What's that green gunk on the sensor bolt hole? I wonder if the harness shielding relies on proper metal to metal contact. Grant, on the "open" pin, do you get continuity between that and the metal shim or bolt? Now that you have the car in the air, did you find an engine (or gearbox) to chassis bonding wire?
Green gunk is a ziptie to hold spacer and not forget to take it off The grounding wire for the chassis is there and in decent shape, as well as the one from the alternator
No, no continuity from the open pin to metal shzim or bolt or bolt hole This is the ground for the chassis
Thanks, Grant This starter inhibit on early gated cars has got me beat. I did some resistance checks and the starter solenoid wire doesn't directly go to any of the pins on the Immobiliser ECU or the Immobilizer Interface Unit. This means that the Immobiliser or Interface Units must be controlling an undocumented relay somewhere in the starter solenoid power circuit. Or maybe the Motronics ECU is controlling that undocumented relay. There is still a small pink-black wire coming from the Motronics ECU (pin 42) which I've been unable to trace. It disappears into a large harness at the forward end of the centre console (see pin 2 on plug 41024). It has a 48ohm resistance (to earth), so perhaps a relay coil? Anyway, this is off topic for you...
Well in my case the immobilizer needs to be deactivated to even communicate with the mainecu so it would not suprise me if the immobilizer would need to be deactivated before the ecu would engauge the relay for the starter for cars that react that way.
Well, blow me down. I just discovered that my gated '98 5.2 car has a starter relay in the same place as your F1 TCU-controlled starter relay (sans fuses). I don't know how many times I've looked at the passenger footwell relay panel and not asked myself what it was for. Wiring it up to something is a different issue, however. This could take a while. It's not wired up at all like the F1 car. There is an immobiliser ECU input (pin B4 or 5 as I suspected), and one wire goes to the starter solenoid, but the rest is a mystery. I thought I'd found the other end of the mystery pink-black wire, but it turned out it was white-black.
My 96 car ecu will not talk to the code reader until immobilizer is Off. Must hit fob when ignition is on just before start. It's amazing how there are a few variants to these cars
Just checked continuity on pin 20 and pin 78 and ground to chassis all are less than 1 ohm Not sure if i had checked that yet. Wiggled the hell out of all wires, pulled etc and they are all good as I can tell from both sides computer and sensor.
Actually, I think that's the only non-variatiant All 5.2 cars seem to need the immobiliser off to get ECU comms. I did some further wiring checks and found that the ignition key (in "start") provides power to the start relay coil on the white-black wire. Even with all the ECU and Immobiliser plugs disconnected, ignition key start power still went to the white-black wire. Therefore, it's safe to say that the Immobiliser simply provides an earth (during start) on the grey wire to complete the coil circuit. I just have to figure out the attachment points of the relay wiring to the car. The start relay on both the F1 and early gated cars may be added before or after the footwell fuse/relay panel. The ignition key start power has to go to the footwell panel at some point to inhibit some of the cars system during start (to give the starter as much power as possible).
I've had all sorts of trouble with the crank angle sensor giving all sorts of wired start issues. I'm not convinced it's the cam sensor being the issue here it test OK. In saying that I'd like to be proven wrong. These sensors work in tandem when the eng is running. Cam phase tells engine when No1 is coming up for fire in its cylinder. Crank angle tells ecu where eng is at. I've seen ECU's log a cam phase sensor fault if it misses in 10 cycles. Sometimes sensors just worn out. Can someone lend you a sensor to try. Hell id post one if I was on your side of the world.
Seems like we're running out of options. Do you get about 850 ohms on the crank sensor measured from the ECU (pins 20&78) with the ECU plug disconnected? Are you waiting on a new crank sensor before attempting another start? What else could inhibit ignition other than the immobiliser? Do knock sensors just change ignition advance/retard or shut off spark?
One other thing I've learnt with my car is when starting clutch always depressed. On shut down I let clutch out and just when it starts to load up key Off. Bit hard to do with an F1. There was some info on here about harmonics upsetting the signal if the flywheel grease was having some contamination. It upsets the signal. If the crank signal is upset maybe it's giving the cam phase a bad signal. Knock sensors from my understanding on these cars only work when the engine sees detonation Ian.
That's the 3-pin diagnostic plug near the Motronics ECU. However, USA cars have a big 16 pin OBD2 port under the dash, so perhaps that 3-pin diagnostic plug (if you have it) goes to the OBD2 port. This is what happens on the F550 Maranello (which has a similar ECU & Immobiliser setup). When a previous owner of my car installed an F1 engine harness on my car instead of a gated one, it had a 3 pin plug (capped), so I'm assuming you have one.
If you have time, Grant, would you be able to stick your head under the steering column and look at the big ignition power plug. There will be a big white wire on the steering column side and another wire on the car side. Can you see if it's another big white wire, or if it's a small white wire with a black tracer. On the 2.7 car, there was a big white wire on both sides of the plug. I notice I only have a small white-black wire on my '98 gated car (on the car side). I discovered a few hours ago this is the wire which provides power to the starter relay coil in the passenger footwell. So, the starter solenoid current no longer runs through the ignition lock. Less power, less sparks/wear and tear on the lock contacts, I guess.
I would check those ground circuits, as well as the power distribution circuits using voltage drop which is more of a dynamic test. Just ohm checking a ground and voltage checking a power circuit is more of a static test.
Voltage testing of ground isn't a good idea. The voltage drop will be dependent on the resistance between to two contact points and any resistance that comes before or after. The only question is, is 1 ohm sufficiently low? Image Unavailable, Please Login
That's news to me. I've tested voltage drop on ground circuits many times. Again, it's meant to be a dynamic test (loaded) to measure the circuit as it is in use. Why wouldn't that be a good idea?
As I said, the voltage you measure will float depending on what circuits are energized. Consider the circuit below. If the switches for Y and Z are open V will have one value. Close switch for Y and the measured voltage will increase. The close switch Z and it will increase again. How much depends on the values of X, Y, and Z. If they are larger compared to the resistance in the ground circuit it won't make much difference. But say for argument that X, Y, and Z are all the same value. When all three are in the loop the current the current would be approximately 3 times what it is when only one is in the loop, neglecting the effect of the ground resistance. With 3x the current the voltage drop across the ground resistance will be 3 times as high. Say each branch draws 1 amp. Then the voltage measures would vary between 1 and 3 volts for 1 ohm ground resistance. If the ground resistance was 0.1 ohm it would vary between 0.1 and 0.3 V. Having said that, you could observe the variation in V and it would tell you something about the load resistances relative to the ground resistance. So I guess I can see your point. If you measure the ground resistance as 1 ohm and your test shows a small V which is pretty constant, then you could say 1 ohm is good enough. FWIW, on my car the resistance between block and chassis is less than 0.1 ohms after compensating for the VOM leads. Image Unavailable, Please Login Image Unavailable, Please Login
Yes John, I think we are on the same page sorta. So that diagram in your post is not what I would look at, instead I would leave the - lead where it is and put the + lead on the - battery post and turn the circuit on and that would test the integrity of the ground only. Testing the entire circuit in your diagram would be from the + lead to the + post.
Perhaps you aren't fully understanding my figure. What it represents is, for example, is the - lead connected to the battery - post and the + lead connected to, for example, the engine block. The 1 ohm resistance would represent the resistance between engine block and battery -. We are on the same page. But I still don't think Grants problems are ground based.