101sean Posted August 18, 2009 Share Posted August 18, 2009 Trying to get to the bottom of why my brother in law's 2005 130 is down on power, hard acceleration is really sluggish. The intercooler has been flushed and oily injector loom changed. Connected it to my Nanocom (no faults found) to record fuelling and compare it with mine. Would be grateful for opinions on what I found. 2005 130 TD5, standard , nothing binned (yet ) Air flow idle 40 - 50, 3000 revs 280 - 350 Max boost 190 - 200 (struggles to get there!) Wastegate modulator 40% @ around 150 boost 2000 110 Td5, centre box removed, no EGR, ITG filter, standard tune, goes very well. Air flow idle 20 - 30, 2500 revs 160 - 180 (seems low?) Max boost 205 consistently Wastegate modulator 25% from 160 - 190 boost. The graphic views of the two look compltely different All other readings look fairly consistant. Quote Link to comment Share on other sites More sharing options...
Philip Tonkin Posted August 20, 2009 Share Posted August 20, 2009 I don't understand your numbers for boost? WHen you say 190 do you mean 19psi? decipounds per square inch perhaps? Quote Link to comment Share on other sites More sharing options...
101sean Posted August 20, 2009 Author Share Posted August 20, 2009 kPa, it's the units the Nanocom puts out. ~100kPa is atmospheric pressure (think that's correct!) Anyway, pulled plug on the MAF, and it flies! Going to stick another in or swap it with mine and try again. Didn't initially think it was the MAF as it's showing right figures at idle. Quote Link to comment Share on other sites More sharing options...
110WestCape Posted August 21, 2009 Share Posted August 21, 2009 kPa, it's the units the Nanocom puts out. ~100kPa is atmospheric pressure (think that's correct!) Anyway, pulled plug on the MAF, and it flies! Going to stick another in or swap it with mine and try again. Didn't initially think it was the MAF as it's showing right figures at idle. I have noticed a decrease in turbo lag on mine as well when the MAF sensor is unplugged. Would like to know what purpose the MAF has when the EGR is blanked off ? Any effect on the ECU and pulses to the injectors perhaps? Any known consequences if the MAF is disconnected permanently ? Cheers Wikus Quote Link to comment Share on other sites More sharing options...
Philip Tonkin Posted August 23, 2009 Share Posted August 23, 2009 The MAF tells the ECU how much air is being put into the engine, without it how would it know how much fuel to use. The EGR has nothing directly to do with this as the recirculated air entered the plenum after the MAF Quote Link to comment Share on other sites More sharing options...
101sean Posted August 23, 2009 Author Share Posted August 23, 2009 Without the MAF connected, the ECU uses default values so is partly guessing how much fuel to inject. You may get excessive fuel consumption and black smoke. Quote Link to comment Share on other sites More sharing options...
110WestCape Posted August 24, 2009 Share Posted August 24, 2009 okay ..... The quantity of fuel injected would be a function of a potentiometer signal. If the accelerator is pushed in, the potentiometer would send a signal to the ECU regarding its position on a "map" which would influence fuel delivery into the injection chambers. I assume that actual airflow is measured via the MAF and converted to a a calculation by the ECU. In the event of the absence of the MAF information it seems to revert to a default air/fuel mixture map. This would enable the engine to run near normal but not optimised for actual fuel & air mixture. This could cause over or under fuelling relevant to the demand vs actual airflow. I disconnected the MAF this weekend and did a +- 120 km trip. The increase in power at pull away is noticeable and thereafter seems to be a decrease in performance. The TD5 struggled somewhat on inclines. I'll try to clean the MAF filaments with surgical alcohol and see if it is okay ..... else it's a new MAF I suppose. Quote Link to comment Share on other sites More sharing options...
Philip Tonkin Posted August 24, 2009 Share Posted August 24, 2009 okay ..... The quantity of fuel injected would be a function of a potentiometer signal. If the accelerator is pushed in, the potentiometer would send a signal to the ECU regarding its position on a "map" which would influence fuel delivery into the injection chambers. I assume that actual airflow is measured via the MAF and converted to a a calculation by the ECU. In the event of the absence of the MAF information it seems to revert to a default air/fuel mixture map. This would enable the engine to run near normal but not optimised for actual fuel & air mixture. This could cause over or under fuelling relevant to the demand vs actual airflow. I disconnected the MAF this weekend and did a +- 120 km trip. The increase in power at pull away is noticeable and thereafter seems to be a decrease in performance. The TD5 struggled somewhat on inclines. I'll try to clean the MAF filaments with surgical alcohol and see if it is okay ..... else it's a new MAF I suppose. Make sure you get a genuine MAF, some of the replacements on ebay give dodgy figures Quote Link to comment Share on other sites More sharing options...
Andrew Chua Posted August 25, 2009 Share Posted August 25, 2009 yes, you can run a Td5 without the MAF sensor connected. The ECU uses the default value, hence you'll get black smoke on harsh acceleration. no harm will be done to the engine, i've taken mine off for over 9mths before i got it replaced. cleaning the filaments on the MAF? not a good idea. be very very very careful, they are super easy to break. it's a like an old light bulb, one the filaments are old, they break easily. invest in a new one will solve your headaches. Quote Link to comment Share on other sites More sharing options...
110WestCape Posted August 25, 2009 Share Posted August 25, 2009 New MAF is on order. I managed to clean the filaments with a cotton bud and surgical alcohol. Although there was no dirt visible I still managed to clean some stuff off it. Some have said that a thin film of an oily substance accumulates on the filaments over time which causes them to provide incorrect readings. This can be removed with a non corrosive solvent that leaves no residue. It tested okay but would like to run it a bit more before I can confirm if its sorted or not. Cheers Wikus Quote Link to comment Share on other sites More sharing options...
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