rich, cutting out at 4500 rpm, guru chipped
03-11-2005, 09:05 PM
#1
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rich, cutting out at 4500 rpm, guru chipped
ohhh... I got a problem.
Friends 944 turbo, an 86, fitted with 3.0 bar fpr, guru (promax chips), acuboost controller, external boost guage, shimmed wastegate.
symtoms, the car seems to be running really rich... under accelloration its smoking grey smoke, which makes the eyes of people driving behind me start streaming and smells of fuel. hit 4500 at full throttle and its like overboost protection, as if I have let off the throttle and hit the brakes... feather the throttle and you can drive right through 4500 to the redline, even with boost.
Have fitted a VDO boost guage, turned down the boost (its only making 10psi above atmospheric) and it still does the same thing..
Bypassed the cycling valve, as I thought it may be faulty... ran the accuboost direct to the wastegate, plugged the other pipe to the cycling valve at the intake boot (the one with the bypass valve)... still no better...
Put a multimeter onto the klr pins 22 and 23 to check the throttle sweep, it had some black spots, so I took it apart and diagnosed the wipers not contacting the tracks very well, so stripped the unit down and bent the arms in a little to increase pressure on the track... it now sweeps within range as per the workshop manual, so refitted it... same symptoms..
checked opperation of the idle contact at the DME, all is good.
replaced all the vacuum hoses... still not good
replaced the bypass valve with a 993 twin turbo item... still no good
Checked all the pipes for cracks, replaced a couple of them,.... still no good,
The engine on this car isnt perfect, is it possible that the knock sensors are hearing mechanical noises in the engine and reporting it as knock? would this make sense? if so, how to I check??
have plugged in an LED to the diag plug, no codes blink, unless I force on by disconnecting the tps...
So what does everyone think????
HELP!!!
Friends 944 turbo, an 86, fitted with 3.0 bar fpr, guru (promax chips), acuboost controller, external boost guage, shimmed wastegate.
symtoms, the car seems to be running really rich... under accelloration its smoking grey smoke, which makes the eyes of people driving behind me start streaming and smells of fuel. hit 4500 at full throttle and its like overboost protection, as if I have let off the throttle and hit the brakes... feather the throttle and you can drive right through 4500 to the redline, even with boost.
Have fitted a VDO boost guage, turned down the boost (its only making 10psi above atmospheric) and it still does the same thing..
Bypassed the cycling valve, as I thought it may be faulty... ran the accuboost direct to the wastegate, plugged the other pipe to the cycling valve at the intake boot (the one with the bypass valve)... still no better...
Put a multimeter onto the klr pins 22 and 23 to check the throttle sweep, it had some black spots, so I took it apart and diagnosed the wipers not contacting the tracks very well, so stripped the unit down and bent the arms in a little to increase pressure on the track... it now sweeps within range as per the workshop manual, so refitted it... same symptoms..
checked opperation of the idle contact at the DME, all is good.
replaced all the vacuum hoses... still not good
replaced the bypass valve with a 993 twin turbo item... still no good
Checked all the pipes for cracks, replaced a couple of them,.... still no good,
The engine on this car isnt perfect, is it possible that the knock sensors are hearing mechanical noises in the engine and reporting it as knock? would this make sense? if so, how to I check??
have plugged in an LED to the diag plug, no codes blink, unless I force on by disconnecting the tps...
So what does everyone think????
HELP!!!
03-11-2005, 09:08 PM
#2
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well everything youve checked would've been the reason why youve been running rich but youve fixed them all.i say bad set of chips.just send back the chips and get a new set.
03-11-2005, 09:26 PM
#3
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Did this just start when you installed the chips? If so, then I'd check if it drives properly with stock chips. (To isolate it to the chips)
The TPS is not really supposed to be serviceable, so I'd wonder about taking it apart like that. Probably ok if it sweeps right on a multimeter.
A turbo car that can be feathered to redline, but can't be floored to redline, always makes me question the ignition. I've had this happen in several different turbo cars, including the 951. When did you last change the plug wires? the cap and rotor? the plugs? (It seems rich because the fuel is not being burned.) The heat under the hood of a turbo car seems to be particulalry hard on plug wires.
The TPS is not really supposed to be serviceable, so I'd wonder about taking it apart like that. Probably ok if it sweeps right on a multimeter.
A turbo car that can be feathered to redline, but can't be floored to redline, always makes me question the ignition. I've had this happen in several different turbo cars, including the 951. When did you last change the plug wires? the cap and rotor? the plugs? (It seems rich because the fuel is not being burned.) The heat under the hood of a turbo car seems to be particulalry hard on plug wires.
03-11-2005, 09:29 PM
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One thing I have not checked, the air flow meter...
