bad injector?
 

got a p1128 the other day. been hearing some ticking from the engine. checked my oil the other day and it had a gas smell to it.

bad injector? if it was stuck open, would there be any other codes?

so, looking at my durametric manual (at work) it looks like i can individually turn off injectors to force a cylinder misfire. theoretically then, if my injector was stuck open and causing my symptoms, then turning it off with my durametric should have no effect - i should be able use the tool to isolate the problem injector (all the functioning injectors would cause a misfire when turned off).

if that is the case, how often do injectors fail? i ask because one new injector on pelican is $300, but i can buy six used ones for under $100 on ebay ...

Undoubtably they all need to be cleaned & tested & replaced if faulty, so that would give you the best final result.

yeah. i'll try my test tonight. if it yields results i'll repalce all of the little basturds. any recommendations on non-oem replacements that might be a little less expensive? bosch is bosch, right?

Injectors do not fail often, but when they do, you need to either have a reputable shop retread them, or buy new. I really would not be comfortable with buying used injectors off flea bay, you have no idea what shape they are in. I'd also suggest giving Sunset Porsche in Beaverton, OR a call for new unit pricing.

I was talking about out of the car cleaning at a speciality shop like the one I use in Torrance CA : rceng.com

i live way out in the sticks, so options are limited. hoping to run a test with my durametric (and some of the other tests out there - measure resistance, etc.) and see if i can get an easy answer that way. if the injector is the obvious culprit then i am faced with replacing all or just the bad one, as my car would be out of commission for a month if i sent mine out to be tested/serviced. at $135 for a bosch unit (as opposed to $300 for the porsche product) i might want to do all 6 just to be safe, but if they rarely fail mebbe i just do the bad one(s).

Another option is to buy one replacement (from Sunset, they are cheaper), and then send your bad one out to be corrected. You can individually fire the injectors from Durametric, but the problem is that you cannot see what the actual spray pattern looks like, or what condition the internal components are in, that requires a special test fixture that any decent fuel injector shop would have.

I'm not trying to push RCeng But I have sent several sets of injecters there & there are always 1 or 2 partially clogged. Never had any that needed replacing, every injecter was improved by the cleaning & average flow improvement is about 10cc per minute. Always smooths engine idle noticeably & improves power thruout rpm range. I am sure there are shops all over that can do this I just have never used anyone but RCeng & they guarantee 2 day turnaround. :cool:

I "third" rceng, just sent mine in on my other car got them back within a couple days. Excellent service, great price, quickly shipped back. I do live only @100 miles away but from my sending them out to getting them back was 3 days. Send all of them in, cost is $24 for each... that's a LOT cheaper than buying a new one and still not know if the others are "matched".

No affiliation just a very satisfied customer.

Steve

1 + on RC Engineering,

Quick turn around time and for the price they charge is a bargain, you will love the way the engine runs afterwards..

.

well, good news and bad news. good news - my car is about to get a lot faster. bad news as follows:

logic. have p1128 which is bank 1 to 3 too rich. if it was p1128 AND p1130 (bank 4 to 6 too rich) i'd think issue with maf. with just one bank having trouble it's either an 02 sensor or something with the air and/or fuel supplies.

check my oil - smells of gas. this may be a result of an injector stuck open. when the car sits, it dribbles gas into the combustion chamber, which then leaks past the rings into the oil. in hindsight, it may also be a cause of the smoking i see on start-up - rich rich rich fuel getting pumped out the exhuast.

so, thinking injector issue.

start engine, connect durametric.

knowing that i have p1128 which is bank 1 to 3, i start on bank 4 to 6 to get a benchline.

using the durametic to turn off individual injectors, i can feel the engine start to run rough every time i turn an injector off. cool.

going to bank 1 to 3, turning of injector 3 gets the rough running condtion. good. unfortuately, it looks like both injectors 1 and 2 are bad, as turning either 1 or 2 off gets no effect.

so, looks like i'll pull all 6 and send them out for refurbishing. RCEng looks the ticket; thanks for the help guys. also time for an oil change - want that gas outta there.

Awesome job! I actually didn't know you could easily turn off injectors via Durametric....thought one needed the professional version. I will be getting this software set up soon....don't see a manual.

Good catch on the oil!

ok, i'm about to chuck in the towel. i got the passenger side injectors out easily enough (and this is the side where i have the problem injectors) but how the heck do you get the driver side injectors out with the airbox in the way??!?!? looks like the cold air intake project just got advanced ...

Left plenum out won't do it??

Just a quick clarification. A P1128 actually means your car is running lean and the DME trim has been adjusting mixture and reached it's max rich threshold. It still could be a bad injector but other possibilities are more likely:

P1128 (oxygen sensing adaptation area 2--cylinders 1 and 3--rich threshold)

Causes for P1128

– Incorrect signal from MAF sensor
– Intake air system leaking
– Fuel pressure too low
– Volume supply of fuel pump too low
– Fuel injectors fouled
– Exhaust system leaking

gotcha. still, can't explain the car not reacting to shutting injectors off to cyls 1 and 2, and gas smell in oil? perhaps injector is stuck partially open? i'm going to give the FPR a visual inspection while everything is apart and i already have gas all over the place and, regardless, injectors are off for servicing. and did you know - cost to service an injector is the same as cost for ups to deliver the repaired product to my little town up north. robbers (ups, that is). second regardless - gave me impetus to finish my intake project (destroyed the oem airbox to get driver side injectors out).

vindication! got the injectors back today, complete with the rce report. can't figgure out how to post a pdf, so here's the data:

injector - cc/min, pattern

before

1 - 235, good
2 - 229, good
3 - 218, dripping
4 - 234, good
5 - 230, good
6 - 228, dripping

after

1 - 241, excellent
2 - 240, excellent
3 - 239, excellent
4 - 241, excellent
5 - 240, excellent
6 - 240, excellent

so, gas in oil due to two dripping injectors. no response to turning off injectors at two cylinders due to two dripping injectors. p1128 due to lean condition at max rich due to two injectors producing low cc/min.

best money spent yet; excellent work rce!!!

ps - sniff your oil!!! gas in oil apparently can facilitate ims breakdown (gas acts as a solvent to scour grease and oil from the bearing i guess). a dripping injector, coupled with not running your engine long/hard enough to burn the gas out of the oil (hence the rumoured trend of ims failure happening more to cars driven lightly or with a long interval between oil changes) could create these conditions.

Sniff the oil is good advice (an artical I read a while ago):

What's that smell?

Glad to hear you've solved the problem.

Regards,
paul...

your 3.2 will be howling now!