1.6 Gti Starting Problem

[20foive 0]

Hello!

Okay I've been helping a friend try to get his Visa Gti running but haven't had much luck yet so I thought I'd try here as you guys are the experts! (BTW the car has 105bhp XU engine with LE2 Jetronic)

 

I believe the problem lies with the fuel pump not performing its initial prime when the ignition is first turned but not sure how to rectify this issue, I have searched and searched but can't find th relevant infomation,

 

Here is what has been checked so far:

 

All voltages at tachometric relay present and correct (1 terminal to - side of the coil had the correct resistance to the terminal but open circuit to the two connecting wires which confused me somewhat, not sure if thats right?)

voltage at fuel pump and fuel pump runs when cranking

fuel is delivered to fuel rail, although when the hose was unscrewed there didn't appear to and build of fuel pressure -seemed like a bit bit of an airlock? (before petrol pumped out)

 

injectors have been removed and appear to be spraying fuel which is weird because it wont fire at all

 

Pressure regulator has been removed where there was significant fuel pressure (sprayed out of rail)

Ignition spark is present

 

compression is fine

 

Tried a different ECU / ignition module / fuel pump / tachometric relay which made no difference (although these were spares with the car so no guarantees that they work)

 

So as previously stated I believe the non starting is linked to the initial prime not happeninng but am unsure how this function is actually performed electronically? so am not sure what circuits to test (Citroen Hayne is useless in this area). After cleaning up the terminals on the coil and replacing a spade connector on the + side the fuel pump primed (ignition was on) although it didn't make a difference to the car starting. Could it be that the relay is part functioning?

 

Any help and suggestions will be received with the greatest of thanks as we are really stuck on this at the moment!

[20foive 0]

Forgot to say we took the sparkplugs out and sprayed easy start into each cylinder and it started to fire.

[Anthony 1,003]

Sometimes Jetronic cars don't do an initial prime of the fuel pump, so that could be a red herring.

 

If it starts on easy start, then it's probably reasonable to assume that the ignition side of things is fine and compression/timing are OK.

 

What has happened to the car since it last ran?

 

Is the ECU temperature sensor plugged in and giving a sensible reading - should be around 2500 ohm at 20 degrees, so a bit higher than that around freezing.

 

Is the AFM plugged in and the flap inside moving freely? You can test this with a multimeter to confirm that it's working to a point (resistance should smoothly change as the flap is opened), but haven't got the pinout to hand.

 

After an failed attempt to start, if you unplug the injectors does it fire up briefly? If so, suggests that it's injection so much fuel that it's flooding.

[20foive 0]

Thanks for the response Anthony!

 

'Sometimes Jetronic cars don't do an initial prime of the fuel pump'

 

Yeah I remember it having the 'prime noise' before the problem started, thats why I am convinced its something to do with the non starting.

 

 

'What has happened to the car since it last ran?'

 

It last ran about a year or so ago

 

Engine wise its had the AFM meter removed, ignition module removed, dizzy removed all of which were obviously bolted back in. The sockets and connections have all been checked.

 

 

'Is the ECU temperature sensor plugged in and giving a sensible reading'

 

Not sure where thats located? Is that water temperature sensor?

 

 

'Is the AFM plugged in and the flap inside moving freely?'

 

Plugged in yes, I'll double check it hasn't seized up and tet the resistance also.

 

 

'After an failed attempt to start, if you unplug the injectors does it fire up briefly?'

 

It used to do that very slightly - After cranking and leaving it for say 5 minutes it spluttered alittle on the next try but it doesn't even seem to do that anymore. It doesn't appear to be flooding as the plugs are normal looking when I've pulled them out.

 

Other than the priming issue I did wonder if the injectors had partially siezed up where they spray some fuel but not enough to start the engine, not sure if that is a likely occuarnce.

 

Thanks Again!

[pug_ham 244 3 Cars]

'Is the ECU temperature sensor plugged in and giving a sensible reading'

 

Not sure where thats located? Is that water temperature sensor?

 

The ecu temp sensor isn't the water temp sensor strictly speaking as it doesn't have anything to do with the dash gauge, this only sends a signal to the ecu letting it know the engine coolant temperature to adjust the injector opening times for a cold engine, albeit minutely.

 

I think on the Visa it'll be in the coolant temp sensor housing below the dizzy, it's a blue plug on the 205 & most likely the same on the Visa.

 

Other than the priming issue I did wonder if the injectors had partially siezed up where they spray some fuel but not enough to start the engine, not sure if that is a likely occuarnce.

 

The injectors are an electric solenoid valve so I'd be very surprised for them to seize but the fuel could have gone off & waxed them up from being stood so they aren't injecting a good spray pattern any more which can cause poor starting.

