RR is not revving to good

[Knight Rider S4]

Well having a bit of a head scratcher here ...recently bought a RR but has a issue with revving past 2k...Start no prob

Pulled Codes

Engine Coolant G62

Intake Air temp Sensor G42

Barometric Pressure F96

Visual check of hoses they are all good,,dizzy rotor is new as well as cap ..

Problem is funny as it ticks over sweet as a nut but when it has to rev above 2K it pops and farts all over the place ..havent seen sensors make a car run like that beofre but everyday is a new day


HAve been thinking it might be knock sensor problem?


Cheers


Steve

[newsh]

You say intake air temp sensor, is it showing a code for that? Broken wire to that sensor or sensor faulty can cause misfire usually above 2-3 k

[Knight Rider S4]

You say intake air temp sensor, is it showing a code for that? Broken wire to that sensor or sensor faulty can cause misfire usually above 2-3 k

Yes showing code for it ...I was thinking the same as the IAT links with knock sensors?...I have a ABY one and plug for wiring so will change over tomorrow and see if it helps

[newsh]

Not sure what the dc resistance of the 3B/RR one is (100 Ohm??) but its worth metering it from the ECU plug through the loom to make sure there's continuity. Sometimes the sensor is ok but the wire is broken near the plug on the IM cos of the constant movement.

[dkw_dude]

My 3B held back boost when disconnecting IAT sensor, but ran smooth. When disconnecting knock sensors it also ran smooth.

I tested disconnecting those sensors some years ago but I'm pretty sure thats how it behaved. I'm also pretty sure RR=3B motronic wise.. Sounds like boost leak, visually inspection of hoses doesn't reveal 100% if they are capable of holding boost IMHO.. Or maybe ignition leads, the part that goes over the spark plugs develop cracks and spark doesn't reach the plugs.. BTW plugs are they Bosch platinums/in good shape?

[220bhp]

Steve I had knock sensor problems when I first got my car,no misfire just would not pull or boost stayed in limp mode most of the time and no codes.you say the dizzy cap is new what about the alignment of the dizzy

[Knight Rider S4]

The problem with the car started , like overnight , drove fine then got parked up ..first thing in the morning went to drive off and it started playing up

I understand what you guys are saying about boost hoses and the rest ...But the car will not rev properly when stationary..so no load/boost on the engine at all

Timing wise nothing has moved as we all know if the dizzy is not 100% bang on the car would not start

Plug leads are fine ...HAve to still test the coil as this might be the issue but not sure ..have a 3B one spare so will see if that will fit on to it

[Acidburn]

Check the main coil lead is not caught anywhere as I had mine caught on my s2 and it caused all sorts of issue's, moved it and ran fine afterwards. Btw got any pics of the car?

[newsh]

Mmm, worth double checking the dizzy alignment.

[S2central.net]

I'd also have to go with dizzy alignment... Check all the timing carefully from 1st principles... Then proceed from there with crank sensors being the next plan of attack as the other fault codes seem to be of secondary concern to me on this revving issue.

Are all the spark plugs nice and snug ?

Wouldnt hurt to do a compression test either.

[Knight Rider S4]

Update on my progress:

Double checked the timing via cam and crank on the timing belt all good , tried swapping coil , have wired up ABY style plug for IAT and that is all working now , double checked all hoses again (not many so very easy and all good ) , had a issue with fuel pump but sorted that but was not cause of problem , but highlighted clicking noise from dizzy area gear which has started to get louder....So have started dismantling that area and going to see if there is a issue with cam wheel gear been fecked ....Dizzy has never been touched as the anti tamper plate is / was still covering holding nut ..fingers crossed it is this

PIctures of her added

[Knight Rider S4]

Had another couple of hour tonight spare so thought I would get back onto this ...Changed over the dizzy and no joy ..boo !!

Have done compression test and all good ...have check all likely culprits in engine bay but nothing staring me in the face saying I am goosed !!

Plugs are fouled up black as running rich because of misfiring above 2K

Was wondering what the symtoms would be is the FPR was goosed?

I am going to try and change the ECU over just to double check the fault is not there...what is the easy way to get it out ?..looks like a right PITA to pull out ..centre console out job?


Cheers


Steve

[Acidburn]

i'd probably go towards the fpr, sounds like you've got worse symptoms to what europeanme had with his.

[Phil Payne]

Not sure what the dc resistance of the 3B/RR one is (100 Ohm??).

450-550 Ohm. Factory originals close to 491 Ohm, recent shipments slightly higher.

I have a spare.

G62 (engine coolant) is 1.5k to 3.0k Ohms.

[Phil Payne]

Yes showing code for it ...I was thinking the same as the IAT links with knock sensors?

Nope. Separate function in the ECU code - the knock routine shfts values that the IAT sensor then uses.

There are those that are not impressed (!) by the knock sensor's noise elimination code.

If you ever have good access to the knock sensors it's always a good idea to retorque them.