240 1984 Turbo No Start Weirdness

1984 245ti converted to LH 2.2 (?), previously schaff70 and then woodenpudden's

I think there are a couple of things going on here, but basically the car won't start. There a few prior incidents where it would not start, I'd fumble with fuses, electrical connections, and it seemed to start and run just fine. This was a random "fix" though, there's something more than this going on. I've searched the other related threads here and have done some debugging and was hoping for some advice.

Some notes:
- It's not the coil, I swapped another because it was easy and made no difference. Coil primary & secondary resistances are ok.
- It doesn't seem to be the power stage, passes voltage tests
- EM2 switch on the fuel pump relay doesn't close (EM1 does), possibly indicating hall sensor (it was replaced a couple years ago so it's not that old)
- Insulation on the hall sensor connector was kinda bad, so I cleaned it up but made no difference
- Both fuel pumps run when jumped from the fuse panel
- It's not the 25A inline fuse from the battery to ECU

Now here's the weird part. Separate issue, but perhaps is related. Battery connected, keys out, I have +12V at both terminals of the coil. Key to 'on', same deal. I go to start the car, it would come to life for a split second, then die. Voltage on the coil terminals (1 and 15 both to ground) are 0.3V. I'm not sure what's happening here...does the ECU think everything is ok and then kill the car when it realizes that the hall sensor is dead? Car will drain the battery if left overnight, and has always been the case since I've had it. The drain comes through the circuit with the 25A blade fuse.

I'm not sure why +12V at the coil with the car off and battery connected. Could be a bad ignition switch or some other relay stuck somewhere?

I still need to test hall sensor wiring voltage and will report back. Car is at work, so it's tough to get to. I get the slightest bit of movement from the tach needle at first (when I first have +12v at the coil), but then no movement with subsequent cranking.

In short, I suspect hall sensor, hall sensor wiring, or (I hope not) the ECU for the no start. I also haven't ruled out that perhaps it could be fuel...if correct fuel pressure isn't sensed, would that kill the spark?

Not sure what's up with the car being 'on' with the battery connected.

Thanks in advance for your help.

Get out your trusty test light and voltmeter. You have some wiring to verify. I would start at the fuse box to try and address the battery drain. There are several fuses that are switched with the ignition switch. Check with the test light and see if they are 'hot' when the key is off. If they are then I'd start looking at the ignition switch. The right side connections on the fuse box are the circuits. So, you can disconnect one wire at a time to find the drain if it's through the fuse box. You can also disconnect the fuel ecu and the ezk to see if one of them is the source. Make sure you disconnect the battery when you are making he disconnects.

For your no start. LH2.2 has to think it is making spark before the ecu will turn on the fuel injectors. Start with taking a look at your plugs. They could be fouled from gas from all the starting attempts. Make sure the gap is proper. If still no spark at the plug. Then move to the ignition amp and test with a meter for a fluctuating input switching signal when cranking. If you don't have that then you can work toward wiring, the EZK box or the hall sensor. You can ohm out the hall sensor but it's best to check for the output from it with a meter or scope.

If you do have the switching input but no putout then the ignition amp or something in the secondary spark system like the cap and rotor. You can also use your test light on terminal 1 on the coil to check for the switching from the ignition amp. If should flash the test light very quickly when cranking.

Assuming that your wiring matches an 87 or 88 LH2.2, the power to the coil comes directly from the ignition switch. It goes to the fuse block first, but continues on to the coil without going through a fuse (wired using 2 spades on the same side of the fuse box). Losing +12 on the coil suggests a bad switch. With a meter or test light on coil +, try turning on and wiggling the switch to see if +12 at the coil is flakey.

As an experiment, I'd try adding a jumper wire from battery +12 to coil +, and see if it starts (leave the existing coil + wires alone so that they can back-power the Chrysler box too). Watch carefully - if something is shorting the coil to ground, your jumper wire may draw very high current.

Update -- car started, started debugging

dl242gt said:

Get out your trusty test light and voltmeter. You have some wiring to verify. I would start at the fuse box to try and address the battery drain. There are several fuses that are switched with the ignition switch. Check with the test light and see if they are 'hot' when the key is off. If they are then I'd start looking at the ignition switch. The right side connections on the fuse box are the circuits. So, you can disconnect one wire at a time to find the drain if it's through the fuse box. You can also disconnect the fuel ecu and the ezk to see if one of them is the source. Make sure you disconnect the battery when you are making he disconnects.

For your no start. LH2.2 has to think it is making spark before the ecu will turn on the fuel injectors. Start with taking a look at your plugs. They could be fouled from gas from all the starting attempts. Make sure the gap is proper. If still no spark at the plug. Then move to the ignition amp and test with a meter for a fluctuating input switching signal when cranking. If you don't have that then you can work toward wiring, the EZK box or the hall sensor. You can ohm out the hall sensor but it's best to check for the output from it with a meter or scope.

If you do have the switching input but no putout then the ignition amp or something in the secondary spark system like the cap and rotor. You can also use your test light on terminal 1 on the coil to check for the switching from the ignition amp. If should flash the test light very quickly when cranking.

