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Old 03-15-2015, 10:02 PM
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99 2.5 hard starts

Symptoms - 3-5 seconds of cranking before motor starts. Then idle low and kinda rough for the next 3 seconds.

If I cycle the ignition several times before cranking, it doesn't help. If I push the throttle in a bit while cranking, it does help. And it reduces the rough idle.

If I turn the motor off and quickly start it again, it will fire right up with no problem.

I can hear the fuel pump priming when ignition is in the ON position but the motor is not running yet.

I have read ALOT here on the forums. Yesterday, I pulled the throttle body, cleaned the shit out of it, replaced all vacuum lines with new hose.
I have read about replacing the CPS and also replacing the fuel pump.
I have also read about a check valve that keeps the fuel line primed but I'm not sure if its in the fuel rail or in the fuel pump itself.


My other symptom is a slight loss of power at 3000 rpm. I can feel the power loss in all gears. I feel it more so when I'm heavier into the throttle. Not sure if it's related to the above symptom. I have replaced all plugs, wires and ignition coil. It did get better after I replaced the above.

I'm not sure what to do next, other than throw parts at it but that's the last thing I want to do.

Any help will be appreciated. Thx guys.

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Old 03-16-2015, 09:34 AM   #2
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The check valve is in the fuel pump assembly.

I would try and get a fuel pressure reading while running and then in the off position to see if she is holding pressure, Should be about 49 PSI

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Old 03-16-2015, 09:51 AM   #3
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The long crank is the fuel pressure regulator. I would bet that the miss at 3K RPMs is the fuel pump. As for giving it some throttle and not having rough idle that is indicative of the IAC. If you cleaned it really well and still having issues I would replace the IAC. I would also replace the fuel pump assembly which will cure the long crank problem and probably the miss if it is indeed the pump causing that. Read fuel pressure when driving and see what it reads when you get up to the trouble spot (3K RPM).
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Old 03-16-2015, 04:38 PM
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Thanks guys,

I can check pressure at the shrader valve on the rail, correct?
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Old 03-16-2015, 04:44 PM   #5
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Thanks guys, I can check pressure at the shrader valve on the rail, correct?
that is correct
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Old 03-16-2015, 05:01 PM   #6
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That it starts faster and idles better when stepping down on the gas pedal indicates just one thing to me, that your IAC (idle air control) is dirty and sticking, which causes it to not let air in for starting or idle RPMs. Stepping down on the gas pedal provides the air it is missing for both starting & idle RPMs. The main valve plate on top of the throttle body is completely closed when not stepping down on the gas pedal so the engine's sole source of air when starting and at idle RPMs is via the Idle Air Control Module.

I'd go buy an aerosol can of throttle body cleaner and spray the inside of the throttle body while the engine is running. Spraying it at or as close as possible to idle RPMs will cause the IAC to suck the cleaner into itself via the Idle Air Control Passage Inlet (see below) and clean its air passage. The IAC doesn't suck air (and the cleaner) through itself at higher RPMs so keep the RPMs as low as possible. The engine will die when you get a bunch of the cleaner in the IAC air passage but that's good, just restart the engine. I'd use the entire can, no doubt the entire throttle body's interior is dirty.
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Old 03-16-2015, 07:38 PM
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Thanks.
I took the TB this past weekend and thought I cleaned it very well. I'll try your method.
Would it be wise to remove it IAC off of the TB and clean it that way?
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Old 03-17-2015, 12:09 AM   #8
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Since you already cleaned the TB, I'd next remove the IAC and clean its plunger and the orifice in the tb the plunger fits into. IIRC only two T-25 torx screws hold it to the TB.
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Old 03-17-2015, 08:33 PM
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I removed the IAC awhile ago and cleaned it. I mean really cleaned it. It wasn't what I would call gunked up but still had some residue and a thin layer of crap on the tip and the shaft. I also cleaned the seat that is inside the housing attached to the TB. I reinstalled and also sprayed TB cleaner in the IAC intake slot while the motor was running.
Turned the motor off and cranked it again. Fired right up, but like I said before, it usually will fire right up after it has already been running.
We'll see how it goes in the morning and will let you know.
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Old 03-19-2015, 03:32 PM
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Update - Cleaning the iac and resetting ecu did not help.
Cranking is still 3-5 seconds.
Resetting ecu actually made the loss of power at 3000 rpm alot more noticeable. Significant loss in power. That leads me to beleive that at 3000 rpm the motor is either getting to much fuel or not enough. Motor is actually bogging down now instead of studdering.
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Old 03-19-2015, 06:07 PM   #11
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That it started faster by stepping on the gas pedal no longer makes sense then. A dirty IAC is about the only thing that can make it faster/easier to start by stepping down some on the gas pedal.
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Old 03-19-2015, 08:41 PM   #12
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Update - Cleaning the iac and resetting ecu did not help.
Cranking is still 3-5 seconds.
Resetting ecu actually made the loss of power at 3000 rpm alot more noticeable. Significant loss in power. That leads me to beleive that at 3000 rpm the motor is either getting to much fuel or not enough. Motor is actually bogging down now instead of studdering.
Like in my first response I will say again.... The long crank before it starts is caused by the fuel pressure regulator which is inside the fuel tank and part of the fuel pump assembly. It can be changed independently, but I still have a feeling that the pump is going bad as well, which is causing the loss of power at 3K RPM.

If you have cleaned the IAC valve and it still starts better when you step on the gas then that tells me that the IAC is bad. Make sure to use a Mopar replacement though as many parts store sensors just do not perform well. I would start with the replacement of the IAC. That's just me.
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Old 03-19-2015, 08:59 PM   #13
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That it started faster by stepping on the gas pedal no longer makes sense then. A dirty IAC is about the only thing that can make it faster/easier to start by stepping down some on the gas pedal.
I meant to say dirty or bad IAC. It now sounds like the IAC is just bad.
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Old 03-19-2015, 09:55 PM
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Agreed.
Earlier today, my concern about the motor bogging started to out weigh the long crank issue. I picked up a new throttle position sensor.
I now have ZERO motor stutter while driving. Full rpm range is solid and smooth. I had no idea how much power I was losing throughout the entire rpm range. Not just at 3000 rpm.
So, issue number two SOLVED.
FYI, I am using BWM parts from O'Reilly. Been using them for years with no issues thus far. When they fail I'll let you know so you can say I told you so. (joke)

I also picked up a new IAC but didn't have time to install it. I'll throw it in tomorrow after work and report back. Even if it solves the long crank, I still have plans to replace the entire fuel pump assembly and do the 19 gallon mod while I'm in there.
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Old 04-03-2015, 07:10 AM   #15
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any updates to this?

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