hesitation when cold

My 1993 9000 cse 2.0 lpt has stated not firing on all cylinders immediately after a starting in the morning. It takes about a mile to get it going normally. DI replaced just one month ago, spark plugs and air filter replaced only 4 months ago. So what could be the problem?

Reply to
johannes
Loading thread data ...

Possibly leaking head gasket into one or more cylinders when the engine cools, and metal contracts. The misfiring is the non- combustible coolant(water) that is present in the cylinder. Check the plugs and see if there is ceramic missing on the firing end, this is a sure sign. Otherwise pressure test overnight with plugs out and look in each cylinder for coolant. Gerald

Reply to
Certainly

OK, I will check next weekend. I was thinking of fuel filter or injectors, but the car dives OK once the engine is warmed up.

Reply to
johannes

Did you gap the plugs correctly? Is there a pressure relief valve on the fuel pump on the 9000s? I know on the Classic 900s, that's one of the first places to look when encountering what feels like a fuelling problem.

Reply to
PJGH

The correct NGK plugs come already correctly gapped.

Graham

Reply to
Eeyore

This sounds like one of the many sensors (that I don't grasp) in injection/catalyst cars.

My experience of head gaskets was that the car was much worse when hot.

If it helps a little Charles

Reply to
Charles C.

Yes, I believe they are. I always buy the pre-gapped NGK BCPR7ES-11 and didn't experience problems before after such short time. The plugs should last 24,000 miles. The new DI should make it work perfectly.

Again, there is only symptoms when starting in the morning. The rest of the day it's OK. But un-burnt fuel can't be too good for the CAT.

Reply to
johannes

I think that if it was the head gasket, the hesitation would disappear gradually as the engine warms up and dispose the moisture. My problem was more intermittent, the car could be ok immediately after start and then a few returning hiccups before it had cleared. Since MOT was in the offing, I treated the petrol tank with a course of "D-Tox" made by Comma I have some confidence in Comma as I have used their antifreeze. The small print on the box said it was Catalyser friendly. Anyway, I did work very well. No more morning hesitation or flat spots. Today it passed MOT with no prob.

Reply to
johannes

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.