frosty
Part of things
Posts: 120
|
|
Oct 23, 2014 15:45:07 GMT
|
Howdo!!
I've recently fitted a 3.9 EFI V8 to my MGB but I'm having a nightmare to get it running properly.
Info: The engine was taken from an auto 1991 Range Rover Classic which was running LPG (not sure if that makes a difference?!?!) and had no cats or lamba's fitted.
It's now manual with no extras (AC, Power steering, etc) and I've got the ecu wired in correctly to my MG loom.
Problem: With the MAF not connected, the engine runs pretty good until you give it a bit of beans then it splutters quite a bit but doesn't cut out! (Pretty sure its running richer than a footballer!)
Connect the MAF up and it starts, revs quite hi and then cuts out!!!. Baught a new MAF off fleabay so very doubtful it's a faulty MAF!
Electrics all seem good. Good spark, good fuel and timed up well enough! As i say it runs without it connected but as soon as its plugged in and started it doesn't want to know!!!
Anyone got any idea what's going on?!?!? I'm in Stafford if there's any local RV8 nuts around!!!
Cheers chaps!
|
|
Last Edit: Oct 23, 2014 15:46:56 GMT by frosty
1970 MGB GT 3.9 V8 efi Sebring
2007 Audi A3 Sport (Diesel)
|
|
|
|
|
Oct 23, 2014 17:32:55 GMT
|
Which MAF has it got ? Is it the flap one or straight through one? If the engine was running gas, the timing will be set up to run on that as the gas has a different ignition properties as opposed to petrol.
Make sure that the ignition is set up to run on petrol and that the plugs are the correct ones, as sometimes plugs used for gas are a different spec due to the igniting properties.
When you disconnect the MAF , the engine runs a default ignition map to enable it to limp home, that will explain the poor running when disconnected and giving it beans. The new MAF, was it defo from a 3.9 ? If not , then that may be why it runs as it does, although the fuel pump may be the reason for it cutting out if it cannot keep up with the fuel flow required. Do you have a part number of the new MAF and one for the old one?
Lastly, do you have the full details of the donor vehicle,as this might help finding further info for you.
|
|
'88 Cadillac Brougham hearse (white) '91 Carlton GSi 24v '72 Dodge dual cab pick up '99 Mercedes S55 AMG
|
|
sowen
Club Retro Rides Member
Posts: 2,245
Club RR Member Number: 24
|
RV8 3.9 EFI MAF Troublesowen
@sowen
Club Retro Rides Member 24
|
Oct 23, 2014 17:46:13 GMT
|
Have you fitted all the required resistors for the ecu to read so it fuels for a manual without aircon etc? linkI'm running hotwire on my 3.5, and after a short discussion with those in the know and some research, there is no significant differences with the hotwire type maf's throughout production. Have you tried another known good maf? What about the sensors, water temperature, throttle position etc, are they working correctly?
|
|
|
|
frosty
Part of things
Posts: 120
|
|
Oct 23, 2014 19:28:48 GMT
|
It's a Hotwire MAF. Other than 1991 Range Rover classic v8 don't know much else!
It did the same with the old MAF connected. Not sure if the other sensors are working or not. Not sure how best to check them?!?!
The donor car was apparently running before the engine was removed but can't guarantee it!!!
How do I check the other sensors?
|
|
1970 MGB GT 3.9 V8 efi Sebring
2007 Audi A3 Sport (Diesel)
|
|
frosty
Part of things
Posts: 120
|
|
Oct 23, 2014 19:33:01 GMT
|
I've set the timing myself and it's got new plugs, leads, coil, dizzy cap and arm. It's on luminition ignition too!! All of which is spec'd for the donor car!!!
|
|
1970 MGB GT 3.9 V8 efi Sebring
2007 Audi A3 Sport (Diesel)
|
|
GavinJ
Club Retro Rides Member
MGB 3.9 v8 Sebring
Posts: 927
Club RR Member Number: 209
|
RV8 3.9 EFI MAF TroubleGavinJ
@gavinj
Club Retro Rides Member 209
|
Oct 23, 2014 19:56:48 GMT
|
|
|
|
|
frosty
Part of things
Posts: 120
|
|
Oct 23, 2014 20:22:19 GMT
|
Yes but it doesn't make any difference if it's connected or not!?!?
|
|
1970 MGB GT 3.9 V8 efi Sebring
2007 Audi A3 Sport (Diesel)
|
|
GavinJ
Club Retro Rides Member
MGB 3.9 v8 Sebring
Posts: 927
Club RR Member Number: 209
|
RV8 3.9 EFI MAF TroubleGavinJ
@gavinj
Club Retro Rides Member 209
|
Oct 23, 2014 20:32:58 GMT
|
Not sure matey to be honest was just a thought. I can imagine your frustration with this, how have you got your fueling set up? Is it just a temp set up at the mo just to get it running?
|
|
|
|
frosty
Part of things
Posts: 120
|
|
Oct 23, 2014 20:39:52 GMT
|
Sorry wasn't being arsey!!!
Didn't write the reply very well.
The fuel setup is pretty temporary but it still has a low pressure filter then hi pressure pump then hi pressure filter! The inlet to the pump is really big though so I've had to sleeve the hose going onto the li pressure filter to get it to fit!!
Dya think it could be too low fuel pressure? I wasn't sure if it would be with it running without a MAF but I guess it's using more readings when it is connected.
