E34 sohc question........

[Valvebounce 2]

I got 10 mins to play with it today.

The leads for my multi meter are rooted. (I bought some from Jaycar today, but they didn't fit :-( )

But using my test light there is definately power at the coil. I had coffee with my mate who I bought it off at lunch today. He also remembered that there wasn't power there when we were f-ing with it while it was still his.

If I can get the right leads for my meter tomorrow, I can begin looking at the other stuff.

[hotwire 352]

I thought you had confirmed for sure there was no power to the coil. The way i read your response above - you say there is when checking with a test light. It did seem very unlikely to me there would not be - but for the possible reasons i mentioned.

Word of advice. Whenever checking a circuit (whether using a meter or test light) make sure that the tester is working on a known power source.

A: to make sure the meter/lamp works

B: to make sure you have a good earth

Otherwise, as you have found, you are simply chasing your tail on a problem that doesn't exist.

In all seriousness, & no disrespect, it may be simpler to get an auto sparky to check it for you

[Valvebounce 2]

That's my last resort.

I don't doubt I'm fully capable of finding out why it doesn't run.

I've rewired entire cars before. It's just that these cars are completely new to me.

Ask me about a Datsun or a valiant and I don't even need to consult the manual.

This thing is going to run if it kill me.

[Valvebounce 2]

I had all knds of fun with my multi meter. I would up having to take it apart to get it to work.

The today I tried to check to see which of the plug up out of the way outta sight and hard to even reach w=has continuity with Pin 47 of the ecu plug. I simply couldn't find them well enough to find a cicuit. (They're in a prick of a spot)

Anyway, I gave up on that. And decided to check the resistance of the crank sensor. I'd been reading the haynes manual which came with the car. I made notes on post it notes, and stuck them in the folder that the manual is in.

Anyway, my notes sad that the circuit between the yellow and black (Going from memory here) was supposed to be 500-600 ohms. for starters the wire is pretty well insulated, so you have no way of knowing which whie is which.

The only terminals inside the plug which offered any sign of life on that plug only showed 0.003 ohms resistance.

u mate who I got the car off has a spare one. I'm going to borrow his meter too. (Incase it's my meter which is coozed too)

[will 169]

This will help. Pins 1-2 are the ones to test, pin 3 is the shield. 540 ohms is ideal. There is no need to try to read from the plugs though, just plug the speed sensor into one of the engine loom plugs, then test at pins 47-48 (speed sensor) and 8-31 (cyl ID sensor) on the MCU plug. Whichever gives you a reading is the one you plugged the sensor into. Swap if necessary.

[Valvebounce 2]

You are the man Will!

If ever our paths cross irl, I owe you a cold one. (Proabably grant too)

[Valvebounce 2]

Just visited my mate, and grabbed the spare crank sensor.

HIs meter read 521 ohms. I've borrowed his meter too, since mine is a bit iffy.

I'm going to be one happy SOB if that's all thats wrong.

The oil level sensor on the old motor seems to have longer wires on it too. The OLS on the motor in the car has it's plug teathered to the bolts on the alternator mounts. The plug which looks like it belongs to it seems to be too short to reach where it lives. I may yet have to swap that sensor over too.

[Valvebounce 2]

Also for what it's worth, (not a f**k of a lot)

I know why I orginally thought there was no power at the coil.

There is little to know circuit between the strut top, and the motor/earth terminal.

Most car I've worked on have had a good earth on the strut top.

But I would assume that the beemer strut top has too good of a paint job, and the top hat doesn't have a decent earth, So the battle goes on.

[_ethrty-Andy_ 2122]

engine earths on the lower right hand side by the bumper shocks, you will see an earth strap. Is that what you are asking?

Pity someone didn't tell you to check the sensor in the first couple posts ;P

[hotwire 352]

Also for what it's worth, (not a f**k of a lot)

I know why I orginally thought there was no power at the coil.

There is little to know circuit between the strut top, and the motor/earth terminal.

Most car I've worked on have had a good earth on the strut top.

