Delayed Start

Discussion in 'Fox 5.0 Mustang Tech' started by John Dirks Jr, Aug 21, 2013.

  1. My 92 LX has had a condition of delayed starting from day one since I owned it. Not that I've been specifically trying to fix it yet, but none of anything I've done that you all may have heard me discuss on here has changed the condition.

    It always starts but it cranks unusually long. Maybe 4 or 5 seconds of cranking before starting. Occasionally it will start quicker but not often. I tried putting the key to the on position for a few seconds before cranking to get the fuel pump pressuring up but that doesn't help.

    Any ideas on what could be causing it?
  2. is it a slow hard crank or is it turning at normal speed?
  3. Normal cranking speed.

    I think it's some kind of delay in adequat fuel delivery on start up but I'm open to any other possible causes.
  4. How are your battery connections? I had a slow and inconsistent start on my 94 Cobra clone, and it turns out I had corrosion between the negative battery lead and the clamp. Cleaned that out and the car starts quickly and reliably each time.
  5. Connections at the battery terminals are clean and tight.
  6. Check connections at the solenoid and at the starter
  7. do a starter draw/voltage drop test along the starter circuit. You may have a loose/corroded cable.
  8. Are you guys suggesting that the cranking is drawing so much voltage that there is little left to generate decent spark at the plugs?

    The actual cranking is normal.

    I will check all related wiring while doing the other work scheduled for this weekend. The list includes the following.

    1) Speedo gear swap including drive gear in transmission and install new speed sensor on cable end. (check throwout bearing)

    2) Smog pump delete.

    3) Under drive pulleys.

    4) Install shorty headers, off road x pipe and Flowmaster American Thunder.

    5) Front spring swap.

    I have Sunday, Monday and Tuesday with no other obligations. That gives me 3 full days to get all this done. Wish me luck.
  9. I would see how fast it bleeds off fuel pressure. A faulty fuel pump (they can still work for a long time, they just bleed off pressure very fast), fuel pressure regulator, or leaky fuel injectors can all cause long cranking issues. I do not lean towards it being a voltage issue if the speed is normal. I would also want to know that the ignition timing isn't out of whack.
  10. I initially suspected fuel pressure bleed down. With that in mind I would turn the key to the run position (which should energize the fuel pump) and leave it to pressure up for 5-10 seconds before cranking. Doing this does not help the problem. I would think that if bleed down was the issue, this trick would overcome the problem and confirm a diagnosis. Furthermore, once the engine is running there are no ill symptoms related to fuel delivery. Even full throttle all the way to redline and it runs perfect. If its getting enough volume and pressure for that, then it should be able to handle fuel delivery for start up without any trouble.

    As far as ignition timing is concerned. I just set it at 12 BTDC. Prior setting was 7 BTDC. The delayed starting symptoms are the same at both timing settings.
  11. You still did note eliminate the fuel pressure regulator. I would like to see fuel pressure readings to be certain - you could be correct that it is fine, but I like hard numbers.

    How does the car idle? Have you tried to pull any codes?
  12. Car idles good at about 8-850 after warmed up and smooth with no erratic changes.

    I have not pulled codes.
  13. Dump the codes: Codes may be present even if the Check Engine Light (CEL) isn't on.

    Dumping the computer diagnostic codes on 86-95 Mustangs

    Revised 26-July-2011. Added need to make sure the clutch is pressed when dumping codes.

    Codes may be present even if the check engine light hasn’t come on, so be sure to check for them.

    Here's the way to dump the computer codes with only a jumper wire or paper clip and the check engine light, or test light or voltmeter. I’ve used it for years, and it works great. You watch the flashing test lamp or Check Engine Light and count the flashes.

    Post the codes you get and I will post 86-93 model 5.0 Mustang specific code definitions and fixes. I do not have a complete listing for 94-95 model 5.0 Mustangs at this time.

    Be sure to turn off the A/C, and put the transmission in neutral when dumping the codes. On a manual transmission car, be sure to press the clutch to the floor.
    Fail to do this and you will generate a code 67 and not be able to dump the Engine Running codes.



