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Bosch Injectors #1634126
22/07/2019 13:40
22/07/2019 13:40
Joined: Feb 2019
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clanger Offline OP
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I know the standard Bosch 0280150450 20vT injectors were discontinued in 2008. My question is has anybody found a replacement? I've seen reference to Lucas Denso and they seem to produce a 360 cc injector but the impedance is 12 rather than 16 Ohms and I suspect this would cause a problem.

My current injectors are visibly dripping; fuel rail drops from 3 bar to 2 bar in 10 mins. After half an hour all pressure lost. This is causing hard starting from flooding (I can smell fuel on the engine oil) and I can hear vapour being pushed back in to a full tank of fuel if I cycle the ignition key several times before trying to start. I've changes the O rings, filter baskets etc. and they have a good uniform spray pattern but warm start is just a pain.

Really don't want to buy second hand from ebay as they could equally be shot and don't trust units from the far east.

Any advice?

Re: Bosch Injectors [Re: clanger] #1634128
22/07/2019 14:54
22/07/2019 14:54
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You could try having them cleaned, eg. https://www.asnu.com/service-centres

or buy a cheap ultrasonic cleaner from ebay and DIY.

Re: Bosch Injectors [Re: clanger] #1634134
22/07/2019 18:41
22/07/2019 18:41
Joined: Dec 2005
Posts: 32,248
Hemel in the Hempstead
barnacle Offline
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I discussed this very subject with Joe only the other day (though I don't recall which injectors he was asking about, the impedances were very similar). He had come across a car with 12 ohm impedance which had been running for some time without issue.

Here's the (electronics engineer hat on) deal.

1) current through a circuit is proportional to the loop resistance of the circuit - in this case, the current therefore would increase by about 33%.
2) power dissipated in a circuit is equal to the voltage across that circuit multiplied by the current - so the power dissipated by each injector will be around 16W, most of which is absorbed through the manifold and the fuel flowing through the injector. We can assume that Lucas are happy with that sort of load.
3) the injectors are switched on using a transistor in series with the injector coil. That transistor - one per injector - is in the ECU housing. The transistor is always either off (and dissipating no power) or hard on, with a voltage drop of about 0.2v (guessing here from 1990's power transistor spec; I don't know which transistor is actually used) and so when it's turned on, the power dissipated by the transistor's internal resistance will be around 200mW; no great problem as it's bolted on to a heat sink on the case of the ALU.
4) the bad news: between those two extremes, the transistor is either switching on or off, and it can't do that instantaneously. The time it takes to do that depends on the transistor characteristics (which I don't know), the circuit configuration (which I don't know) and the speed the engine is running. While it's switching, it's not a switch, it's another resistor in the circuit and it's dissipating like mad. As the engine runs faster, the proportion of the time that it spends in this switching time vs either on or off increases, so the worst time is when you're running maximum revs - where each transistor would be dissipating around 33% more than the ECU was designed to...

Ok, we do have a couple of points: first that Joe knows of at least one case where they have been successfully run for some time (I don't know how long). Secondly, no designer worth his salt would use transistors running particularly close to their limits, particularly where the environment in which they would operate is so harsh, and where they're expected to work for decades. Personally, I'd spec at least two hundred percent overload, and try and get five hundred past the production engineers (they're more expensive!).

So, my *BEST GUESS*, no guarantees, is that at normal speeds there will be no issues. I'd check the ECU after a fast run with the correct injectors and see if it got too hot to touch; if it does, I would be very wary of changing to those lower impedance injectors. If it feels ok, change them and then do the same test. 'Too hot to touch' is about 60C at the heatsink, so the transistor cores will be at maybe 80 or 90C. Most electronics are specified for 0-70C, those for cars from -20 to +85. Running components at elevated temperature degrades their operation... make you own mind up laugh

Neil

p.s. Injectors with impedances in the 10-14 ohm range are referred to as 'high impedance'. Don't even think about fitting 'low impedance' injectors with an impedance of around an ohm.


