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car started, and now it just cranks

1K views 19 replies 11 participants last post by  3MiataFamily 
#1 · (Edited)
so got the car running, it was running for a good 15 minutes then just died as if i turned the key off. Started it again then it stayed on again for awhile then it died again.

Now it cranks strong but wont start.

ideas anyone?

car is a 99 running a FMII kit with a TecII standalone.

UPDATE: car isn't getting spark
 
#3 ·
I don't know how much of this will relate to your car since your running an aftermarket ECU. But maybe this may help. But its a good step by step troubleshooting list.

Let me know what you think.

This article is not comprehensive enough to go into how to repair each of the problems that you may find, it is designed to help you isolate and identify where the problem or problems are in the system. Developed using Factory Workshop Manual, Enthusiast's Shop Manual and a 1990 Miata that wouldn't start.

1)Step 1: Starter and related systems- This is a pretty easy step- when you turn the key to “START,” what happens? If it cranks, don’t bother reading this, just go to Step 2. If you’re not getting any cranking, keep reading. The solution is most likely very simple.
a)Battery- especially if the car has been sitting lately, of if it is very cold, the battery may be dead. Have it load-tested at an auto parts store- it may be showing 12V but not have much current in it.
b)Ignition switch- try cleaning the ignition switch. Several issues have been traced to the connections becoming dirty over the years.
c)Solenoid and starter- If battery checks out, it’s time to check the solenoid and starter.
i)Check for power reaching starter, listen for solenoid clicking.

2)Step 2: Cranks but will not fire- this scenario is a bit more complex, but manageable.
a)When the key is turned to “RUN,” does the Check Engine light come on?
i)If YES: Pull stored fault codes from ECU and refer to the article to decipher them. I would recommend doing this twice- pull the codes, clear the codes by temporarily disconnecting the battery, try to start it, and then pull the codes again. This will be particularly useful if there are a lot of old codes sitting in the computer’s memory.
ii)If NO: The ECU is not firing the Check Engine Light. This means that power is not reaching the ECU, power is not reaching the Check Engine Light or the computer is bad.
(1)Remove the access panel under the driver’s dash and locate the fuse box. Check the 10A “ROOM” fuse in the bottom left of the box. This supplies a constant 12V to terminal 1A of the ECU. If the fuse is good, check for bad wiring by checking for power at ECU 1A.
(2)Check the Main EFI 30A fuse in the underhood fuse/relay box.
(3)Check the Main EFI Relay. Putting the key in “RUN” and unplugging/plugging the relay to see if it clicks is a very basic test here, but a failed relay can still click a little bit (mine did) and lead you astray. I would recommend you check for continuity by applying +12v to terminal A, grounding terminal B and checking for continuity between terminals C and D. This procedure is detailed in the Enthusiast’s Manual, page 5:42.
(a)Depending on the age of your Miata, the old relay may read “B6S8” or “JE16.” The new part number is JE16-18-811
(b)If failed, replace. Note that this is a dealer part. Some auto parts stores can try to cross it to another relay, but I wouldn’t risk it unless you know for sure that the guy on the other side of the counter is GOOD, and they can verify that the terminals and mounting will be identical. .
(4)If these are good, check for +12V at terminal (X) of the ECU with the ignition in “RUN.”
(a)If no voltage, there is a bad connection somewhere in the circuit. Refer to the wiring diagram on pages Z18-21 in FWM.
(b)If there is voltage, there may be a problem with the ECU, it would be best to swap it for a known good unit.

3)Step 3: Ignition System Checks
a)First, check for spark at each cylinder. If no spark observed, continue here. If good, strong spark observed at each cylinder, continue to Step 4. Also, while plugs are removed, visually inspect them for damage, excessive buildup, oil in the plug wells, or other obvious issues. Check to see if they are wet- if not, fuel is not reaching the cylinders.
b)Inspect the spark plugs. They should not be fouled or otherwise unserviceable. Check the spark plugs’ gaps- they should be 0.039-0.043in (1.00-1.10mm).
c)Inspect the ignition coils.
i)With the key in “RUN,” there should be voltage at the positive terminal of the ignition coil connector.
(1)If no voltage here, check the wiring. We have already ruled out the fuses and ECU.
ii)Check the resistances of the coils. The specifications are:
(1)Primary Coil: .78-.94 Ω
(2)Secondary Coil: 11.2-15.2 kΩ
(3)Primary Terminal to Case (insulation check): greater than 10M Ω
(4)Spark plug wires should be in good condition and securely fastened to the coil packs and spark plugs. While it is highly unlikely that plug wires would cause a sudden failure unless chewed up while the car was in storage, the specified maximum resistance on them is <16 kΩ per meter- the actual maximum resistance for each lead must be determined by measuring each wire.

4)Step 4: Fuel System Checks- If there is a good, strong spark at each cylinder, or if spark plugs are dry after cranking and not firing, check the fuel system.
a)The Circuit Opening Relay is a likely cause of failure here- it is located under the dash. Pull the access panel to locate it (photo, diagram). It will be up
i)To test this relay in the car, jump terminals FP and GND- this will bypass the AFM contact points and the ground group under the brake booster- and turn the ignition key to RUN. The fuel pump will be difficult to hear, so perform this test in a quiet location, and you may want to listen in the fuel filler if you can’t hear the pump elsewhere.
b)If you do not hear the pump, remove the access panel under the rear deck carpet. Check for +12V at the L/R terminal with the FP/GND jumper in place and the key in “RUN.”
i)If no power detected, there is an opening in the circuit to be found.
ii)If power is detected, the pump itself is most likely at fault.
c)If the pump is good but fuel is not reaching the cylinders, check the connections to the injectors. (More detail needed)
Taken from m.net.
 
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