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        General >> Problems >> Hesitant running when cold
        
(Message started by: brewer on Jun 10^th, 2005, 2:05pm)

Title: Hesitant running when cold
Post by brewer on Jun 10^th, 2005, 2:05pm

My '95 2.9 24v Ultima runs well except when cold-it moves off OK but is reluctant to accelerate for the first 200 or 300 yards.It then picks up , sometimes a little suddenly,and is OK from then on.
The autobox/torque converter are new replacements and a recent OBD check found nothing wrong at all. Is it just the engine management system protecting the cat or something?

Title: Re: Hesitant running when cold
Post by OddJob on Jun 10^th, 2005, 10:56pm

Welcome Brewer

It could possibly be the air charge sensor (cold start sensor) located on the inner side of the plenium chamber under the Cossy cover (on your left looking from the front of the car) near as opposite the throttle position sensor. Maybe giving the ECU false temp readings.

Title: Re: Hesitant running when cold
Post by brewer on Jun 11^th, 2005, 8:26am

Thanks.How do I check it,or is it dealt with on the site?

Title: Re: Hesitant running when cold
Post by OddJob on Jun 12^th, 2005, 7:21am

Technical Data - typical Ford though not specific to the specified vehicle.

1. Intake air temperature sensor (IAT)

# Ensure ignition switched OFF.
# Disconnect sensor multi-plug.
# Check ambient air temperature.
# Check resistance between sensor terminals.

Temperature 15-25*C......38000 Ohm Resistance approx.

http://www.fordscorpio.co.uk/iatdata.htm

This Brewer was just a thought on possible problem and may not actually be the problem.
Other possibilities may include:

2. Engine coolant temperature sensor (ECT)

# Ensure ignition is switched OFF.
# Disconnect ECT sensor multi-plug.
# Relieve residual pressure in cooling system.
# Remove ECT sensor from engine.
# Immerse ECT sensor probe in coolant of specified temperature.
# Check resistance between ECT sensor terminals.
# ECT sensor may be checked in situ if engine temperature and readings are compared.

0*C....... 95000 Ohm Resistance approx.
20*C......38000 Ohm Resistance approx.
40*C......16000 Ohm Resistance approx.
60*C......75000 Ohm Resistance approx.
80*C......38000 Ohm Resistance approx.

http://www.fordscorpio.co.uk/ectdata.htm

Other items may be checked with an OBD2 scan where available (try Harwood meet)

3. Heated Oxygen sensor(s)

http://www.fordscorpio.co.uk/obd2scan2.htm

4. Fuel pressure/delivery rate/ fuel pressure regulator

http://www.fordscorpio.co.uk/obd2scan6.htm

5. Engine systems

http://www.fordscorpio.co.uk/obd2scan3.htm

Title: Re: Hesitant running when cold
Post by brewer on Jun 12^th, 2005, 7:32am

Thanks.
Previous owner had OBD2 check quite recently,no faults found.
Funnily enough,didn't do it yesterday but the brake assistance went about 5 minutes later!Would there be a connection?

Title: Re: Hesitant running when cold
Post by admin on Jun 13^th, 2005, 12:01pm

Yes there could be - the servo is connected to the inlet manifold so a problem between those two items could manifest itself as a brake problem and/or a running problem. See what the repairer finds relating to the servo and lack of braking assist - I'm thinking it's the one way valve that's at fault but there could also be a manifold leak.

Title: Re: Hesitant running when cold
Post by brewer on Jun 13^th, 2005, 12:56pm

Thanks.Hope it resolves itself.

Title: Re: Hesitant running when cold
Post by brewer on Sep 2^nd, 2005, 10:58am

Further developement - I noticed that the coolant level was low , a misfire occurred when starting up and eventually the car wouldn't go over 30mph!
Diagnosis as you've guessed is a blown head gasket,repair cost £1400! Last time I had a head gasket go was on my MG and it cost £10 plus a morning's work.
Thank goodness for Warranty Direct!

Title: Re: Hesitant running when cold
Post by brewer on Oct 3^rd, 2005, 6:25pm

Not the head gasket apparently but manifold gaskets ! Only £700 this time but not covered by the warranty :-(

Title: Re: Hesitant running when cold
Post by howiedintheplace on Oct 3^rd, 2005, 8:18pm

Who the hell is charging them prices :o

That's alot even for Ford.

Title: Re: Hesitant running when cold
Post by howiedintheplace on Oct 3^rd, 2005, 8:24pm

I would check all the vacuum pipes first as it is usally them that cause the trouble not the manifold gasket which is so easy to do yourself for about £20 ;) not £700. 8)

Title: Re: Hesitant running when cold
Post by brewer on Oct 4^th, 2005, 1:21pm

It's quite a long story - the car wouldn't go over 30mph so I took it to a local Ford dealer.The problem was thought to be head gaskets.They submitted the claim to Warranty Direct who insisted on their own repairers.The repairers couldn't do head gasket work so the car was sent to the main Ford dealers. They in turn reported back that it wasn't the head gaskets after all but the work could be done for half the previous estimate.This all happened about 100 miles from home so I couldn't be directly involved so I had little choice but to go ahead.I don't know how the costs arose but the relief of not having to fork out £1400 probably softened me up a little!