VEMS Community Forum

VEMS => Modifications and Repairs => Topic started by: [email protected] on November 16, 2008, 10:00:47 PM

Title: No RPM? Relay drivers not working? Perhaps you have a dead P259
Post by: [email protected] on November 16, 2008, 10:00:47 PM
A dead P259 is caused by the grounding rules not being followed, or misunderstood;)

To get testing again you need to remove the P259, you can cut pin 21 (4th pin from the top on the right) and test the crank trigger, I use some very small sharp side cutters.
(http://www.vems.co.uk/VEMSTech/P259one.jpg)
It is easy to bridge the cut with solder if the P259 is not dead. But to replace it you will need to remove the chip in its entirety:
(http://www.vems.co.uk/VEMSTech/P259two.jpg)
Cutting the pins then de-soldering the bits of the pins that are remaining avoids possible damage to the PCB.
Title: Re: No RPM? Relay drivers not working? Perhaps you have a dead P259
Post by: Sprocket on November 30, 2008, 06:54:12 PM
Interesting Rob.

I did the exact oposite to the grounding rules ;D and now the relay output chip has smoked, however, Its still picking up an rpm signal. Would this loss of rpm signal depend on VR or Hall, as the hall needs a 5v supply and pull up, where as the VR generates its own voltage?
Title: Re: No RPM? Relay drivers not working? Perhaps you have a dead P259
Post by: laine_16v on March 14, 2009, 09:41:48 PM
Is there someone in the UK that can do this?

I think mine has blown as im not getting an RPM reading. :(

Also you are saying you can cut pin 4 and it will make it work again, but cutting this pin, what will it disable, i.e. if you cut it and it started working again, why would you have to then buy another chip?
Title: Re: No RPM? Relay drivers not working? Perhaps you have a dead P259
Post by: Bat on March 15, 2009, 04:22:16 AM
Hi,
You cut the pin off the chip to allow the RPM signal to work again.
However the chip, which is used to switch the fuel pump & cooling fan relays aswell as driving the tacho, will not work so therefore will need replacing. 
Does the fuel pump run when you switch the ignition on? Assuming it is switched on by the VEMs ECU
Cheers,
Gavin :)
Title: Re: No RPM? Relay drivers not working? Perhaps you have a dead P259
Post by: laine_16v on March 15, 2009, 04:56:48 AM
I see,

Well thats good i suppose becuase.... the fuel pump on my car is directly wired to an ignition live at the moment, and the fan uses the standard care relay setup, so the VEMS is controlling neither. So i may well snip that pin and just run it like that :)
Title: Re: No RPM? Relay drivers not working? Perhaps you have a dead P259
Post by: PeepPaadam on March 15, 2009, 01:28:18 PM
Yes, but you should investigate the reason why did the P259 chip blew in first place!

Where did you connect the ground wires? In case you didn't read the manual, these have to be connected to engine block or head and not to chassis, battery etc. This is the most common reason why P259 chips blow (2nd most common seems to be using rude battery chargers when VEMS is connected).
Title: Re: No RPM? Relay drivers not working? Perhaps you have a dead P259
Post by: laine_16v on March 15, 2009, 02:04:49 PM
I have a prebuilt V3 Harness, that has just 1 earting lead on it, and the ECU is in the passenger footwell of the car, i earthed it too a place in the footwell on the chassis (it seems a very good place), had no idea you couldnt do that though? i dont have any instriuctions as i bought it all 2nd hand.
Title: Re: No RPM? Relay drivers not working? Perhaps you have a dead P259
Post by: Bat on March 15, 2009, 04:34:29 PM
Hi,
Manual....
http://www.vems.hu/wiki/index.php?page=MembersPage%2FPhatBob%2FUserGuide (http://www.vems.hu/wiki/index.php?page=MembersPage%2FPhatBob%2FUserGuide)
Cheers,
Gavin :)
Title: Re: No RPM? Relay drivers not working? Perhaps you have a dead P259
Post by: [email protected] on March 15, 2009, 10:14:18 PM
If you're using a VEMS harness, and the thing about the reading occasionally coming back  ( http://195.159.109.134/vemsuk/forum/index.php/topic,802.msg8306 ) then I really doubt that you've got a problem with the P259 as the ground connections are text book - but that doesn't always mean that you have a good connection to the car's chassis

It is bloody odd though, thats for sure - what sort of voltages are being shown when you're cranking - strange things can happen when a battery is put in the boot for example...

Have we tried changing the connection on the sensor's plug?  Swapping the wires at the sensor end NOT at the VEMS end.
Title: Re: No RPM? Relay drivers not working? Perhaps you have a dead P259
Post by: laine_16v on March 15, 2009, 10:28:20 PM
Lol your right its REALLY odd.

