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348 DIY "Restoration"
- Thread starter irarref
- Start date
Regarding other things to check, Jeff, not sure if you do this anyway but periodically (as in once every couple of years or so) I go through all my electrical connections and use contact cleaner on them. Also an ECU reset would be a must after running with a duff MAF for a while. Remember the way that's done? Sorry if that's a daft question.
:thumbsup:
Edit: Was the reset done with a bad MAF still in? If so you'll obviously have to do it again with both MAFs good or the ECU relearn may be effected.
Kyodo
Active member
Absolutely. Terrible for the people involved.
Hi,
I have been surfing this forum occasionally for several years and owned a 348 for around 20 years. Understand all the issues you face as I too find the electrics the biggest issue with these cars. Sooooo temperamental. I have always worried about the MAFS and the price of them given they must be similar to others out there for more reasonable prices.
picked this thread up on the other side :-
348 Mass Air Flow sensors available
Discussion in '348/355' started by m.stojanovic, Jan 16, 2019
which does quote alternatives electrically bar some mechanical differences which may be surmountable. These are far cheaper with alternaive makers to BOSCH for reasonable prices on autodoc and the likes.
May be of help to others with a bit of technical/mechanical know how. Seems they are used on some Volvo & SAAB cars
cheers
I have been surfing this forum occasionally for several years and owned a 348 for around 20 years. Understand all the issues you face as I too find the electrics the biggest issue with these cars. Sooooo temperamental. I have always worried about the MAFS and the price of them given they must be similar to others out there for more reasonable prices.
picked this thread up on the other side :-
348 Mass Air Flow sensors available
Discussion in '348/355' started by m.stojanovic, Jan 16, 2019
which does quote alternatives electrically bar some mechanical differences which may be surmountable. These are far cheaper with alternaive makers to BOSCH for reasonable prices on autodoc and the likes.
May be of help to others with a bit of technical/mechanical know how. Seems they are used on some Volvo & SAAB cars
cheers
irarref
Active member
Hi John - thanks for that - I'm on those chats too 
I actually bought one of my MAFS from a SAAB breaker and as well as sending 2 of my MAFS for repair with FIC (Fuel Injection Corporation) Ive ordered an eBay £40 special so I can compare them all.
Will be interesting all the different offerings.
I actually bought one of my MAFS from a SAAB breaker and as well as sending 2 of my MAFS for repair with FIC (Fuel Injection Corporation) Ive ordered an eBay £40 special so I can compare them all.
Will be interesting all the different offerings.
irarref
Active member
My £40 ebay MAF arrived today so just tried it out tonight.
THe quality of the casing etc. as far as I can tell is a match for the original Bosch. The only thing missing is teh little nodule that locates the air box hose on it but TBH thats not required. The other thing I noticed is that the 1st and 6 pins registers 0 ohms rather than 383 ohm etc on the originals.
Here's the MAF installed and like Nicks good MAFS if you disconnect it you can hear the bank go down and then when put back run fine again. I took it for a drive and had no complaints whatsoever
https://youtu.be/N0Wdk4Gocx8
Just ordered another one for £40 - if nothing else theyll be handy to have as emergency spares when I get my Bosch ones back from FIC.
I've also put my fusebox/relay panel back in p0lace after applying some electrical tape to the suspected short and everything appears to be working ok. I'll be doing some more testing tomorrow morning woth a longer drive to check everything works for more than 5 minutes! LOL
THe quality of the casing etc. as far as I can tell is a match for the original Bosch. The only thing missing is teh little nodule that locates the air box hose on it but TBH thats not required. The other thing I noticed is that the 1st and 6 pins registers 0 ohms rather than 383 ohm etc on the originals.
Here's the MAF installed and like Nicks good MAFS if you disconnect it you can hear the bank go down and then when put back run fine again. I took it for a drive and had no complaints whatsoever
https://youtu.be/N0Wdk4Gocx8
Just ordered another one for £40 - if nothing else theyll be handy to have as emergency spares when I get my Bosch ones back from FIC.
