Crank, Spark, Injector pules and fuel but no start.

Hello to all from England

Have a starting issue on a Golf 2000, AGU engine. 1.8t 20v

Started by checking coil feeds and ECU triggers, 12v and earth good, trigger from Power OutPut Stage flashes LED
Next checked the injectors, 12v feed good and earth trigger from ECU flashes LED
checked fuel pump was pumping fuel, fuel being pumped on initial key on prime and on turn-over. Haven't checked pressure.

Diagnostic Checks
Tried my £4 Ebay adaptor, no connection to ECU

Used friends SnapOn Ethos. No connection to ECU Only connects to dash clocks and gives the following errors.
01314 Engine Control Module no communication
01316 ABS Contol Module no communication
01321 Airbag ECU - j234 no communication

The car will crank and almost start but then doesn't. Still turns over and will try to start again but fail.

This car was being used as normal with no modification to ECU.

I've removed the aftermarket radio to see if faulty installation caused the no comms issue but it made no difference.

Where do I check next, was thinking CAN Bus wiring or power supply but I can't find the wiring diagrams? Could the starting issue be separate to the no comms issues?

Any help or ideas of where to check will be much appreciated. I have acces to a multi meter and and SnapOn ETHOS.

Hey Holmes! My initial thought is that the no communication issue is NOT related to the no start, since you observed spark/injection pulse/fuel pump operation. I could be wrong, of course, and we may come back around to the no comm, but my first instinct would be to skip the scanner and stay under the hood.

The almost-start thing you mentioned makes me wonder about a mechanical timing issue. If the UK market Golf is similar to the US model, then the upper timing cover can come off pretty easily, and there's timing marks on the crank pulley and lower cover. Paul did a case study on a Honda with similar symptoms:



If you wanted to make sure fuel pressure isn't an issue, you could try adding some alternate fuel to the intake during cranking. If the engine now starts, we can follow a fuel problem. If not, then we can put fuel aside and go in another direction.

The non-com issue is almost certainly due to the aftermarket radio, istr the problem isn't the radio itself but the adaptor between the radio and the VW wiring which shorts the K-line to 12v.

Like Tyler my first thoughts were also to look for a tming issue I am not familar with VAG engines codes but if this type has belt drive camshaft it sounds very like a stripped timing belt

Thank you very much for the reply.

Excellent video, fancy one of those PICO scopes and pressure transducers. Time to start saving.
I shall try these ideas out tomorrow and update with the findings.

Until tomorrow, Thanks.

Morning

I've checked the timing and it is spot on both cam and crank are at 12 o'clock with flywheel showing TDC.

Removed the center section of the exhaust, makes no difference.

Brake cleaner in the air inlet, this makes a difference. The car will tick over very slowly but stall as soon as accelerator touched or brake cleaner used up. Have a spare engine here, swapped over fuel rail and injectors and have exactly the same result. All four injectors squirt fuel out. There seems to be no returning fuel with either fuel rail(don't know what I should be expecting).

vimeo.com/217493526

The radio is out and there are no adapters installed, still no Comms.

Thanks for the help.

It is now pointing towards a fuel pressure issue, only way to be sure of the pump is put a pressure test gauge on the supply line.
This is one from the subscription channel

Indeed fuel pressure sounds like the next tree to bark up, I have changed a fair few blocked fuel filters on these engines, don't bother with the crappy eurocarparts one, their is actually a choice on these engines, one works at 3.0 bar, can't remember the other, go to TPS (trade part specialist). Genuine VAG parts and not stupidly priced.

All that been said do test the pressure first....

Morning

Signed up for the premium videos and they're even more awesome, have to order a book soon.
I'm now the owner of a fuel pressure tester, it would seem to me that there is something not quite right as you suggested.

I have filmed the results for your opinion.

vimeo.com/217655336

The information about Euros and TPS is most awesome to know too, thanks.

Thanks for the awesome help

Love the videos! Can I take a second to say how jealous I am that the left hand drive owners can reach in and run the key while working the throttle at the same time. :lol:

Also, congrats on the Premium membership. Fantastic material in there.

Not sure what the fuel pressure spec is on this one, but 40-ish PSI definitely sounds low. Adding the brake cleaner was a good move. Power and ground at the fuel pump would be my next move.

Kinda seems abit slow to build up pressure too, do you have a prime? If you just turn key in barrel til dash lights come on but don't crank it, should prime up to system pressure.
Checking on AutoData apparently 3 bar is what your looking for, although it also states regulated pressure with vacuum should be only 2.5 bar, seems low to me. I'm starting to wonder if this could be an immobiliser fault, but then again I wouldn't expect you to have injection pulse/coil control. Indeed whip up that back seat and check out that pump/ wiring

Hello

Never thought about the old reach around and crank maneuver, lucky us

I too thought the initial prime build up was low. Changed the pump and fuel filter just as an educational exercise to see the difference (I have a similar dead car sat here so no money spent). Fuel pressure now builds up on prime and has the same characteristics as before.

Watched these videos


Now understanding that fuel pumps could have different triggers in both start and run states I was hopeful that this was it, fits perfect with the symptoms we have. However, it seems not to be the case.

Pump voltage readings at the plug on the pump read 12.48v on KEY ON for a second then drops to 0v, primes OK.
Engine crank 12.48v, almost start 13.80, then stall 12.48v.
The pump runs the whole time and a little bit more until KEY OFF. Doesn't appear to have any voltage drop due to current use or supplied controlled power feed.

