Noob Needs Help wiith US Fuel Injection 280i
Discussion
Greetings Gents!
This is my first post on your already helpful site. I just received my '85 280i S2 FHC from a long distance purchase and have been having some issues with the engine missing and sputtering past 3K RPM. I initially suspected that I had a blown head gasket but my mechanic/friend has told me that the gaskets are good, and that the problems appear to be tune up related. So while he is taking care of this for me, he is also trying to get the car ready for it's California Smog Inspection. We've noticed a blocked off line on the Air flow meter sensor plate housing (this is probably not the correct terminology) as well as an open connector on the air filter housing. Bud, the mechanic, believes that there should be a hose between the two with a deceleration valve somewhere in the middle. I'm including photos of the areas (sorry about the quality of the photos but the car is across town at the shop and I just happened to have these photos on hand). These blocked and open fittings will send up big warning flags for the local emission testers so I need to have this resolved so that the car can be inspected, registered and then driven!
The first photo shows the blocked off portion on the sensor plate housing:
The next photo barely shows the unused nipple on the air filter housing:
What Bud is looking for is a diagram of the connections but I would imagine that a decent photo would be just as good. I don't know if this is a US only setup or whether it is universal but your help would assist me greatly in getting my car on the road.
Here's a couple of pics of the car... I am looking forward to blasting around some hills and canyons as soon as I can. Thanks for any help you can provide!
Being towed home on it's maiden voyage:
Safely at home in the driveway:
Eric Sands
Sandsini
This is my first post on your already helpful site. I just received my '85 280i S2 FHC from a long distance purchase and have been having some issues with the engine missing and sputtering past 3K RPM. I initially suspected that I had a blown head gasket but my mechanic/friend has told me that the gaskets are good, and that the problems appear to be tune up related. So while he is taking care of this for me, he is also trying to get the car ready for it's California Smog Inspection. We've noticed a blocked off line on the Air flow meter sensor plate housing (this is probably not the correct terminology) as well as an open connector on the air filter housing. Bud, the mechanic, believes that there should be a hose between the two with a deceleration valve somewhere in the middle. I'm including photos of the areas (sorry about the quality of the photos but the car is across town at the shop and I just happened to have these photos on hand). These blocked and open fittings will send up big warning flags for the local emission testers so I need to have this resolved so that the car can be inspected, registered and then driven!
The first photo shows the blocked off portion on the sensor plate housing:
The next photo barely shows the unused nipple on the air filter housing:
What Bud is looking for is a diagram of the connections but I would imagine that a decent photo would be just as good. I don't know if this is a US only setup or whether it is universal but your help would assist me greatly in getting my car on the road.
Here's a couple of pics of the car... I am looking forward to blasting around some hills and canyons as soon as I can. Thanks for any help you can provide!
Being towed home on it's maiden voyage:
Safely at home in the driveway:
Eric Sands
Sandsini
OK, the USA models had some extra bits for emission control, but basics are the same.
Top photo with blocked off hole - No there's nothing missing, a lot of Euro ones are exactly the same as that.
Don't know about extra hole in air filter box, not seen that before (Euro models). Can't see it very well....
If engine runs perfectly at low speeds and idle, then my suggestions to check first are -
Check connectors are all clean. Don't forget the distributor plugs either. Check plug leads (loose, cracked....)
Distributor not advancing properly.
Although it's contactless, the dizzy is still the old style springs and weights design, and it's not unknown for this to gum up/corrode and so doesn't advance
enough at higher engine speeds. Take of dizzy cap (two bolts) and have a look inside. As it's contactless, owners often forget about it completely....
(could also be the coil or the Duraspark, or even the resistance wire, but these tend to be quite reliable, or give trouble lower down rpm too - save for next try !)
Partly blocked fuel filter.
This should also show up if you put your foot down at medium revs, but mine didn't even misfire on highway/motorway, it just went 'flat'. New filter fixed it.
I can see the filter on your photo right at front of bay.
Metering flap fouling or not lifting properly.
You can take off the cover to the metering unit (large jubille clip) and remove air filter, and you should be able to easily lift the main metering flap.
