Fuel injection problems

t-ha

Hey guys, have a problem with a 98 Fiat Punto (I know, I know). Basically I was driving along happily when my engine started to lose power and then pretty soon afterwards cut out. The fuel injection warning light came on when the problem started as well. When I try to start it it turns over fine (no problem with starter motor) but it never kicks in.

Any ideas what to check first or should I just bring it to a dealer to run a diagnostics check (money is a big issue for me)? Was thinking of checking the fuel lines for fuel pressure, then the fuel filter and failing that maybe checking the fuel pump?

One thing, I was doing some other work on the car a while ago and broke the foil hose from the exhaust manifold up to the air inlet. I thought it didn't really matter at the time because it was the start of the summer and I meant to replace it later but, well, you know the rest. Anyway, it's been getting cold lately so it's possible that that has caused a problem (not enough warm air to mix with the cold in the air inlet). Any idea what would break in that instance?

Cheers for any help.

DublinDilbert

t-ha wrote: »

Hey guys, have a problem with a 98 Fiat Punto (I know, I know). Basically I was driving along happily when my engine started to lose power and then pretty soon afterwards cut out. The fuel injection warning light came on when the problem started as well. When I try to start it it turns over fine (no problem with starter motor) but it never kicks in.

Any ideas what to check first or should I just bring it to a dealer to run a diagnostics check (money is a big issue for me)? Was thinking of checking the fuel lines for fuel pressure, then the fuel filter and failing that maybe checking the fuel pump?

One thing, I was doing some other work on the car a while ago and broke the foil hose from the exhaust manifold up to the air inlet. I thought it didn't really matter at the time because it was the start of the summer and I meant to replace it later but, well, you know the rest. Anyway, it's been getting cold lately so it's possible that that has caused a problem (not enough warm air to mix with the cold in the air inlet). Any idea what would break in that instance?

Cheers for any help.

Ideally you'd get someone with a suitable code reader to pull the codes as to why the engine light is on. Probably won't give you the exact problem, but might point you in the correct direction.

You'll need to use the mechanic's mantra "air" "fuel" & "spark"!

If the car is turning over you could see if it would start and run on carb cleaner ( spray it into the air intake ).... if it starts and runs for a few seconds on carb cleaner, more than likely you have a fuel problem. Next would be to check the fuel rail pressure.

you can check for a spark by using an old spark plug, disconnect one of the plug leads & connect to the old spark plug. ground the metal part of the plug to the engine, turn over and make sure you have a spark. Repeat for each of the 4 plugs.

Masada

Is the injector light staying on still? what key do you use for the car? blue or red/brown?
if you have the red key try that.
In the mean time you can leave the battery dissconnected for a few hours to reset the ECU and see what happens then.

the foil your talking about wont make any difference, thats just for the air intake to get warm air from the exhaust manifold when cold starting. its not really needed.

You'll know if the fuel pump is acting up by listening to it. it'll make a "whrrrr"ing kinda sound for about 5 seconds when you turn the ignition on (not engine started) and comes from under the rear seat.,

Will it start if you floor the accelerator and crank the engine? if it does but runs badly theres a good chance its the coil pack that's acting up. that's an easy enough repair.

Look under the oil cap for any whitish grunge looking stuff and in the coolant bottle for rust or oil/iridium colour that would suggest a dodgy head gasket.,

t-ha

Thanks guys - will head out to it tonight if possible and try out a few of those ideas.

The injector light is on all the time - I use the blue key. What difference does the red key make? Does it reset the ECU?

Hadn't thought about the battery thing either - will definitely try that if it's not the fuel pressure or the pump.

macroman

t-ha wrote: »

Thanks guys - will head out to it tonight if possible and try out a few of those ideas.

I take it it's the SPI version, problems like this usually point to a relay failure or else a Lambda probe failure (oxygen sensor). I'd say it could be the latter.

Either way it will come up in a scan.

t-ha wrote: »

The injector light is on all the time - I use the blue key. What difference does the red key make? Does it reset the ECU?

Hadn't thought about the battery thing either - will definitely try that if it's not the fuel pressure or the pump.

Red key is used to reset the ECU and to code additional blue keys if they're lost. Wasn't very popular and Fiat dropped the system in 1999 in favour for the rolling code option.

RICARDO1982

I wouldnt worry too much about the foil hose being broken that is only
to help the car run better on cold mornings.

Check your coolant level punto head gaskets are notorious..If not

Also could be a broken timing belt.. If not.....

What i would try is the crankshaft position sensor. It runs from a block connector at the top of the timing belt cover down the side of the timing belt cover (exhaust side) to a holder at the side of the crank pulley,

If you have a friend or relative who has a similar punto swap them and at least then you are not wasting money while trying to determine the cause
of your problem

Try this at your own risk

macroman

RICARDO1982 wrote: »

What i would try is the crankshaft position sensor. It runs from a block connector at the top of the timing belt cover down the side of the timing belt cover (exhaust side) to a holder at the side of the crank pulley

Yes, this and cam sensor can often dislodge if you hit a pothole or if you wash the engine

t-ha

Cheers guys - don't think it's the head gasket or the timing belt. I did actually hit some mothers of potholes last weekend so I'll check that the crank TDC sensor's not obviously out of place.

Will report back this week and let ye know how I got on!

t-ha

Hey guys, well, time for an update.

Managed to get out to the car twice since I first posted. First time was able to establish that the crankshaft pos sensor is fine, as is the timing belt, head gasket/coolant etc. The ignition relay also looks ok.

I indid the fuel inline from the throttle body and turned the key to check the fuel line pressure and got a spurt out of it so the fuel pump/filter and line are ok. Unfortunately the battery had run down so I had to take it away and charge it.

Went back yesterday and tried running the car with petrol dripped past the injector directly from a bottle. It worked! It also set the throttle body on fire! So it would seem that the plugs are sparking when fuel is applied directly, and also that the fuel pump is sending fuel up to the injector, so it looks like the problem is either with the injector or the pressure sensor.

Either way, my plan is to just replace the whole throttle body/inlet manifold. Anyone know if the scrappers at Dun Laoire Pier are open on Saturdays?

t-ha

Wow, EUR 85.00 for a new throttle body! Wasn't expecting that tbh but I suppose it could be worse.

Just hope this fixes it.

galwaytt

you're complaining you got a whole throttle body for Eur 85??

Jeez, wait 'til you graduate from a Punto - you'll never see a bill that small again...........!!

t-ha

galwaytt wrote: »

you're complaining you got a whole throttle body for Eur 85??

Jeez, wait 'til you graduate from a Punto - you'll never see a bill that small again...........!!

Ha ha, yeah I suppose but as a percentage of the total value of the car it's still pretty high!