Sapph 4x4 Misfire...Any Suggestions???
19-07-2004, 05:56 PM
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Sapph 4x4 Misfire...Any Suggestions???
Stage 3, T34 4x4 IC, NGK 9's @ .65mm.
Symptoms are as follows:
Drives ok upto 4400rpm.
Turbo comes in fine at around 3000rpm.
Then the engine splutters and will not accelerate beyond the 4400rpm. It pops and spits and splutters.
Tried following other parts for fault diagnosis:
Map Sensor
Phase Sensor (Gap Checked)
TDC Sensor (Gap Checked)
Ignition Amp
ECU Chip
Anybody got any idea's of anything else i could check.
or better still, anyone had this same problem???
Cheers
Symptoms are as follows:
Drives ok upto 4400rpm.
Turbo comes in fine at around 3000rpm.
Then the engine splutters and will not accelerate beyond the 4400rpm. It pops and spits and splutters.
Tried following other parts for fault diagnosis:
Map Sensor
Phase Sensor (Gap Checked)
TDC Sensor (Gap Checked)
Ignition Amp
ECU Chip
Anybody got any idea's of anything else i could check.
or better still, anyone had this same problem???
Cheers
19-07-2004, 07:34 PM
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Dave,
Thanks for the reply.
Not sure about off load. It doesn't seem to matter whether you feed the throttle in slowly at around 3000rpm of Open it fully up, once it hits 4400 off it pops...
Might me worth me trying it again, with no boost at all to see if it'll rev over 4400rpm smoothly.
Although the boost was slowly increased from 10psi upto 16 its at now, and it made no difference...
Dont think its a Split hose, as they are all new Samco's. And ive looked at them only yesterday.
Fuel Reg.
No idea.
Would these be similar symptoms of a failure?
How can i check if it is this?
I have a Fuel Pressure gauge mounted under the bonnet fro setting idle, perhaps i should extend it into the car so i can see when its popping and banging???
Thanks for the reply.
Not sure about off load. It doesn't seem to matter whether you feed the throttle in slowly at around 3000rpm of Open it fully up, once it hits 4400 off it pops...
Might me worth me trying it again, with no boost at all to see if it'll rev over 4400rpm smoothly.
Although the boost was slowly increased from 10psi upto 16 its at now, and it made no difference...
Dont think its a Split hose, as they are all new Samco's. And ive looked at them only yesterday.
Fuel Reg.
No idea.
Would these be similar symptoms of a failure?
How can i check if it is this?
I have a Fuel Pressure gauge mounted under the bonnet fro setting idle, perhaps i should extend it into the car so i can see when its popping and banging???
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22-07-2004, 05:32 PM
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Wastegate is ok 
I decided to run it up on Axle stands to check with No Boost if it still Misfired.
No...
Redline through all the gears
Ive also Earthed The Plenum and the Ign. Amp straight from the Battery as i have read STU say in another post about doing this for misfires...
I'll have to road test it again in a day or two.
I decided to run it up on Axle stands to check with No Boost if it still Misfired.
No...
Redline through all the gears
Ive also Earthed The Plenum and the Ign. Amp straight from the Battery as i have read STU say in another post about doing this for misfires...
I'll have to road test it again in a day or two.
22-07-2004, 05:41 PM
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you didnt need to put it on axle stands though, just revv it in neutral to see if it would clear above 4K.
my bet is weak ignition ( plugs, leads or coil) as it only appears to collapse the spark when loaded up.
let us know how the road test goes wih the extra earth and stuff though.
my bet is weak ignition ( plugs, leads or coil) as it only appears to collapse the spark when loaded up.
let us know how the road test goes wih the extra earth and stuff though.
22-07-2004, 06:12 PM
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Thing is, I only put it on Axle stands and drove the wheels as it did not misfire when in neutral.
I wonder if it could be the leads. They are the originals...
As i have a Brand New Coil and Brand New NGK 9's
I wonder if it could be the leads. They are the originals...
As i have a Brand New Coil and Brand New NGK 9's
02-08-2004, 07:55 PM
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Update:
Changed the plug leads today for 909 Blue Motorsport ones.
and Earthed from Battery Ignition Amp and straight to plenum....
Only difference was it still misfired at 4400rpm but would splutter through up about 5200rpm.
Still not really any better.
