misfire on '97 mpi

Hey group, hope you all had a good Christmas!

I want to pick your collective brains if possible.

My '97 1.3mpi has developed a misfire, but it seems a bit intermitant.Sometimes when its cold, or damp it is quite bad, other times it is fine. Once you raise the rev above 1500 rpm it goes, unless you are accelerating hard, when it sometimes happens in second gear. It has also happened at high speed a couple of time, overtaking at 70mph plus, which can be quite disconcerting I can tell you!

Ive changed the plugs and leads, NGK plugs and Autospark leads. The fuel filter was changed a month ago as the car had been stood for 6 months or so before I was given it.

Ive checked all the connectors to the coil but they seem OK.

One thing Ive noticed the spark on plugs 3 and 4 seems a bit weaker than 1 and 2 but Im not sure how to check the coil accurately by resistance etc.

Any suggestions?

I use the car every day to go to work 30 - 35 miles so I want to get it sorted over the holidays.

Ben.

Reply to
Ben & Claire
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Hi Ben!

Have you checked the compression on each cylinder? Head gasket might be gone

Have you checked the lambda sensor output when it is hot? If that is fouled then you will need to replace it. It should read between .5 and

1v if I remember rightly

Check the injectors are both spraying cleanly.

Can you borrow a Fault code reader and check the ecu for error codes?

I will get back to you when I find my little book with the coil pack resistances in!

Good luck!

miniman

Reply to
miniman

Misfire has got a lot worse over the last two days, been on a couple of long runs and its getting to be pretty bloody awful. Gonna get the compression checked tommorrow. I just hope Ive not got a blown HG. I just found out Ive got to go on my MOT training course at VOSA in 10 days time and I dont think Ive got time to change the gasket before. Ben

Reply to
Ben & Claire

Sorry forgot to ask, where is the diagnostic socket on the '97. Ive got access to a scantool at work.

Ben

Reply to
Ben & Claire

I don't know anything about mpi's but a head gasket should be easily replacable in an afternoon,

Steve.

Reply to
Steve68s

Checked the compression today, and it seems fine about 145(psi?) on all four cylinders. It was at the upper end of the green scale on the gauge.

One thing I did notice, spark plugs number 1 and 4 were a lot blacker than 2 and 3. 1&4 are plugged into the lower bank of the coilpack, so Im guessing that may have something to do with it.

Havent checked lambda sensor yet, didnt have time tonight after work but Ill hava look tommorrow

Spray pattern looks ok, certainly seems to burn OK on cylinders 2 & 3 anyway.

Ive got a fault code reader at work but Im buggered if I can find the socket. The component location book says it should be on the left hand bulkhead under the bonnet. But its not there!

Reply to
Ben & Claire

I had a similar type of misfire on my 1.3 single point , turned out to be the ECU plug was trying to disconnect its self, the harness is attached to the engine and the ECU is on the wing, whenever the engine moved or went over a bump, the car misfired, Longshot but worth a try Fitzy

Reply to
Fitzy

I've never looked that closely at the MPI, but I can say that on an SPi there are two similar looking sockets.

One is on the bulkhead, sort of tucked away below the fuse box, coloured green with a black rubber sock over the end.

The other is found fairly close to the MAP fuel trap - a little black box on a bracket coming off the inlet manifold, with a pipe that goes to the ECU - and is white with a similar rubber sock.

To use a fault code reader with the SPi, the white socket should be used. I think the green one is for reprogramming the alarm or something. Regardless, fault code readers don't even start up properly when connected to the green one...

erik.

Reply to
erik fishead

Thanks. Ill give it a try.

Ben

Reply to
Ben & Claire

Woo Hoo!

Would you believe after all the hassle of checking every connection under the bonnet. Spending 2 hours trying to get our P.O.S. fault code reader to work (By the way the socket on the mpi is to the left of the steering column under the dashboard) I finally found out the problem.

Crap on the Crank Position Sensor.

(Its positioned under the starter motor into the bell housing.)

She now runs a dream. 800-900 idle. Picks up brilliantly and solid acceleration thro the range.

HAPPY NEW YEAR!

Ben

Reply to
Ben & Claire

I have an MPI Mini that cuts out over 2000 rpm.

Tester says bad Crank Sensor, changed but still the same.

What did you do to the Crank Sensor, did you remove and clean the sensor, or just clean the connection.

Cheers

Alan

I finally found out the problem.

Reply to
Scaleracing

I just removed the sensor from the housing, it was caked in crap, bits of clutch dust and a fine coating of oil.

i looked in the hole, expecting to find the flywheel covered in oil from a seeping rear main seal but it was OK.

I cleaned the sensor with a little brake and clutch, cleaned the crap from around the hole and away she went.

A bit of background, I got the car for free because the previous owner thought the gearbox was blown. copious amounts of oil down the front etc and especially in the area of the crank sensor, but in actual fact the oil filter seal had blown out. I told him it was just the oil filter, but he said NO take the car, I would rather someone have it who was going to apreciate it, and anyway Ive just bought a Saxo. So the car was mine! Yipee!

Reply to
Ben & Claire

Good on you mate, Fitzy

Reply to
Fitzy

let me know if you hear of any more of these free ones won't ya? ;)

Reply to
Mian

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