So after replacing the knocker sensors, got the h2 back from the garage, and the power was really bad. If I put my foot down, NOTHING happened. You had to drive it really gingerly to get to move. The garage told me there was now a fault with the EMS. So they found a new unit, and fitted and reprogrammed it. However, still it is not great, yet they claim this is correct? The problem? If you go from stand still and press the gas pedal 40-50% it will hesitate for a split second, and then go. it accelerates seemingly OK, (makes lots of noise like it always has! I bought new in 2006). But if you floor it, maybe needing to really move fast, out of a junction etc....nothing happens! It doesn't move! You have to ease off and then will. This is surely not right, and certainly not how it used to drive. I am lost when it comes to EMS. I don't trust anyone in this place (Dubai) as they all lie. Can anyone shed any light? Could I get a NEW EMS and have it programmed as per factory? So it;'s all like it was? Or can I get this one re-programmed. The garage told me they used some company in Germany, that tunes them, they connect their computers to each other and pay for the tune and it uploads. All sounds pretty rubbish to me, and is clearly not doing the job? Can I buy the interface, and download a program etc? ANY help at this stage would be really helpful, as it's ruined my experience of the car I love and drive daily. Many thanks indeed

 

maybe check your throttlebody and pedal for flat spots in the curve. have someone slowly press the pedal while watching the throttlebody butterfly. also make sure the throttlebody is clean. a good scan tool would show these curves while viewing live data. also make sure there is no air leak between the MAF and throttlebody and since they had to remove the intake make sure there are no air leaks.

 

thanks so much @bronxteck really helpful. I think they did this, as they also cleaned the injectors. Today for instance I got in, and just on and in park, if I slowly press the gas, the revs go up as expected. If I floor it quickly, then equally the revs shoot up, lots of noise, again as expected, and all seems normal. If however I floor it whilst in drive, from standstill, nothing. It waits around, so I actually have to lift off or decrease the gas pedal to around 40-50% and then something happens. Once I am rolling, 15-20mph, if I floor it, then it changes down, revs shoot up and it flies, well as much as a hummer h2 would! So it really seems the problem is only from standstill, and seeing that the EMS has been reprogrammed, my powers of deduction would point in this direction. Given the new info, would you concur. I will of course check all you suggested, I am very grateful. Thanks mate

 

Throttle Body Cleaning with Throttle Body Cleaner only is a maintenance item every 30-50k miles. When was the last time you cleaned your Throttle Body?

 

Hey @Doc Olds it was cleaned a few months ago, but I might simply 'do it myself' again, and the MAF, and check TPS etc.....cannot rely on garages here! but also its 120 degrees so working on the car outside is a little roasty!

 

Use only the correct products, use MAF Cleaner on the MAF and Throttle Body Cleaner on the TB. You should also get yourself a can of CRC Electronics Cleaner if you do not already have one. Clean the connectors to the TB, MAF and Accelerator Pedal.

Keep in mind, in extreme heat your ECM is going to retard timing as a programmed strategy to reduce risks of overheating and you will notice that as reduced performance.

Good luck.