But I would assume that the beemer strut top has too good of a paint job, and the top hat doesn't have a decent earth, So the battle goes on.

Hence my statement a few posts back to check your meter/light is working on a known source BEFORE you probe the wire in question. Ok if you confirm you have a circuit when first checking, but if you have none (as you thought) - you are leading yourself on a goose chase on a problem that doesn't exist. I have seen this sort of miss diagnosing so much over the years.

Andy, we were thrown off the scent by believing there was no power supply to the ign coil.

[Valvebounce 2]

Well I'm still here, haven't had any spare time to do Jack lately. ('tis a busy time of year)

I can confirm (In case anyone ever reads this thread seeking the same info I originally sought) that the Crank angle sensor goes into the rearmost plug underneath the manifold. And the sensor wire from the spark plug lead goes into the forward most plug.

The last time I had the bonnet up I had a very very brief go with my mates multi meter. It looked as though the crank angle sensor on the car was showing 521 ohms too.

Next time I get a decent chance, I'll plug the sensor into the plug, and measure the resistance again at pins 47, and 48 at the ECU plug.

Wont be for a while though I'd say. The mrs is 6 days overdue to have our 2nd kid.

so my poor little 34 waits.......

And the coilovers in my nissan continue to crush the gel packs in my spine. 1st world problems................

[_ethrty-Andy_ 2122]

Andy, we were thrown off the scent by believing there was no power supply to the ign coil.

yes but no CPS reading means the DME wont send coil signal, thats why I said it.

[hotwire 352]

yes but no CPS reading means the DME wont send coil signal, thats why I said it.

But Andy, he said there was no power supply to the coil, this comes straight from the ign switch. Certainly there will be no low tension switching from the DME without a CPS signal to it

[_ethrty-Andy_ 2122]

But Andy, he said there was no power supply to the coil, this comes straight from the ign switch. Certainly there will be no low tension switching from the DME without a CPS signal to it

12V comes from the switch correct, but it grounds through the DME

Edit: at least on the E30 325i with the M20 it does. Im very sure it is the same on the E34 525i with the M20

Edited December 24, 2014 by _Ethrty-Andy_

[hotwire 352]

Yep - exactly as I said but in different terminology Again though - he said there was no ign supply TO the coil (mistakingly diagnosed as it turned out) hence us at the time suggesting that being the issue. Without that supply, nothing will work, DME included.

It has since transpired that there is infact power to the coil, so now yes - other factors - CPS etc come into the equation.

[Valvebounce 2]

Hey guys,

Today I got a random txt from a mutual friend of the guy I bought this car off. He got my number off my mate, and was pumped to help. So I used this as levrage to garner permission from the mrs to go have a play with the E34. (Plus the mother in law was taking our toddler out for the afternoon, which really sealed the deal)

So we meet where I have the par stored. He's some kind of computer designer/expert/foamer/anorak. In fact he bought a hand hand ocsiliscope to aid with testing stuff. (I know what they are, but their use is miles and miles over my head)

This was the first time I'd had the opportunity to even look at the car since I checked another car and confirmed that the crank angle sensor indeed plugged into the rearmost plug under the intake manifold.

Despite the fact that we'd had the plug plugged in before, the cable seemed to short. So I had to route it in behind the steel water pipe, and run the cable in behind the water pump pulley.

Also found that the crank angle sensor to chopper wheel on the crank gap was up over 2mm. I couldn't find any feeler gauges, but I managed to get it down to just a minute fraction under .8mm. (The book says .7-1.3mm is the spec)

Also checked the resistance of the crank angle sensor at pins 47, and 48 at the ECU plug once it was plugged in. Came up at 528 ohms. Which is still in spec.

Fuel line - return is the one coming from the pressure regulator on the rail. Supply is obviously the other.

So am I correct in assuming that the pressure reg is the small daiphram with a vac hose on it on one of the hose nipples on the fuel rail?

if so they were connected back to front. so I swapped them over. (Mate reckoned they looked back to front to him too).

Then we had a well earned beer. But when the moment of truth came, the battery was flat. Womp, womp, waaaahhhh..............