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Re: Bosch Injectors [Re: clanger] #1634136
22/07/2019 21:05
22/07/2019 21:05
Joined: Feb 2019
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clanger Offline OP
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Thanks GrahamL. I thought about that and it might be a solution - I ran 1 liter of acetone through each injector at 3 Bar pressure, alternating constant flow and pulsing using a pp9 battery. It improved the spray pattern such that they are all now the same and on a cold start the engine now revs out to 1500 revs and then progressively drops down to 750 rpm idle. At that point I thought I might have fixed it, it was that good! However whilst cold start has improved impressively it has turned out to make no difference to the clearly observable injector tip leak frown So my concern is spending money on injectors that might just be past it - 124k miles.

Thanks Neil. What you have said all makes sense, I remember my V/IR and tbh I had not given a thought to the injector heat dissipation. My concern was the effect it might have on the ECU transistors but as you have described it might be worth pursuing. The only source I can find for the Lucas Denso @350 cc 12 Ohm at present is the US, the price is good but as usual they don't respond to mails. I'll give it a bit longer then give them a call.

Re: Bosch Injectors [Re: clanger] #1634268
29/07/2019 14:47
29/07/2019 14:47
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If its of any use- on the issue of sonic cleaning -I had an injector issue last year - and had all of the injectors sonic cleaned/patterns checked etc. Maybe that made some of them healthier/spray better.

The non working one however still didn't work - they seem to have the tendency to be fine when cooler- but when hotter and the demand is high- so long hard driving - there at their weakest.

In the future this too is going to become (is starting to be) a real issue for coops. Be good if there was a go to solution...

Regards

MM

Re: Bosch Injectors [Re: clanger] #1634285
29/07/2019 21:30
29/07/2019 21:30
Joined: Dec 2005
Posts: 32,248
Hemel in the Hempstead
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We have thought for some time that the sonic welded joints have a tendency to stop working at elevated temperatures.


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Don't get no respect! [b]Coupe Fiat 1994-2000 - an owner's guide[/b] <-- clicky!
Re: Bosch Injectors [Re: clanger] #1635329
07/09/2019 13:12
07/09/2019 13:12
Joined: Feb 2019
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Update: After a great deal of research on fuel injectors in general, specs etc. I decided to change the injectors. I had established they were the cause of my problem but given the age of the vehicles I was not confident that spending money on second hand ebay injectors was a solution. I read this thread https://www.fiatcoupeclub.org/forum/ubbthreads.php?ubb=showflat&Number=653322 which established the real world flow rate of the standard injectors to be 360cc. I then made contact with a company asking their advice and they recommended these:

https://www.finjector.com/ev14_12_ohm_373cc_e_20_jetronic_o_o_61_mm_tot_78mm-p-137105-0

They obviously flow a little more at 3 bar but I figured it would be within limits. My concern was the impedance being 12 ohms but given what barnacle said and looking at a french forum where others had used 12 ohm injectors with success I went ahead and ordered. They supplied a flow matched set with printed sheet showing the static and dynamic flow rate and msec resolution from 8-15 volts.

Long story short; I installed without issue, ECU reset and immediate start settling into a perfect idle. Approx. 500 miles later, no sooty tail pipe, perfect starting hot and cold, plugs look perfect compared to sooty black before, mpg increase and the car pulls like a train. It has a narrow band lambda gauge fitted and all looks OK off and on boost. Not a cheap fix but it now runs like a new car.

Hope this might help someone in future

Re: Bosch Injectors [Re: clanger] #1635335
07/09/2019 19:03
07/09/2019 19:03
Joined: Dec 2005
Posts: 3,681
Pothole City
GrahamL Offline
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That's very interesting. smile

My plugs are sooty black as well and I was warned at last MOT about emissions being a borderline fail so I was thinking I'd either need to try changing the cat in the exhaust (not easy when the entire thing is welded together) or else the injectors.

Did you test if the 20 degree spay pattern was the same as the original Bosch injectors? It sounds about right from memory when I was cleaning the Bosch injectors but not sure if it's exactly the same. And the number of holes at the tip is very different, original Bosch only has 4 and these ones have 12... although maybe it doesn't really matter if they're all still spraying towards the intake valves OK.