I've also put my fusebox/relay panel back in p0lace after applying some electrical tape to the suspected short and everything appears to be working ok. I'll be doing some more testing tomorrow morning woth a longer drive to check everything works for more than 5 minutes! LOL
Sorry Jeff, probably a stupid question but I take it you were able to alter the resistance between pins 1 and 6 to be 383 ohms in order for it to work properly?
irarref
Active member
Hi Pete
The simple answer is "nope" LOL It just worked straight out the box with no adjustment. I'm going to try and find out some more info.
If you check out the manual below (I've done a bit of editing so its just the English) the resistor is to adjust the CO2 and if Iunderstand the thread properly on FChat doesnt affect the signals being sent to the ECU. Not really sure - all I know is it works (see the video above of MAF plugged in vs MAF unplugged). Whether it passes emmissions at MOT time may be another matter.
It will be intersting to see what the car runs like when I get the 2nd ebay one and its running with just 2 ebay ones.
Also, when I get my old ones back from FIC it will be intersting to see whether they have changed the mechanism inside the case - Ive seen comments on FChat that they just replace all the internals so hopefully I'll be able to confirm that.
The simple answer is "nope" LOL It just worked straight out the box with no adjustment. I'm going to try and find out some more info.
If you check out the manual below (I've done a bit of editing so its just the English) the resistor is to adjust the CO2 and if Iunderstand the thread properly on FChat doesnt affect the signals being sent to the ECU. Not really sure - all I know is it works (see the video above of MAF plugged in vs MAF unplugged). Whether it passes emmissions at MOT time may be another matter.
It will be intersting to see what the car runs like when I get the 2nd ebay one and its running with just 2 ebay ones.
Also, when I get my old ones back from FIC it will be intersting to see whether they have changed the mechanism inside the case - Ive seen comments on FChat that they just replace all the internals so hopefully I'll be able to confirm that.
I'm trying to understand this but surely the whole point of the MAF is for the hot wire to change resistance as the airflow changes in order to tell the ECU to inject more or less fuel. Essentially the MAF is the equivalent to the carb on a car and it's using the resistance of the hotwire to regulate fuel flow so the engine burns at optimal fueling. If the MAF is sending incorrect resistance readings to the ECU I'd think the engine will run but it will be either rich (so adversely effect fuel consumption and I'm guessing emissions) or lean (so run hot). I don't understand the MAF not sending a signal to the ECU, if that's the case what's the point of it?
I'm far more at home with carbs than MAFs but would like to hear Nicks take on it, even if to say I'm well off. My interest is really that I was wondering whether to pick up a spare as a backup but I'm a bit reticent if that resistance number is off on the cheap ones.
Last question, have you tried altering the resistance with the screw?
Pangea
Active member
Hi Pete, You are basically on the money..The workings of this type of MAF are all in the WSM page Jeff put in the thread. These knock offs dont have the CO trim screws incorporated so there is no circuit to measure...ie. the 383 ohms. A signal is sent to the ecu from the MAF but obviously without the screw you cant adjust the CO level for that bank. Thats all. The MAf will obviously still work without the CO circuit as demonstrated as it dosnt affect the functioning of the unit, only the ecu trim. I dont know how this is overcome... . Without measuring CO levels I cant comment on the emissions aspect. If the preset electronics in the MAF are right the emmisions shouldn't be far off. The knock offs cant be that bad as Jeffs car appears to run ok with it fitted. I dont know. Its all a bit of an unknown quantity. Over to Jeff for testing on the road.. Glad I have some good, spare originals though.
Read the full workshop manual description . Start Page C9.