Ive just CUT
all 3 connectors from the back of the loom off completely and resoldered them. Im REALLY hoping thats all it was (as its been suggested on here several times for a cure to misfires), but to be honest im not convinced as the plugs and contacts inside looked absolutely fine with no corrosion at all....
If anyone has any other idea's....
Please say so....
Changed the plug leads today for 909 Blue Motorsport ones.
and Earthed from Battery Ignition Amp and straight to plenum....
Only difference was it still misfired at 4400rpm but would splutter through up about 5200rpm.
Still not really any better.
Ive just CUT
all 3 connectors from the back of the loom off completely and resoldered them. Im REALLY hoping thats all it was (as its been suggested on here several times for a cure to misfires), but to be honest im not convinced as the plugs and contacts inside looked absolutely fine with no corrosion at all....If anyone has any other idea's....
Please say so....
02-08-2004, 09:20 PM
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Will do.
Doubt i'll get a chance to drive until next week now, but i'll post with every change i do and the result for anyone else who is or might be in the same position....
Doubt i'll get a chance to drive until next week now, but i'll post with every change i do and the result for anyone else who is or might be in the same position....
02-08-2004, 10:10 PM
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Nope afraid not 
It already had the original BERU leads, so i tried a set of 909's....
With the 909's it will go over the 4400rpm albeit misfiring, but with the standard leads it wont
It already had the original BERU leads, so i tried a set of 909's....
With the 909's it will go over the 4400rpm albeit misfiring, but with the standard leads it wont
12-08-2004, 10:25 AM
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Hopefully if the suns comes out, i'll try and see if its fixed in the next few days.
Trouble is, to do fault finding that'll help others you need to check one part at a time until you find the fault. As i dont have alot of time to work on my car when i do, i have to do as much as i can.
Its ready to be roadtested again.
So far, ive cut off the connectors at the back of the loom and soldered them direct.
put the original BERU leads back on in place of the 909's.
Cleaned the rotor arm.
All i need to now is drive it on the road and see if there's any difference.
If not, ( ) then i'll have to try changing some parts.
Will post with findings as soon as i can...
Trouble is, to do fault finding that'll help others you need to check one part at a time until you find the fault. As i dont have alot of time to work on my car when i do, i have to do as much as i can.
Its ready to be roadtested again.
So far, ive cut off the connectors at the back of the loom and soldered them direct.
put the original BERU leads back on in place of the 909's.
Cleaned the rotor arm.
All i need to now is drive it on the road and see if there's any difference.
If not, (
) then i'll have to try changing some parts.Will post with findings as soon as i can...
13-08-2004, 10:53 AM
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Update:
Managed to take it for a quick blast....
No different. 4400rpm it just coughs and splutters.
Ive tried another ACT sensor, ive put the BERU's back on.
soldered the connectors on the rear of the loom.
However, one thing.... If you use the throttle lightly (and i mean REALLY lightly) you can get it to go through the spit/cough stage and onto the redline...
Does that give anyone any more suggestions?
Managed to take it for a quick blast....
No different. 4400rpm it just coughs and splutters.
Ive tried another ACT sensor, ive put the BERU's back on.
soldered the connectors on the rear of the loom.
However, one thing.... If you use the throttle lightly (and i mean REALLY lightly) you can get it to go through the spit/cough stage and onto the redline...
Does that give anyone any more suggestions?
13-08-2004, 01:58 PM
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Not quite sure from the posts whether you actually check the fuel pressure. It does sound like a fuel pressure regulator problem, the favorite is when people think it's a good idea to remove the solder plug and wind in the grub screw, this penetrates the diaphram and hey presto she is knacked.
HTH
HTH
13-08-2004, 02:03 PM
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I have a mechanical gauge under the bonnet.
Perhaps i'll extend it into the engine bay just for a quick run to see if there's any problems there.
Perhaps i'll extend it into the engine bay just for a quick run to see if there's any problems there.
13-08-2004, 02:52 PM
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when was the last time the timing belt was done ? could be a tooth out and when not accelerating hard the advance/retard in the ecu is not coming into play and so not becoming apparent?