This 'floats' in the airflow to control fuel mixture, and so should be very light on the pivots. push gently with fingers. it should fall back quickly.
Any resistance here will cause all sorts of fuel issues.
There's lots of stuff on the web - look up "Bosch K-jet" or "Bosch CIS" because that's what this system is. It's the same as used on many VW and Audi
cars of the 80's, Golf/Rabbit etc. It looks complex, lots of pipes, but actually it's quite simple in the way it works.
Injectors actually tend to give trouble more at LOW rpm, because of the way the system flows, so don't suspect those (from what you described)
Hope this helps....
Top photo with blocked off hole - No there's nothing missing, a lot of Euro ones are exactly the same as that.
Don't know about extra hole in air filter box, not seen that before (Euro models). Can't see it very well....
If engine runs perfectly at low speeds and idle, then my suggestions to check first are -
Check connectors are all clean. Don't forget the distributor plugs either. Check plug leads (loose, cracked....)
Distributor not advancing properly.
Although it's contactless, the dizzy is still the old style springs and weights design, and it's not unknown for this to gum up/corrode and so doesn't advance
enough at higher engine speeds. Take of dizzy cap (two bolts) and have a look inside. As it's contactless, owners often forget about it completely....
(could also be the coil or the Duraspark, or even the resistance wire, but these tend to be quite reliable, or give trouble lower down rpm too - save for next try !)
Partly blocked fuel filter.
This should also show up if you put your foot down at medium revs, but mine didn't even misfire on highway/motorway, it just went 'flat'. New filter fixed it.
I can see the filter on your photo right at front of bay.
Metering flap fouling or not lifting properly.
You can take off the cover to the metering unit (large jubille clip) and remove air filter, and you should be able to easily lift the main metering flap.
This 'floats' in the airflow to control fuel mixture, and so should be very light on the pivots. push gently with fingers. it should fall back quickly.
Any resistance here will cause all sorts of fuel issues.
There's lots of stuff on the web - look up "Bosch K-jet" or "Bosch CIS" because that's what this system is. It's the same as used on many VW and Audi
cars of the 80's, Golf/Rabbit etc. It looks complex, lots of pipes, but actually it's quite simple in the way it works.
Injectors actually tend to give trouble more at LOW rpm, because of the way the system flows, so don't suspect those (from what you described)
Hope this helps....
Edited by RCK974X on Friday 4th August 21:58
Love the blue sky!
On the UK model there is pipe from the connection in your first photo the the oil filler breather cap...
These caps are readily available here in the UK if you need one.
There is no connection on the top of my air box...
If you can't get the injection system working could you junk it and pass your emmissions with a carb?
I have a question for you if you don't mind. Perhaps you could PM me when you get a minute?
On the UK model there is pipe from the connection in your first photo the the oil filler breather cap...
These caps are readily available here in the UK if you need one.
There is no connection on the top of my air box...
If you can't get the injection system working could you junk it and pass your emmissions with a carb?
I have a question for you if you don't mind. Perhaps you could PM me when you get a minute?
Also mixture IS ADJUSTABLE - for the smog testing shop.
There is a CO (mixture) adjustment using an extra long Allen key. Check on web as they will have good diagrams so you can find it.
It's possible US ones will have a blanking cap, I don't know. I understand some carb adjusters were blanked off for US export...
Again, older VW mechanics will know all about it !!
There is a CO (mixture) adjustment using an extra long Allen key. Check on web as they will have good diagrams so you can find it.
It's possible US ones will have a blanking cap, I don't know. I understand some carb adjusters were blanked off for US export...
Again, older VW mechanics will know all about it !!
Thank you RCK974X, for the very complete response! Thanks to cross posting on the Wedge Facebook page I managed to get most of that info. My mechanic was able to trace the issue down to a clogged air filter (what a fool I am not to have checked it!). In the meantime he's replaced the plugs, checked the dizzy condition and advance, which was all in good order, and adjusted the mixture. This is solved the hunting idle and he says it is running well. I'll know when I pick it up tonight.
