Wont rev past 3.5k

niz406 · Post by **niz406** » Thu Dec 27, 2007 2:00 pm

OK guys need some tips on what to check as there is no warning light on or and other indication that there is a fault... car ticks over fine, starts first time but will not rev past 3.5k, there is mental backfiring when it tries, as if its reached the rev limiter but a much more agressive sound...

Anyone got any ideas??

mjb · Post by **mjb** » Thu Dec 27, 2007 3:47 pm

dodgy flywheel timing sensor?

niz406 · Post by **niz406** » Thu Dec 27, 2007 4:57 pm

Not sure, although tonight after coming out of work.... it seems to be back to normal... fuel blockage somewhere??

mjb · Post by **mjb** » Thu Dec 27, 2007 6:22 pm

I'm not much of an engine guru, but wouldn't a limited flow rate just make it difficult to rev? Messed up timing on the other hand could cause fuelling at the wrong time leading to backfiring which would forcibly limit revs. A dodgy sensor is the sort of thing that'd exhibit problems based on revs too. An oscilloscope on the sensor connections should prove/disprove it

niz406 · Post by **niz406** » Thu Dec 27, 2007 10:07 pm

It bloody happened again this evening when I went out... I'm wondering if its a collapsed CAT, as there is a rattle from the exhaust on start up, then under pressure there is popping and misfiring from it and it will not break 3.5k on the revs... I don't have the time at the moment to look at it, as I'm at work tomorrow then off for a few days with friends for new years....

Where's James.... he must have run into this! !

jameslxdt · Post by **jameslxdt** » Fri Dec 28, 2007 12:06 pm

get underneath and give the cat a whack, you'll soon tell if its fudged, does sound more like a knock sensor fault, which could mean, you've got a duff piston

, dodgy knock sensor or wiring, or the ignition timing is waaaaay over advanced, which wouldnt supprise me considering your power output, and amazingly the knock senso wont flag the K light, you need to get a fault code read out if the cat seems ok

niz406 · Post by **niz406** » Fri Dec 28, 2007 1:46 pm

Ah ok james, will check that... I have a spare engine with full electrics, so if its a sensor I have a spare

Failing that I will put the decat back on... and errmmmmm add petrol and a match to it!

MikeMac · Post by **MikeMac** » Fri Dec 28, 2007 3:43 pm

The potential Cat rattle is far more likely to be as a result of damage from the backfiring to be honest.

My money would be on a loose sensor.

sriturbO · Post by **sriturbO** » Sun Jan 06, 2008 10:32 pm

niz can i see pics of your decat and did you buy from a company or have it made by one

niz406 · Post by **niz406** » Fri Jan 11, 2008 9:21 pm

I will try and sort a picture out for you... I brought the flange and lambda sensor boss from a manufacturer local to me.. and then had the PowerFlow dealers make it up for me, and a proper job they did too... so its a full stainless system ! !

As for the car, took it for diagnostics.... they say TDC sensor and possibly ECU, luckily I have a spare ECU

so just got to buy the sensor... circa £19 but they say that alone may not cure it and I might need the ECU too... told them I had spare everything for the engine, loom, ECU, turbo, etc... so they say visit them again if the two parts dont fix the problem....!

James - does that sound about right to you??

When its not wet out i'll also refit the decat!

niz406 · Post by **niz406** » Fri Jan 11, 2008 9:28 pm

mjb wrote:dodgy flywheel timing sensor?

Oh winner by the way lol

mypugscool · Post by **mypugscool** » Sat Jan 12, 2008 9:21 am

my brother inlaw had one come in the garage with what sounds like the same as what you have and it turned out to be fuel pump, it just would get enough pressure

niz406 · Post by **niz406** » Sat Jan 12, 2008 10:15 am

mypugscool wrote:my brother inlaw had one come in the garage with what sounds like the same as what you have and it turned out to be fuel pump, it just would get enough pressure

Thats what I thought originally because the Fuel level sender was playing up too and I thought maybe the pump had picked some crap up off the bottom of the tank and their was a restriction in the pump feed.... causing a loss in flow rate at higher revs.... guy at garage reckons not!

jameslxdt · Post by **jameslxdt** » Sat Jan 12, 2008 3:37 pm

if it was the TDC it wouldnt run

niz406 · Post by **niz406** » Sat Jan 12, 2008 6:14 pm

jameslxdt wrote:if it was the TDC it wouldnt run

Thats the interesting part.... it starts fine, ticks over perfectly, then when you rev it... he said the diag picked up a TDC sensor fault at 3.5k and when the fault occurred the injectors didn't fire. They couldn't guarantee that the TDC replacement would cure it, and then went on to say about the ECU being faulty.

So I'm just going of what the diags and engineer said..

Any other ideas James?

406oc.co.uk

Wont rev past 3.5k

Wont rev past 3.5k

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