fc24151

1997 Geo Tracker Fuel Delivery Issue

6 posts in this topic

Hoping I'm right about this one, but would like to hear what you guys think. I had a slight sputtering issue at high rpm. A can of injector cleaner and it would run great for a couple dozen miles,  then pick up again. I decided to fill it up with high octane and a half can of sea foam for good measure. Now, it's much worse. Almost like it's struggling to pull fuel. It sputters and shudders pretty bad. I replaced the fuel filter and pcv, cleaned egr valve to no avail. My main issue is I can't find the adapter to hook up a fuel pressure tester to the rail. I've looked and it seems you have to special order it. Question for you guys- could the catalytic converter be causing this and throwing an egr code? I'm guessing it would be injectors, plugs, or fuel pump but hadn't considered the cat until a buddy told me about a similar experience he had that was caused by a clogged cat. Any similar experiences and outcomes would be greatly appreciated too

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fc24151...Sounds like fuel starvation or an O2 sensor getting contaminated.  Yes, a clogged catalytic converter could cause issues, perhaps even an EGR code.  More likely the EGR code would be a reaction to the EGR system's inability to reduce the combustion temperature.  An unseated EGR valve could cause a lean fuel burn.

Lean fuel burn and high speed hesitation could also be the insufficient fuel supply that you suspect.  You changed the fuel filter, though water in your fuel tank could quickly clog the new filter, and Sea Foam could pick up tank water and carry it into the filter.  A paper fuel filter will swell and clog when exposed to water.

The fuel pump sock or fuel pump itself could be at fault.  You're on the right track trying to test the fuel rail pressure.  While you're at that, also check the fuel flow/volume at the EFI rail.  This will help determine whether there is a restriction in the fuel system like a clogged sock or filter.

Usually, a common EFI fuel pressure gauge kit will have the right adapter for your rail test.  Harbor Freight has an inexpensive fuel pressure test kit if you're not making a career or daily use out of the tool.  If you have a Harbor Freight in your area, see whether the kit has the fitting you need.  If no store nearby, try Harbor Freight online.  Or try National Tool Warehouse...Also, OTC Tools has a number of adapters for its EFI pressure tester, check out the OTC Tools official catalog online.  Also check the Summit Racing catalog online...

Moses

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Great...someone with the same type issues as i am now experiencing...not sure how old thread is...but looking also for help. 
I have changed fuel filter with new factory unit, looked like fuel was passing through it just fine as it spilled all over me removing it..lol.I have also checked fuel pressure and it holds at 46-50psi. The easiest way to do this was to simply take rubber ose off steel line just down below fuel rail as the 2000 has no adapter to tee into. That is unless you take end plug out of rail....? I will TEE into same location and check flow today to see if that shows anything.  I have also changed plugs, and air filter at first as a tune up need. The vehicle is also not throwing any codes which is making me question fuel pump even if it sounds perfectly fine and holding pressure...?  A  buddy suggested I smell for a fuel odor at the valve above the charchol canister....couldn't smell anything obvious.  Tank is full. The orginal issue was hard to start, turned over fast but wouldn't catch as it should. It finally died at a traffic light which is why it's now off road so to speak. When it is running which it does, it runs great and accellerates well when punched. It does have a very slight hesitation but we are talking about a Tracker after all, not a F1 machine...lol.

Is there any other things to check before spending huge $$$ for a new pump..?   Starting to pull what little hair out i have left...lol

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WeeePiggy...Not sure where fc24151 went with his troubleshooting and a solution.  I like your idea of checking fuel pressure, also check the fuel volume flow while you're cranking the engine and actually experiencing this inability to start.  The pump and its pickup sock have two functions: sufficient fuel pressure and sustained fuel flow at the right volume.

As a consideration, I'll share a fuel pressure bleed-off issue that occurs with my XJ Cherokee 4.0L.  Cranking takes longer if I simply start cranking the engine over.  If, instead, I turn on the key for just a few seconds to pick up fuel prime at the rail, the engine will start instantly.  This suggests a fuel pressure bleed-off issue when the vehicle sets.  Quick restarts are no problem, the issue occurs only when the vehicle sets for a period of time.

To bleed off, there must be an issue at the pressure regulator on my 1999 Jeep.  Simply priming the system creates a quicker start.  Try this key on before cranking trick with your Tracker system; see if that makes any difference in its starting ability.  See whether you have a fuel pressure bleed-off problem at the fuel pressure regulator.

I would also check the engine's compression and the valve timing.  If the valve timing is retarding, you will have the fast spin-over without starting.  A worn timing chain or stretched timing belt can create this symptom.  So can a belt that's a tooth off or "jumped".  Have you changed the timing belt?  Is there a camshaft position sensor on your engine, and if so, is it throwing a code?

Moses

 

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I think we have it figured out. The wiring to the coil packs was very brittle and broken but operated perfectly as it didn't die when I wiggled it. But I did notice a bit of corrsion on one pin  of the can position sensor...I thought well while at the Junk yard why not pick one up just for shits and giggles etc along with a new wiring harness.  Didn't realize there was so many single wires inside it...lol. Took a few  hours of pian stakenly connecting and strink wrapping each wire etc. That fixed it...touch wood. Ran perfectly for an hour on the driveway and now has done a few miles without an issue. Damned good thing I didn't take full tank down only to find it wasn't that!  Pump pressure was good also.

Thanks for the help and suggestions. Appreciate it for sure!

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You're welcome...Good troubleshooting there!  A lot of work in changing out a harness or even splicing in a section, but if that's the cure, well worth it.  Glad you stayed away from the fuel tank at this point.  Normal fuel pressure and enough volume are all the engine needs to run right...This emphasizes the importance of the camshaft position sensor and its signals.

 

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