I am soo relieved that the problems were minor and I'm looking forward to finding out just how one of these cars drives! It will be my first other than trying to limp it home last week after picking it up from the transporter.
Cheers,
Eric
I am soo relieved that the problems were minor and I'm looking forward to finding out just how one of these cars drives! It will be my first other than trying to limp it home last week after picking it up from the transporter.
Cheers,
Eric
V8sforme...
interesting photos.
On Euro models, there was a PCV valve on the rocker cover which fed directly to pelnum, and cap was open to atmosphere.
I guess the USA added that pipe to make sure everything went via air filter. OK makes sense.
Your second photo - the regulator on EU models was connected to engine vacuum (same as servo) to richen mixture
on heavy acceleration. I'm surprised it runs OK with that disconnected as in your pic, unless it's a USA specific mod .....
interesting photos.
On Euro models, there was a PCV valve on the rocker cover which fed directly to pelnum, and cap was open to atmosphere.
I guess the USA added that pipe to make sure everything went via air filter. OK makes sense.
Your second photo - the regulator on EU models was connected to engine vacuum (same as servo) to richen mixture
on heavy acceleration. I'm surprised it runs OK with that disconnected as in your pic, unless it's a USA specific mod .....
RCK974X said:
.....Your second photo - the regulator on EU models was connected to engine vacuum (same as servo) to richen mixture on heavy acceleration. I'm surprised it runs OK with that disconnected as in your pic, unless it's a USA specific mod .....
Do you mean this bit?
If so, then where should it be connected to?
![](https://thumbsnap.com/sc/TjN7a9yB.jpg[/img]</a> <a href="https://thumbsnap.com/xumldFlT" Target="_blank" rel="nofollow">[img]https://thumbsnap.com/sc/xumldFlT.jpg)
v8s4me said:
Do you mean this bit? If so, then where should it be connected to?
Yes, that bit.{Adjusting brain for steering wheel and brakes on other side...... }
OK.....
The brake servo pipe will connect to the other side of the engine, and on Euro models this had an adapter with a couple of different diameter pipe connectors, and one of those connects goes to the regulator, so it gets a plenum vacuum signal.
Here is photo of mine, RHD, but shows the pipe runs along top of engine beside plenum - front is hidden under auxiliary air valve....
Edited by RCK974X on Saturday 5th August 03:14
I'm curious, is this the car from Swedish Motors in Pennsylvania? That listing is gone now. I recall it was a nice car in the ad. Good luck with it. Have you found the Yahoo TVR threads and the North American TVR Club yet ? They're both useful, but you'll find more FHC specific content on PH.
Keep us posted on passing California emissions. A shame you'll have to retain the evil catalytic converter that lives under the oil pan and serves to heat the sump.
Drew
Keep us posted on passing California emissions. A shame you'll have to retain the evil catalytic converter that lives under the oil pan and serves to heat the sump.
Drew
Question for Andy.
I can see on yours that the second take off on the plenum adapter is blanked off as on mine, see 'B' in this photo..
Tube 'A' in this photo is now connected to point 'A' in the following photo...
I say " now connected" because until five minutes ago it wan't connected to anything! I don't know how long it's been like that but it might explain some of the idling issues I've been having recently.
Are you saying that 'B' in the second photo should be connected to the plenum and if so should I use 'B' in the first photo?
BTW and to clarify, mine is a RHD/UK car.
Many thanks.
Joe
I can see on yours that the second take off on the plenum adapter is blanked off as on mine, see 'B' in this photo..
Tube 'A' in this photo is now connected to point 'A' in the following photo...
I say " now connected" because until five minutes ago it wan't connected to anything! I don't know how long it's been like that but it might explain some of the idling issues I've been having recently.
Are you saying that 'B' in the second photo should be connected to the plenum and if so should I use 'B' in the first photo?
BTW and to clarify, mine is a RHD/UK car.
Many thanks.
Joe
There are schematics in the 'Wedge Parts Manual' available here ( https://www.tvr.at/grafiken/wedgemanual.pdf ) and elsewhere. They may not always show exactly which tube goes where, but the components are listed with at least semi-functional descriptions and that may be enough for your mechanic. The US variations are included in this doc too. Printed copies are also sold by the North American club regalia office.