Just in case someone has opened it up and moved the spring around a couple of notches, is there any way of checking its set right? such as a reference voltage or resistance level it should be at when the flap is opened by set amounts??
I hope its not the chips, that would mean that I have been chasing my tail for nothing for the last few days! (having said that, I have been finding lots of faults that needed sorting out anyway)
Just in case someone has opened it up and moved the spring around a couple of notches, is there any way of checking its set right? such as a reference voltage or resistance level it should be at when the flap is opened by set amounts??
I hope its not the chips, that would mean that I have been chasing my tail for nothing for the last few days! (having said that, I have been finding lots of faults that needed sorting out anyway)
03-11-2005, 09:41 PM
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I was worried about the ignition side myself, so have replaced the cap and rotor, the plugs are also new.. but not the leads.
If it was just going rough at full throttle and 4500 rpm, I would suspect the leads even more than I do at the moment... but it really does loose all power, like a switch being thrown, let off the throttle and its ok again.
I have another friend with a 944 turbo, his had a sticking wastegate, but that car behaved differently to this car... with his, when it got the overboost comming in, it would run rough until you switched it off and back on again... this car is ok as soon as you let off the gas.. but it will not make it past 4500 - 5000 rpm at full throttle, no matter what you do...
My friend who owns this car had the engine blow up, the specialists who fitted the replacement engine (used) also fitted the chips, shims and accuboost at the same time.. and its been doing this ever since... So I am unsure if they have messed with something, have not set something up properly, or if something was damaged in the engine swap..
I think he was robbed... this engine although sounds ok, takes a while to get oil pressure first thing in the morning (4 to 10 seconds sometimes), and does not sound as silky smooth as my lux.. which is why I thought it may be a knock sensor hearing a rattle at 4500 rpm and shutting something down (is this what the knock sensors will do?? wouldnt I get a blink code?)
If it was just going rough at full throttle and 4500 rpm, I would suspect the leads even more than I do at the moment... but it really does loose all power, like a switch being thrown, let off the throttle and its ok again.
I have another friend with a 944 turbo, his had a sticking wastegate, but that car behaved differently to this car... with his, when it got the overboost comming in, it would run rough until you switched it off and back on again... this car is ok as soon as you let off the gas.. but it will not make it past 4500 - 5000 rpm at full throttle, no matter what you do...
My friend who owns this car had the engine blow up, the specialists who fitted the replacement engine (used) also fitted the chips, shims and accuboost at the same time.. and its been doing this ever since... So I am unsure if they have messed with something, have not set something up properly, or if something was damaged in the engine swap..
I think he was robbed... this engine although sounds ok, takes a while to get oil pressure first thing in the morning (4 to 10 seconds sometimes), and does not sound as silky smooth as my lux.. which is why I thought it may be a knock sensor hearing a rattle at 4500 rpm and shutting something down (is this what the knock sensors will do?? wouldnt I get a blink code?)
03-11-2005, 09:48 PM
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with the TPS, i knew this one wasnt working correctly (it seemed to have a blind point (open circuit) around idle and again at 75% open.) so I had nothing to loose... it came apart quite easily, and is remarkably like an AFM inside... so I applied the same repair (bodge, kludge,,, call it what you like! 
) that I have to my AFM in my lux... now its back together, it seems to work fine and seems to opperate how it should, without a blind spot.
So.. not a servicable item... but what the heck, it was screwed up anyway, nothing to loose... will probably replace it anyway, as it may be ok now, but on a late raining evening, just when my friend needs the car, will probably be the time when my amazing repair decides to turn into a exploding parts diagram of its own..
) that I have to my AFM in my lux... now its back together, it seems to work fine and seems to opperate how it should, without a blind spot.So.. not a servicable item... but what the heck, it was screwed up anyway, nothing to loose... will probably replace it anyway, as it may be ok now, but on a late raining evening, just when my friend needs the car, will probably be the time when my amazing repair decides to turn into a exploding parts diagram of its own..
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03-11-2005, 11:52 PM
#8
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I had a very simialar problem - turned out ot be a bad plug wire. I spent a lot of time and some money too, chasing that problem. The wire looked good on the outside but had a shaky contact between the wire core and the little clip that attaches to the plug. I didn't have the smoke you have tho...Bruce
03-12-2005, 01:29 AM
#9
Nordschleife Master
10psi on chips mapped for probably ~15psi will not work very well, you will run rich.
Turn up the boost to where it should be and see how it runs!
If you still have problems, revert back to stock chips and FPR and see if your problem dissapears.
Turn up the boost to where it should be and see how it runs!
If you still have problems, revert back to stock chips and FPR and see if your problem dissapears.