Click to expand...

Thank you Dave, your post is very informative.

Regarding the battery drain/coil at +12V with key out: I started with with the fuse box, these fuses are hot with the key out:
6: Stop lamps/courtesy light relay (this is probably normal?)
7: Main fuel pump (this seems suspect)
8: Courtesy/glove box/engine bay lamps (this seems normal)
9: Hazard (normal?)
10: Power windows (normal?)

With the exception of 7, the others seem to be ok to be hot (~12.4V) with the key out. The in-tank pump (position 5) is off with the key out, and only goes hot on/after an engine start as normal. Also, position 4 (seat belt/key reminder) goes hot when you put the key in, but don't turn it as normal. So that part of the switch seems to be correct.

Disconnecting both the EZK and the Fuel ECU did not change the hot voltage on fuse 7.

There are three circuits on fuse 7 and I didn't get to trace to see what they are. The two smaller gauge wires were pulled, no change to anything. This leave the final, third red fat wire which I imagine is the main fuel pump supply is the one pulling the voltage. I pulled that one off and not only did fuse 7 voltage go to zero (ok, obviously), but fuses 6, 8, 9, 10 all went to 0V with the key out too. Again, I'm not sure how this has been wired up and it was getting dark so I didn't do any more digging. I'm not sure if this would be a faulty ignition switch, or faulty fuel pump wiring. An additional note, fuse 7 (16A) gets really hot when the car is running so we're pulling some amperage there. It's probably worth taking a look at the main pump wiring next, if only the car wasn't so friggin' low!

If all of the above is normal behavior, then, IIRC, I had looked at current draw at the battery awhile back and found that the biggest draw was coming from the 25A bladed fuse circuit (going to the EZK?).

Regarding the no-start: TD;LR I got it to start, and I think the difference maker was taking the distr cap off and putting it back on. Or, it was a fluke (again).

More detail:
I didn't think I'd get any pulses at the ignition amp or coil because voltage was always 0.3V. I was going to test for pulses with my meter, but then the car started. Due to this, I now assume that ignition amp, hall sensor and wiring are all okay. Both switches on the FP relay close (the second with the key on "start" as they should. I don't think I got this right on my first look.

The hall sensor wiring passed the voltage test; red wire at 10.4V (spec'ed 12V) and blue wire at 5V (spec'ed 5V). Wire insulation is suspect, but I temporarily separated and isolated the strands so no potential shorts would happen.

Weird observation; I put a test light on the blue +5V hall sensor wire and it sounded like the main fuel pump and perhaps the injectors turned on? Note that I tried starting the car after this and it wouldn't start. I then looked at the cap.

I'm not ruling out a fuel pump issue at this point. Maybe a pump was stuck and getting it running free started to prime the system...and taking the dizzy off ended up being a red herring.

I'll be putting on a new cap and rotor as a precaution because it's cheap and easy. Maybe a new main fuel filter too. I'll continue to watch the fuel system, but should probably think about new high pressure in-tank pump, new wiring, new high pressure feed fuel lines to replace the k-jet pumps setup.

bobxyz said:

Assuming that your wiring matches an 87 or 88 LH2.2, the power to the coil comes directly from the ignition switch. It goes to the fuse block first, but continues on to the coil without going through a fuse (wired using 2 spades on the same side of the fuse box). Losing +12 on the coil suggests a bad switch. With a meter or test light on coil +, try turning on and wiggling the switch to see if +12 at the coil is flakey.

As an experiment, I'd try adding a jumper wire from battery +12 to coil +, and see if it starts (leave the existing coil + wires alone so that they can back-power the Chrysler box too). Watch carefully - if something is shorting the coil to ground, your jumper wire may draw very high current.

Click to expand...

It looks like we may have similar setups. Yeah, I think it's LH 2.2 because the fuel ECU is a Bosch 0 280 000 541. This is a cool trick, I'll give it a try if all else fails next time.

The interesting thing about all of this is after the car sits for awhile, battery disconnected, and then re-connected, I see +12V on the coil, keys out. Sometimes it will be 0.3V also. Sometimes, when connected, it's 12V, and you go to start it and then it shows 0.3V. Maybe it's worth replacing the ignition switch too.

Does anyone know if the aftermarket ignition switches (around $40 from IPD) are any good, or should I just go with the Volvo $130 version?

On this car, the red 12V feed to the coil is coming from an always-on spade at the fusebox, check it/follow the wire back from the coil through the firewall. It needs to be coming from a terminal on the ignition switch that is on when the key is in the on position and start position.

One of the things on the big list that I never got around to fixing due to ease of battery disconnection

woodenpudden said:

On this car, the red 12V feed to the coil is coming from an always-on spade at the fusebox, check it/follow the wire back from the coil through the firewall. It needs to be coming from a terminal on the ignition switch that is on when the key is in the on position and start position.

One of the things on the big list that I never got around to fixing due to ease of battery disconnection

Click to expand...

