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Cliff notes: Fuel pressure is present at the fuel rail but no evidence of fuel entering any of the cylinders which leads me to believe it’s an electrical problem inhibiting the injectors from actuating. Through research, crank position sensors on this car are a common high fail-rate part. Would a failed crank position sensor allow me to get good spark but at the same time not allow the fuel injectors to actuate?
Back story:
So my sister’s 06 c230 died on the freeway. Realized there was no fuel pressure at the fuel rail. Turned out the fuel pump was bad (verified by connecting it to a battery). I ended up replacing the pump, filter, and sending unit (broke the stupid plastic nozzle). Filled the car with gas and started it up and it ran great. I start to put the back seat on and 5 minutes later it sputtered and died. I started it and it ran for 10 seconds and sputtered out again. Now it just cranks but wont start.I have pressure to the fuel rail(how much, I have no clue) and i can hear the pump working. I removed a spark plug from a cylinder and cranked it. I still have spark but it seems like my injectors aren’t firing because I don’t smell any gas or see any puffs of fuel coming out of the cylinder. Just for the hell of it my dad sprayed some starting fluid into the manifold via a vacuum line and the car started and ran off the starting fluid.
I’m not sure what direction to take next. Do fuel injectors need a specific fuel pressure in order to operate? Through research, crank position sensors on this car are a common high fail part. Would a failed crank position sensor allow me to get good spark but at the same time not allow the fuel injectors to actuate?
Thanks for any help or direction you could give.
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Sounds like you botched the new fuel pump install. Perhaps the connection between the new pump and line has failed. Measure the fuel pressure with a gage. Or, could it be that the fuel pump was not the original problem but it was instead the fuel pressure regulator. Measure the fuel pressure with a gage.
I haven’t ruled out that I screwed something up. The only thing that bugs me about that is that it ran great for 5-10 minutes before it decided to die out. Which if the fuel pump install was botched, why did it run at all? The fuel pump could possibly not be the main underlying problem but it was definitely a symptom. I hooked the bad pump directly to a good battery and verified it wasn’t working. Thanks for the input, I’ll go rent a gauge tomorrow.
Don’t rule out a faulty replacement either. In either case, as Jotmon stated you’ll need to measure the pressure, either with a guage, or using a scan tool capable of reading fuel pressure from the sensor.
I went thru 2 aftermarket from a company to attempt to fix my own check valve issue. It worked for a solid 3 drives, then left me stranded in a parking lot, I had to bang on the tank to get it to work again. Got me to the gf’s apartment complex, then died utterly. I won’t even attempt to use the replacement the company gave me. I put the old OEM back in, and I’ll get an OEM later, or not bother.
Good tip! The “new” pump ended up being defective. It was only pushing out 10psi. Bit the bullet and bought an OEM one and the car runs great! Never even crossed my mind that the brand new pump could be defective so thanks for the tip!
Thanks for the update. Had a similar problem with brake shoes. Could not see why they would not work properly but the OEM shoes fixed the problem I was having.
NP. Glad it worked out.
This is one part where I whole-heartedly agree with Eric on going OEM unless you know of a proven after-market one that’s seen to work reliably over a considerable time-frame by multiple people. In my case I knew I was rolling the dice, so it annoyed/disappointed me, but it just cost me some pride and time putting my OEM back in an apartment complex parking lot. 😉
I have had very few problems with aftermarket parts but, after being on this forum for a few weeks and reading a crap load of resolutions like this I am probably going to go with oem from now on. At least for the parts that are a pain to get to.
Yes the injectors DO need a specific pressure to run. I would suggest checking the actual fuel pressure and comparing it to spec. In addition to see if the injectors ARE firing you can use what’s called a ‘noid light’ which plugs into the fuel injector connector and flashes a light when it’s being told to fire. That will tell you if the injectors are getting a signal or not.
That is only the beginning. If you find that your fuel pressure is not where it should be the first thing to check is your fuel pump install but it could also be an electrical issue that’s causing the problem. In addition if you find that the fuel injectors are not firing as they should then it could also be an electrical issue.
My point is to stay away from assumptions and stick to the facts you find as you do the work. Also don’t guess, test.
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