Fuel injection problem?

[Broken G60 0]

Dear All,

 

Please can anyone help me with my 1992 J reg G60? I have just spent £1,300 having the block skimmed and the gearbox rebuilt, but I am having a number of problems. I got my brother, who is a mechanic, to coordinate getting all the work done, but my car is still suffering from the following problems, and he isn't sure what to do next.

 

Problems:

 

i. HIgh petrol consumption;

ii. Car stinks of petrol when in use;

iii. Erratic tick-over/idle revs;

iv. When the throttle is fully opened, the engine takes around 20 seconds to return to a normal idle rev range; and

v. The car appears to have no power; fully depressing accelerator makes the revs increase slowly, but with seemingly very little increase in power.

 

My brother tried soaking the ISV overnight in some cleaning product and replaced the throttle cable, to no effect. He showed me that the throttle cable was closing completely okay, so presumably that isn't wasn't the problem. He also replaced the water temperature sensor switch, although that might have been to fix a different problem.

 

Also, please can anyone tell me what the sensor on the boost tube between the intercooler and the air inlet manifold does please?

 

Thanks for your time.

[dr_mat 0]

Does sound like you might have bad injectors or a fuel supply problem. Have you checked all the fuel lines for leaks? I hear that a common problem on G60s is a leaky fuel line to the injector rail under the bonnet.

[Supercharged 2]

Sounds like a combination of a few probs... fuel leak, faulty ISV maybe a vacumn leak and possibly timing is out

[Banana Man 0]

Have a look on the back of the throttle body there is a micro switch on the back if this has got bent and isn't making contact when the throttle is in it's neutral position that will cause most of your problems. I had this one a while back and was getting the same syptoms high fuel consumption, revs taking ages to settle back down and the car feeling really sluggish.

[Broken G60 0]

Gentlemen,

 

Thank you very much for your help. Particularly big respect & thanks to Banana Man, I did indeed have a bent micro switch. This has solved the problem of revs returning slowly to idle and now the car smells of petrol a lot less. I now just need to work out why there seems to be a lack of power and a high fuel consumption. According to my brother the fule lines weren't leaking. I tried testing the boost pressure. I had a read of 670 at idle and 1730 at redline in 3rd. As far as I can tell from http://the-corrado.net/.archive/forum/viewtopic.php?t=8800 this seems about right. I think my brother is suggesting a trip for the car to a local garage staffed by ex-VAG staff to see if they can come up with anything.

 

Thanks again!

[GazzaG60 0]

get a AF gauge if you havent got one. sounds like the o2 probe may be tired. also the blue temp switch may not be giving the correct signal to tell the engine to drop enrichment.

 

A stretched/sticky throllte cable can also cause problems with the idle.

 

The sensor on the boost tube is the CO_Pot. it measures inlet temperature and corrects fueling to the set values. the CO_pot has a default setting of around 450-500ohm. set it to this. To do this connect a multimeter to the 2 outer pins on the sensor. the middle is for temp. take it off the tube first its easier then.

 

replace the hose from the throttle body to the ECU. it must be 1m long. get it from the dealer so the materials are the same as factory spec. its the cloth covered tube.

[andrewdowd 0]

yea i had a faulty blue temp sensor that caused my g60 not to run and it foulded up the plugs with fuel, when it did run it was sluggish at low revs but boy didnt she go when she was wound up!! :wink: !

[Broken G60 0]

Back again!

 

Unfortunately I have already had the blue temperature sensor and throttle cable replaced, so hopefully it isn't an issue with either of those two.

 

Next thing to try is apparently is to remove the cat and see if that helps.

 

Thanks.

[Henny 0]

Just picking up on something you said in your first post Broken G60... You had your BLOCK skimmed?!? Surely you mean your head? If not, then I dread to think why you'd ever skim (or how you'd even skim!) a cast Iron block!

 

I take it you've checked the obvious things like the ends of the fuel lines aren't torn/worn/ porus and that all of the injector seals are OK. Also that the Fuel Pressure Regulator (FPR) is bolted on to the end of the fuel rail properly and that the fuel pressure switch on the other end of the rail is also OK....

 

After that lot, I'd look at getting a new Lambda sensor if it still smells of fuel, making sure that your cam-belt is timed up properly (ie, you're not a tooth out on the camshaft pulley or similar) and that the vacuum hose from the throttle body to the ECU is OK and exactly 1meter long and all of the other vacuum hoses are OK too...

 

If it's anything other than these problems, it's probably worth seeing if you can borrow an ECU off a mate with the same car to see if that makes it any better.... It may also be worth having a look at the earth straps on the engine (one from throttle body to the chassis by the coil, and one from the Gearbox to the chassis and then onto the battery) If these have corroded (gone green) none of your sensors on the engine will be working properly and so willl mess every setting up there is... :|

 

Hope this helps... 8)

[Broken G60 0]

Dear Henny,

 

I've just checked the invoice for the rebuilt and I did indeed have the head, not the block, skimmed. Sorry about that, I'm clearly a muppet. Honestly, I just enjoy driving the car (or at least I used to..) and I don't know much about how it works.

 

I generally get my brother to fix it, but I think he's at the end of his patience. But thanks for giving me your thoughts, I will definitely pass them onto my brother. In case none of that works (or he just bursts into tears & gives up!), could anyone suggest a good garage nearby who might be able to help me? I live in Cambridge. I've checked the sticky on recommended garages and I was thinking using the Lion Garage in Nottingham. I think I'd better get my brother to call them and see if they get involved in mysterious performance problems.

 

Thanks,

 

Sam