Low High pressure fuel codes
This car occasionally sets a check engine light on with the above codes. There are no drivability issues . We have replaced the low and high pressure sensors as well as the high pressure pump. we have also checked for leaking injectors and the car has the latest calibrations. We suspect a streched chain causing this problem . The dealer tells us the same . There are no timing codes on this car, but the dealer has told us the slight slack in the chain causes the code to set because it doesnt see the pressure rise at the rate it is suppose to on a cold start. The vehicle has 100,000 kms on it ,The tensioner is the old design and its extended pretty far out. Watching the data on cold and hot starts, the desired and actual pressures are right on . What do you all think ?
We have seen it a few times. It will often trigger fuel pressure faults before cam deviation faults. There is a PID I forget the address. Cam phase deviation. It is represented in degrees of crank rotation. Anything over 6 and you have a stretched chain.
Can you access global obd 2 data and look at mode 6 data for variable cam timing to see how close it is to failing?
You can check for chain stretch by removing round plug in lower timing cover and counting exposed teeth on chain tensioner and also check intake camshaft adaptation with scan tool it should be no more than 5 degrees. See attached document for more info.
Will mode 6 data show how close it is to failing before code setting?
I'm not sure we are a euro only shop and don't have much 0BD2 experience.
Do you have a scan tool that can access global obd 2 ? if so you will be able to see mode 6.
Mode 6 data monitor id $35, test id $80, minimum 2.5degrees kw, maximum 28degrees kw. Very curious what your vehicle shows. This are the specs for the vehicle you are working on.
Not sure what these numbers mean but they don’t seem to match your numbers
Cycle completed = no if you cleared codes test result invalid until monitor runs.
With you saying “The vehicle has 100,000 kms on it ,The tensioner is the old design and its extended pretty far out. ” There is no choice but to doing timing chains. If I see old style tensioner it needs to be changed. If I see a extended tensioner thru the removable timing case plug it needs to be changed. You can see the duty cycle of low side pressure module for in tank pump on a scanner 60%…
Have you looked at mode 6 on this vehicles for that particular problem?
It needs timing chains. We have seen that generation 2.0 set both high/low fuel rail pressure codes at the same time. If you've inspected the timing chain and it's noticeably extended then listen to the dealer.
If that is a flex fuel vehicle, meaning it has an aluminum intake manifold and your chain tensioner is over extended then you need to start with the timing chain repair. That is a pattern failure with a P0088 fault on flex fuel vehicles with chain stretch. Non flex fuel vehicles will run until they either set correlation faults or finally jump time and bend valves.
Yes, the chain was stretched. A very grateful thank you to all who took the time to respond !!!
Got a pic of the top and right chain guides? Are they longer and rapped around chain and sprocket? Really curious for the if they held it together enough not to bend valves. Anytime you see 6 steps of adjuster that is bad! Good Luck