    If your car is an 86-88 stang, you'll have to use the test lamp or voltmeter method. There is no functional check engine light on the 86-88's except possibly the Cali Mass Air cars.


    The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.

    89 through 95 cars have a working Check Engine light. Watch it instead of using a test lamp.


    The STI has a gray connector shell and a white/red wire. It comes from the same bundle of wires as the self test connector.

    WARNING!!! There is a single dark brown connector with a black/orange wire. It is the 12 volt power to the under the hood light. Do not jumper it to the computer test connector. If you do, you will damage the computer.

    What to expect:
    You should get a code 11 (two single flashes in succession). This says that the computer's internal workings are OK, and that the wiring to put the computer into diagnostic mode is good. No code 11 and you have some wiring problems. This is crucial: the same wire that provides the ground to dump the codes provides signal ground for the TPS, EGR, ACT and Map/Baro sensors. If it fails, you will have poor performance, economy and driveablity problems

    Some codes have different answers if the engine is running from the answers that it has when the engine isn't running. It helps a lot to know if you had the engine running when you ran the test.

    Dumping the Engine Running codes: The procedure is the same, you start the engine with the test jumper in place. Be sure the A/C is off, and clutch (if present) is pressed to the floor, and the transmission is in neutral. You'll get an 11, then a 4 and the engine will speed up to do the EGR test. After the engine speed decreases back to idle, it will dump the engine running codes.

    Trouble codes are either 2 digit or 3 digit, there are no cars that use both 2 digit codes and 3 digit codes.

    Your 86-88 5.0 won't have a working Check Engine Light, so you'll need a test light.
    See AutoZone Part Number: 25886 , $10

    Alternate methods:
    For those who are intimidated by all the wires & connections, see Actron® for what a typical hand scanner looks like. Normal retail price is about $30 or so at AutoZone or Wal-Mart.

    Or for a nicer scanner see Equus - Digital Ford Code Reader (3145) – It has a 3 digit LCD display so that you don’t have to count flashes or beeps.. Cost is $30-$36.
  14. Thanks for the info on dumping codes. I'll do it tomorrow. I have to wait until the exhaust is back on. I've got the headers on already and the x-pipe, mufflers and tailpipes are tomorrow along with the steering rack and front springs.

    Today I stripped the factory exhaust and installed the shorty headers, deleted the smog sump, pulled and disassembled transmission to change internal speedo drive gear and re-installed transmission. (my speedometer will now be spot on for my 3.73 rear gear).

    There were a few complications but I over came and didn't mess anything up. It was a good day. Lets hope for the same tomorrow.

    Thanks again to everyone who contributes to this forum by posting to help people. What a great resource!
  15. If it's not turning over quickly, then it has nothing to do with fuel/air/spark. That's the starter and the voltage to it, alone. I guess there could also be an excessive drag on the motor from one of the accessories, but that would probably be obvious as it would manifest itself by a squeaking belt/pulley or failing accessory. Therefore, I would guess it's a bad ground, battery, connection, or wiring to the starter.
  16. He said it was normal cranking speed, but a long start.

  17. This statement is correct. It cranks normal with plenty of speed. No indications of weak battery or bad connections related to cranking.

    To me, a delay in the delivery of fuel or spark would explain what its doing.

    I'm going to do further testing on this issue soon. For now, there are other things going on.
  18. Disregard. I skimmed to quickly. Yeah, your timing sounds right, assuming the balancer isn't off. Does it help to go into choke mode by applying full throttle during startup?

    Have you adjusted the EEC's tune?
  19. I wasn't aware I could go choke mode by applying full throttle. I haven't tried it yet. I have not done any tuning of the EEC. I doubt anyone has done it. It's probably stock.

    However, I found a vacuum hose off and put it back on. It was to a canister like thing in the lower front passenger area of the engine compartment. (is that the evap canister?) Also, I changed the fuel filter. The old one was still the original and it was fairly plugged up. It took quite a bit of effort to blow through it. After these things were corrected, the starting delay problem has improved. We'll see how a cold start does tomorrow morning.
  20. Yep, it's an evap canister.