. My fuses on the 109 harness are in good shape.

I have swapped the 180 with another and get the same results of no start with the glow plug lights staying on way too long for the ambient temps. Also much longer than they did in the past at these temps. I am inclined to believe I have some sort of electrical issue between the glow plugs and the ecu.

Still plugging away at this, smelly. When its running its worth every hour of trouble shooting. When I do get it running again ill have to have my rc2 chips transplanted to the new stock ecu. Doubt the stock tune will be as drivable but I will test fuel economy for comparison.

Edit: used my btobd2 to find that the coolant temp sensor is dead. That explains my long glow times... on to test the pump electronics

Starter is on its way out now, unfortunately.

I noticed I'm not getting any exhaust smells after cranking - does that seem strange? I thought my exhaust would have a bunch of fuel in it by now. I've probably cranked 40-50x at 8-10 seconds long. Any one think this might mean there is no fuel getting into the engine, even tho it comes out when I loosen the injector lines and turn the engine over?

Man, this has got me confused. Still waiting on someone else to assist with a second vcds to see if I can read anything out of the ordinary.

So I got it started today and have found the issue.

Now, to figure out how to solve it long term...

I jumped the IP solenoid directly from the battery and the thing fired right up.

Comparing voltages from the battery vs the IP solenoid connection from the wiring harness shows 12.16v vs 9.XXv when in the glow plug start position (just before cranking). Battery is cranking real strong and measures 12.16v across the terminals. I've charged it from the wall a few times now so i know the batt is good.

How am I losing voltage from this lead to the IP solenoid? I guess I need to chase the single wire through the firewall and into the loom to diagnose... but just for reference 9v won't power the dang solenoid - guess it needs closer to 12v.

Perhaps the solenoid is dieing and needs a full 12v to fully operate. Can anyone comment on this to save me from going through a maze of wires for no reason?

Now I'm getting 0.0X at the solenoid whether cranking or just glow plugs. Anyone have ideas on whether this is a relay dieing off? Think its 409 relay... time to find that and test it.

Have you removed the solenoid? There is a plunger, spring and o-ring in there. I've seen the o ring dislodge and cause a no start. Long shot but it may be in there incorrectly causing 9v to be not enough and 12v be enough to start. Plus, it is easier to check than chasing wires.

Ideally, you could find another solenoid to swap to use for a test.

Solenoid seems fine so that leads me to believe my wiring has a fault or the 409 relay (which I cannot find) has issues.

I have put a tank of fuel on it with the solenoid powered by an open aux fan fuse port from the jeeps underhand fuse box. No issues other than a cel.

I'll sort this out when it gets warmer. I wrench in the elements as I don't yet have the luxury of a garage.

I've got the solenoid wired to a jeep relay under the hood.

The tach has stopped working and the glow plug light is flashing for the needle lift sensor code. Weird. Still have power and I'm still driving it.