I was playing around with it and a mate came over and gave me a hand, ive been testing it with the injectors and coi dissconected, but we put them in anyway, sometimes it would fire every now and then, and it probably saw 400rpm or so once on the reading before dieing.

ANd then would shoot off the aboslute loudest bang you've ever heard after youve stopped cranking out the exhaust lol.

Ive unravveled the prebuilt loom a bit and jiggled the earths around while cranking, does nothing.

OTher sensors read fine, the coolant and air temp are both reading 18 degrees C today, so suggests a good earth for them to be reporting properly?

Um i have to jump my car off another car to crank as my battery is dead, but it shows like 12v while cranking, and the other car running, its all normal and fine.

BAttery is in the normal place. Is it possible because im jumping off another car its screwing with the crank signal?

The connections everywhere are solid and read a consist resistance when moved around and jiggled. Help me before i shoot myself or lob this ECU in tbe bin and buy an emerald.
Title: Re: No RPM? Relay drivers not working? Perhaps you have a dead P259
Post by: [email protected] on March 16, 2009, 02:01:52 PM
Starting with a bad battery is going to give problems but jump starting it shouldn't effect the ECU's ability to read the RPM.  As it came from a running car, and known good loom then I'm thinking that there has to be something different on the car.  You've tried your ecu in another car, what happens if they try their ECU in yours?

I'm a bit concerned when you said that you'd jiggled the earths around - you've not disconnected them have you?  It sounds like you've moved them around to see if theres a dry-joint in there somewhere.

Have you definately tried swapping the crank sensor wires?

I'd advise against shooting yourself or binning the ECU, if you were to spend money on an Emerald then you might be no further forward if theres something up with the crank sensor setup.

Also connecting the injectors isnt a good idea, if you've got any cranking signal at all you'll get injector pulses and that will put fuel into the engine - without a spark you're going to get fuel all over the place and possibly contaminate the oil - meaning you wipe out your crank bearings when the engine finally does run up.
Title: Re: No RPM? Relay drivers not working? Perhaps you have a dead P259
Post by: Sprocket on March 16, 2009, 02:03:29 PM
What about the possability of an inverted VR signal?

Funny story. Matty over on EFi Minis managed to get his engine started, all be it very badly. I went to help tune it, but couldnt get the engine started, even though it had been running earlier in the week. We spent hours looking at all the connections and the trigger set up, but still there was no rpm signal. I suggested we try and swap the wires over on the sensor even though none of the wiring had been changed. Turn of the key and the engine spluttered to life with a strong rpm signal.
Title: Re: No RPM? Relay drivers not working? Perhaps you have a dead P259
Post by: laine_16v on March 16, 2009, 08:47:39 PM
I have not tried their ECU in my car, but i shall do that over the next couple of days.

I did jiggle the earths around but didnt get a lot of joy, i didnt cut or move any of the looms joints i kept them intact.

Yeah have disconnected coil and crank for the time being.

Swapping crank sensor wires is the only thing ive not done, but i will do that tonight so i can tick off another thing ive tried.
Title: Re: No RPM? Relay drivers not working? Perhaps you have a dead P259
Post by: laine_16v on March 16, 2009, 11:26:31 PM
OK guys, i got home straight away and changed the polarity of the wiring on the sensor, and its made it a lot better i get quite a few more RPM readings now and it tried to fire, but it still wont quite catch.

All i did was solder the connections over and this happened...

http://www.youtube.com/watch?v=JUdXt4w1fhM&feature=channel_page

So then i thought hmmm what if i resolder the connections back to how they were and again it was just like the video above so it seems it doesnt matter what way the sensor is.

But ive localised the problem to a small bit of loom for the crank sensor.

The backfire at the end only happens on cylinder 1, for some reason as soon as the ignition is turned on the VEMS hold the injector on CONSTANTLY in cylinder 1? any ideas?
Title: Re: No RPM? Relay drivers not working? Perhaps you have a dead P259
Post by: Sprocket on March 17, 2009, 12:27:53 AM
Does this car have the exact same injectors fitted?
Title: Re: No RPM? Relay drivers not working? Perhaps you have a dead P259
Post by: laine_16v on March 17, 2009, 06:08:05 AM
Yup same injectors.
Title: Re: No RPM? Relay drivers not working? Perhaps you have a dead P259
Post by: [email protected] on March 17, 2009, 03:43:32 PM
What did the plugs look like after that event?
What's the cranking timing looking like in comparison to the cranking advance on the software?  Have you got a simple timing light or one with an adjustable advance (as these don't work well with wasted spark and will show double the advance unless they can be set in 2-stroke mode).

How do you know that channel 1 is constantly on?  You're going to get flooding problems if this is the case.