So frustrating to have it running but running badly! Cheers for the help though!! Extremely appreciated as I'm no genius with cars!!!
|
|
1970 MGB GT 3.9 V8 efi Sebring
2007 Audi A3 Sport (Diesel)
|
|
sowen
Club Retro Rides Member
Posts: 2,245
Club RR Member Number: 24
|
RV8 3.9 EFI MAF Troublesowen
@sowen
Club Retro Rides Member 24
|
Oct 23, 2014 20:55:03 GMT
|
Some useful info on the hotwire efi here link
|
|
|
|
|
|
|
Oct 23, 2014 21:35:14 GMT
|
one thing that just crossed my mind, is the plenum chamber sealed ok? As any erroneous air getting in will throw it all out. sensors will have a resistance usually, if you know of someone with a suitable similar engine, you could check the resistance of sensors they have to the ones you have, the water temp ones are a usual suspect from memory. The hotwire MAF i found was more reliable in the long run. Lastly ,do you have a picture of the engine in place, out of curiosty
|
|
'88 Cadillac Brougham hearse (white) '91 Carlton GSi 24v '72 Dodge dual cab pick up '99 Mercedes S55 AMG
|
|
frosty
Part of things
Posts: 120
|
|
Oct 23, 2014 21:55:21 GMT
|
Ah!!! It might not be 100% sealed. I've had to get it machined down and it's currently sitting on the rocker cover a bit so might not be sealing perfectly!!
Good shout!
Don't know anyone else with this motor but I might be able to find figures out online!!!
I've done a build thread on here with pics in but I'll try and find one now for you!
|
|
1970 MGB GT 3.9 V8 efi Sebring
2007 Audi A3 Sport (Diesel)
|
|
frosty
Part of things
Posts: 120
|
|
Oct 23, 2014 21:57:54 GMT
|
Think this is the best one. Still got a lot of detailing and bits to sort but want it running right first!
|
|
1970 MGB GT 3.9 V8 efi Sebring
2007 Audi A3 Sport (Diesel)
|
|
sowen
Club Retro Rides Member
Posts: 2,245
Club RR Member Number: 24
|
RV8 3.9 EFI MAF Troublesowen
@sowen
Club Retro Rides Member 24
|
Oct 24, 2014 11:12:14 GMT
|
The link I posted a few up^ has some of the resistances buried in the text if you look hard enough. I could be wrong but I thought the maf's like to have a bit more straight air going to and from them, the elbow between the plenum and the maf maybe too sharp?
|
|
|
|
frosty
Part of things
Posts: 120
|
|
Oct 24, 2014 17:44:01 GMT
|
Cool I'll have a good read through and make a note of the figure.
I know what you mean about the elbow but I struggled to find one the right diameters that would fit without causing the MAF to be hitting the wing!!! Think I still have the old hose from the Range Rover and try that. See if it makes any difference!
Got family over this weekend though so diagnostic time will be very limited unfortunately.
|
|
1970 MGB GT 3.9 V8 efi Sebring
2007 Audi A3 Sport (Diesel)
|
|
|
|
Oct 24, 2014 19:05:04 GMT
|
Hmm... have these two pipes been plugged imgur.com/WoP0AzH or dealt with accordingly ?
|
|
Last Edit: Oct 24, 2014 19:05:39 GMT by deaddave72
'88 Cadillac Brougham hearse (white) '91 Carlton GSi 24v '72 Dodge dual cab pick up '99 Mercedes S55 AMG
|
|
GavinJ
Club Retro Rides Member
MGB 3.9 v8 Sebring
Posts: 927
Club RR Member Number: 209
|
RV8 3.9 EFI MAF TroubleGavinJ
@gavinj
Club Retro Rides Member 209
|
Oct 24, 2014 21:16:18 GMT
|
The one on the left is the brake servo vacuum and the right is the pre heat to the throttle housing. I reckon the plenum not sealing is a good call as just spent a bit of time googling and airleak is reasonable cause...
|
|
|
|
|
|
Oct 24, 2014 21:36:26 GMT
|
i remember having a few challenges from my decade dealing with landrovers on a daily basis, it slowly comes back i remember having challenges with air leaks on one before, it was the idle air valve in that case though. If the plenum hasnt been sealed down , the unmetered air will cause merry hell with the readings and the ECU freaks out a tad.
|
|
'88 Cadillac Brougham hearse (white) '91 Carlton GSi 24v '72 Dodge dual cab pick up '99 Mercedes S55 AMG
|
|
frosty
Part of things
Posts: 120
|
|
Oct 24, 2014 22:41:43 GMT
|
Awesome. Cheers guys!
Well I had half an hour before the folkes arrived tonight so I took the plenum off, removed the preheated but the was fouling on the rocker cover and have refitted it. There's no gasket for it though so do I just use gasket sealer or do I need to try and buy an actual gasket for it?!? I also took out the idle air valve from the back of the plenum. It was pretty gunked up with black greasy stuff but I plugged the wires back in and it does move a bit when you turn the ignition on and then off again!! Only problem is the little fibre washer/gasket has had it so need to get another one on to get a good deal there too!!
Cheers again guys, will update when I've tried running it again!!!
|
|
1970 MGB GT 3.9 V8 efi Sebring
2007 Audi A3 Sport (Diesel)
|
|
frosty
Part of things
Posts: 120
|
|
Oct 24, 2014 22:45:32 GMT
|
Hmm... have these two pipes been plugged imgur.com/WoP0AzH or dealt with accordingly ? Sorry just seen this. The vacuum is now connected to the brake servo as mentioned by Gavin and I've just removed the preheater. The larger pipe from the throttle body goes to the breathers on the rockers from what I can find online which at the min they don't but didn't think this would cause too much of an issue as I thought it was just a breather?!? Is that not true? If so I might try and get some breather tube tmw and hook that up!!
|
|
1970 MGB GT 3.9 V8 efi Sebring
2007 Audi A3 Sport (Diesel)
|
|
|