13-08-2004, 03:12 PM
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was it ok beofre that......?
a VERY common mistake it to time it up to the groove in the bottom pulley at TDC, and not the post next to the groove as it should be. its an easy check. get the cam belt cover off. dizzy cap off and the rotor arm should lie in the mliddle of the scribed mark on the dizzy edge, the 2 top pulleys should point their pointer exactly towards each other and the bottom pulley should point the post (next to the goove) at the TDC mark on the block (looking down from above the engine)
a VERY common mistake it to time it up to the groove in the bottom pulley at TDC, and not the post next to the groove as it should be. its an easy check. get the cam belt cover off. dizzy cap off and the rotor arm should lie in the mliddle of the scribed mark on the dizzy edge, the 2 top pulleys should point their pointer exactly towards each other and the bottom pulley should point the post (next to the goove) at the TDC mark on the block (looking down from above the engine)
13-08-2004, 03:19 PM
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Thanks for the reply.
It has been ok since that....
Then one day developed this fault.....
and as of yet ive not been able to trace it down.
It is timed to the TDC post and not the 16deg timing mar.
It has been ok since that....
Then one day developed this fault.....
and as of yet ive not been able to trace it down.
It is timed to the TDC post and not the 16deg timing mar.
11-09-2004, 08:52 AM
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Update...
Ive just taken it for a drive and read the Fuel Pressure whilst doing so.
Fuel Pressure is fine at idle (3.3bar)
Under Full Throttle, Boost climbes towards its 15psi, Fuel Pressure rises to just under 5Bar.
The fuel pressure climbs steadily until it reaches about 4.9bar then the needle twitches around 4.9 and 5bar....
Im not sure what this means....
Ive just taken it for a drive and read the Fuel Pressure whilst doing so.
Fuel Pressure is fine at idle (3.3bar)
Under Full Throttle, Boost climbes towards its 15psi, Fuel Pressure rises to just under 5Bar.
The fuel pressure climbs steadily until it reaches about 4.9bar then the needle twitches around 4.9 and 5bar....
Im not sure what this means....
11-09-2004, 09:10 AM
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fuel pressure sounds fine
i had your problems but a new fuel reg sorted this out
ill rack my brains and try to think of anything else that could be causing the prob
i had your problems but a new fuel reg sorted this out
ill rack my brains and try to think of anything else that could be causing the prob
11-09-2004, 11:56 AM
#35
Hi,
Sorry, seem to have missed this topic
This sounds imidiately to me from reading post one like a Phasing error between cam and crank sensors. Dave has kindly told you how to check it, and ive highlighted the important part you need to check.
Check this is fine before proceedeing any further as the phasing correlation becomes of huge importance to Marelli around the 4K engine speed area. Best of luck.
P.S.
Im presuming here that the crank and cam sensors have been checked/changed?
Sorry, seem to have missed this topic
This sounds imidiately to me from reading post one like a Phasing error between cam and crank sensors. Dave has kindly told you how to check it, and ive highlighted the important part you need to check.
Originally Posted by Dave Henshall
get the cam belt cover off. dizzy cap off and the rotor arm should lie in the mliddle of the scribed mark on the dizzy edge, the 2 top pulleys should point their pointer exactly towards each other and the bottom pulley should point the post (next to the goove) at the TDC mark on the block (looking down from above the engine)
P.S.
Im presuming here that the crank and cam sensors have been checked/changed?
11-09-2004, 01:56 PM
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I'll triple check the phase and CAS correlation but i have done it before, and am pretty sure its right.
Could the ECU be at fault? Just wondered as ive not checked this.
Is there anybody who can Test Ecu's???
Could the ECU be at fault? Just wondered as ive not checked this.
Is there anybody who can Test Ecu's???
11-09-2004, 02:37 PM
#37
Also check the phase sensor is plugged in correctly.
The wire nearest the top of the unit, goes to the pin on the plug nearest to the sensor. If that makes sense?
ECU testing is never great on marelli, so easiest way to do it is to find a member whos willing to let you try your ecu in their car for 5 mins. Should be simple enough to find one.
The wire nearest the top of the unit, goes to the pin on the plug nearest to the sensor. If that makes sense?
ECU testing is never great on marelli, so easiest way to do it is to find a member whos willing to let you try your ecu in their car for 5 mins. Should be simple enough to find one.
11-09-2004, 03:44 PM
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Originally Posted by Stu @ M Developments
The wire nearest the top of the unit, goes to the pin on the plug nearest to the sensor. If that makes sense?