Have you tried swapping the wasted spark pair around?
Title: Re: No RPM? Relay drivers not working? Perhaps you have a dead P259
Post by: laine_16v on March 18, 2009, 10:14:20 PM
Quote from: [email protected] on March 17, 2009, 03:43:32 PM
What did the plugs look like after that event?
What's the cranking timing looking like in comparison to the cranking advance on the software?  Have you got a simple timing light or one with an adjustable advance (as these don't work well with wasted spark and will show double the advance unless they can be set in 2-stroke mode).

How do you know that channel 1 is constantly on?  You're going to get flooding problems if this is the case.

Have you tried swapping the wasted spark pair around?

Um i snapped my spark plug tool and havent got a deep anough socket to take them out unfortuantely lol!

Havent got a clue about crank timing, and crank advance, but abosolutely none of the configuration has changed anyway, dont have a timing light.

I've just purchased this: http://shop.vems.hu/catalog/product_info.php?cPath=1_5&products_id=44&osCsid=0018c27c029a3032a91c615f4780188f

To redo my wiring completely, should fix it then :P
Title: Re: No RPM? Relay drivers not working? Perhaps you have a dead P259
Post by: [email protected] on March 18, 2009, 11:19:46 PM
Is this on the same engine as the VEMS was setup with? 
Title: Re: No RPM? Relay drivers not working? Perhaps you have a dead P259
Post by: laine_16v on March 19, 2009, 12:16:48 AM
Not quite, the engine was rebuilt, high compression pistons, and a different set of cams....but anyway update...

After much much playing i got it started!

I changed the crnak sensor wiring for some dedicated new stuff, to see if it made a difference, it didnt. BUT it consistantly reads crank speed about 75% of the time now.

I got it to run by unplugging injector 1, it would splutter lots and then just about get enough momentum to start, when it started the crank reading was fine, would rev upto 4000rpm fine, didnt want to rev it higher on 3 cylinders.

SO i decided to plug injector 1 back in, and the engine died straight away. ?

Can someone check my megasquirt file settings to check they are ok?

Once the engine had started on 3 cylinders i ran it for about 2 minutes before it cut out (when i plugged injector in), then after that i couldnt get it to run at all, so im guessing the spark plugs are aboslutely drenched ?

I want to work out this injector problem now. Ill put a link to my megasquirt file in a bit.

Also is there a way to boost Crank sensor signal a bit? i reckon that is all it needs...
Title: Re: No RPM? Relay drivers not working? Perhaps you have a dead P259
Post by: laine_16v on March 19, 2009, 01:19:13 AM
Link to my file..

http://www.mediafire.com/?sharekey=639c82fbb9222b711bee9a6e9edd9c76e04e75f6e8ebb871
Title: Re: No RPM? Relay drivers not working? Perhaps you have a dead P259
Post by: [email protected] on March 19, 2009, 02:07:18 PM
Nothing looks too nasty in there, just as an aside though:
Extras -> Boost alternate settings should be all disabled.

Here's what I'd do...
Move the wire for injector channel 1 (EC36pin7) to channel 16 (EC36pin9)
In MegaTune Settings->Injector Outputs change Injector output 3 from 1 to 16
Title: Re: No RPM? Relay drivers not working? Perhaps you have a dead P259
Post by: laine_16v on March 19, 2009, 10:11:08 PM
OK ran a few little tests....

Injector Plugs

12v feed

Plug 1 = 12.15v
Plug 2 = 12.15v
Plug 3 = 12.15v
Plug 4 = 12.15v

Injector grounding, with ECU connected to loom, but ignition OFF completely.

Plug 1 = Grounds to earth ( Ohms 5 <)
Plug 2 = No Ground
Plug 3 = No Ground
Plug 4 = No Ground

Injector grounding with ECU dissconected from loom

Plug 1 = No Ground
Plug 2 = No Ground
Plug 3 = No Ground
Plug 4 = No Ground


Am going to try swapping injector 1 to injector channel 16 now...
Title: Re: No RPM? Relay drivers not working? Perhaps you have a dead P259
Post by: laine_16v on March 19, 2009, 11:00:39 PM
Have swapped to channel 16 and that has stopped it from firing constantly. Still cant get it to run, i think the car is out of fuel now.
Title: Re: No RPM? Relay drivers not working? Perhaps you have a dead P259
Post by: [email protected] on March 20, 2009, 12:35:20 AM
check that you've not contaminated your oil with petrol, big end bearings don't like it.
Title: Re: No RPM? Relay drivers not working? Perhaps you have a dead P259
Post by: AjRose on April 20, 2009, 01:56:37 AM
Rather than desoldering each pin you can use a piece of tinfoil to surround the chip then go at it with a heat gun(on low) With some pliers you can lift the entire chip right out.