Ah, I see....
The pipe from plenum should be connected to the TOP (B) , and the lower pipe (A) should be open to the air, as far as I know.
Or put it another way -
What that little unit does is a pressure regulator, so it controls the whole fuel mixture, by applying a controlled pressure to the main air
flap (you can trace the pipes to see). On our Euro models, there was no 'feedback' emission control, so the unit only does two things.
1. warm-up enrichment (=choke). 2. full throttle enrichment (why it's connected to plenum).
Now I understand USA export wedges had extra bits, so it's quite possible they used a different regulator unit, and used that lower pipe to tweak the
mixture - THIS IS JUST A GUESS though....
The unit on mine does not have a lower connector pipe (A) at all, and those fuel pipes are not OE, so it makes me wonder if that's a replacement unit,
or it's also possible later OE units had the extra pipe.
Typically units with lower pipe connector (A) were used on turbo models, and enrich according to turbo pressure, A connects to turbo (outlet pressure).
This from what I've seen of the various K-Jets in UK and NZ, so not guaranteed to be right
Later K-jets became KE_jet, and used an EGO, and had an extra 'lump' on the side of the main fuel head, which also controlled fuel pressure, but not via the regulator,
and had an electronic control unit to drive this extra lump (a controlled valve), giving better accuracy....
Note that my distributor is also blanked off on photo - this is recommended change (by Ford) when resetting for unleaded fuel. It originally connected around to a small pipe on throttle body. Remember 2.8 was originally for leaded 4 star (98 octane - probably 105-ish on US measuring system), so USA export models would likely have had different dizzy curve too !!
I hope that all this helps explain......and why we have a bit of a hole in knowledge with USA cars.
There are some good web explanations of what the various bits do for K-jet systems, have a search around, and don't worry if it takes you to a VW or Audi site, it's the same system. In fact it was also used on Mercedes, Volvo, even Ferrari !! Later systems were KE (as above), but it's still the same arrangement with a few extra add ons......
The pipe from plenum should be connected to the TOP (B) , and the lower pipe (A) should be open to the air, as far as I know.
Or put it another way -
What that little unit does is a pressure regulator, so it controls the whole fuel mixture, by applying a controlled pressure to the main air
flap (you can trace the pipes to see). On our Euro models, there was no 'feedback' emission control, so the unit only does two things.
1. warm-up enrichment (=choke). 2. full throttle enrichment (why it's connected to plenum).
Now I understand USA export wedges had extra bits, so it's quite possible they used a different regulator unit, and used that lower pipe to tweak the
mixture - THIS IS JUST A GUESS though....
The unit on mine does not have a lower connector pipe (A) at all, and those fuel pipes are not OE, so it makes me wonder if that's a replacement unit,
or it's also possible later OE units had the extra pipe.
Typically units with lower pipe connector (A) were used on turbo models, and enrich according to turbo pressure, A connects to turbo (outlet pressure).
This from what I've seen of the various K-Jets in UK and NZ, so not guaranteed to be right
Later K-jets became KE_jet, and used an EGO, and had an extra 'lump' on the side of the main fuel head, which also controlled fuel pressure, but not via the regulator,
and had an electronic control unit to drive this extra lump (a controlled valve), giving better accuracy....
Note that my distributor is also blanked off on photo - this is recommended change (by Ford) when resetting for unleaded fuel. It originally connected around to a small pipe on throttle body. Remember 2.8 was originally for leaded 4 star (98 octane - probably 105-ish on US measuring system), so USA export models would likely have had different dizzy curve too !!
I hope that all this helps explain......and why we have a bit of a hole in knowledge with USA cars.
There are some good web explanations of what the various bits do for K-jet systems, have a search around, and don't worry if it takes you to a VW or Audi site, it's the same system. In fact it was also used on Mercedes, Volvo, even Ferrari !! Later systems were KE (as above), but it's still the same arrangement with a few extra add ons......
Edited by RCK974X on Saturday 5th August 22:09
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