I despair at some garages "competence".....

I lift share with a colleague who has a Suzuki Alto Swift Y reg.

I went on holiday.

He took it for an MoT. It failed due to emissions and some welding was required.

He asked for repairs to be done along with an annual service to get said car through its re-test.

He gets the car back with a full MoT, with an oil change, new filters and new spark plugs.

It was running roughly. he spoke to garage. Garage said that's because we had to reset the timing to get the emissions sorted.

The MIL came on a few days later.

He took car back to garage last saturday. They put it on their diagnostic machine.

They then proceed to adjust the timing and reset the MIL.

Car was still running roughly.

I then come back from Holiday.

The MIL light came back on a few days later on Monday. (he finishes work after garage closes, so earliest he could take car back is next Saturday.)

I offer to plug my own EOBD reader in to tell him the fault code.

Comes up as PO304. which is misfiring No 4 cylinder.

I proceed to remove No 4 spark plug and inspected it.

The electrodes were touching completely with no air gap.

I look up on net to find out what the spark plug gap should be for a Suzy Swift Alto. This is 0.7 to 0.8mm.

I then get feeler gauges out to set the gap to 0.75mm and refit spark plug.

I then reset the MIL with my EOBD reader. car now runs sweet as a nut.

I reckon one of the new spark plugs must have fallen and hit the floor, causing the earth electrode to make contact with the nose electrode.

Is it really beyond the wit of a vehicle technician to know that a P0304 codes does not point to a timing issue, that it actually points to a problem with a misfiring no 4 cylinder? Given that the car has a mechanical distributor cap, logic should say that the problem is usually an electrical fault between the 4th output of said dizzy cap and the spark plug?

Goodness only knows what they would have come up with Next Saturday had he taken it back there.....

Stephen.

Reply to
Stephen H
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Quite.... its possible that they did set the gap but the plug hit something closing said gap prior to being screwed into plug hole.

or perhaps someone walking by car knocked a gapped spark plug onto floor and picked it up and put back without vehicle technician allocated to the car noticing.

Reply to
Stephen H

In message , Stephen H writes

I don't know about codes, but who fits plugs without checking the gap. Sheesh!

Reply to
Gordon H
[...]

More to the point, what garage would not be able to identify a faulty plug as the cause of a car running with one cylinder not firing?

Chris

Reply to
Chris Whelan

One who relies on a computer to diagnose faults for them. Ie, most.

Reply to
Dave Plowman (News)

*Ding*

Garages are now staffed by fitters, not motor engineers.

JB

Reply to
JB

A few years ago, SWMBO had a Mini- the proper one with an A-series and a sumpfull of gears, but with an ECU and injection. It broke down- engine turned over, but didn't fire, and she called Green Flag. The bloke that came out tried it- and it started. He said "it needs diagnostics" and gave her a card for his garage, and followed her home.

I got home, started it, and did the standard wiggle test, and found a loose coil HT lead- just like on the one my Mom had had 10 years ago.

Reply to
Chris Bartram

I saw an example the other day: head had to be rebuilt on a renault diesel after a genuine ex-kwik fit fitter had changed the cambelt, he had done up the crank pulley with an air wrench instead of with a gbfo torque wrench plus an angle gauge. After a mile or so it ran rough, then rougher and stopped. The crank pulley is not keyed and due to the lack of correct tightening (iirc 330 lbft plus 130 degrees, with a new bolt, also not used) it had slipped bending all 16 valves.

Reply to
Mrcheerful

A Jaguar main dealer could not get an E-type started after a service, they rang a local car dealer well known for being knowledgeable about Jags, he asked if they had pulled the choke right out. What's a choke? they asked.

Hard to believe, but that is a true, recent account.

Reply to
Mrcheerful

I wonder why they don't key the shaft? Seems odd to fix an angle critical component using only friction.

Tim

Reply to
Tim+

well it saves a few pence and may allow slightly more accurate timing. Many engines are like that now and have been for a long while, IIRC Fiesta 1.25 was the first one that I changed the belt on that had non keyed crank and cams.

Reply to
Mrcheerful

How do the employers allow them to get away with all of the remedial costs? the incompetence must cost them a fortune. JB

Reply to
JB

Dear merciful christ. I must change my career....eevn at this late stage.

JB

Reply to
JB

Alfa V6 doesn't have keys or pins on the cam pulleys. They supply a set of cam lock blocks at an eye watering price. The blocks replace a cam bearing cap on each cam and have milled recesses that match the profile of the adjacent cam to hold the cams at set timing while the bolts are done up. Branded copies cost a lot too.

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So re-profiled cams are going to require a custom set of lock blocks. Mate got some cheap £60 copies off Internet. Used as the manual described and block 1 on cam 1 etc. He promptly bent all the inlet valves on the rear head. Having just done the head gasket the head had to come off again. Turned out that 2 of the blocks had the position marks interchanged.

Even if there is a key, if the bolt is not properly tight the torsional variation will loosen it up and rip the key to bits in quite a short time ~ 1000 miles. All it needs is a belt guide plate to have been replaced off center so the pulley sits on a crescent and not a full circle.

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Gleasson Curvic coupling is the best device for transmitting high torque though a bolted shaft joint.

Reply to
Peter Hill

about a grand a time if you take the cost of materials, labour, hire car etc. but the worst thing is the loss of reputation/goodwill/trust, this is the second time this mechanic has done it too, the other was a 1.6 focus. The boss is not happy at all.

Reply to
Mrcheerful

The issue is spotting that it is running on three, so anyone reluctant to remove the plug leads in turn on a running engine because of the scary high voltage warning.

Reply to
newshound

there are many reasons NOT to remove plug leads these days, some personally dangerous, some very expensive. A better solution is to earth out each plug lead in turn, very safe compared to pulling leads.

Reply to
Mrcheerful

I was discussing this at my mates dad's garage a few weeks ago.

He told me he had made a mess of 2 engines following belt changes in

30odd years. One on the zillionth K series he had done and he was still at a loss to explain why it went wrong. The second was when his son started doing belts, he failed to check it properly and son had ballsed up. He tells me both customers still use the garage because he sorted out keeping them fully informed and at no extra cost. His view was its just one of them things that happens occasionally and as long as you sort it out then all is well.
Reply to
Tom Burton

OK, I remember when you didn't actually need a plug cap, you stripped the lead and fixed it to the thread with the little screwy thing. So you could easily short each plug to earth with a screwdriver.

Presumably in the trade you use some sort of adaptor or extension?

Reply to
newshound

On suitable vehicles I usually pull back the cover at the coil end and short it there. Or put an extension on the top of the plug made of 4mm studding and short that (not always feasible) If there are individual coils and it has individual injectors then you can remove one of their connectors at a time. Or you can remove a plug lead with the engine stopped and earth it, then restart, repeat as needed, with the engine cold it is sometimes easy to see which one is not running by the temp of the exhaust outlets. Whichever way you choose remember that modern ignition systems could be fatal.

Reply to
Mrcheerful

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