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irarref
Active member
Hi Pete take a look at this post - pretty much what Nick is saying.
https://www.ferrarichat.com/forum/posts/149183601/
If I understand correctly the adjustment screw is there to do a bit of fine tuining and is not supposed to be adjusted afterwards - hence the plugs or "anti tamper plugs" to give them their correct name.
https://www.eurospares.co.uk/Parts/144092/Ferrari/New/12817
Hopefully when I get my mafs back from FIC I'll have 2 genuine bosch working ones that have been refurbished, one original unfurnished, one original broken and 2 ebay knockoffs. Surely I'll have enough to keep the car running! I intend to keep spares in the car so if the problem ever recurs I can just swap them over anf confirm if thats the problem.
https://www.ferrarichat.com/forum/posts/149183601/
If I understand correctly the adjustment screw is there to do a bit of fine tuining and is not supposed to be adjusted afterwards - hence the plugs or "anti tamper plugs" to give them their correct name.
https://www.eurospares.co.uk/Parts/144092/Ferrari/New/12817
Hopefully when I get my mafs back from FIC I'll have 2 genuine bosch working ones that have been refurbished, one original unfurnished, one original broken and 2 ebay knockoffs. Surely I'll have enough to keep the car running! I intend to keep spares in the car so if the problem ever recurs I can just swap them over anf confirm if thats the problem.
Cheers guys. Would be quite interesting to know what the emissions are with 2 of the new MAFs fitted, Jeff. If emissions are spot on I guess there's really no problem. Do you have a nice friendly little local garage that'll test it for you? Would go a long way to saying whether they are exactly right or not.
I guess it's possible with far more modern electronics they have a way of ensuring it's correct and stays correct unlike the OEM MAFs which can vary over time hence the need for the correction screw. It's odd, when it comes to electronics, especially to do with the engine, I'm always a bit reticent with aftermarket parts whereas with most other parts I'll acknowledge that aftermarket parts made today are quite often superior to OEM parts from 1993. And yet there's probably been more advances in electronics to make them more precise and more reliable than any other items.
A while ago when browsing I found these but shied away from them as a spare simply because they aren't OEM so don't know whether to trust them:
https://www.atcdrivetrain.co.uk/p/ferrari-348-petrol-ecu-motronic-m27.html
It's altogether possible and even likely that they are superior in every way to the OEM ECUs in my car. Equally it's also possible that the new MAFs you have, Jeff, are far better than the OEM ones in every respect - more precise, more robust, more reliable - and yet it somehow doesn't compute that they are only £40 compared to the alternative of getting the originals rebuilt. Those emissions tests would be extremely interesting, especially if you can compare to originals. Give me a shout if you can't, I may do it out of curiosity.
Bottom line though is the £1,600 being asked for a pair of replacement 348 MAFs is a bit rich (if you'll excuse the pun) when a Saab 9000 one which is far closer to £40 and is essentially the same type of MAF.
I guess it's possible with far more modern electronics they have a way of ensuring it's correct and stays correct unlike the OEM MAFs which can vary over time hence the need for the correction screw. It's odd, when it comes to electronics, especially to do with the engine, I'm always a bit reticent with aftermarket parts whereas with most other parts I'll acknowledge that aftermarket parts made today are quite often superior to OEM parts from 1993. And yet there's probably been more advances in electronics to make them more precise and more reliable than any other items.
A while ago when browsing I found these but shied away from them as a spare simply because they aren't OEM so don't know whether to trust them:
https://www.atcdrivetrain.co.uk/p/ferrari-348-petrol-ecu-motronic-m27.html
It's altogether possible and even likely that they are superior in every way to the OEM ECUs in my car. Equally it's also possible that the new MAFs you have, Jeff, are far better than the OEM ones in every respect - more precise, more robust, more reliable - and yet it somehow doesn't compute that they are only £40 compared to the alternative of getting the originals rebuilt. Those emissions tests would be extremely interesting, especially if you can compare to originals. Give me a shout if you can't, I may do it out of curiosity.
Bottom line though is the £1,600 being asked for a pair of replacement 348 MAFs is a bit rich (if you'll excuse the pun) when a Saab 9000 one which is far closer to £40 and is essentially the same type of MAF.
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irarref
Active member
Swapped my old supposedly working MAF back in this morning to give a combination my old working MAF plus new ebay MAF. Although gave myself a fright when I forgot to reconnect teh lead as you can see on pic and it ran terribly LOL
Decided to do the wash test so covered the engine with a shower curtain to protect teh engine.