My coupe has been off road since January but I'm tempted to try a set of these injectors and then take it for an MOT. smile

Re: Bosch Injectors [Re: clanger] #1635346
08/09/2019 11:01
08/09/2019 11:01
Joined: Feb 2019
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clanger Offline OP
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Hi Graham,

No I did not do a spray comparison before fitting, I knew the original spec was 20 degrees and took Bosch at their word on the new ones. There is a coding system for that type where A = thin spray C = cone spray and E = twin spray followed by the degrees between the two sprays, its listed as an E20 so I went for it. I remember seeing another spray pattern version of that injector listed there somewhere...

One issue I was concerned with was the potential for poor low engine speed running, but these modern injectors seem to of moved on a bit. The resolution or dead time at 12 volts is 1.4ms and at 13v 1.3ms and this has been born out with a perfect engine idle and pick up - I'm starting to sound like a Bosch salesman but the difference for me has been night and day.

If you do go for it be aware that they are approx 0.5 mm longer which means you need to apply a firm pressure to the fuel rail to get the mounting screws started, alternatively you could just elongate the holes a little but I did not find it necessary.

Guy

Re: Bosch Injectors [Re: clanger] #1635399
09/09/2019 13:30
09/09/2019 13:30
Joined: Sep 2007
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Thanks for this post Clanger,

This is really helpful. I'm guess the up shot of a new injector is that technology has moved on in what- nearly a quarter of a century and these new injectors I presume are likely better then the OEM from in the day. Or at least as good as the 25 year old OEM injectors which are starting to break down.

I'm keeping this link in favs!

Regards

MM

Re: Bosch Injectors [Re: clanger] #1635400
09/09/2019 13:32
09/09/2019 13:32
Joined: Sep 2007
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Freedom
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ohh and the website coverts into Eng-er-lish as well!

Bonus!

Re: Bosch Injectors [Re: clanger] #1635412
10/09/2019 06:59
10/09/2019 06:59
Joined: Feb 2017
Posts: 54
Tasmania
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Grigio Offline
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This is a great thread, I've learnt more about fuel injection in the last 10 posts than I have in the last 10 years.


2000 grigio moon 20VT Plus.
Re: Bosch Injectors [Re: clanger] #1635416
10/09/2019 12:03
10/09/2019 12:03
Joined: Jun 2019
Posts: 42
suffolk, UK
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Thank you Clanger, I’m certain many coupe owners will be grateful for the information you have passed on that will help keep the cars on the road.

Re: Bosch Injectors [Re: clanger] #1635420
10/09/2019 14:39
10/09/2019 14:39
Joined: Dec 2005
Posts: 3,681
Pothole City
GrahamL Offline
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Originally Posted by clanger
If you do go for it be aware that they are approx 0.5 mm longer which means you need to apply a firm pressure to the fuel rail to get the mounting screws started, alternatively you could just elongate the holes a little but I did not find it necessary.


Thanks for the info, doesn't sound like a major problem. I've already replaced the fuel rail bolts with normal hex bolts so that should make it even easier.

I've ordered a set of the injectors and will try to get some pics of the spray pattern of these + the original Bosch before fitting. May take a while as my garage is all taped off inside with plastic sheeting for spray painting so I can't access my coupe or tools at the moment.

Re: Bosch Injectors [Re: clanger] #1635439
11/09/2019 10:03
11/09/2019 10:03
Joined: Feb 2019
Posts: 68
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clanger Offline OP
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I found that Finjector put up a Youtube of the injector spray pattern https://www.youtube.com/watch?v=SYxF4bi1tlE

Looks same to me except more atomized. What do you think?

Re: Bosch Injectors [Re: clanger] #1635446
11/09/2019 14:22
11/09/2019 14:22
Joined: Dec 2005
Posts: 3,681
Pothole City
GrahamL Offline
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Yes, I'm sure that's what Fiat would have used in the first place if they'd been available at the time. laugh

Re: Bosch Injectors [Re: clanger] #1635520
14/09/2019 07:49
14/09/2019 07:49
Joined: Feb 2017
Posts: 54
Tasmania
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Grigio Offline
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I've bought a set, I don't need them, but you know how it goes! The link from Finland fell over if I tried to pay with Paypal, so I paid with a card, after the transaction went though I got a message that the freight wasn't enough and that my phone number wasn't recognised, so I cancelled the order and bought some from the US for a similar price. I got an email from the Finnish mob about my card refund, but it went to my spam folder and I accidentally deleted it. So I'll have to keep an eye on my card transactions and hope the refund goes through in the next day or two.


