u.m. please help

Discussion in 'SVT Tech Forum' started by hotcobra03, Apr 23, 2008.


  1. hotcobra03

    hotcobra03 Active Member

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    hey um my cobra just started running like crap.it feels like an older car with water under the cap...it spits,sputters and stumbles...i just changed all 4 o2 sencors and all the plugs...passenger side back plug was almost flat,,all the others were weyt with gas...feels like the car is starving for something..i started to do a commpression test,front left side cyl. was 148 than the starter took a crap on the next try..im gonna try again today..what do i want to see with commpression test
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  2. Uncle Meat

    Uncle Meat Banned

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    Check the FRPS while you're at it. If the diaphram has been ruptured it can cause symptoms such as you describe. In addition to the compression test I'd also perform a leak down test on any suspect cylinders. Normal compression on our cars is anywhere between 150-170, but the important thing is that all the cylinders are within 10% of each other.

    Here is a quick run through on performing the compression test correctly (Stolen from another website.... Shhhh :p ):

    1. Bring engine up to operating temperature.
    2. Remove fuel pump relay.
    3. Remove all eight COPs and spark plugs.
    4. Open throttle body and affix so it stays open constantly.
    5. Insert compression tester into cylinder #1.
    6. Crank motor for about five seconds and record results.
    7. Proceed through cylinders #2 to #8.
    8. If any one cylinder varies from the other, try to squirt some oil down the spark plug hole and retest. A good retest would indicate bad rings or light damage to the ring lands.
    9. If cylinders vary and oil solution does not result in higher numbers, do a leak-down test.

    Don't forget the small stuff like disconnecting the fuel relay, warming up the motor first, or opening the throttle body, they all can impact the compression test results.

    U.M.
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  3. hotcobra03

    hotcobra03 Active Member

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    thanks um.. what about bad gas ...how bad would it run?my tank is almost empty,,
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  4. hotcobra03

    hotcobra03 Active Member

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    how bad would it run on bad gas or 87 octane...also this frps ..is this the sensor that on the left side fuel rail with a vacuum hose to it?
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  5. Uncle Meat

    Uncle Meat Banned

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    Bad or contaminated gas could cause it to run poorly. Additionally you should NEVER run an 03/04 Cobra hard when it has less than a quarter tank of gas. There's a possibility of sucking up air during hard acceleration or cornering which can lead to a lean condition.

    87 octane could be DETRIMENTAL to the motor even at stock boost levels if you were getting on it and allowing the motor to experience detonation. Remember our cars don't have an anti-knock sensor so there's really no safety net against detonation.

    Yes the FRPS is that little black square attached to the end of the drivers side fuel rail. Yank the vacuum hose off of it and smell it, does it smell strongly of gas? If so it may be blown. If it does smell like gas try pulling your dipstick and smelling the oil on it... does it smell like gas too? If so it's a very good chance your FRPS is blow in which case you'd need to do an oil & filter change along with FRPS replacement.

    U.M.
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  6. hotcobra03

    hotcobra03 Active Member

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    Major problem?

    u.m. i started to do a compression test..1st cyl was 160 when i when to check #2 the starter wouldn`t engage..this happened on the frist attempt before I asked you..put plugs back in and starter worked?????????wtf......no for the good one,,after removing air inlet oil was pouring out of the throttlebody...u.m. it looked like someont took a 1955 oil pan and poured it in thier..it was very gooie and thick,,very black as if i have been sucking oil threw pcv and the blower is completly cloged with baked on oil...any thoughts????????
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  7. Uncle Meat

    Uncle Meat Banned

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    Sucking oil into the intake from the PCV is a common problem with these cars when running more boost. There's a few theories as to why this is happening though. It's usually due to a crappy stock PCV valve. For a good read on the problem and on using breathers and one-way check valves to solve it, go read this: http://www.modularfords.com/forums/showthread.php?t=85651

    Good discussion by a well known tuner.

    U.M.
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  8. hotcobra03

    hotcobra03 Active Member

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    what about my blower? u.m. what if my water pump is not working and my blower needs to be cleaned out...do i need to remove it or can i spray cleaner in it while running,,,also while doing my compression test starter wouldnt work for second try...do i really need to hook up a push button instead of turning key?
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  9. Uncle Meat

    Uncle Meat Banned

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    Your blower is fine. Might have a little residue in it, but nothing to worry about.
    Not sure where or when the water pump came into this? As for cleaning the blower out most guys wait until they are ready to port their Eaton and then clean the whole assembly (intercooler especially) while it's off the car. You could spray some cleaner in there if you're carefull... but until you fix the issue the oil will just pool up in there again.
    I'm baffled as to why your starter is giving you troubles.