Thank you sir, that ties up a piece of this.

Could it also connect to the starter as well, or is this something different? Currently, the coil has your red wire, and also a blue wire on terminal 15.

I've seen in the Green Books that there's a red wire from pin 30 from the ignition switch -> power distribution block red wire -> battery+ red wire -> starter solenoid pin 30 -> brown wire to ballast resistor -> terminal 15 on coil.

I don't think there's an external ballast resistor on this car.

Thanks.

Just to give this a quick bump...there' a lot of meat (or fluff) in my previous post and I'm concerned about Fuse 7 (main fuel pump) being hot with the key out. Pump isn't running, I suppose the FPR turns it on. Could someone please tell me if this is normal?

The in-tank pump is not hot with the key out, it only turns on when the car is started.

Thanks.

Let's see... fuse 7 should always be hot, assuming you mean getting 12v, not physically hot, with key off, per the wiring diagram below.

kyote said:

Let's see... fuse 7 should always be hot, assuming you mean getting 12v, not physically hot, with key off, per the wiring diagram below.

Click to expand...

Thank you!

Yes, +12V, which is fine, I agree. I hadn't seen this diagram and it makes sense now that Fuses 6-10 are all at +12V all the time.

It is normal for fuse 7 to get too hot for you to hold your finger on it when running. It's only a 16 amp fuse on a circuit that usually draws about 10-11 amps. Those kjet fuel pumps draw more current than the stock efi ones do.

BTW check out fuse 13 on a kjet car. It powers the fuel pump relay and will give you a no start if that fuse is open.

woodenpudden said:

On this car, the red 12V feed to the coil is coming from an always-on spade at the fusebox, check it/follow the wire back from the coil through the firewall. It needs to be coming from a terminal on the ignition switch that is on when the key is in the on position and start position.

One of the things on the big list that I never got around to fixing due to ease of battery disconnection

Click to expand...

woodenpudden - do you remember any more details of the K-Jet to LH2.2+EZK conversion wiring?

Where did the EZK wiring harness come from, and how did it get wired in? (Factory 240 LH2.2 uses Chrysler ignition, but the 740 Turbo LH2.2s used a EZ115K box.) Was there a writeup here that you followed for the EZK conversion?

Was the original K-Jet fuel pump relay removed? Or is there both a K-Jet relay and a LH2.2 relay?

I always thought the LH2.2 turbo uses an EZK117 box. Hall sensor triggered instead of VR like 116EZK.

bobxyz said:

woodenpudden - do you remember any more details of the K-Jet to LH2.2+EZK conversion wiring?

Where did the EZK wiring harness come from, and how did it get wired in? (Factory 240 LH2.2 uses Chrysler ignition, but the 740 Turbo LH2.2s used a EZ115K box.) Was there a writeup here that you followed for the EZK conversion?

Was the original K-Jet fuel pump relay removed? Or is there both a K-Jet relay and a LH2.2 relay?

Click to expand...

I believe Todd did the swap on the car, who traded it to WoodenPudden for a green 244, and after it got wrecked, I bought it, fixed it, put almost 100k on it, and now my niece drives it, so I am kinda party to this saga lol.

dl242gt said:

It is normal for fuse 7 to get too hot for you to hold your finger on it when running. It's only a 16 amp fuse on a circuit that usually draws about 10-11 amps. Those kjet fuel pumps draw more current than the stock efi ones do.

BTW check out fuse 13 on a kjet car. It powers the fuel pump relay and will give you a no start if that fuse is open.

Click to expand...

Gotcha, that's good to know, thanks.

bobxyz said:

woodenpudden - do you remember any more details of the K-Jet to LH2.2+EZK conversion wiring?

Where did the EZK wiring harness come from, and how did it get wired in? (Factory 240 LH2.2 uses Chrysler ignition, but the 740 Turbo LH2.2s used a EZ115K box.) Was there a writeup here that you followed for the EZK conversion?

Was the original K-Jet fuel pump relay removed? Or is there both a K-Jet relay and a LH2.2 relay?

Click to expand...

I believe it was taken from a 740 Turbo. I'll try to get pics, but it's a Bosch p/n 0 261 201 012 which is EZK 117.
Also, I think it's white FPR which I believe is the LH. The K-jet FPR is gone.

dl242gt said:

I always thought the LH2.2 turbo uses an EZK117 box. Hall sensor triggered instead of VR like 116EZK.

Click to expand...

Yes, that's what this car has.

In short, once the coil wiring is put to a switched +12V, the wiring should be in order, mostly. The car does run and I was able to drive it home -- after a wiggle of the dizzy.

Thanks again for all of your replies.

kyote said:

I believe Todd did the swap on the car, who traded it to WoodenPudden for a green 244, and after it got wrecked, I bought it, fixed it, put almost 100k on it, and now my niece drives it, so I am kinda party to this saga lol.

Click to expand...

Yes, that's the car! It's a TB family heirloom at this point, haha...and it probably deserves another thread to at least document the next chapter of it's life. I don't mean for this to be that thread, lol.