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While I was chasing down an issue with my 87 S4 refusing to rev quickly (opening throttle quickly at idle caused it to bog down) and was down on power, I did a few jobs:
Sent the MAF to Injection Labs for a rebuild. This didn't help. The guy said it wasn't badly out of spec, but was heading in that direction.
While checking spark plugs, I stupidly broke two of the plug lead connector things that connect to the plugs, so I replaced all of the leads with a new set. Expensive mistake!
Replaced vacuum lines and connectors (good vacuum now while the car is running)
Replaced old fuel lines (the one leading from the fuel cooler to the fuel regulator had a major indentation, so I was hoping this fuel restriction was my issue
Replaced the injectors - Probably not really necessary, but I came across this thread about using different injectors and after some searching I bought a set of Bosch 62354/0280155821 (mentioned in that thread). It was necessary to replace the lower o-rings with fatter ones that matched the stock size. I decided to do the injectors because It worked out only marginally more expensive than having my 37-year-old injectors professionally cleaned, so it seemed like like a good idea to rule out the possibility of a dodgy injector.
After redoing all of my fuel lines, vacuum lines, injectors and MAF, the car is running even worse! It starts without any throttle input, but hunts around at idle. When I cover the intake at the maf sensor with my hand, the revs climb and it's smother. So I'm guessing it's running lean. No fuel smell or smoke from the exhaust, so I don't think it's being over-fueled. That's my non-expert guess.
I found a thread about replacing the relays - should this be my next step, or do the new injectors need some sort of update/flash to the EZK computer? From what I read, they were basically a straight swap - same impedance and also 19lb
where are you located?
how many miles on the engine?
did you do an intake refresh?
can you provide pictures of the engine bay?
did the LH computer get rebuilt?
Did you replace the O2 sensor?
Did you install a new temp 2 sensor and connector?
where are you located?
how many miles on the engine?
did you do an intake refresh?
can you provide pictures of the engine bay?
did the LH computer get rebuilt?
Did you replace the O2 sensor?
Did you install a new temp 2 sensor and connector?
I'm just outside Toronto, Canada. Odo shows 151000km / ~94k miles
I have not done an intake refresh yet. (I was hoping to push that out by a year or so because I've already spent a lot in the last few months. did TB/WP job as well)
I haven't had the LH computer rebuilt and didn't replace the O2 or temp sensor. I'm guessing those are the most likely suspects?
I'll take a few photos and add them here a bit later today
Originally Posted by FredR
There are many fake injectors on the market. Did you purchase from a known reliable source?
AEM, Aeromotive, Bosch, NGK etc... fakes are all over Amazon, eBay, and yes even Rock Auto. It wouldn't surprise me if some of these bogus parts made their way onto the shelf at your local auto parts store.
I'm just outside Toronto, Canada. Odo shows 151000km / ~94k miles
I have not done an intake refresh yet. (I was hoping to push that out by a year or so because I've already spent a lot in the last few months. did TB/WP job as well)
I haven't had the LH computer rebuilt and didn't replace the O2 or temp sensor. I'm guessing those are the most likely suspects?
I'll take a few photos and add them here a bit later today
Yes - I got them from RockAuto
Replace the O2-sensor for sure, they rarely last much past 100K kms. But that's only a factor once the engine warms up a bit-- 60C or so.
You had the MAF checked, do the same for the LH-- they are partners in the fueling game. Rebuilding is recommended but at least get it checked. The "hybrid circuit" in the LH is a known weak point, and will fail if not replaced-- which is always part of a rebuild.
And send your factory injectors out for cleaning/testing, you've already noted that your new ones made things worse.
Just took a look at the Rockauto website and all I could find was an offer to refurbish your injectors at US$28 per injector with a core charge of US$9 - presumably if one does not want to turn in the original items- aka US$37 a pop or US$296 a set. This leaves me wondering what exactly it was that you purchased from them ?
For reaasons I cannot explain but have personally experienced one can have injectors cleaned and tested such that they work perfectly and yet as little as two weeks later an injector may simply not work. How long have you had those injectors? As a stop gaap test you can apply 9 volts to each injector terminal [pull all the connectors off first] and check to ensure they all "click".
Roger offers a set of 4 hole injectors for US$325 and you can bet your life savings they will be genuine Bosch items. Not sure what our other parts vendors offer but probably something similar.
Just took a look at the Rockauto website and all I could find was an offer to refurbish your injectors at US$28 per injector with a core charge of US$9 - presumably if one does not want to turn in the original items- aka US$37 a pop or US$296 a set. This leaves me wondering what exactly it was that you purchased from them ?
He didn't drill down to make / model / year and pick injectors for a 928, since what he ordered (and what most of us use) are not OEM to the 928.
Yes - of course it will not show under the 928 fitment as those are 4 hole injectors and therefore not a direct replacement officially speaking.
If they are genuine Bosch then they are incredible value . I suppose it is possible that even this outfit may have been fooled somehow as to originality. Either way it may be prudent for the OP to enquire with this outfit to see if they have any "suggestions'.
In the mean time perhaps the OP should try to eliminate as many of the other possibilities as possible.
If they are genuine Bosch then they are incredible value . I suppose it is possible that even this outfit may have been fooled somehow as to originality. Either way it may be prudent for the OP to enquire with this outfit to see if they have any "suggestions'.
Rock Auto is the Amazon of car parts. You don't enquire with them, you either keep the part or send it back for a refund. They won't know and don't care where they came from or if they are genuine or not. The OP will be wasting their own time trying to investigate this. Recently I ordered 50 V-Belts for an internal project. 40 of them were very old stock, dirty faded packaging and the belts looked iffy. After sending them photos they simply refunded the money and told me to throw them away.
Rock Auto is the Amazon of car parts. You don't enquire with them, you either keep the part or send it back for a refund. They won't know and don't care where they came from or if they are genuine or not. The OP will be wasting their own time trying to investigate this. Recently I ordered 50 V-Belts for an internal project. 40 of them were very old stock, dirty faded packaging and the belts looked iffy. After sending them photos they simply refunded the money and told me to throw them away.
Interesting- I have no knowledge of this outfit whatsoever. Sounds as though the OP might do well to pull them and return them for a refund then get in touch with Roger or use the refund to have his stock injecgtors cleaaned and tested.
I had no prior knowledge of the company I purchased my 30lb Design 2 injectors from- an outfit called 5 O Motorsports as I recall - I was highly interested because new versions of those injectors were as rare as rocking hose droppings on Route 66! I did some internet research and it seemed they got excellent reviews so took a bit of a risk- they have been in my 928 for over 10 years now and have performed flawlessly..
04-16-2024, 10:39 AM
New Injectors and running rough