With brake cleaner in the air intake it idles very slowly and won't rev up at all, just dies. If fuel was the only issue would I be able to rev the car?

This an excellent learning car/curve.

I shall video the new fuel pressure readings and the car idling on brake cleaner for your opinions.

Can not wait to figure this one out, thanks for the help so far it has been most awesome.

Have you got access to any scan data, I'm just wondering if we're missing something silly like a stuck open EGR, possibly throw a vacuum gauge on it. Also I guess it wouldn't hurt to check your 5v circuit as you have the no comms to the PCM.

you definitely have a fuel delivery issue

Aw man, I was sure we were on the right track with the fuel pressure.

OBD Rick might be on the right track with the vacuum gauge - possibly a plugged exhaust? It doesn't quite match with the addition of alternate fuel, but can definitely account for a start/stall. I've never tried revving an engine I'm running on brake cleaner, not sure if it should work or not. :lol:

A quick an easy test for a plugged exhaust would be to remove the upstream O2 and try to start it again. If you see an improvement in symptoms, then we're on the right track.

For our info, how did this one become a no start?

Hello sorry for the delay in getting back to you.

This car has been sat in a garage for over a year with no one being able to fix it. It had the Power Out Put Stage replaced twice on previous visits(possibly with seconded hand ones). The customer was driving this car when it stalled and had to be recovered to the garage. This was found to be faulty on my first inspection with no spark on two cylinders. I replaced this. The garage thought there may be a wiring issue causing these to go, I can not find any shorts to each other or ground, the wires have good continuity.

I've had a poke about with multimeters. I have various readings from around the engine bay.
Camshaft Position Sensor(3pin) 4.99v, 11.57v, Neg.
Intake air temp(2 pin) 4.68v, Neg.
Evaporative purge valve(2pin) 12.47v, Neg.
Waste Gate Bypass valve(2 pin)12.68v, Neg.
Mass Air Flow(4pin) 12.00v, Neg, Neg, Neg.
This shows a voltage output on two pins when starting the engine. Video of MAF readings.
vimeo.com/219273185 variable DC output, rests at 0.022v after ignition on and then changes on engine turnover.
This video shows the 12v power feed to MAF, same circuit as fuel pump, turns on with ignition on and then off until starting.
vimeo.com/219273722

Looking at the fuse box and relay panel. I can find power that is controlled by the fuel pump relay and ignition relay. Seems to be working OK.

Fuel pump power video. Same circuit as MAF. vimeo.com/219274181
Fuel pressure readings. vimeo.com/219274962

Trying to start video. vimeo.com/219274458

Starting on brake cleaner. vimeo.com/219274695

I have no scan data as I can only connect to the clocks, this gives me the comms errors from the first post. Is there another way to get any data?

I have removed the centre section of the exhaust, this was easier than removing the upstream O2 sensor. Should I still have a go at removing it?

I haven't checked anything in the vacuum direction. Can you recommend any Videos?

Does this engine have electric throttle plate? I assume it does as all of the 1.8 in that year here in the states do and it sounds like you could be having a problem with throttle body adaptation which would require a vag com scanner to adapt it but you would have to fix no comm issue first . On a side note I've had cars that none of my aftermarket scanners would connect to but my vag com scanner would... you said you removed the radio the problem with these as mentioned above is a short on the k line did you remove the wiring adapter harness as well? The harness is where the problem is on these cars.

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Hello

I don't have access to a VAG-COM device. The Throttle is a cable and has a position sensor on the throttle body (7 wire). Three of these wires have a 5v signal. I noticed that the position sensor makes a buzzing noise on Key On and doesn't stop making this noise, I'm not sure if this is correct. I'm thinking it should make a noise and then stop once it's done whatever it's doing. Is throttle body adaption the process of matching it to the sensor on the acceleration pedal? If I fit another throttle position sensor would it need to be programmed, I have a spare one sat on a scrap car.

It was mentioned previously that the EGR valve might be stuck open but I can't find an EGR valve in the engine bay, don't think this car has one.

There is no adaptor cable installed for the radio, it's just the standard connectors.

Are there any tests I can do with multimeters on the K-line system?

Is it a viable test to disconnect the K-line at the ECU and connect straight to an OBD2 socket to test the ECU with nothing else attached?

Thanks for the help so far, it has been awesome. Can't wait until I know enough to help others on here.

Is this what it looks like ? Is so this is an electric throttle body with a cable to the pedal these still need to have the TBA for them to run .

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Some people on the internet have claimed success with the chicken dance adaptation.... but I've performed quite a few adaptations for people who said they tried the chicken dance first....the tale goes that you have to have the hood and all doors open and disconnect the battery for 10 mins then reconnect battery and turn key to run position but keep your feet out of the vehicle so you don't bump a pedal wait 2 mins and there should be some noise from the throttle body and finally a click sound and no more noise then try to start the vehicle

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Yup, that's the Throttle body.

I have done the Chicken Dance and there's an improvement. I disconnected the Battery for 10 minutes, opened all doors, reconnected the battery. The Throttle position sensor made it's usual noise immediately but then stopped after just over a minute. The car now nearly starts every time and doesn't stall when pressing the accelortor but actuly tries to rev a little befor stalling.

First thing that has made a diference and it's called the chicken dance, awesome.

Now It would seem its time to attack the no comunication issue so I can Adapt the Throttle position sensor.

I shall check the OBD2 connector to see if it is CAN or K-line. I have seen some checks that I can do on the CAN system but not much for the K-line system, any ideas?

Thanks to all so far, looks like we might be getting to an answer.