It does catcha surprising amount of water which is a bizarre design
My daugfhter has bought me a bottle og mcguiars polsih and since teh weather was so nice I decided to give the car a polish too before taking it for a run this evening. Although it was fine once warmed up it jerked a little bit whilst cold - going to swap a maf back in tomorrow to see if its the ebay one or my old one - wouldnt be at all suprised if thats past its best too.
Decided to do the wash test so covered the engine with a shower curtain to protect teh engine.
It does catcha surprising amount of water which is a bizarre design
My daugfhter has bought me a bottle og mcguiars polsih and since teh weather was so nice I decided to give the car a polish too before taking it for a run this evening. Although it was fine once warmed up it jerked a little bit whilst cold - going to swap a maf back in tomorrow to see if its the ebay one or my old one - wouldnt be at all suprised if thats past its best too.
irarref
Active member
Although the car now runs reasinably ok with either Nicks MAFS or any combination of my ebay MAF or my working one I'm still getting a slight jerking/misfire when accelerating. I think this corresponds with putting my relay/fuseboard back as prior to that whn trying the working mafs it ran smooth. GRRRR!!!
Anyway, I decided to hunt around cleaning any electrical connectorts I could find with contact cleaner and also some fine wet and dry if anything looked particularly bad, checked the big red connectorunder the air filter housing and also checked earthing points with a multimeter for teh eraths around the injectors etc but nothing improved.
Think I'm going to inspect the condition of the plugs this morning plus put Nicks MAFS back and do a full relearn (never really like doing that for fear of upsetting the neighbours).
Cleaned the plugs for the 2 auxiallry air vales (ringed in yellow) plus the 2 plugs for ??? ringed in blue.
Vaccum control valve connections (pic is prior to cleaning)
Checked the big red connector was tight.
Just as an aside does anyone have a good pic of the lay of the
On the replacement MAF front the 2 I have sent off for refurb have still not arrived but are in the US - its a slkow process! :-(
And as if to add insult to injury the second MAF I ordered from ebat (different seller from first one) has been cancelled due to safety reasons!!! :-(
I've ordered another one from another seller so well have to see how I get on.
Curiously when looking at Ferrariparts website I notice they do an alternative MAF (alkthough still rediculously expensive) bit notice the casing on it has those 2 threaded holes just like my ebay one. mmmm!!! Obviously theresa have the CO2 adjuster screw that mine doesnt but you do wonder if there is another MAF that fits. I cant help feeling we are all being rinsed on tghe price of these as every other car seems to have them for about £50. Ferrari tax at its finest!
https://www.ferrariparts.co.uk/part/ferrari/136374-a?id=436947
Anyway, I decided to hunt around cleaning any electrical connectorts I could find with contact cleaner and also some fine wet and dry if anything looked particularly bad, checked the big red connectorunder the air filter housing and also checked earthing points with a multimeter for teh eraths around the injectors etc but nothing improved.
Think I'm going to inspect the condition of the plugs this morning plus put Nicks MAFS back and do a full relearn (never really like doing that for fear of upsetting the neighbours).
Cleaned the plugs for the 2 auxiallry air vales (ringed in yellow) plus the 2 plugs for ??? ringed in blue.
Vaccum control valve connections (pic is prior to cleaning)
Checked the big red connector was tight.
Just as an aside does anyone have a good pic of the lay of the
On the replacement MAF front the 2 I have sent off for refurb have still not arrived but are in the US - its a slkow process! :-(
And as if to add insult to injury the second MAF I ordered from ebat (different seller from first one) has been cancelled due to safety reasons!!! :-(
I've ordered another one from another seller so well have to see how I get on.
Curiously when looking at Ferrariparts website I notice they do an alternative MAF (alkthough still rediculously expensive) bit notice the casing on it has those 2 threaded holes just like my ebay one. mmmm!!! Obviously theresa have the CO2 adjuster screw that mine doesnt but you do wonder if there is another MAF that fits. I cant help feeling we are all being rinsed on tghe price of these as every other car seems to have them for about £50. Ferrari tax at its finest!
https://www.ferrariparts.co.uk/part/ferrari/136374-a?id=436947
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