 

You could try temporarily hard wiring the fuel pump as a test to see if it is a fuel pressure issue by bridging into the fuse box output so the pump runs continually with the ignition on, effectively bypassing the tachymetric relay.

 

g

[20foive 0]

Thanks for the help pug_ham

 

'The ecu temp sensor isn't the water temp sensor strictly speaking as
it doesn't have anything to do with the dash gauge, this only sends a
signal to the ecu letting it know the engine coolant temperature to
adjust the injector opening times for a cold engine, albeit minutely.

I think on the Visa it'll be in the coolant temp sensor housing below

the dizzy, it's a blue plug on the 205 & most likely the same on
the Visa.'

Okay thanks for that, as I was working in that area it might be a bit dislodged. If it goes open circuit would it stop the injectors from working altogether?.

 

 

'You could try temporarily hard wiring the fuel pump as a test to see if
it is a fuel pressure issue by bridging into the fuse box output so the
pump runs continually with the ignition on, effectively bypassing the
tachymetric relay.'

Yeah we did that to check the circuit and voltage but only briefly, so yeah try jumping the terminals and then actually try starting it. Should have thought of that

Thanks again!

[pug_ham 244 3 Cars]

If it goes open circuit would it stop the injectors from working altogether?.

 

No, it could make starting worse due to over fuelling but the injectors are controlled separately within the ecu & aren't directly connected so they will still fire with it unplugged.

 

g

[20foive 0]

No, it could make starting worse due to over fuelling but the injectors are controlled separately within the ecu & aren't directly connected so they will still fire with it unplugged.

 

g

 

Okay thanks for explaining that for me.

 

 

'You could try temporarily hard wiring the fuel pump as a test to see if

 

it is a fuel pressure issue by bridging into the fuse box output so the

 

pump runs continually with the ignition on, effectively bypassing the

 

tachymetric relay.'

 

To try and start the car like this I'll have to jump 87 and 87b terminals at the relay wont I? (Fuel pump & Injection circuit) Sorry if this is obvious

[pugdamo 111 2 Cars]

As you said it fired on easy start have you tried some fresh fuel?quite often the simple things are easily overlooked.

[20foive 0]

As you said it fired on easy start have you tried some fresh fuel?quite often the simple things are easily overlooked.

 

I agree the obvious things are often overlooked, but yes we put fuel in in October so should still be fine. Guess it wont hurt to put some fresher stuff in though. Thanks!

 

Seriously considering putting twin 40's on this car if we can't get it sorted. But i don't really agree this idea until the first problem is fixed...

[welshpug 1,661]

I think fitting an MI16 would be better than 40's...

[20foive 0]

I think fitting an MI16 would be better than 40's...

 

Yeah agreed! I only said that as there are some lying around and its tempting to try to get out of this situation. But yeah an Mi16 conversion is all the more reason for us to get this annoying fuel injection delivery problem sorted! that is unless the Mi16 is on carbs!

[lfallgti 12]

Did you get this sorted.

 

My car did exactly the same, does the car have a crank sensor? I tried everything with mine and had exactly the same issues then remembered that motronic runs a crank sensor, plugged that in and it fired up first crank.

[20foive 0]

Hello


We managed to get the engine running!

It turned out to be something quite, but not instantly, obvious

Problem1:
The injector loom plugs were taped up by the previous owner, so I pulled them apart and cleaned them up as the contacts had copper grease on
them. Obviously the copper grease was put there to stop corrosion but unfortunely its not conductive (i've only just learnt this), once
removed the engine fired straight away . Weirdly the engine did run with the grease in place when the car was purchased so I guess it congealed over time and stopped any electricity passing through the contacts leading to a non starting engine. I hadn't realised the copper grease was non conductive at first, I had seen some
on other contacts but not thought anything of it, after getting the engine running and doing some research I will be cleaning all connectors to avoid future problems.


Problem2:
The earth connection on the tachometric relay seems a bit loose and I think the connector was getting pushed down when inserting the relay contact thus not making a very good contact (contributing to te below symptoms). This may have happened/got worse since the relay has been put in and out constantly whilst trying to get the engine started.

The engine isn't exactly running that well (cutting out and running a bit roughly on initial start up - once onto fast idle engine is fine), I expect this to get better after we
thoroughly remove the copper grease from the injector plugs etc and sort the earth on the relay socket.

Annoyiingly I bought a new tachometric relay from ebay which doesn't work - it won't operate the fuel pump

So the lesson learnt here is if you see copper grease on electrical contacts don't overlook it, REMOVE IT or it will eventually give you massive headaches

Thanks to everyone for all the suggestions and help! :D :D

Edited May 14, 2013 by 20foive