Battery is probably poo'd truth be told. But I think it will take a charge, and the ol' bitch will go or it wont.

I'll be sure to report back.

[hotwire 352]

So am I correct in assuming that the pressure reg is the small daiphram with a vac hose on it on one of the hose nipples on the fuel rail?

if so they were connected back to front. so I swapped them over. (Mate reckoned they looked back to front to him too).

Then we had a well earned beer. But when the moment of truth came, the battery was flat. Womp, womp, waaaahhhh..............

Battery is probably poo'd truth be told. But I think it will take a charge, and the ol' bitch will go or it wont.

I'll be sure to report back.

Yes the diaphram on the rail is the pressure regulator & is the return line. Simple to confirm the supply hose - assuming the pump is working, key on & see which hose fuel is supplied from.

[Valvebounce 2]

That's what I did.

Although it only squirted fuel while cranking.

I'm 99% sure nissans will energise the pump for three seconds when the key is first turned to the "on" position to prime the system.

even though it's not gone Vrooom! yet, I'm feeling like I'm getting somewhere. If it doesn't play ball, I supose I'm back to plain old fault finding again. Next time I'll take my feeler guages too. (Get everything right, so as to eliminate all the variables)

[hotwire 352]

You will normally get a short prime, not 3 secs as with others though.

Cant recall now - did it infact have spark in the end?

[Valvebounce 2]

The battery was dead, so I couldn't find out.

I have the crank sensor plugged into the right plug, (Which was my original bugbear) and the gap and resistance are in spec.

So if it was ever going to have spark, it would be now. I guess I'll know soon enough.

[Valvebounce 2]

Aaaaaand,

It runs!

So it was just the gap being too wide. (And the lack of knowing where the f-k it was meant to go)

Pretty happy really.

Still have the oil level sensor warning on the dash. The plug doesn't seen to reach. I'm going to unteather the sensor plug from the lower alternator mounting bolt, and then it will hopefully reach.

I also have no oil light. And I'm seeing the oil pressure switch warning on the dash too. So either the sensor is poo'd, or I have a bad connection/broken wire. It's entirely possible that this wire was missed when the old motor was removed. And it might have been pulled or pinched.

I wasn't keen to run it too long with no oil light though. (Better safe than sorry)

So those two things to sort, add some antifreeze, and find a battery hold down. and It's WOF time.

[kiwi535 538]

please flush the brake fluid and check the brakes

[hotwire 352]

Aaaaaand,

It runs!

So it was just the gap being too wide. (And the lack of knowing where the f-k it was meant to go)

Pretty happy really.

Still have the oil level sensor warning on the dash. The plug doesn't seen to reach. I'm going to unteather the sensor plug from the lower alternator mounting bolt, and then it will hopefully reach.

I also have no oil light. And I'm seeing the oil pressure switch warning on the dash too. So either the sensor is poo'd, or I have a bad connection/broken wire. It's entirely possible that this wire was missed when the old motor was removed. And it might have been pulled or pinched.

I wasn't keen to run it too long with no oil light though. (Better safe than sorry)

So those two things to sort, add some antifreeze, and find a battery hold down. and It's WOF time.

Great news! Re oil pressure light - your statement is confusing - you have no oil light but you are seeing oil pressure warning on the dash??

[kiwi535 538]

Great news! Re oil pressure light - your statement is confusing - you have no oil light but you are seeing oil pressure warning on the dash??

low oil level light

[Valvebounce 2]

Yes I'm defo going to change the Brake fluid.

All the fluids are going to get done. No-one ever changes the brake, gearbox, or diff oils. Except when something breaks/goes wrong. And an ounce of prevention is better than a pound of cure.

I'm getting the "oil lever sensor" message flashing up on the dash. It's not plugged in yet, so that's to be expected.

I'm sure it was giving me a message saying "oil pressure sender" too?

Does the E34 have an oil light on the dash with the standard old oil can symbol? Because I'm not seeing one. (Thus me thinking there's a fault with the sender/sender wire)

Edited January 20, 2015 by Valvebounce