Timing belt issue

[kiteman]

Just a thought, if the timing belt was out by one tooth, what would be the symptoms be.
Reason I ask is, my track car, while having a few mods, I believe is not as fast as my bog standard runabout.
I've had numerous tests done on both cars to do a comparison, and all that was discovered is,
1/ track cars injectors are opening for 25% longer.
2/ track cars vacuum is about 9% lower.
3/ I have had the occasional backfire when changing down on the track.

Mechanic who carried out the tests, says the symptoms suggest to him the belt may be out by one tooth.

Your comments will be appreciated.

[Turbo_Steve]

Sounds about bang on to me.

[kiteman]

Sounds about bang on to me.
Thanks for that Steve, I'm bringing it to him tomorrow to have it check and value your opinion.
Tommie
Ps, some rep on its way to you

[Turbo_Steve]

Hey thanks!

Mine ran like an absoloute pig on full throttle until I changed the cambelt. I didn't change the timing at all (though I did check it) and the conclusion I came to was that the belt had probably stretched.

Just need to work out why I only get 17mpg next :(

[Turbo_Steve]

Did you get any news on this? Been considering other possibilities, and the only other I can come back with is a problem with the MAF, which woud result in ultra-rich running at high load.

[raph]

Or a bad 02 sensor or a coolant temp sensor telling the ecu its -20°C all the time?

Hope no one has a 60 degree thermostat wonder why the cars pig rich?

Or ask someone to swap their MAF for a day ?

[fuel]

timing belts don't usually stretch they would start freying at the sides or lose a tooth or two before that happens. Plus if it did stretch the hydraulic auto tensioner would take up the slack anyway.

Just out of curiousity have you done a compression test on this engine? An engine with lower compression is going to have more difficulty maintaining higher vacuum readings

[Turbo_Steve]

Sounds like you were closest, Fuel: it had a non-operational valve rocker! :)

Temp sensor will make you a lot richer than 25% IDC, Raph. A LOT richer!

[kiteman]

Valve lifter came adrift

Hey guys, looks like I have 2 posts going on the same topic. Dont know how to put up a link to the other one, but above is the heading its under.
For those who have come late to this ongoing saga, I'll explain.
As I have 2 legnums I was able to swop components around to check comparisons.
First was the MAF, then the 02 senser, then the ECU, then the temp senser and on and on.
Lets see, to date I have done compression test all 6 cylinders showing identical high pressures.
I also did a cylinder leakage test, all was fine there.
The final findings can be found on the post mentioned at the start of this one.
Thanks for your imput,
Tommie