    U.M.
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  10. hotcobra03

    hotcobra03 Active Member

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    the oil that came out looked like an old metal valve cover with baked on oil....i do not see any movement in reserver? the starter problem stumps me too,,engine cranks no problem on first ,than spins but doesnt engage on next try...the first starter i pulled out and jump it on the ground,,starter drive spun but starterdrive only kicked once out of 5 trys...last nite i put plugs back in and starter worked fine,,can i test with plugs in?
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  11. Uncle Meat

    Uncle Meat Banned

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    That came out of the throttlebody?
    The intercooler reservoir or the engine coolant reservior?
    Very strange. Starter should operate regardless of whether the plugs are in or out.
    You can, but this can skew the results. You really need to have all of them removed to get the correct readings across all cylinders.

    U.M.
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  12. hotcobra03

    hotcobra03 Active Member

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    sorry for so many questions but my car is 60 miles away from my computer..i am talking about the tank for the intercooler for the supercharger...i have remembered when i replaced the heat exchanger that i could watch the flow inside of the tank....my very first thought was my car was starving for air...what if pump stopped working and the blower wasnt cooled for awhile...the blower sounds wierd when engine heats up.. u.m. the amount of sluge inside of just the elbow was like a half of a quart...after changing plugs/o2`s/cleaning air filter and all tubing,,etc car starts fast and will rev at the tap on the throttle,,,but while holding 2000rpm car is rough,,,,if a pile of sludge went into intake could it clog it up
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  13. Uncle Meat

    Uncle Meat Banned

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    Okay first things first.... if you don't see any water circulating in the reservior then that's a problem. Although you can still drive the car without this working the computer is going to pull all the timing as soon as the engine begins to warm up due to the high IAT2 temps. This alone would cause your car to run like crap and have a massive loss of power.

    I am however concerned about the quantity of oil you said you found in your intake... Did you read the article I linked to above? You may need to replace your stock PCV valve with a better one and then do a remove & cleanse on your your blower/intake/intercooler. The excess oil in the intake or blower is not all that big of a deal, but if it's so bad it's clogging the intercooler then you'll need to clean it all out.

    U.M.
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  14. hotcobra03

    hotcobra03 Active Member

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    yes i did read that...im gonna ck the fuse/relay for the pump..any quick thoughts about driving the car verse letting car sit at idle....or should i just remove the intake and really check it out.....car was running just fine prior to this...at idle it feels like i have a wild cam but a quick tap and it goes to 6000 rpm....
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  15. Uncle Meat

    Uncle Meat Banned

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    If the fuse looks good you could always try running a jumper and see if the intercooler pump comes on then. To do this all you need to do is to place a jumper across the contacts as shown below...

    [​IMG]

    [​IMG]

    [​IMG]

    I'm not sure what exactly you're asking when you state, "any quick thoughts about driving the car verse letting car sit at idle"

    U.M.
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  16. hotcobra03

    hotcobra03 Active Member

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    good info thier thanks....thought that driving the car would help clean the intake? i have another air bypass valve ill try also ..the oil did reach that
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  17. Uncle Meat

    Uncle Meat Banned

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    Driving the car with the same faulty PCV valve on there will only continue to cause a build-up of more oil blow-by into the intake tract.

    U.M.
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  18. hotcobra03

    hotcobra03 Active Member

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    ok im going to go to the car ill let you know later....thanks U.M.
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  19. Uncle Meat

    Uncle Meat Banned

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    Let me know how it goes...

    U.M.
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  20. hotcobra03

    hotcobra03 Active Member

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    ok U.M. went to car..never tryed to start it..just started with pulling off throttle body and elbow...thier was some sludge present..not like yesterday,,took some pics with cel phone...on the pump fuse thier was no power present key on/off..with engine off...fuse check out ok when powered....pulled the relay.as per pic where the jumper wire is..the right side is live with key off the slot just in front of the jumper wire is hot with key on...with jumper wire pump did not spin,,,we taped on pump and it just spun slow than stopped..you said that this is known to pull timing...with predator hooked up it said it was running 10 deg ..i assume after but manual says 10 deg btc...after install of new pump,do I need to reset anything?
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