12 replies to this topic

[danyeates]

My NA with a Regal stage 1 map, precat removed, and Courtenay sports air filter is running a bit rough at idle. The revs vary up and down and it vibrates a lot. It has also had a few problems starting as well, it has started and spluttered and died, then it wouldnt start for a while. It does start in the end, but its a bit of a pain. It runs ok and still performs fine it's just not very nice to sit in when it's idleing roughly. Also the other day when I fired it up there was no response from the accelerator, it didnt do anything just idled. There was also the engine light on on the dash. I turned it off and back on and it was fine. I think it may have been a loose connection on the pot on the accelerator and probably unrelated to the previous problem. This has only happened once.

[johnaachen]

accelerator pedal or MAF sensor

[danyeates]

going to take the plugs out next time i'm back at my parents, will check the MAF sensor

[christurbo]

Yep accelerator sensor failure defo. Do a search on me for more info - but... You need to unclip, clean, and re establish a good connection on the bus connectors on the following locations:- Accelerator sensor - pedal N/S rear wheel arch [by expansion tank] Throttle body Then pull fuse 8 out for 10/20 mins.

[snoopstah]

I didn't think the NAs had a MAF... Second problem is definately accelerator sensor related.

[johnaachen]

I didn't think the NAs had a MAF...

Second problem is definately accelerator sensor related.

All modern engines have a MAF (Mass Air Flow meter) so that teh engine knows how much air is coming into teh engine and therefore how much fuel to inject

[RichH]

Is that different from the AMM on the turbo?

[johnaachen]

okay you guys call it an AMM (Air Mass Meter) its the same thing just different name. It measures in kg/s and is the mass of air into the engine per second. These sensors normally have a temperature sensor as well so the ECU can adjust whatever calcualtions it does to estimate the volume of air into the engine.......

[snoopstah]

Most NA engines don't have a MAF/AMM/whatever you want to call it. They use a MAP sensor which measures exhaust pressure (I believe), and are a lot more reliable. My understanding is that the 2.2 is one of the many that don't have a MAF sensor - hence why you can use induction kits.

[Bakazan]

I get similar problems - if there is an AMM / MAF how were you going to test it? I thought the problem may be related to the EGR valve. Is this a variable control valve or just a shut off valve? Can it be tested without specialist equipment?

[speedster]

My NA with a Regal stage 1 map, precat removed, and Courtenay sports air filter is running a bit rough at idle. The revs vary up and down and it vibrates a lot. It has also had a few problems starting as well, it has started and spluttered and died, then it wouldnt start for a while. It does start in the end, but its a bit of a pain.

With vibes at idle its sounds like a fuel or DIS pack problem.

AFAIK at idle the throttle pedal sensor is not in play, the ECU is programmed to hold the throttle open a few % on idle. Do check the actual throttlebody pots (2 of) and throttlebody main connector though.

The MAP sensor which all NA use can also be a factor. Its function is to measure air pressure at the intake manifold point. I replaced a faulty MAP a while back - One good indicator of a faulty MAP sensor is high fuel consumption and jerky throttle response. In some cases a faulty MAP sensor appears not to throw a MAP specific DTC, in my case I got an O2 sensor code.

The primary O2 sensor is can also be a culprit as can the crank sensor, but these should throw sensor specific DTC's so your EML will be on.

I had one (crazy) instance where the fuel cut-off switch was faulty. This meant the fuel pump was running intermittenly and therefore fuel pressure was all over the place and the car was running very bad.

Basically outside of Wide Open Throttle there's a bunch of things that the ECU utilises to maintain good fuelling. If your near a dealer they can use their computer systems to run a full sensor and fuel pressure check, sometimes the quickest and cheapest route to the problem.

Edited by speedster, 14 May 2006 - 06:25 PM.

[johnaachen]

Most NA engines don't have a MAF/AMM/whatever you want to call it. They use a MAP sensor which measures exhaust pressure (I believe), and are a lot more reliable.

My understanding is that the 2.2 is one of the many that don't have a MAF sensor - hence why you can use induction kits.

It measures intake air pressure not exhaust

[speedster]

Most NA engines don't have a MAF/AMM/whatever you want to call it.  They use a MAP sensor which measures exhaust pressure (I believe), and are a lot more reliable.

My understanding is that the 2.2 is one of the many that don't have a MAF sensor - hence why you can use induction kits.

It measures intake air pressure not exhaust

MAF's or AMM's are a different type of sensor to a MAP senor. The turbo ECU is probably more fussy about the air volume reading hence the use of a AMM whilst the humble NA is happy with simple air intake pressure readings.