Thread: 4.6 rough idle and excess fuel (more than normal) post head gaskets & cam swap

does it go ok?
lumpy idle could be maf,,

Goes ok, MAF shows no faults and is <6mths old.

Has codes:

P0134 Lambda Sensor Bank 1 Upstream
P0134 Lambda Sensor Bank 2 Upstream
P0135 O2 Sensor Heater Bank 1
P0135 O2 Sensor Heater Bank 2
P0155 O2 Sensor Heater
P0175 Mixture Adaption Factor Bank 1
P0175 Mixture Adaption Factor Bank 2
P1000 Lambda

134 & 135 show up a few times, for both banks and hi, lo and missing signals.

Reset the adaptive settings again and let it idle for 10 min without touching anything to let it warm up and it's still the same. At first startup it idles at around 200 - 250 rpm while it works itself out. With a prod of the accelerator up to around 1500 - 1700 it has slight backfire on overrun. Once sorted it idles at around 600-680 rpm (which by comparison is a bit low to previous).

Disconnecting the MAF has the symptoms and with the same usual effects.

Normally one would have to say given the work done, that the cam timing is out... If it's burning that much fuel, the fault codes you've given aren't telling you anything you don't already know.

I assume you have checked that all sensors are actually plugged in, coolant temp signal to ecu for example, and verified the ignition leads are in the correct place (wouldn't be the first to mix up leads on the D2 coil pack arrangement...)


Did you get the heads machined while they were off, and which head gaskets did you use, tin or composite? Wondering about lifter preload...


I'm also curious as to what you used the degree wheel for when you were checking your setup? Are they genuine timing gears, or aftermarket?

Just a thought that I certain up with if you did cam and the like did you do camshaft and crankshaft sprockets ?? The reason is that the gems and Bosch cam sprockets have different timing windows for the cam sensor and have seen the wrong one fitted and causes dry rich running, poor idle, high fuel consumption and the like.

The gears and chain were done, all the stuff was genuine ordered from Turners. The cam gear matched the one coming off it which was the original.

Leads were marked and fastidiously checked. Heads weren't machined but were checked and flat, pressure tested etc. Composite gaskets, the same type and brank that came off. Used the degree wheel as you usually would to check the cam timing.

Originally Posted by clubagreenie

Used the degree wheel as you usually would to check the cam timing.

This is the bit I'm not quite following... With the standard gears, from memory, there is no adjustment provided, simply a case of line the dots up on the two gears. And further to that, from memory, the timing gears have keyways to the shaft, so it's simply a case of slide the two gears on, line up the dots, and away you go?


I can't see the point of using even a dial gauge to verify TDC, as due to the keyway mount there's nothing you can do about it if it's wrong. The only reason I could see for going to that trouble was if you were setting up aftermarket adjustable timing gears....


I'm sure I must be missing something here...

Cluba, I think your timing is out some how. If the cam,gears and chain are all standard you should not have needed to use a degree wheel as the crank and camshaft gears have alignment marks and there is no other adjustment provided for according to RAVE.
Crank gear has a keyway locating and the cam has one way fit only location and bolt.
I temper this observation by saying Im only going on RAVE, not having an 8 pot screamer myself
Cheers Scott

I know everything is "std" and keyed, dotted etc and shouldn't be able to be stuffed up but I've seen it before where the dots are aligned and it's not timed right.

Going to throw the old O2 sensors in and hopefully eliminate their faults and start from there. Got rid of the cam sensor fault while it was apart. The old oring had melted itself into the taper and for all purposes looked like a rubber seal vulcanised into the cover. It meant that the airgap was too large when the oring was added as is required.