2000 grigio moon 20VT Plus.
Re: Bosch Injectors [Re: clanger] #1635521
14/09/2019 08:21
14/09/2019 08:21
Joined: Jun 2019
Posts: 36
Ely
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Originally Posted by clanger
Update: After a great deal of research on fuel injectors in general, specs etc. I decided to change the injectors. I had established they were the cause of my problem but given the age of the vehicles I was not confident that spending money on second hand ebay injectors was a solution. I read this thread https://www.fiatcoupeclub.org/forum/ubbthreads.php?ubb=showflat&Number=653322 which established the real world flow rate of the standard injectors to be 360cc. I then made contact with a company asking their advice and they recommended these:

https://www.finjector.com/ev14_12_ohm_373cc_e_20_jetronic_o_o_61_mm_tot_78mm-p-137105-0

They obviously flow a little more at 3 bar but I figured it would be within limits. My concern was the impedance being 12 ohms but given what barnacle said and looking at a french forum where others had used 12 ohm injectors with success I went ahead and ordered. They supplied a flow matched set with printed sheet showing the static and dynamic flow rate and msec resolution from 8-15 volts.

Long story short; I installed without issue, ECU reset and immediate start settling into a perfect idle. Approx. 500 miles later, no sooty tail pipe, perfect starting hot and cold, plugs look perfect compared to sooty black before, mpg increase and the car pulls like a train. It has a narrow band lambda gauge fitted and all looks OK off and on boost. Not a cheap fix but it now runs like a new car.

Hope this might help someone in future

Awesomely helpful feedback post, thank you clanger laugh

Re: Bosch Injectors [Re: clanger] #1635524
14/09/2019 16:42
14/09/2019 16:42
Joined: Feb 2019
Posts: 68
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clanger Offline OP
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Thanks all for the appreciation. I have been helped out enormously in the past by people returning with a solution on forums and indeed for my Coupe by all the information on this great site.

@Grigio I'm sure you will get your money back, Marko seemed like a professional guy when I had contact with him, very responsive and fast to ship. Did you order the injector extenders and additional O rings too from the US supplier?

Re: Bosch Injectors [Re: clanger] #1635537
14/09/2019 23:46
14/09/2019 23:46
Joined: Feb 2017
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Tasmania
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Grigio Offline
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Originally Posted by clanger
@Grigio I'm sure you will get your money back, Marko seemed like a professional guy when I had contact with him, very responsive and fast to ship. Did you order the injector extenders and additional O rings too from the US supplier?


I'm not concerned about the card refund, he was up front about it, the refund email from his system turned up in my spam folder, but after I hit delete it's gone, and not to my deleted items folder. I didn't know I required the extra bits, that's what happens when fools rush in where angels fear to tread. Do you know what size the extenders are? I'd better track some down or I'll just end up with another impulse buy of shiny bits sitting on a shelf in the shed.


2000 grigio moon 20VT Plus.
Re: Bosch Injectors [Re: clanger] #1635539
15/09/2019 08:23
15/09/2019 08:23
Joined: Feb 2019
Posts: 68
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clanger Offline OP
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The Finjector page I linked to provides for the purchase of the injectors, adaptors and O rings as one packaged product for the price quoted plus VAT. If you set the page to english up on the top right and then move down the page you will see it says "This product contains the following items" it then lists the injectors, adaptors and O rings along with their part numbers.

Re: Bosch Injectors [Re: clanger] #1635550
16/09/2019 04:09
16/09/2019 04:09
Joined: Feb 2017
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Grigio Offline
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Originally Posted by clanger
The Finjector page I linked to provides for the purchase of the injectors, adaptors and O rings as one packaged product for the price quoted plus VAT.


Thanks Clanger, after having a look, doing some homework and cross referencing I've found a set of height extenders from a local mob that should get here before the injectors from the US. It would have been cheaper to source the whole lot from Marko, but at the time it fell in to the too hard basket.


2000 grigio moon 20VT Plus.

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